Localized Right Precordial QRS Prolongation as the Basic ECG Finding in Arrhythmogenic Right Ventricular Dysplasia Cardiomyopathy

Background: Since the first description of arrhythmogenic right ventricular dysplasia (ARVD) in 1977 several attempts have been made to find the ideal diagnostic technique. Localized QRS prolongation in right precordial leads gained general interest in 1993, although the definition and value of this diagnostic criterion is not well established. Method: In different cohorts of patients (93 healthy volunteers, 84 patients with task‐force criteria of ARVD, 54 patients with dilated cardiomyopathy, and 16 patients with hypertrophic cardiomy‐opathy) QRS duration was measured in precordial leads in standard ECGs with a paper speed of 50 mm/s. Two different ECG algorithms were used to differentiate ARVD: (a) QRS duration in V1, V2, or V3 < 110 ms and (b) QRS duration in (V1 + V2 + V3)/(V4 + V5 + V6) < 1.2. The frequency of right precordial T wave inversions, incomplete and complete RBBB, and left ventricular hypertrophy was analyzed in addition. Results: The frequency of right precordial T inversions in ARVD was moderately high (64%), the frequency of incomplete RBBB (n = 2), complete RBBB (ri = 6), and left ventricular hypertrophy (n = 1) was low. A QRS duration 2 110 ms in right precordial leads was found in 80% with an overall specificity of 89%. The ECG feature of outstanding importance was a ratio of QRS duration in (V1 + V2 + V3)/(V4 + V5 + V6) == 1.2, which was present in 97% with a specificity of 100%. Conclusions: Localized right precordial QRS prolongation best defined as a QRS duratio ratio in (V1 + V2 + V3)/(V4 + V5 + V6) s 1.2 seems to be a sensitive and specific finding in ARVD even in cases with incomplete or complete RBBB and, at least, in one case with left ventricular hypertrophy. Other forms of cardiomyopathies with certain right ventricular involvement and a control group of healthy volunteers can be differentiated with outstanding safety.