SMLE cardiology questions

Diabetic patients, especially those with autonomic neuropathy, often present with atypical or silent ischemia such as fatigue, dyspnea, nausea, or epigastric pain rather than classic chest pain. Diaphoresis with hemodynamic changes in this setting should raise suspicion for acute coronary syndrome regardless of the absence of chest pain. An ECG and troponin are rapid, low-risk tests that can confirm or exclude myocardial infarction within minutes. Delaying cardiac workup in favor of a gastrointestinal diagnosis risks missing a time-critical MI.

• A. Reassurance without cardiac evaluation could miss a silent MI, which is common in diabetics.
• C. Endoscopy delays diagnosis and does not address the possibility of an acute cardiac event.
• D. Symptomatic treatment without investigation ignores the risk of silent ischemia in this high-risk patient.

ST elevation in leads II, III, and aVF localizes the infarct to the inferior wall of the left ventricle, which is supplied by the right coronary artery in most patients (right-dominant circulation in about 80-90%). Reciprocal ST depression in leads I and aVL further supports an inferior territory injury. Anterior STEMI from LAD occlusion would show ST elevation in V1-V4, while a lateral or anterolateral pattern from circumflex occlusion would show changes in I, aVL, V5-V6. Right ventricular infarction frequently accompanies inferior STEMI and should prompt a right-sided ECG.

• A. LAD occlusion produces anterior ST elevation in V1-V4, not the inferior pattern described.
• C. Circumflex occlusion typically causes lateral changes in leads I, aVL, and V5-V6.
• D. Left main occlusion usually causes diffuse ST depression with ST elevation in aVR, a pattern of extensive ischemia rather than isolated inferior elevation.

Guidelines recommend primary PCI if it can be performed within 120 minutes of first medical contact; when this is not achievable, as in this case with an expected delay of 150 minutes, fibrinolytic therapy should be given within 10 minutes of STEMI diagnosis provided there is no contraindication. Timely reperfusion, pharmacological or mechanical, is the single most important determinant of outcome in STEMI. After fibrinolysis, the patient should still be transferred for angiography, ideally within 3-24 hours, or urgently if lysis fails. Waiting for transfer or confirmatory testing in this context only increases myocardial damage.

• A. Observation without reperfusion therapy is inappropriate in a confirmed STEMI with ongoing symptoms.
• B. The diagnosis of STEMI is made by ECG; waiting for troponin unnecessarily delays life-saving reperfusion.
• D. Delaying definitive reperfusion for a transfer exceeding the 120-minute window increases infarct size and mortality.

High-sensitivity troponin assays are highly sensitive but a single value taken very early after symptom onset can be falsely negative because troponin typically begins to rise 3 to 6 hours after myocardial injury, peaking at 12-24 hours. Current rapid-rule-out protocols recommend serial measurement, commonly at 1 or 3 hours after the first sample, using validated delta criteria to confirm or exclude myocardial infarction. Discharging the patient or stopping monitoring based on one early normal value risks missing an evolving infarction. Waiting for symptom recurrence rather than scheduled resampling is not an evidence-based strategy.

• B. Stopping monitoring on the basis of one early troponin is premature given its kinetics.
• C. A single early normal troponin does not exclude MI; discharge without serial testing is unsafe.
• D. Troponin should be rechecked on a fixed schedule, not only if symptoms recur, since silent progression can occur.

After drug-eluting stent implantation for acute coronary syndrome, guidelines recommend dual antiplatelet therapy with aspirin plus a potent P2Y12 inhibitor, such as ticagrelor or prasugrel, for at least 12 months unless the bleeding risk is prohibitive. Ticagrelor and prasugrel have demonstrated superior reduction in ischemic events compared with clopidogrel in ACS patients and are preferred when bleeding risk is not high. Premature discontinuation of DAPT substantially increases the risk of stent thrombosis, particularly within the first year. Clopidogrel remains an alternative mainly when ticagrelor or prasugrel are contraindicated or not tolerated.

• A. Dipyridamole is used for secondary stroke prevention, not as part of post-PCI dual antiplatelet therapy.
• B. One month of DAPT is far too short after stenting for ACS and risks stent thrombosis.
• D. Cilostazol is a phosphodiesterase inhibitor used for peripheral arterial disease, not standard post-PCI antiplatelet therapy.

Elevated jugular venous pressure with clear lungs and hypotension in the setting of inferior STEMI suggests right ventricular infarction, which is preload-dependent. Nitrates and other preload-reducing agents such as diuretics and morphine can precipitate severe hypotension and should be avoided. The treatment of choice is intravenous fluid boluses to maintain right ventricular filling pressure and cardiac output, along with avoidance of further nitrates. A right-sided ECG showing ST elevation in lead V4R would confirm the diagnosis if time permits.

• A. Furosemide reduces preload further and would worsen hypotension in RV infarction.
• B. Morphine and additional nitrates both reduce preload and would worsen the hypotensive, preload-dependent state.
• D. A nitroglycerin infusion would worsen the hypotension already caused by preload reduction.

ACE inhibitors such as ramipril reduce post-MI mortality largely by limiting adverse left ventricular remodeling, reducing afterload, and attenuating neurohormonal activation (renin-angiotensin-aldosterone system), which is particularly beneficial in patients with reduced ejection fraction. Aspirin and clopidogrel reduce mortality through antiplatelet effects preventing recurrent thrombotic events, not remodeling. Beta-blockers like bisoprolol reduce mortality mainly by lowering myocardial oxygen demand, reducing arrhythmic risk, and reducing heart rate, rather than remodeling per se.

