Premature Ventricular Contractions

Premature ventricular contractions (ventricular ectopic beats) are early depolarisations arising from the ventricles, producing wide, bizarre QRS complexes. They are very common in healthy people and are generally benign in structurally normal hearts, but a high burden or presence of heart disease changes the risk.

• Triggers: caffeine, alcohol, stimulants, stress, sleep deprivation, hypokalaemia, hypomagnesaemia, hypoxia, thyrotoxicosis, sympathomimetic drugs, digoxin toxicity, tricyclics.
• Structural causes: previous myocardial infarction, cardiomyopathy, heart failure, myocarditis, hypertensive heart disease, valve disease, arrhythmogenic right ventricular cardiomyopathy.
• A burden above 10 to 15 percent of beats over 24 hours can cause a reversible cardiomyopathy.
• Outflow tract origin (tall R waves in inferior leads) is the commonest benign pattern in healthy young people.

• Palpitations, skipped beats, a thump, or a pause then forceful beat; may be asymptomatic.
• Often more noticeable at rest, in bed, after meals and during anxiety; may fall or disappear on exercise.
• Fatigue, light headedness or dyspnoea when frequent.
• Examination: irregular pulse, premature beats; assess for murmurs, heart failure signs, hypertension.
• Red flags: syncope, chest pain, exertional symptoms, family history of sudden cardiac death or cardiomyopathy, runs of nonsustained ventricular tachycardia, ectopics increasing with exercise, known heart disease, abnormal ECG.

• 12-lead ECG: premature, broad (over 120 ms) QRS without a preceding P wave, discordant ST-T change, and a full compensatory pause. Note the morphology (left bundle branch block with inferior axis suggests outflow tract origin).
• Bloods: urea and electrolytes, magnesium, calcium, thyroid function, full blood count, glucose, troponin when ischaemia is possible.
• 24 to 48 hour ambulatory ECG to quantify burden (percentage of total beats), morphology, couplets, runs and exertional behaviour.
• Echocardiography in all with frequent ectopics (above 1000 per day), symptoms, or abnormal ECG. Exercise ECG to assess the response to exertion.
• Cardiac magnetic resonance imaging in selected patients (burden above 10 percent, family history, abnormal echo, suspected arrhythmogenic or inflammatory disease).
• Differentials: premature atrial contractions with aberrant conduction, ventricular tachycardia, atrial fibrillation with aberrancy, bundle branch block.

Low burden, structurally normal heart, no red flags

• Reassure; no treatment needed.
• Avoid caffeine, alcohol, nicotine and stimulants; manage anxiety, sleep and stress; correct potassium and magnesium (target potassium 4.0 to 5.0 mmol/L, magnesium above 0.8 mmol/L).
• Review sympathomimetic drugs.

Symptomatic (bothersome palpitations)

• Bisoprolol 1.25 to 5 mg orally once daily (up to 10 mg), or metoprolol 25 to 50 mg orally twice daily, or propranolol 10 to 40 mg orally two or three times daily. Contraindications: asthma, severe bradycardia, heart block, decompensated heart failure.
• Verapamil modified release 120 to 240 mg orally daily as an alternative in the absence of heart failure or conduction disease.
• Review at 4 to 6 weeks.

High burden, ectopy with cardiomyopathy or heart disease (specialist)

• Catheter ablation is first line for high burden (above 10 to 15 percent) with symptoms or reduced ejection fraction.
• Antiarrhythmic drugs such as flecainide (contraindicated in structural heart disease or after myocardial infarction) or amiodarone under cardiology direction.
• Treat heart failure and ischaemia as indicated.

Special groups

• Pregnancy: usually benign; assess with ECG and echocardiography; use beta blockers cautiously after specialist advice.
• Athletes: pre-participation assessment, advice on risk if ectopy persists or worsens with exertion.
• Children: usually benign if abolished by exercise and heart is structurally normal.

Follow up and referral

• Urgent cardiology referral for syncope, exertional symptoms, runs of ventricular tachycardia, abnormal echocardiography, family history of sudden death, burden over 10 percent, or ectopics that increase with exercise.
• Otherwise review 6 to 12 months with repeat monitoring if symptoms change.