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Signal-averaged electrocardiography in hypertrophic cardiomyopathy
T R Cripps1, P J Counihan, M P Frenneaux
1Department of Cardiological Sciences, St. George's Hospital Medical School, London, England.
Insights
The signal-averaged electrocardiogram (ECG) can help predict sudden cardiac death in hypertrophic cardiomyopathy patients. Abnormal ECG results were more common in patients, indicating potential electrical instability.
Area of Science:
- Cardiology
- Electrophysiology
Background:
- Hypertrophic cardiomyopathy (HCM) management aims to predict sudden cardiac death.
- The high gain signal-averaged electrocardiogram (ECG) is evaluated for its predictive value in HCM.
Purpose of the Study:
- To assess the utility of the signal-averaged ECG in identifying patients with hypertrophic cardiomyopathy at risk of sudden cardiac death.
Main Methods:
- 64 HCM patients and 50 controls underwent signal-averaged ECG.
- Association with nonsustained ventricular tachycardia (NSVT) and cardiac arrest history was analyzed.
Main Results:
- Abnormal signal-averaged ECG was significantly more frequent in HCM patients (20%) vs. controls (4%).
- Abnormalities correlated with NSVT (47-86%) and cardiac arrest history (3/4 patients).
- No association found with family history, syncope, symptoms, or LV wall thickness.
Conclusions:
- Signal-averaged ECG is a valuable tool for detecting electrical instability in HCM.
- It shows promise in identifying patients at higher risk for sudden cardiac death.
Abstract:
A major goal in the management of patients with hypertrophic cardiomyopathy is the prediction of sudden death. To evaluate the high gain signal-averaged electrocardiogram (ECG) in this setting, 64 patients with hypertrophic cardiomyopathy and 50 age- and gender-matched control subjects were studied. An abnormal signal-averaged ECG was more common in patients than in control subjects: 13 (20%) of 64 patients with hypertrophic cardiomyopathy had abnormalities compared with 2 (4%) of the 50 control subjects (p less than 0.001). There was a significant association between the presence of nonsustained ventricular tachycardia on 48 h ECG Holter monitoring and the presence of an abnormal signal-averaged ECG: 8 (47%) of the 17 patients with nonsustained ventricular tachycardia and 6 (86%) of 7 patients with more than three episodes of nonsustained ventricular tachycardia per 24 h had signal-averaged ECG abnormalities. There was no association between an abnormal signal-averaged ECG and a family history of premature sudden cardiac death, a history of syncope, symptomatic status, maximal left ventricular wall thickness, the presence of systolic anterior motion of the mitral valve or maximal rate of oxygen uptake on exercise. However, of four patients with a history of cardiac arrest, three had an abnormal signal-averaged ECG. Sensitivity was 50%; specificity was 93% and positive predictive accuracy was 77% for the signal-averaged ECG in detecting patients with electrical instability (defined as a history of cardiac arrest or the presence of nonsustained ventricular tachycardia, or both).(ABSTRACT TRUNCATED AT 250 WORDS)