• B. Reduces mortality through antiplatelet activity preventing stent thrombosis and recurrent infarction, not remodeling.
• C. Reduces mortality mainly through heart rate reduction and antiarrhythmic effects, not primarily remodeling.
• D. Works synergistically with aspirin via P2Y12 inhibition to prevent thrombosis, not via remodeling.

Organic nitrates are prodrugs that require free sulfhydryl (thiol) groups to be converted to nitric oxide, which activates guanylate cyclase, raising cyclic GMP and causing vascular smooth muscle relaxation. With continuous nitrate exposure, intracellular sulfhydryl groups become depleted, reducing nitric oxide generation and causing tolerance. This is prevented clinically by scheduling a nitrate-free interval of 8-12 hours daily, typically overnight. Tolerance is not primarily due to altered hepatic metabolism, renal clearance, or receptor downregulation.

• A. Renal clearance of metabolites does not explain the rapid tachyphylaxis seen with continuous nitrate use.
• C. Receptor downregulation is not the established mechanism; the defect is in nitric oxide generation from the prodrug.
• D. Hepatic metabolism changes are not the principal mechanism of nitrate tolerance.

Transthoracic echocardiography is the key investigation for classifying heart failure, as it directly measures left ventricular ejection fraction, distinguishing HFrEF (ejection fraction 40% or less), HFmrEF (41-49%), and HFpEF (50% or greater, with evidence of diastolic dysfunction or structural abnormality). It also assesses diastolic function, left atrial size, and valvular disease, which support the diagnosis of HFpEF. Electrocardiography and chest radiography provide supportive but nonspecific information and cannot quantify ejection fraction. Cardiac MRI is reserved for specific indications such as suspected infiltrative or inflammatory cardiomyopathy, not as the first-line test for this distinction.

• A. Cardiac MRI is a second-line test reserved for specific diagnostic uncertainty, not the initial test of choice.
• B. Chest x-ray shows congestion or cardiomegaly but does not quantify ejection fraction.
• D. ECG may show nonspecific changes but cannot measure ejection fraction or classify heart failure type.

Current heart failure guidelines (ACC/AHA/HFSA and ESC) recommend rapid, simultaneous or near-simultaneous initiation of all four pillars of guideline-directed medical therapy, since each class has shown independent mortality benefit and delaying any one of them delays risk reduction. This patient's vital signs, potassium, and renal function do not contraindicate any of the four classes, so sequential initiation at low doses with up-titration over days to weeks under close monitoring is preferred over the traditional stepwise approach. Waiting months between drug classes, as was historically practiced, is now considered outdated and exposes the patient to unnecessary risk during the delay. No single agent among the four is preferentially started first in isolation; rather, early combination therapy is the goal.

• A. MRAs are not preferentially initiated before other pillars, and this patient's potassium and renal function allow all classes to be started.
• B. Delaying all other agents for 6 weeks is not supported by current guidelines and prolongs patient risk.
• D. This reflects the older sequential approach, which unnecessarily delays additional mortality-reducing therapies.

Furosemide inhibits the Na-K-2Cl cotransporter in the thick ascending limb of the loop of Henle, reducing sodium and chloride reabsorption at that site. This increases sodium delivery to the distal nephron, where enhanced sodium reabsorption through epithelial sodium channels in the collecting duct is coupled with increased potassium secretion, leading to hypokalemia. This is distinct from aldosterone receptor blockade, which is the mechanism of mineralocorticoid receptor antagonists such as spironolactone, which cause hyperkalemia rather than hypokalemia. Carbonic anhydrase inhibition and epithelial sodium channel blockade describe the mechanisms of acetazolamide and amiloride respectively, not furosemide.

• B. This describes amiloride's mechanism, which would cause hyperkalemia, opposite to the effect seen here.
• C. This describes the mechanism of spironolactone, which causes hyperkalemia, not furosemide-induced hypokalemia.
• D. This describes acetazolamide's mechanism, not that of furosemide.

Hypokalemia increases myocardial sensitivity to digoxin by enhancing its binding to the Na-K-ATPase pump, while acute kidney injury, here precipitated by volume depletion from diarrhea, reduces digoxin clearance and raises serum levels. Together these are the most common precipitants of digoxin toxicity, which presents with gastrointestinal symptoms, visual disturbances (xanthopsia), and arrhythmias such as PVCs or bidirectional ventricular tachycardia. Hyperkalemia, hypercalcemia, and hypernatremia are not features of this presentation and are not the implicated electrolyte abnormality.

• A. Hypernatremia and alkalosis are not relevant; the measured abnormalities are hypokalemia and renal impairment.
• C. Hypercalcemia can contribute to toxicity but is not present here; magnesium is not mentioned.
• D. The patient has hypokalemia, not hyperkalemia; hyperkalemia is not a typical precipitant of digoxin toxicity.

Spironolactone competitively blocks the mineralocorticoid receptor in the distal nephron, reducing sodium reabsorption and, importantly, reducing potassium and hydrogen ion excretion. When combined with an ACE inhibitor, which already lowers aldosterone-driven potassium excretion, the risk of significant hyperkalemia rises substantially, requiring close monitoring of potassium and renal function after initiation. ACE inhibition is the mechanism of lisinopril, not spironolactone. ROMK channel blockade and direct ENaC inhibition describe the mechanisms of other diuretics (not spironolactone).

• A. This describes the mechanism of ACE inhibitors like lisinopril, not spironolactone.
• B. Direct ENaC inhibition describes amiloride or triamterene, not spironolactone, which acts via the mineralocorticoid receptor.
• D. ROMK channel blockade is not the mechanism of spironolactone.

