Ventricular extrasystole on ECG

Causes and associated conditions

Virtually any organic damage to the myocardium, as well as regulatory failures without structural changes, can cause extrasystoles. Ventricular arrhythmias require special attention due to the high risk of rapid fatal outcome.

Conditions in which ventricular extrasystoles are frequently recorded:

• Hypertrophic cardiomyopathy — associated with a high risk of sudden cardiac death.
• Right ventricular cardiomyopathy.
• Alcoholic cardiomyopathy — arrhythmias arise due to stromal lipomatosis and the accumulation of arrhythmogenic toxins; progression to ventricular fibrillation is possible.
• Mitral valve prolapse.
• Myocarditis — sometimes the appearance of extrasystoles is the only objective sign of ongoing inflammation.
• Toxic drug effects — characteristic of cardiac glycoside overdose (due to increased ventricular automaticity) and rapid intravenous administration of vinca alkaloids.

Topical ECG Diagnostics

When an impulse is generated in the ventricles, it propagates through the myocardium via an abnormal pathway. As a result, the morphology of the extrasystole on the ECG resembles the pattern of a bundle branch block. This is not a true block, but a reflection of the topography of the excitation source.

Functional Ventricular Extrasystole

Clinical and electrocardiographic evaluation is always aimed at determining the nature of the arrhythmia: whether it is functional or the result of an organic lesion.

Criteria for benign (functional) extrasystole:

1. Occurs predominantly in the prepubertal and pubertal periods against the background of hormonal and autonomic shifts.
2. Characterized by inconstancy.
3. Topographically, such extrasystoles most often originate from the right ventricle (or have a supraventricular origin).
4. Key diagnostic test: the number of premature contractions decreases sharply or they completely disappear during physical exertion (e.g., during cycle ergometry) and upon changing body position to vertical (orthostasis).

Patient Examination Tactics

Patient complaints of paroxysmal pounding heartbeat, episodes of dizziness, presyncope, or syncope are direct indications for Holter ECG monitoring (Holter ECG).

An important differential diagnostic principle: if during continuous monitoring the patient notes the onset of their habitual symptoms, but no arrhythmia is recorded on the ECG at that moment, a cardiac cause is ruled out. In such cases, extracardiac factors must be sought.

Expanded search includes:

• Holter ECG to assess circadian dependency (association with sleep and wakefulness).
• Provocative tests (cycle ergometry, treadmill test, pharmacological tests with atropine or beta-blockers).
• Echocardiography and chest X-ray to rule out an organic substrate.
• Neurological status assessment (EEG, REG) and consultations with related specialists (neurologist, endocrinologist, ENT) due to the frequent extracardiac genesis of arrhythmias in children and adolescents.

Class and exam questions

What else to study on this topic

• Atrioventricular extrasystoles and their variants
• Supraventricular paroxysmal tachycardia and the re-entry mechanism
• Wolff-Parkinson-White (WPW) syndrome and ventricular pre-excitation
• Second-degree AV blocks: differential diagnosis of Mobitz type I and Mobitz type II
• Age-related ECG norms: respiratory sinus arrhythmia and incomplete RBBB in children

Other topics in the "Additional Topics" section

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