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Objective-To study diVerences between repetitive monomorphic ventricular tachycardia (RMVT) of right ventricular origin, and ventricular tachycardia in arrhythmogenic right ventricular dysplasia (ARVD). Patients-Consecutive groups with RMVT (n = 15) or ARVD (n = 12), comparable for age and function. Methods-Analysis of baseline, tachycardia, and signal averaged ECGs, clinical data, and right endomyocardial biopsies. Pathological findings were related to regional depolarisation (QRS width) and repolarisation (QT interval, QT dispersion). Results-There was no diVerence in age, ejection fraction, QRS width in leads I, V1, and V6, and QT indices. During ventricular tachycardia, more patients with ARVD had a QS wave in V1 (p < 0.05). There were significant diVerences for unfiltered QRS, filtered QRS, low amplitude signal duration, and the root mean square voltage content. In the absence of bundle branch block, diVerences became nonsignificant for unfiltered and filtered QRS duration. Mean (SD) percentage of biopsy surface diVered between RMVT and ARVD: normal myocytes (74(3.4)% v 64.5(9.3)%; p < 0.05); fibrosis (3(1.7)% v 8.9(5.2)%; p < 0.05). When all patients were included, there were significant correlations between fibrosis and age (r = 0.6761), and fibrosis and QRS width (r = 0.5524 for lead I; r = 0.5254 for lead V1; and r = 0.6017 for lead V6). Conclusions-The ECG during tachycardia and signal averaging are helpful in discriminating between ARVD and RMVT patients. There are diVerences in the proportions of normal myocytes and fibrosis. The QRS duration is correlated with the amount of fibrous tissue in patients with ventricular tachycardia of right ventricular origin. (Heart 1998;79:388-393) Keywords: arrhythmogenic right ventricular dysplasia; electrocardiography; endomyocardial biopsy; ventricular arrhythmias It is not always easy to diVerentiate idiopathic or repetitive monomorphic ventricular tachycardia (RMVT) of right ventricular origin from tachycardia in early stages of arrhythmogenic right ventricular dysplasia (ARVD).1 From a clinical point of view, the major points helpful in the recognition of RMVT remain the absence of overt cardiomyopathy and myocardial dysfunction.2 A good tolerance of the arrhythmia (which does not exclude symptoms) is also suggestive of RMVT.3 RMVT is thought to have a good long term prognosis. Unfortunately, patients aVected by ARVD in the early stages often also have a normal heart at routine examination and even after full noninvasive and invasive investigations the diagnosis is not always definite. This is embarrassing, as some patients with ARVD may experience palpitations due to minor ventricular arrhythmias, while others may die suddenly. 4 Furthermore, ARVD can progress to left ventricular disease, making confusion with other pathology possible (for example, dilated cardiomyopathy). 5To improve our understanding of the two diseases, we analysed clinical data, routine ECG data, ECG data during ventricular tachycardia, QT measurements, and signal averaged elec...

Changes in HR, SD, and an increased number of PACs herald AF from at least 30 min before onset, more pronounced in accelerators. Spectral HRV parameters are not useful to foresee AF onset. This has possible implications for device therapy.

P wave signal averaging was performed in 91 consecutive patients undergoing coronary artery bypass grafting to detect patients at risk of postoperative atrial fibrillation (AF). Sixteen patients (17.5%) developed AF after surgery. The P wave duration on the signal-averaged electrocardiogram (ECG) and on surface ECG was prolonged in AF patients compared to others (respectively 141 ± 12 vs. 132 ± 12 ms and 124 ± 9 vs. 113 ± 9 ms). The root mean square voltages (RMS) of the total P wave were not different between the two groups; the RMS of the late portion of the P wave (late RMS) was significantly higher (0.25 ± 0.15 vs. 0.17 ± 0.10 µV) and the RMS of the first 110 ms of the P wave (early RMS) significantly lower (0.88 ± 0.28 vs. 1.09 ± 0.33 µV) in AF. The late/early RMS ratio was different (0.29 ± 0.16 vs. 0.17 ± 0.11). In a multivariate analysis only age and the late/early RMS ratio were predictive for AF.

While it is assumed that the normal heart does not predispose to serious arrhythmias, several conditions are now being recognized as being associated with short-lasting ventricular arrhythmias. It also becomes clear that idiopathic VT (or repetitive monomorphic VT) sometimes exists on the background of a compromised heart. Whether this dysfunction is due to the arrhythmia or vice versa is not evident. Finally, VF occurs in patients who, at a first glance, have no apparent heart disease, and it is then called idiopathic VF. These complex electrical abnormalities probably reflect disorders, which often are genetically determined. Recognition of these syndromes, often characterized by abnormal repolarization or a disturbed autonomic function is possible if appropriate techniques are used.

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