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[Effect of amiodarone on signal-averaged and long-term ECG]
L Goedel-Meinen1, M Hofmann, G Schmidt
1Technische Universität München.
Insights
Long-term amiodarone therapy significantly increased QRS duration in patients with heart disease and ventricular arrhythmias. Signal-averaged ECG and Holter monitoring showed no direct correlation, despite a high amiodarone responder rate.
Area of Science:
- Cardiology
- Electrophysiology
- Pharmacology
Context:
- Patients with dilated cardiomyopathy or coronary heart disease and high-grade ventricular arrhythmias often have poor response to antiarrhythmic drugs.
- Amiodarone is a potent antiarrhythmic medication frequently used in refractory cases.
- Signal-averaged electrocardiography (SAECG) and Holter monitoring are non-invasive tools to assess cardiac electrical activity and arrhythmias.
Purpose:
- To investigate the long-term effects of amiodarone on signal-averaged ECG parameters.
- To correlate SAECG findings with simultaneous 24-hour Holter monitoring data.
- To evaluate the responder rate to amiodarone therapy in a specific patient cohort.
Summary:
- Long-term amiodarone therapy in 23 patients with heart disease and ventricular arrhythmias led to a significant increase in total filtered QRS duration (114 ms to 127 ms).
- The incidence of late potentials on SAECG remained stable, with a high overall responder rate (41-81%) observed.
- No significant correlation was found between SAECG parameters and 24-hour Holter monitoring results.
Impact:
- Demonstrates amiodarone's electrophysiological effects on QRS duration, suggesting potential proarrhythmic or protective influences.
- Highlights the limited correlation between SAECG and Holter monitoring in patients on amiodarone.
- Provides insights into amiodarone's efficacy and SAECG utility in managing complex ventricular arrhythmias.
Abstract:
This prospective study examined the influence of long-term amiodarone therapy on the parameters of the signal-averaged ECG and their relation to simultaneously derived Holter monitoring data. For this purpose, 23 patients with angiographically confirmed dilated cardiomyopathy or coronary heart disease and high-grade ventricular arrhythmias, in whom an average of four class I antiarrhythmic drugs had proven ineffective, were stabilized on amiodarone. Before the beginning of therapy, as well as after 2 months and, subsequently, every 3 months, a resting ECG, a signal-averaged ECG by Simson's method, and Holter monitoring were performed. Compared to the initial measurement, we found a significant increase in the duration of the total filtered QRS complex from an average of 114 +/- 24 ms to 127 +/- 35 ms, while the change in voltage did not reach the significance level. The incidence of late potentials remained largely constant under amiodarone; 10 patients showed a constant late potential, 12 patients had no late potential, and one patient with coronary heart disease developed a new late potential. In the long-term follow-up, we ascertained a relatively high responder rate under amiodarone between 41% and 81%. No relation could be detected between the results of the signal-averaged ECG and those of 24-h Holter monitoring.
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