Her CHA2DS2-VASc score is 4 (age 65-74 = 1, female sex = 1, diabetes = 1, hypertension = 1), which is well above the threshold of 2 for women at which oral anticoagulation is recommended to reduce stroke risk. Aspirin alone is no longer recommended for stroke prevention in atrial fibrillation given its inferior efficacy compared with anticoagulation. Delaying treatment with a repeat ECG is inappropriate once a significant score is calculated. Left atrial appendage occlusion is reserved for patients with contraindications to long-term anticoagulation, not as first-line therapy.

• A. The diagnosis and risk score are already established; delaying anticoagulation increases stroke risk unnecessarily.
• B. Left atrial appendage occlusion is a second-line option for patients unsuitable for anticoagulation, not first-line therapy.
• C. Aspirin monotherapy is not recommended for stroke prevention in atrial fibrillation due to inferior efficacy.

In older patients with long-standing permanent atrial fibrillation and minimal symptoms, a rate control strategy using a beta-blocker is preferred, as rhythm control strategies have not shown mortality benefit over rate control in this population and carry additional procedural or drug toxicity risks. Catheter ablation and cardioversion are more appropriate for younger, symptomatic patients or those with recent-onset atrial fibrillation. Amiodarone carries significant long-term toxicity (thyroid, pulmonary, hepatic) and is better reserved for cases where rhythm control is specifically indicated.

• A. Cardioversion is not indicated in permanent, minimally symptomatic atrial fibrillation of long duration.
• C. Amiodarone has significant long-term toxicity and is not preferred when rate control is adequate and the patient is minimally symptomatic.
• D. Ablation is generally reserved for symptomatic patients or those failing medical therapy, not a minimally symptomatic elderly patient preferring a conservative approach.

Multifocal atrial tachycardia is characterized by an irregular rhythm with a ventricular rate over 100/min and at least three distinct P wave morphologies with varying PR intervals, classically occurring in patients with underlying pulmonary disease such as COPD exacerbations. Atrial fibrillation lacks discrete P waves, showing instead a chaotic fibrillatory baseline. Atrial flutter shows a sawtooth pattern of regular atrial activity at around 300/min. Wandering atrial pacemaker has the same morphological criteria as MAT but by definition occurs at a rate under 100/min.

• A. Atrial flutter shows a regular sawtooth flutter wave pattern, not multiple distinct P wave morphologies.
• B. Atrial fibrillation does not show discrete P waves; it shows a chaotic fibrillatory baseline without organized P waves.
• D. Wandering atrial pacemaker shares the P wave criteria of MAT but occurs at a rate under 100/min, whereas this patient's rate is 116/min.

Direct oral anticoagulants are contraindicated in patients with mechanical heart valves because trials (including one testing dabigatran in this population) showed increased rates of thromboembolism and bleeding compared with warfarin, likely due to inadequate inhibition of thrombin generated on the prosthetic surface. Warfarin, a vitamin K antagonist, remains the only recommended oral anticoagulant for mechanical valves, with a target INR individualized to valve type and position. None of the DOACs, including apixaban or rivaroxaban, have demonstrated safety or efficacy in this setting, and DOACs do not require INR monitoring.

• A. Apixaban has not been shown to be safe or effective in mechanical valve patients and is contraindicated.
• B. Rivaroxaban does not require INR monitoring and is contraindicated in mechanical valves regardless.
• D. Dabigatran was specifically studied and found inferior to warfarin in mechanical valve patients, with higher thromboembolic and bleeding events.

This patient has a hemodynamically stable narrow-complex regular tachycardia consistent with supraventricular tachycardia (SVT), most likely AV nodal re-entrant tachycardia. After an unsuccessful vagal maneuver, the next step per ACLS and SCFHS-endorsed guidelines is rapid intravenous adenosine, which transiently blocks AV nodal conduction and terminates re-entrant circuits using the AV node. It is given as a rapid bolus followed by a saline flush, starting at 6 mg and escalating to 12 mg if needed. Electrical cardioversion is reserved for hemodynamically unstable patients or when pharmacologic therapy fails.

• A. Cardioversion is reserved for hemodynamically unstable SVT or failure of adenosine, not as the initial next step in a stable patient.
• C. Amiodarone is not first-line for stable narrow-complex SVT and is used mainly in wide-complex or refractory tachycardias.
• D. Beta-blockers are second-line after adenosine fails and are not the immediate next step.

This patient has Wolff-Parkinson-White (WPW) syndrome with pre-excited atrial fibrillation, evidenced by the irregular wide-complex tachycardia with changing QRS morphology and prior ECG showing a short PR interval with a delta wave. AV-nodal blocking agents such as verapamil, diltiazem, beta-blockers, and adenosine selectively slow conduction through the AV node without affecting the accessory pathway. This shifts conduction preferentially down the accessory pathway, which can increase the ventricular rate and precipitate ventricular fibrillation. The treatment of choice in pre-excited AF is procainamide or ibutilide, or electrical cardioversion if unstable.

• A. While verapamil can reduce cardiac output, this is not the specific reason it is contraindicated in pre-excited AF.
• B. QT prolongation is not the primary mechanism of danger with verapamil in pre-excited AF; the concern is accessory pathway conduction.
• D. Verapamil does not act via reflex sympathetic activation to worsen this arrhythmia.

This patient has sustained monomorphic ventricular tachycardia with signs of hemodynamic instability, including hypotension and altered mental status, but he has a pulse. According to ACLS guidelines, hemodynamically unstable VT with a pulse should be treated with immediate synchronized electrical cardioversion rather than pharmacologic therapy, which takes longer to act and may not be effective in the setting of instability. Synchronization avoids delivering a shock during the vulnerable T wave, which could induce ventricular fibrillation. Amiodarone is reserved for stable VT or as an adjunct after cardioversion.

