Ventricular trigeminy and benign PVC

ECG: Sinus rhythm (positive P wave in leads I, II and negative in aVR); normal PR (190 ms); narrow QRS with left anterior fascicular block (left axis with poor R wave progression from VI to V4); trigeminal premature ventricular complexes with alternation between two conductive QRS and a premature beat; probably benign, premature complexes from the right infundibulum: relatively narrow complexes, non-fragmented, with left delay (negative in V1 and positive in V6), transition in V4 (delayed, suggestive of a right ventricular origin) and infundibular “arrow-like” pattern (high amplitude with positive deflection in the inferior leads); retrograde atrial conduction (negative P’ waves inferiorly) with post-extrasystolic sinus pause;

Comments: The pattern found on this electrocardiogram corresponds to benign right ventricular premature complexes. They occur in patients without underlying cardiac disease or metabolic abnormalities and in the absence of a specific territory of predilection. Analysis reveals monomorphic ventricular premature beats, with a left delay pattern and a descending vertical axis, originating from the right ventricular outflow tract. They are typically tall, unnotched and moderately widened, with long and fixed coupling interval. They are at times very numerous, even bigeminal. In order to suggest their benign nature, the remainder of the electrocardiogram should also be within normal ranges.

Cardiac echocardiography, Holter-ECG are exercise test are part of the first-line assessment upon discovery of this type of premature complexes.

The contribution of cardiac echocardiography is important in this instance in order to eliminate an underlying cardiac disease. It should be emphasized, however, that the efficiency of echocardiography is somewhat limited for the diagnosis of early arrhythmogenic right ventricular dysplasia, the main differential diagnosis in the presence of premature complexes originating from the right ventricle.

The Holter-ECG allows assessing the degree of polymorphism, with benign premature ventricular complexes in a healthy heart being representing the overall majority of monomorphic cases. While some cases have shown the possible existence of two different morphologies in a healthy heart, the presence of a heart disease appears certain in instances of three or more morphologies.

The exercise test allows assessing the behavior of the premature ventricular complexes during a catecholaminergic activation. The effect of exercise on the benign premature ventricular complexes can be variable with possibility of reduction or exacerbation during exertion, or during recovery. An onset or increase upon exercise can, however, constitute a criterion of poor prognosis, and a major argument for the presence of an underlying cardiac disease (coronary desease, dysplasia).

After this first phase, in the absence of certainty, the assessment can be further investigated by performing pharmacological tests or ventricular late potential measurements. Cardiac MRI is currently the benchmark for right ventricular or left ventricular myocardial substrate analysis.

In subjects with an «apparently» healthy heart, the discovery of benign premature ventricular complexes is not associated with an increased risk of sudden death compared to that of the general population. They hence do not justify treatment or restriction of physical activity if the patient is asymptomatic. The objectives will be to reassure the patient and propose simple hygienic-dietary rules (decreasing stimulants such as coffee and alcohol). Drug treatment is only considered in patients who are symptomatic, patients with impaired left ventricular function due to possible rhythmic cardiomyopathy, or patients with premature ventricular complexes with severity criteria.

Beta-blocker or calcium channel blocker therapy is often proposed as a first-line treatment. In the event of failure, sodium channel inhibitors (flecainide, propafenone) are often effective and often lead to less adverse effects than the above-mentioned treatments (fatigue for example). However, they can only be prescribed after formal exclusion of any structural heart disease. Indeed, the CAST study demonstrated that in patients with heart disease, anti-arrhythmic class Ic treatment allowed to “clean” the Holter-ECG by decreasing the number of premature ventricular complexes at the cost of a deleterious paradoxical effect of increased mortality in the treated group.

When the premature ventricular complexes are numerous, monomorphic and generate symptoms, radiofrequency ablation is an interesting option since it allows treating the problem in a definitive manner.

Take-home message: Benign right ventricular premature beats occurring in a healthy heart, are monomorphic, tall, unnotched and very little widened, with a long and fixed coupling interval, a left delay pattern and a descending vertical axis originating from the right ventricular outflow tract. The remainder of the electrocardiogram should also be within normal ranges without signs of arrhythmogenic right ventricular dysplasia.