Sections View Full Chapter Figures Tables Videos Annotate Full Chapter Figures Tables Videos Supplementary Content + Download Section PDF Listen ++ For further information, see CMDT Part 10-35: Ventricular Premature Beats (Ventricular Extrasystoles) + Key Features Download Section PDF Listen +++ ++ Ventricular premature beats or PVCs are isolated beats typically originating from the outflow tract or His-Purkinje regions of ventricular tissue In most patients, the presence of PVCs is a benign finding; however, they may trigger ventricular tachycardia or ventricular fibrillation, especially in patients with underlying heart disease + Clinical Findings Download Section PDF Listen +++ ++ Patient may or may not sense the irregular beat Exercise generally abolishes premature beats in normal hearts, and the rhythm becomes regular Wide QRS complexes, differing in morphology from normal beats and usually not preceded by a P wave Fully compensatory pause (no change in PP interval) usually Bigeminy and trigeminy Arrhythmias in which every second or third beat is premature Confirm a reentry mechanism for the ectopic beat + Diagnosis Download Section PDF Listen +++ ++ Ambulatory ECG monitoring may reveal more frequent and complex ventricular premature beats than occur in a single routine ECG An echocardiogram should be performed when Holter monitoring has documented more than 10,000 PVCs per day + Treatment Download Section PDF Listen +++ ++ If no associated cardiac disease is present and if the ectopic beats are asymptomatic, no therapy is indicated Patients with mild symptoms or anxiety from palpitations can be reassured about the benign nature of this arrhythmia If ectopic beats are frequent, the following should be excluded: Electrolyte abnormalities (especially hypokalemia or hyperkalemia and hypomagnesemia) Hyperthyroidism Occult heart disease Pharmacologic treatment is indicated only for patients who are symptomatic or in whom cardiomyopathy develops (thought to be due to high burden of PVCs [generally > 10% of daily heart beats]) Beta-blockers or non-dihydropyridine calcium channel blockers are appropriate as first-line therapy Class I and III antiarrhythmic agents May be effective in reducing ventricular premature beats Poorly tolerated Can be proarrhythmic in up to 5% of patients Catheter ablation is a well-established therapy for symptomatic individuals Who do not respond to medication Whose burden of ectopic beats has resulted in a cardiomyopathy