• A. Unsynchronized defibrillation is used for pulseless VT or ventricular fibrillation, not for VT with a palpable pulse, where synchronization prevents inducing VF.
• B. Amiodarone is appropriate for stable VT, not unstable VT, where electrical therapy is faster and more reliable.
• D. Lidocaine is a second-line antiarrhythmic and not the immediate treatment for unstable VT with a pulse.

This patient has classic findings of mitral stenosis, most commonly caused by rheumatic heart disease, supported by her history of childhood sore throats and joint pains suggestive of prior rheumatic fever. The physical examination reveals a loud S1, a mid-to-late diastolic rumbling murmur at the apex with presystolic accentuation, and an opening snap, all characteristic of mitral stenosis due to a stiffened, fused valve. Chronic left atrial pressure and dilation from mitral stenosis predispose to atrial fibrillation, seen here as the irregularly irregular rhythm without discrete P waves. Mitral stenosis is confirmed by echocardiography showing valve thickening, reduced mitral valve area, and commissural fusion.

• B. Tricuspid stenosis causes a diastolic murmur best heard at the lower left sternal border that increases with inspiration, not at the apex.
• C. Mitral regurgitation presents with a holosystolic murmur radiating to the axilla, not a diastolic murmur with an opening snap.
• D. Aortic regurgitation causes an early diastolic decrescendo murmur at the left sternal border, not an apical diastolic rumble with an opening snap.

Because the patient shows features suggesting a white-coat effect, current guidelines (ESC/ESH, ACC/AHA) recommend confirming elevated clinic readings with out-of-office measurement, either ambulatory blood pressure monitoring (ABPM) or home blood pressure monitoring, before labeling someone as hypertensive. ABPM is the reference standard because it captures daytime, nighttime, and 24-hour averages and can detect white-coat or masked hypertension. Starting treatment on clinic readings alone risks over-diagnosis and unnecessary lifelong medication in a patient whose true average pressure may be normal. Repeating clinic measurements after a long interval delays diagnosis and does not address the suspected white-coat effect.

• A. A single opposite-arm reading does not confirm sustained hypertension or exclude white-coat effect.
• B. An unnecessarily long delay that does not resolve the diagnostic uncertainty.
• C. Treatment should not start before confirming true sustained hypertension given suspected white-coat effect.

In patients with diabetic nephropathy and albuminuria, an ACE inhibitor or angiotensin receptor blocker is first-line because it reduces intraglomerular pressure by dilating the efferent arteriole, lowering proteinuria and slowing progression of diabetic kidney disease beyond its blood pressure-lowering effect. This renoprotective benefit is independent of systemic blood pressure control. Thiazides and calcium channel blockers lower blood pressure but lack this specific antiproteinuric effect, and beta-blockers are not first-line for uncomplicated diabetic nephropathy.

• A. Not first-line for diabetic nephropathy without another specific indication such as coronary disease.
• C. Effective antihypertensive but does not reduce albuminuria like an ACE inhibitor.
• D. Lowers blood pressure but has no specific renoprotective effect on proteinuria.

A sharp rise in creatinine and potassium after starting an ACE inhibitor, combined with asymmetric kidney size, strongly suggests renal artery stenosis, where glomerular filtration in the stenotic kidney depends on angiotensin II-mediated efferent arteriolar constriction. ACE inhibitors remove this compensatory mechanism, causing a marked fall in glomerular filtration rate and hyperkalemia, particularly with bilateral stenosis or stenosis in a solitary functioning kidney. The cough described is a separate, common ACE inhibitor side effect from bradykinin accumulation and does not explain the renal and potassium changes. This patient needs ACE inhibitor discontinuation and renal artery imaging such as Doppler ultrasound or CT angiography.

• B. Blood pressure is well controlled, and this does not explain the acute rise in creatinine and potassium.
• C. Angioedema presents with facial, lip, or tongue swelling and airway compromise, not isolated cough with renal dysfunction.
• D. Typically causes fever, rash, and eosinophilia, not this pattern tied temporally to ACE inhibitor initiation with asymmetric kidneys.

Hypertensive emergency is defined by severely elevated blood pressure accompanied by acute, ongoing target organ damage such as encephalopathy, acute kidney injury, acute heart failure, or retinal hemorrhages, as seen here with confusion, papilledema, and rising creatinine. Hypertensive urgency refers to severe blood pressure elevation without evidence of acute organ injury. The distinction determines management: emergencies require immediate blood pressure reduction with intravenous agents in a monitored setting, whereas urgency is managed with oral agents and more gradual reduction over 24-48 hours. The absolute blood pressure number alone does not define an emergency; a patient can have severe hypertension without organ damage.

• A. Duration is not part of the clinical definition of hypertensive emergency.
• C. Blood pressure level alone, without organ damage, does not define a hypertensive emergency.
• D. Headache alone is a nonspecific symptom and does not by itself indicate acute target organ damage.

The paroxysmal pattern of headache, palpitations, diaphoresis, and markedly elevated blood pressure during episodes with normal pressure between them is classic for pheochromocytoma, a catecholamine-secreting tumor of the adrenal medulla or sympathetic paraganglia. The weight loss reflects a hypermetabolic state from catecholamine excess. Twenty-four-hour urinary fractionated metanephrines (or plasma free metanephrines) is the recommended biochemical test because metanephrines are produced continuously even between symptomatic episodes, giving high sensitivity. Plasma renin-aldosterone ratio evaluates Conn syndrome, renal artery imaging evaluates renovascular hypertension, and dexamethasone suppression testing evaluates Cushing syndrome, none of which fit this episodic catecholamine-excess picture.

