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Is it possible to identify infrahissian cardiac conduction abnormalities in myotonic dystrophy by non-invasive
D Babuty1, L Fauchier, D Tena-Carbi
1Department of Cardiology B, Faculté de Médecine Tours, Hôpital Trousseau, 37044 Tours Cedex, France.
Insights
Infrahissian conduction abnormalities are common in myotonic dystrophy. Signal-averaged electrocardiography effectively identifies these issues, correlating with genetic mutation size and QRS duration.
Area of Science:
- Cardiology
- Genetics
- Neurology
Background:
- Myotonic dystrophy is a multisystem disorder with frequent cardiac involvement.
- Intracardiac conduction abnormalities contribute to morbidity and mortality in these patients.
Purpose of the Study:
- To identify intracardiac conduction abnormalities in myotonic dystrophy patients.
- To correlate clinical, electrocardiographic (ECG), and genetic features with conduction defects.
Main Methods:
- 39 myotonic dystrophy patients underwent clinical evaluation, genetic testing, resting and 24-hour ambulatory ECG, signal-averaged ECG, and electrophysiological studies.
- Analysis focused on identifying prolonged HV intervals and correlating them with clinical and genetic data.
Main Results:
- Over half of patients (53.8%) exhibited prolonged HV intervals, indicating infrahissian conduction abnormalities.
- Larger DNA mutation size correlated with prolonged HV intervals.
- Signal-averaged ECG parameters, specifically QRS duration (QRSD) and low-amplitude signal duration (LAS 40), were significantly prolonged in patients with abnormal HV intervals.
Conclusions:
- Infrahissian conduction abnormalities are prevalent in myotonic dystrophy.
- Signal-averaged ECG, particularly the combination of QRSD ≥ 100 ms and LAS 40 ≥ 36 ms, is a sensitive and specific tool for detecting these abnormalities.
Objective:
To identify intracardiac conduction abnormalities in patients with myotonic dystrophy from their clinical, ECG, and genetic features.
Methods:
39 consecutive patients (mean (SD) age 42. 9 (12.1) years; 16 female, 23 male) underwent clinical examination, genetic studies, resting and 24 hour ambulatory ECG, signal averaged ECG, and electrophysiological studies.
Results:
23 patients suffered from cardiac symptoms, 23 had one or more cardiac conduction abnormality on resting ECG, one had sinus deficiency, and 21 (53.8%) had prolonged HV intervals. No correlation was found between the severity of the neurological symptoms, onset of disease, cardiac conduction abnormalities on ECG, and the intracardiac conduction abnormalities on electrophysiological study. The size of the DNA mutation was longer in the abnormal HV interval group than in the normal HV interval group (3.5 (1.8) v 2.2 (1.0) kb, p < 0.02). Signal averaged ECG parameters (total QRS duration (QRSD) and duration of low amplitude signals /= 100 ms with LAS 40 >/= 36 ms identified patients with an abnormal HV interval with good sensitivity (80%) and specificity (83. 3%).
Conclusions:
Infrahissian conduction abnormalities are common in myotonic dystrophy and can be identified using signal averaged electrocardiography.