Long-term follow-up of patients with myotonic dystrophy: an electrocardiogram every year is not necessary.

A high risk of arrhythmias was reported in myotonic dystrophy (MD). The purpose of the study was to evaluate the value of non-invasive and invasive investigations for the arrhythmias detection and when to repeat the investigations. 129 patients, mean age 41 ± 14 years, with MD, were asymptomatic, except 4. Electrocardiogram (ECG), left ventricular ejection fraction determination, Holter monitoring, signal-averaged ECG, electrophysiological study (51) were obtained and repeated each year in patients without conduction abnormalities. Electrocardiogram and Holter monitoring were normal in 72 and 89 patients, respectively. Standard deviation of the mean RR intervals (SDNN) was <100 ms in 30 patients. Late potentials were present in 32 patients, without ventricular tachycardia (VT) correlation. Ejection fraction was normal in all but six patients (60±10.5%). HV interval was prolonged in 0 of 8 patients with normal ECG, 1 of 9 with isolated first degree atrioventricular block, 9 of 16 with hemiblock, and 10 of 15 with bundle branch block. Atrial fibrillation (AF) was induced in 22 patients, non-sustained VT in 6 patients, and sick sinus syndrome noted in 10 patients. The mean time for the ECG change was 5±1 years. After 10±7.5 years, AF occurred in 15 patients; 12 patients died. Multivariate analysis indicated that both AF at ECG and SDNN lower than 100 ms were independent predictors of death. HV increase was noted only in patients with abnormal ECG. The most frequent arrhythmia was AF and was associated with a high risk of death. The repetition of ECG every year is probably not useful.

Are the results of electrophysiological study different in patients with a pre-excitation syndrome, with and without syncope?

AIMS: Syncope in Wolff-Parkinson-White (WPW) syndrome may reveal an arrhythmic event or is not WPW syndrome related. The aim of the study is to evaluate the results of electrophysiological study in WPW syndrome according to the presence or not of syncope and the possible causes of syncope. METHODS AND RESULTS: Among 518 consecutive patients with diagnosis of WPW syndrome, 71 patients, mean age 34.5 +/- 17, presented syncope. Transoesophageal electrophysiological study in control state and after isoproterenol infusion was performed in the out-patient clinic. Atrioventricular re-entrant tachycardia (AVRT) was more frequently induced than in asymptomatic patients (n = 38, 53.5%, P < 0.01), less frequently than in those with tachycardia; atrial fibrillation (AF) and/or antidromic tachycardia (ATD) was induced in 28 patients (39%) more frequently (P < 0.05) than in asymptomatic patients or those with tachycardia. The incidence of high-risk form [rapid conduction over accessory pathway (AP) and AF or ATD induction] was higher in syncope group (n = 18, 25%, P < 0.001) than in asymptomatic subjects (8%) or those with tachycardias (7.5%). Maximal rate conducted over AP was similar in patients with and without syncope, and higher in patients with spontaneous AF, but without syncope. Results were not age-related. CONCLUSION: Tachycardia inducibility was higher in patients with syncope than in the asymptomatic group. The incidence of malignant WPW syndrome was higher in patients with syncope than in asymptomatic or symptomatic population, but the maximal rate conducted over AP was not higher and another mechanism could be also implicated in the mechanism of syncope.