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Angiographic and electrophysiologic substrates of ventricular tachycardia in chronic Chagasic myocarditis
A A de Paola1, L N Horowitz, M H Miyamoto
1Division of Clinical Cardiac Electrophysiology, Hospital São Paulo, Escola Paulista de Medicina, Brazil.
Insights
Chronic Chagasic myocarditis frequently leads to inducible ventricular tachycardia (VT). Conduction disturbances and left ventricular aneurysms are associated with sustained VT in these patients.
Area of Science:
- Cardiology
- Electrophysiology
- Infectious Diseases
Background:
- Chronic Chagasic myocarditis is a significant cause of heart disease.
- Ventricular tachycardia (VT) is a serious complication in affected patients.
Purpose of the Study:
- To assess the inducibility of VT in patients with chronic Chagasic myocarditis.
- To identify factors associated with sustained VT.
Main Methods:
- Clinical evaluation and 24-hour Holter monitoring.
- Left ventricular angiography and electrophysiologic testing with programmed ventricular stimulation.
- Analysis of electrocardiographic conduction disturbances and left ventricular aneurysms.
Main Results:
- VT was inducible in 81% of patients with sustained VT and 52% with nonsustained VT.
- Conduction disturbances were observed in 94% of sustained VT patients versus 63% of nonsustained VT patients.
- Left ventricular aneurysms were present in 31% of sustained VT patients but none of the nonsustained VT patients.
Conclusions:
- Ventricular tachycardia is frequently inducible in chronic Chagasic myocarditis.
- Conduction disturbances and left ventricular aneurysms are associated with sustained VT in this population.
Abstract:
Forty-three consecutive symptomatic patients with chronic Chagasic myocarditis and ventricular tachycardia (VT) underwent clinical evaluation, 24-hour Holter monitoring, left ventricular angiography and electrophysiologic testing including programmed ventricular stimulation at 3 drive cycle lengths at 2 sites in the right ventricle. The mean ejection fraction was 42 +/- 10%. Sixteen patients had clinical sustained VT and 27 nonsustained VT. VT was reproducibly initiated in 13 of 16 (81%) patients with sustained VT and in 14 of 27 (52%) patients with nonsustained VT. Electrocardiographic conduction disturbances were seen in 15 of 16 (94%) patients with sustained VT and in 17 of 27 (63%) patients with nonsustained VT (p less than 0.05). Five of 16 (31%) sustained VT and none of nonsustained VT patients had left ventricular aneurysms (p less than 0.05). These data indicate that VT is frequently inducible in patients with sustained VT and nonsustained VT and chronic Chagasic myocarditis. An association appears to be present between conduction disturbances on the electrocardiogram, left ventricular aneurysms and development of sustained ventricular arrhythmias.