• B. This evaluates Cushing syndrome, which presents with central obesity, striae, and sustained hypertension, not paroxysms.
• C. This evaluates primary hyperaldosteronism, which presents with sustained hypertension and hypokalemia, not episodic symptoms.
• D. This evaluates renovascular hypertension, which does not typically cause paroxysmal catecholamine-type symptoms.

Hypertrophic cardiomyopathy is an autosomal dominant disorder of cardiac sarcomere proteins causing asymmetric left ventricular hypertrophy, most often involving the interventricular septum, and is the leading cause of sudden cardiac death in young athletes. The murmur characteristically increases with maneuvers that reduce preload or afterload, such as standing from squatting or Valsalva, because reduced ventricular volume worsens dynamic left ventricular outflow tract obstruction from systolic anterior motion of the mitral valve. A family history of sudden death at a young age during exertion is a classic clue. Dilated cardiomyopathy shows a dilated, poorly contracting ventricle rather than wall thickening, and aortic stenosis murmurs decrease, not increase, with standing.

• A. Mitral valve prolapse causes a mid-systolic click and late systolic murmur, not a harsh outflow murmur with septal hypertrophy.
• B. This presents with ventricular dilation and reduced systolic function, not septal hypertrophy.
• C. Aortic stenosis murmurs decrease with standing/Valsalva, opposite to the finding described, and does not cause asymmetric septal thickening.

In hypertrophic cardiomyopathy with dynamic left ventricular outflow tract obstruction, reducing preload or afterload worsens the obstruction because a smaller ventricular cavity brings the hypertrophied septum and anterior mitral leaflet closer together, increasing systolic anterior motion. Nitrates cause venodilation and reduce preload, while diuretics reduce intravascular volume, both of which exacerbate obstruction and can precipitate hypotension, syncope, or cardiovascular collapse, as suggested by this patient's already low blood pressure and tachycardia. Management instead favors beta-blockers or volume administration if the patient is hypotensive. This mechanism does not primarily involve QT prolongation, increased oxygen demand, or conduction block.

• A. This is not the main concern; the central problem is hemodynamic worsening of outflow obstruction, not oxygen supply-demand mismatch from these specific agents.
• B. Not the primary mechanism of harm from nitrates and diuretics in this condition.
• C. Nitrates and diuretics do not characteristically cause bradycardia or heart block.

Chronic excessive alcohol intake causes a toxic (metabolic) cardiomyopathy through direct mitochondrial injury, oxidative stress, and impaired synthesis of contractile proteins (actin and myosin), leading to myocyte loss and compensatory chamber dilation with reduced ejection fraction. This is one of the three classic reversible/treatable causes of dilated cardiomyopathy along with peripartum state and viral myocarditis. Abstinence can lead to significant recovery of ventricular function if initiated early. The echocardiographic findings of an enlarged, thin-walled, hypokinetic ventricle are typical of dilated rather than restrictive or infiltrative cardiomyopathy.

• A. Amyloid infiltration causes restrictive, not dilated, cardiomyopathy with a non-dilated, thickened ventricle.
• B. This describes a mechanism of sick sinus syndrome, not dilated cardiomyopathy.
• C. Granulomatous myocarditis (e.g., sarcoidosis) typically causes conduction disease and a non-dilated or restrictive pattern, not this presentation.

Constrictive pericarditis is characterized by ventricular interdependence, producing discordant (out of phase) right and left ventricular systolic pressures during respiration on catheterization, along with a pericardial knock and respiratory variation in mitral inflow of more than 25%. In contrast, restrictive cardiomyopathy shows concordant RV and LV pressure changes with respiration because the rigid myocardium (not the pericardium) limits filling, and wall thickness is typically increased (e.g., amyloidosis) rather than normal. The normal wall thickness here favors a pericardial rather than myocardial process. Cardiac MRI showing a thickened, calcified pericardium would further support constriction.

• A. Restrictive cardiomyopathy typically shows concordant RV/LV pressure changes with respiration and often increased wall thickness, not the discordance and pericardial knock described here.
• B. Tamponade causes pulsus paradoxus and equalization of diastolic pressures acutely, not a pericardial knock or chronic ascites over months.
• D. Dilated cardiomyopathy presents with a dilated, hypokinetic ventricle and reduced ejection fraction, not preserved EF with normal wall thickness.

The pleuritic positional chest pain, pericardial friction rub, and diffuse ST elevation with PR depression are classic for acute pericarditis, commonly following a viral prodrome. First-line treatment is an NSAID such as ibuprofen combined with colchicine, which reduces symptom duration and significantly lowers the risk of recurrence. Corticosteroids are reserved for cases with contraindications to NSAIDs, autoimmune etiology, or recurrent pericarditis, as early steroid use is associated with higher recurrence rates. The diffuse ECG changes (not localized to one coronary territory) and absence of reciprocal depression argue against an acute coronary syndrome requiring reperfusion therapy.

• A. Anticoagulation is not indicated in pericarditis and may increase the risk of hemopericardium, especially if there is an effusion.
• B. The diffuse, non-territorial ST elevation and clinical picture indicate pericarditis rather than an acute coronary occlusion requiring PCI.
• C. Corticosteroids are second-line therapy due to higher rates of recurrence and are not first-line initial treatment.

This patient has cardiac tamponade, evidenced by Beck's triad (hypotension, elevated JVP, muffled heart sounds), pulsus paradoxus greater than 10 mmHg, and echocardiographic right ventricular diastolic collapse with a plethoric IVC. This is a hemodynamic emergency caused by impaired diastolic filling from pericardial fluid under pressure, and it requires immediate pericardiocentesis to relieve the pressure and restore cardiac output. Delaying drainage for further imaging or medical therapy risks cardiovascular collapse. Diuretics are contraindicated as they further reduce preload and can precipitate shock in tamponade.

