Ventricular couplets and arrhythmogenic right ventricular dysplasia
Ventricular couplets are the succession of two consecutive premature ventricular complexes. Beyond three or five consecutive premature ventricular complexes (depending on definition), it is common to use the term nonsustained ventricular tachycardia (if lasting less than 30 seconds).
Premature ventricular complexes in the setting of arrhythmogenic right ventricular dysplasia usually originate from the right ventricle (left delay) and are related to the location of the fibro-adipose infiltrates. They are shorter, wider, and often polymorphic and notched (different pathological foci, along with slowed and disorganized propagation within the ventricular myocardium), allowing to differentiate these asystoles from benign infundibular premature ventricular complexes. The response to catecholaminergic stimulation (exercise test, isoproterenol test) also differs with a significant increase in exercise irritability. Premature complexes are sometimes the first sign of the onset of this cardiomyopathy.