Sustained ventricular tachycardias associated with myotonic dystrophy

Abstract

275-279 (1991) Clin. Cardiol. 19, 674-677 (1996) Sustained Ventricular Tachycardias Second Department of Internal Medicine, Kansai Medical University, Osaka, Japan Summary: Patients with myotonic dystrophy are reported to have a higher frequency of sudden death than the general population. Although causes of sudden death in myotonic dystrophy are suggested to be due to conduction defects progressing, the HV interval cannot predict whether conduction system disease would develop or progress. We report two cases of myotonic dystrophy complicated with sustained monomorphic ventricular tachycardias (VT), which can cause sudden death. In Case No. 1, although the patient was treated successfully for sustained VT with verapamil in electrophysiologic studies, another sustained VT was confirmed 2 years later. In Case No. 2, the patient showed decreased left ventricular ejection fraction and late potentials, and induced sustained VT that was identical to clinically documented VT. Although VT is believed to be rare in patients with myotonic dystrophy, these cases suggest that VT is a possible cause of sudden death.

Age, conduction defects and restrictive lung disease independently predict cardiac events and death in myotonic dystrophy

“…Tachyarrhythmia also originates from fibrosis. Frequency of supraventricular arrhythmias has been evaluated between 10 and 30% of DM1 patients [16,17], while that of ventricular arrhythmias varied from 0 to 15% [18,19]. Bundle branch reentry could be explained by the conduction disturbances [20].…”

Relationships Among Electrophysiological Findings and Clinical Status, Heart Function, and Extent of DNA Mutation in Myotonic Dystrophy

“…2,18,19,[22][23][24]41,42 Some have been able to reproduce them with programmed ventricular stimulation. 19,[22][23][24]42 In this study, VA was induced in 18% of the patients who underwent programmed ventricular stimulation. These arrhythmias are generally considered nonspecific, especially when induced in asymptomatic patients.…”

“…2,5,7,9,18 -21 The mechanisms of sudden death most often proposed are AV conduction disorders and ventricular tachyarrhythmias. 2,7,18,19,[21][22][23][24][25][26] Therefore, invasive electrophysiological (EP) studies are often performed to estimate the individual risk of arrhythmias.…”

Broad QRS complex tachycardia in a patient with myotonic dystrophy (Steinert disease) (RCD code: V-4O)

“…RNA toxicity and splicing defects also play a role. Cardiac involvement occurs in 60-80% of patients and manifests as a progressive conduction disorder, atrial arrhythmias (atrial fibrillation or atrial flutter), ventricular arrhythmias and systolic dysfunction of left ventricle [1,[4][5][6][7]. The most common ECG changes are first degree atrioventricular (AV) block, intraventricular conduction delay (prolonged QRS complex) and prolongation of QT interval [4,5].…”