• A. There is no evidence of infection here; antibiotics do not address the mechanical compression causing hemodynamic collapse.
• B. CT would delay definitive treatment in a hemodynamically unstable patient; the diagnosis is already confirmed by bedside echocardiography.
• C. Diuretics reduce preload and can worsen hypotension and shock in a tamponade physiology where adequate filling pressure is needed.

The antecedent viral illness, elevated troponin with angiographically normal coronary arteries, and acute global left ventricular dysfunction in a young patient are characteristic of viral myocarditis, most commonly due to enteroviruses (including coxsackievirus B) or, less commonly, other cardiotropic viruses. Myocarditis causes direct myocardial inflammation and injury, which can progress rapidly to fulminant heart failure or cardiogenic shock, so young patients with unexplained heart failure and a preceding viral syndrome should be evaluated urgently with echocardiography and, where available, cardiac MRI or biopsy. Normal coronary angiography excludes an ischemic cause for the troponin elevation and wall motion abnormality.

• A. Takotsubo typically occurs after acute emotional or physical stress, usually in older women, with characteristic apical ballooning rather than diffuse global hypokinesia following a viral prodrome.
• B. Normal coronary angiography excludes an acute infarction as the cause of troponin rise and wall motion abnormality.
• D. Rheumatic carditis typically follows streptococcal pharyngitis by 2-3 weeks and presents with valvulitis (new murmur) rather than isolated global ventricular dysfunction.

This patient has classic features of acute aortic dissection: sudden tearing pain, a significant blood pressure differential between limbs, and a new diastolic murmur suggesting aortic regurgitation from proximal involvement. In a hemodynamically stable patient with normal renal function, contrast-enhanced CT angiography of the chest is the investigation of choice because it is rapid, widely available, and provides high sensitivity and specificity for diagnosing dissection, determining the Stanford classification (A versus B), and planning surgical or medical management. Transesophageal echocardiography is preferred over CT only when the patient is too unstable for transport to the CT scanner.

• A. A chest radiograph may show a widened mediastinum but lacks the sensitivity and specificity needed to confirm or classify a dissection.
• C. Transthoracic echocardiography has limited sensitivity for visualizing the distal ascending aorta and arch compared to CT angiography or transesophageal echocardiography.
• D. Stress testing is contraindicated and dangerous in suspected acute aortic dissection due to the risk of further propagation or rupture.

In acute aortic dissection, an intravenous beta-blocker such as esmolol should be given first to reduce heart rate and the force of left ventricular contraction (dP/dt), which lowers aortic wall shear stress. If a vasodilator like nitroprusside is given before adequate beta-blockade, the resulting reflex tachycardia and increased contractility would increase shear stress on the dissected aortic wall and could propagate the dissection. Esmolol's short half-life also makes it easy to titrate in this acute setting. Target heart rate is generally less than 60/min and systolic blood pressure 100-120 mmHg once negative chronotropic control is established.

• A. Nitroprusside given without prior beta-blockade can cause reflex tachycardia and increased dP/dt, worsening shear stress on the dissected aorta.
• B. Short-acting dihydropyridine calcium channel blockers like sublingual nifedipine cause rapid reflex tachycardia and uncontrolled hypotension, and are not appropriate initial therapy.
• D. Hydralazine is a direct arterial vasodilator that similarly causes reflex tachycardia if given before beta-blockade and is not first-line in this setting.

Current guidelines recommend a one-time abdominal ultrasound screening for abdominal aortic aneurysm in men aged 65-75 years who have ever smoked, as this population carries the highest risk and ultrasound is a safe, inexpensive, and highly sensitive and specific test for detecting AAA. If the aorta is normal, no further routine surveillance is needed; if an aneurysm is found, the surveillance interval depends on its diameter. Unrecognized AAA can rupture, presenting with sudden severe abdominal or back pain, hypotension, and a pulsatile abdominal mass, which is a surgical emergency with high mortality if untreated. CT is reserved for further characterization or preoperative planning, not as the initial screening tool.

• A. Annual CT is not recommended for initial screening due to radiation and cost; ultrasound surveillance intervals depend on aneurysm size only if one is found.
• B. MRI is not the recommended initial screening modality for AAA; ultrasound is preferred due to availability, low cost, and lack of radiation.
• C. His age and smoking history place him in the highest-risk group for whom one-time screening is specifically recommended, so reassurance without screening is inappropriate.

The ankle-brachial index (ABI) here is 96/140 = 0.69, which falls in the 0.41-0.90 range defining mild to moderate peripheral arterial disease. An ABI of 0.90-1.30 is normal, below 0.40 indicates severe disease often with critical limb ischemia, and values above 1.30 suggest non-compressible calcified vessels (common in diabetics) requiring toe-brachial index or imaging instead. The clinical picture of intermittent claudication fits a moderate reduction rather than severe ischemia, which typically presents with rest pain or tissue loss.

• A. A falsely elevated ABI above 1.30 suggests non-compressible vessels, not this low value.
• C. An ABI of 0.90-1.30 would be normal, which this value is not.
• D. Severe disease with critical limb ischemia corresponds to an ABI below 0.40, lower than calculated here.

In a patient with a low-to-moderate pretest probability Wells score, a quantitative D-dimer assay is the recommended next step; a negative result effectively rules out deep vein thrombosis without need for imaging. If the D-dimer is positive or the Wells score is high, compression ultrasonography becomes the next step instead. Starting anticoagulation before confirming the diagnosis exposes the patient to unnecessary bleeding risk. CT venography is reserved for specific scenarios such as suspected iliac or pelvic vein thrombosis, not as a first-line test.

