Right ventricular cardiomyopathy: diffuse dilatation, focal dysplasia or biventricular disease

Abstract

Non-coronary ventricular tachyarrhythmias originating from the right ventricle are frequent events associated in many cases with structural and functional abnormalities of the right ventricle. Primary right ventricular affections such as arrhythmogenic right ventricular dysplasia and secondary right ventricular involvements such as in dilated cardiomyopathy must be distinguished. The value of conventional diagnostic procedures is undetermined. A total of 73 patients (41 males, mean age 40.6±11.4 years) with left bundle branch block ventricular arrhythmias and angiographic aspects of right ventricular outpouchings or aneurysms were divided into three groups: Group 1: diffuse right ventricular dilatation without left ventricular affection, Group 2: focal right ventricular abnormalities (dysplasia) Group 3: biventricular disease. The results of standard ECG, angiography and programmed ventricular stimulation were analysed retrospectively. Clinical monomorphic ventricular tachycardia was more often in diffuse dilatation (82%) and focal dysplasia (57%). In these two groups programmed ventricular stimulation was able to induce clinical tachycardias at a high degree (57–82%). In cases of biventricular disease cardiac arrest as the primary event without inducibility of monomorphic ventricular tachycardia was the predominant feature (44%). Standard ECG disclosed localised right precordial QRS prolongation in `normal' QRS morphology, incomplete and complete right bundle branch block in 66 patients in all three subgroups. Other ECG findings such as left ventricular hypertrophy in four patients with heart failure and single premature beats and left bundle branch block in a patient with rapid ventricular tachycardia and ventricular fibrillation was found only in group 3 supposed to be the most heterogeneous group. In summary, angiographic classification used in this study demonstrates different morphological aspects of right ventricular cardiomyopathy with ventricular tachyarrhythmias as the major clinical aspect. High risk patients with diffuse dilatation or biventricular disease can be identified. Only patients with the angiographic aspect of focal dysplasia seem to be possible candidates for catheter ablation techniques.

Introduction

Right ventricular cardiomyopathy has gained increasing interest since the first description of arrhythmogenic right ventricular dysplasia [1]. Right ventricular abnormalities are frequent in dilated cardiomyopathy and cardiac sarcoidosis 2, 3. Arrhythmogenic right ventricular dysplasia and Uhl's anomaly [4]represent the type of primary right ventricular disease. Most forms of right ventricular cardiomyopathies lead to the clinical presentation of ventricular arrhythmias. Other cases present with symptoms of heart failure. In some cases of arrhythmogenic right ventricular dysplasia with predominant lipomatosis the same histological findings are present in the left ventricle [5], however, in other cases left ventricular involvement is probably due to superimposed myocarditis [6].

Lipomatosis cordis [7]can also lead to the typical histological picture of biventricular dysplasia with ventricular arrhythmias.

The phenotypic variety of right ventricular cardiomyopathy has led to some confusions. Terms such as right ventricular dilated cardiomyopathy [8], arrhythmogenic right ventricular dysplasia [9], and arrhythmogenic right ventricular cardiomyopathy [10]have been used to describe different aspects of right (and left) ventricular disease. However, the question remains as to whether it is possible to define the form of underlying right ventricular cardiomyopathy by angiographic classification, clinical aspects, standard ECG and electrophysiology.