ECG criteria
- T wave: usually unchanged; may be inverted, biphasic, or flattened in II, III, aVF, and sometimes V5–V6 — predominantly in the arrhythmogenic phenotype
- QT interval: measured in II or V5–V6, selecting the longest interval without a U wave; QTc is calculated adjusted for heart rate (Fridericia's formula is preferred when HR deviates from normal); approximately, QTc >450 ms in men and >460 ms in women is considered prolonged, and QTc ≥500 ms significantly increases arrhythmic risk; QT prolongation in MVP is inconstant and requires ruling out other causes
- ST segment: non-specific changes may occur in leads with T-wave alterations; such depression alone does not rule out ischemia — clinical evaluation is required
- Ventricular extrasystoles: VEAs may originate from the papillary muscles, mitral annulus, and other sites; frequency, symptomatology, morphology, presence of couplets, non-sustained or sustained VT are clinically relevant
- Rhythm: supraventricular extrasystoles and paroxysms of SVT are occasionally noted as non-specific incidental findings, not uniquely characteristic of MVP
- QRS axis and voltage: generally without specific deviations
- Arrhythmogenic phenotype of MVP: a combination of MVP with ventricular arrhythmias and/or a set of associated risk markers — leaflet redundancy and myxomatous changes, mitral annular disjunction (MAD), T-wave inversion in inferior/inferolateral leads, papillary muscle or inferobasal myocardial fibrosis on MRI; the listed features do not need to be present simultaneously
What it looks like on ECG
There is no specific ECG pattern for mitral valve prolapse — the diagnosis is made echocardiographically. In most patients, the ECG is within normal limits; some exhibit associated electrophysiological changes that are primarily relevant when evaluating the arrhythmogenic phenotype.
Most commonly, attention is drawn to:
| Element | Parameter | Leads |
|---|---|---|
| T wave | inverted, biphasic, flattened (not present in all patients) | II, III, aVF, sometimes V5–V6 |
| ST segment | non-specific ST-T changes, most often in the inferior and inferolateral leads; they are not a specific sign of MVP and require the exclusion of ischemia based on clinical data and serial changes | inferior/inferolateral when T-wave changes are present |
| QT | usually normal, inconstantly mildly prolonged | measured in II or V5–V6 |
| QRS | ventricular extrasystoles may occur | any leads; the origin is assessed by morphology |
T-wave changes in the inferior leads in a patient with MVP are sometimes referred to as non-specific ST-T changes associated with prolapse (previously termed "MVP syndrome"). These changes do not conform to a coronary artery distribution and do not, by themselves, rule out ischemia — in suspected acute coronary syndrome, ST depression must be interpreted separately, taking into account clinical presentation, ECG dynamics, and troponin levels.
Mechanism
When a leaflet is displaced into the atrium beyond the mitral annulus plane, the papillary muscles and chordae tendineae are placed under tension, creating mechanical stress on the inferobasal wall of the left ventricle and the papillary muscles. It is hypothesized that such mechanical stress, stretch, and subsequent fibrosis of the papillary muscles and inferobasal myocardium may contribute to repolarization heterogeneity and ventricular ectopy; however, the mechanism is multifactorial, and not all arrhythmias originate specifically from these zones — localization is refined using VEA morphology, imaging, and, if necessary, cardiac MRI. Marked myxomatous degeneration of the leaflets with thickening and excessive chordal tension, as well as mitral annular disjunction (MAD), are associated with greater electrical instability of the myocardium, which partially explains the link to ventricular arrhythmias in the arrhythmogenic phenotype of MVP.