• A. Anticoagulation should not be started before objective confirmation of the diagnosis in a low-probability patient.
• B. Ultrasonography is appropriate after a positive D-dimer or in high-probability patients, not as the immediate first step here.
• D. CT venography is not the standard first-line imaging test and is reserved for select cases.

In a hemodynamically stable patient with high pretest probability for pulmonary embolism and no contraindication to contrast, CT pulmonary angiography (CTPA) is the test of choice because it directly visualizes emboli and has high sensitivity and specificity. V/Q scanning is reserved for patients with contrast allergy, significant renal impairment, or pregnancy, where it avoids iodinated contrast. D-dimer is not useful in high-probability patients since a negative result does not reliably exclude the diagnosis and a positive result would still require imaging. Echocardiography can show indirect signs of right heart strain but does not confirm the diagnosis.

• A. D-dimer testing is not indicated in high pretest probability patients because a negative result does not exclude the diagnosis.
• C. Echocardiography may suggest right ventricular strain but cannot confirm or exclude pulmonary embolism directly.
• D. V/Q scan is preferred in patients with contraindications to contrast, such as renal impairment or pregnancy, not in this patient.

A small muscular ventricular septal defect produces a loud, harsh holosystolic murmur at the left lower sternal border because of high-velocity turbulent flow across a small, restrictive defect, and most close spontaneously within the first two years of life as the muscular septum grows. The murmur intensity in VSD is inversely related to defect size, with smaller defects paradoxically producing louder murmurs. Atrial septal defect typically produces a softer systolic ejection murmur at the upper left sternal border with fixed splitting of S2, not a holosystolic murmur at the lower sternal border. Patent ductus arteriosus classically causes a continuous machine-like murmur, and pulmonary stenosis causes an ejection murmur with a click, both of which differ from this presentation.

• B. ASD causes a softer pulmonary flow murmur with fixed split S2, heard at the upper left sternal border.
• C. PDA produces a continuous machinery murmur throughout systole and diastole, not an isolated holosystolic murmur.
• D. Pulmonary stenosis produces a crescendo-decrescendo ejection murmur, often preceded by an ejection click.

In uncorrected atrial septal defect, chronic left-to-right shunting produces sustained increased pulmonary blood flow, leading over years to pulmonary vascular remodeling with medial hypertrophy and intimal fibrosis of pulmonary arterioles. This raises pulmonary vascular resistance until it exceeds systemic vascular resistance, reversing the shunt to right-to-left and producing Eisenmenger syndrome with cyanosis and clubbing. This process typically develops over decades, unlike the more rapid Eisenmenger progression seen with large ventricular septal defects or patent ductus arteriosus. The other mechanisms listed are not the pathophysiological basis of shunt reversal in atrial septal defect.

• A. Right coronary stenosis is unrelated to the pathophysiology of shunt reversal in congenital heart disease.
• B. Mitral valve disease is not a feature of isolated atrial septal defect and does not drive Eisenmenger physiology.
• C. Recurrent thromboembolism is not the mechanism of pulmonary hypertension in uncorrected ASD.

Indomethacin, a nonselective cyclooxygenase inhibitor, reduces prostaglandin E2 synthesis, which is the mediator that keeps the ductus arteriosus patent in utero and in the early neonatal period; blocking this pathway promotes ductal constriction and closure in a hemodynamically significant PDA. Ibuprofen works similarly and is an accepted alternative with a comparable safety profile. In contrast, prostaglandin E1 (alprostadil) is used to keep the ductus open in duct-dependent congenital heart lesions, the opposite therapeutic goal. Furosemide may help manage volume overload symptoms but has no effect on ductal patency.

• A. Prostaglandin E1 infusion keeps the ductus open and is used in duct-dependent cardiac lesions, the opposite effect needed here.
• C. Alprostadil is prostaglandin E1 itself, used to maintain ductal patency, not close it.
• D. Furosemide treats fluid overload but does not promote ductal closure.

Coarctation of the aorta classically causes higher blood pressure in the upper extremities than the lower extremities, with radiofemoral delay and a systolic murmur best heard posteriorly over the back near the left scapula from turbulent flow at the coarctation site. Its association with Turner syndrome, suggested here by short stature and webbed neck, is well recognized, as up to 10-15% of girls with Turner syndrome have coarctation. Takayasu arteritis can cause differential limb pressures but typically affects young women with systemic inflammatory features and upper limb pulse discrepancies, not this classic pattern with Turner stigmata. Aortic valve stenosis produces a murmur radiating to the carotids without a significant limb blood pressure gradient.

• A. Aortic stenosis causes a murmur radiating to the neck vessels, without the limb blood pressure discrepancy seen here.
• B. Takayasu arteritis typically affects pulses asymmetrically in the arms and is not classically linked to Turner syndrome.
• D. PDA causes a continuous murmur and does not produce a blood pressure gradient between upper and lower limbs.

The triad of exertional angina, syncope, and dyspnea with a harsh crescendo-decrescendo systolic murmur radiating to the carotids, a slow-rising (parvus et tardus) pulse, and a soft or absent A2 is classic for severe aortic stenosis. In patients over 65 years, degenerative calcific disease is the most common cause. The carotid radiation and pulse character distinguish it from other systolic murmurs. Confirmation is by echocardiography showing a thickened, calcified valve with increased transvalvular gradient.

• A. Pulmonary stenosis murmur is heard best at the left upper sternal border and does not radiate to the carotids.
• C. Mitral valve prolapse produces a mid-systolic click with a late systolic murmur at the apex, not one radiating to the carotids.
• D. HOCM causes a murmur that increases with Valsalva and decreases with squatting, without carotid radiation or a slow-rising pulse.

This patient has severe aortic stenosis (valve area <1.0 cm², mean gradient >40 mmHg, peak velocity >4 m/s) but is truly asymptomatic with preserved ejection fraction and a normal exercise test. Current guidelines recommend watchful waiting with serial clinical and echocardiographic surveillance rather than intervention, since asymptomatic patients with normal LV function and a normal exercise response have a low risk of sudden cardiac death. Valve replacement is indicated once symptoms develop, LVEF falls below 50%, or very severe stenosis (velocity ≥5 m/s) or rapid progression is present.

• B. Vasodilators can cause dangerous hypotension in significant aortic stenosis due to fixed outflow obstruction and are not standard management.
• C. Balloon valvuloplasty has high restenosis rates and is reserved for bridging therapy or palliation, not for asymptomatic severe AS.
• D. Surgery is not indicated in truly asymptomatic patients with preserved EF and a normal exercise test; intervention is reserved for symptomatic patients or specific high-risk asymptomatic criteria.

Papillary muscle rupture, most often from the posteromedial papillary muscle supplied by the posterior descending artery, is a mechanical complication of inferior MI typically occurring 2-7 days post-infarction. It causes acute severe mitral regurgitation with sudden pulmonary edema and cardiogenic shock, but because the left atrium has not had time to dilate, the regurgitant jet may produce only a soft or even inaudible murmur despite severe hemodynamic compromise. The absence of cardiomegaly on chest X-ray reflects the acute, non-dilated heart. Urgent echocardiography confirms the flail leaflet and emergency surgery is required.

• A. VSR classically causes a harsh holosystolic murmur with a palpable thrill at the left sternal border, which is absent here.
• C. Free wall rupture presents with tamponade, pulseless electrical activity, or sudden death, not pulmonary edema with a murmur.
• D. Chronic MR would show left atrial and ventricular dilation with cardiomegaly on chest X-ray, not an acute presentation after recent MI.

A wide pulse pressure (148/54 mmHg), collapsing water-hammer pulse, de Musset sign (head bobbing), a hyperdynamic displaced apex, and an early decrescendo diastolic murmur at the left sternal border are classic for chronic aortic regurgitation, commonly caused by bicuspid aortic valve in younger patients. The wide pulse pressure results from increased stroke volume and rapid diastolic runoff back into the left ventricle. The murmur is best heard with the diaphragm while the patient leans forward in expiration, maximizing proximity of the aortic valve to the chest wall.

• B. Tricuspid regurgitation produces a holosystolic murmur at the left lower sternal border with a pulsatile liver, not a diastolic murmur with wide pulse pressure.
• C. Mitral stenosis causes a low-pitched diastolic rumble at the apex with an opening snap, not a wide pulse pressure or collapsing pulse.
• D. Pulmonary regurgitation gives a diastolic murmur at the left upper sternal border but does not produce a water-hammer pulse or wide pulse pressure.

The modified Duke criteria require either 2 major, 1 major plus 3 minor, or 5 minor criteria for a diagnosis of definite infective endocarditis. This patient has two major criteria: typical organism (Staphylococcus aureus) in three separate blood cultures, and echocardiographic evidence of a vegetation (oscillating intracardiac mass on a valve). The tender finger nodules described are Osler nodes, a minor criterion, but the diagnosis is already definite based on the two major criteria alone. Intravenous drug use is itself a minor (predisposing) criterion but is not needed once two major criteria are met.

• A. The patient has major criteria (positive cultures and echocardiographic findings), not just minor criteria.
• B. This underestimates the case; two major criteria alone are sufficient for a definite diagnosis without needing minor criteria.
• D. The criteria for definite IE are clearly met, so the diagnosis should not be rejected.

In a hemodynamically stable patient with suspected subacute infective endocarditis, the priority before starting antibiotics is to obtain at least three sets of blood cultures from separate venipuncture sites, spaced over time, to maximize the yield of identifying the causative organism before antimicrobial therapy alters culture results. Empiric antibiotics should only be started immediately without waiting for cultures in patients who are septic, unstable, or in acute heart failure. Since this patient is stable, cultures should be obtained first, and therapy tailored once organism and sensitivities are known.

• A. Echocardiography is important for diagnosis but does not need to precede blood cultures, and delaying cultures for imaging risks lowering their yield.
• C. Immediate empiric therapy without cultures is reserved for septic or hemodynamically unstable patients; this patient is stable, so cultures should be drawn first.
• D. A single dose of antibiotic before adequate cultures risks sterilizing subsequent cultures and compromising organism identification.

Current guidelines restrict infective endocarditis prophylaxis to the highest-risk cardiac conditions, which include prosthetic heart valves (including bioprosthetic and homograft valves), previous infective endocarditis, unrepaired cyanotic congenital heart disease, and cardiac transplant recipients with valvulopathy. For these patients undergoing dental procedures that involve manipulation of gingival tissue or the periapical region of teeth, such as extraction, a single dose of amoxicillin 2 g orally given 30-60 minutes before the procedure is recommended. This patient's bioprosthetic valve places her in the high-risk category requiring prophylaxis for this invasive dental procedure.

• A. Prosthetic valve patients are in the highest-risk category and do require prophylaxis for invasive dental procedures such as extraction.
• B. Oral amoxicillin, not intravenous vancomycin, is the standard regimen; vancomycin is reserved for penicillin-allergic patients unable to tolerate oral medication or specific resistant organism concerns.
• D. Prophylaxis indication is based on the patient's underlying cardiac risk category and the type of procedure, not an arbitrary bleeding duration.