Causes
- Primary prolapse (myxomatous degeneration, Barlow's disease)
- Marfan syndrome and other connective tissue disorders (Ehlers-Danlos)
- Functional mitral regurgitation due to ischemic papillary muscle dysfunction or left ventricular dilation — this is not necessarily true leaflet prolapse, but rather leaflet restriction and tethering
- True secondary prolapse due to local damage or rupture of chordae and other structural causes, confirmed by echo criteria
- Congenital anomalies of the chordal apparatus
- Idiopathic prolapse without structural connective tissue pathology
Differential diagnosis
- Inferior wall ischemia: cannot be distinguished from MVP-related changes on a single ECG; in the presence of symptoms or doubt, evaluate clinical presentation, serial ECGs, and high-sensitivity troponin — the presence of MVP does not rule out ACS
- Prior inferior myocardial infarction: look for a pathological Q wave, which is not characteristic of MVP
- Autonomic dysfunction: similar non-specific T-wave inversion; differentiation requires clinical evaluation, repeat/serial ECGs, review of medications and serum electrolytes, and, when indicated, echocardiography to detect MVP and other structural heart diseases; a causal relationship between T-wave changes and MVP cannot be established from a single ECG
- Early repolarization syndrome: ST elevation and J-point notching rather than T-wave inversion
- Hypokalemia: T-wave flattening combined with a U wave and changes in other leads, corrected upon normalization of serum potassium
Clinical significance and management
In most patients with MVP, the ECG is normal or shows non-specific changes and requires no specific treatment. It is essential for the clinician to:
- avoid interpreting T-wave inversion in the inferior leads as ischemia in the absence of clinical presentation and dynamics, while also not ruling out ACS solely based on a known diagnosis of MVP;
- in newly detected ST-T changes and complaints of palpitations or syncope, rule out a structural cause — echocardiography assessing the degree of prolapse, leaflet thickness and redundancy, and mitral regurgitation;
- in frequent or complex ventricular extrasystoles, paroxysms of ventricular tachycardia, syncope, or a family history of sudden death, evaluate for features of the arrhythmogenic phenotype of MVP (myxomatous, excessively mobile leaflets, mitral annular disjunction, T-wave inversion in inferior leads, complex VEA/VT) — such patients require prompt evaluation by a cardiologist/arrhythmologist with Holter monitoring, echocardiography, and cardiac MRI when indicated; in cases of syncope, sustained or rapid SVT/VT, specialized risk stratification for sudden death and consideration of antiarrhythmic therapy, catheter ablation, or implantable cardioverter-defibrillator placement according to current criteria;
- take into account that risk factors for sudden cardiac death in MVP include marked myxomatous degeneration and leaflet redundancy, mitral annular disjunction, fibrosis on MRI, and complex ventricular extrasystolic activity/VT, but the proportion of such cases among all sudden deaths in MVP cannot be quantified based solely on ECG findings — evaluation requires a comprehensive workup.
Common interpretation errors
- Diagnosing MVP via ECG is impossible; confirmation is exclusively echocardiographic
- Mistaking non-specific T-wave inversion for ischemia and referring the patient for emergency coronary angiography without clinical data, or conversely, ruling out ACS solely based on a known diagnosis of MVP
- Ignoring frequent or complex ventricular extrasystoles in a patient with known MVP without assessing for features of the arrhythmogenic phenotype
- Failing to measure QTc correctly when a visually prolonged QT interval is identified, by using Bazett's formula without accounting for its inaccuracy in tachycardia and bradycardia
- Confusing ST-T changes in MVP with early repolarization or a normal juvenile T-wave variant
1. Which ECG change is more frequently associated with mitral valve prolapse when abnormalities are present?
T-wave inversion or biphasic T waves in the inferior leads are the most typical non-specific findings when ECG changes are present in MVP.
2. How is the diagnosis of mitral valve prolapse confirmed?
The ECG does not confirm MVP and does not visualize the valve leaflets; the cornerstone of diagnosis is transthoracic echocardiography, supplemented in complex cases by transesophageal echocardiography or cardiac MRI.
3. What does the arrhythmogenic phenotype of MVP include?
The arrhythmogenic phenotype is described as a combination of MVP with ventricular arrhythmias and an optional set of risk markers: redundant/myxomatous leaflets, mitral annular disjunction (MAD), inferior T-wave inversion, fibrosis on MRI — not all markers are required simultaneously.
Frequently asked questions
Can mitral valve prolapse be seen on an ECG?
No, ECG does not visualize the valvular apparatus. The diagnosis is established by echocardiography, while in some patients ECG may only show concomitant nonspecific changes — inferior T-wave inversion or ventricular extrasystoles.
Is mitral valve prolapse with ECG changes dangerous?
In most cases, no, the clinical course is benign. The risk increases with the so-called arrhythmogenic phenotype: a combination of MVP with ventricular arrhythmias and associated risk markers — pronounced myxomatous degeneration and leaflet redundancy, mitral annular disjunction, inferior T-wave inversion, and fibrosis on MRI. Such a phenotype requires cardiologist follow-up and Holter monitoring.
How to distinguish ST-T changes in MVP from myocardial ischemia?
A single ECG cannot reliably differentiate them — the presence of MVP does not rule out acute coronary syndrome. If ischemia is suspected, guidance relies on the clinical picture, serial ECG dynamics, and high-sensitivity troponin according to ACS diagnostic algorithms.
Is ventricular extrasystole in MVP treatment required?
The decision depends on the number and morphology of extrasystoles, the presence of couplets or VT, and structural leaflet changes on echocardiography. Rare monomorphic extrasystoles usually do not require intervention, whereas frequent or complex ones are an indication for further evaluation and follow-up.
Which leads are most commonly reviewed when suspecting ECG changes in MVP?
Primarily the inferior leads II, III, aVF, where T-wave inversion or flattening is more frequently observed, and sometimes also the lateral leads V5–V6.
ECG Course
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Related terms
More in the section "Pericardium, Lungs, Brain and Others"
Sources
- Goldberger A.L. Clinical Electrocardiography, latest edition
- Surawicz B., Knilans T. Chou's Electrocardiography in Clinical Practice
- Orlov V.N. Guide to Electrocardiography
Educational material for medical students and physicians. Does not replace clinical guidelines and physical examination; the ECG must always be interpreted in conjunction with the clinical picture.