Ventricular tachycardia during exercise testing as a predictor of sudden death in patients with chronic chagasic cardiomyopathy and ventricular arrhythmias.

Abstract

Objective-To verify the prognostic value of exercise induced ventricular arrhythmias in patients with chagasic cardiomyopathy. Methods-69 consecutive patients (37 male, 32 female; age range 21-67 years) with chronic chagasic cardiomyopathy and ventricular arrhythmias (more than 10 ventricular premature complexes per hour) were evaluated during treadmill exercise testing, using the Bruce protocol. Protocol end points were peak heart rate or presence of sustained ventricular tachycardia. Main outcome measure-Sudden cardiac death. Results-44 patients (group I) developed ventricular tachycardia during exercise testing (five sustained and 39 non-sustained), and 25 did not (group II). After a follow up of 24 (SD 15) months sudden cardiac death occurred in seven patients in group I and in none in group II (P < 0.05). Conclusions-Ventricular tachycardia on exercise testing is significantly associated with sudden cardiac death in patients with chronic chagasic cardiomyopathy and ventricular arrhythmias. (Br Heart3' 1995;74:293-295)

Chagas' heart disease

“…Established or developing heart failure was a strong predictor of mortality, but, quite surprisingly, not aborted sudden death or the presence of sustained ventricular tachycardia 8 . These results conflict with the evidence that ventricular tachycardia detected during exercise testing is a marker of increased risk of sudden death in 44 chagasic patients followed for a mean period of two years 41 . This discrepancy is likely related to the fact that both studies are fraught with the same limitation of small numbers and a relatively short follow-up.…”

“…However, this test may constitute an alternative to ambulatory monitoring for the detection of exercise-related ventricular dysrhythmia 41,65 . A deficient chronotropic response can also be detected in chagasic patients, due to parasympathetic denervation of the sinus node 66,67 .…”

“…Thus, no adequate identification of cardiac involvement is usually provided in most of the rural-based studies [27][28][29][30][31][32][33][34][35][36][37] . Conversely, in hospital-based studies the heart disease is usually well characterized, but their results can not be extended to the whole spectrum of the chagasic population 8,[38][39][40][41] . Furthermore, because of the rather protracted course of heart involvement, from the acute myocarditis to the end-stage heart failure or malignant arrhythmia, no prospective studies encompassing the whole span of the disease in sizable populations are available 7,42 .…”

“…Several observational studies mainly conducted in endemic areas in Brazil, Argentina and Venezuela, since the early 1940s disclosed the natural history of Chagas' heart disease 7,[26][27][28][29][30][31][32][33][34][35][36][37][38][39][40][41][42][43] .…”

“…Very few studies have described case-control populations of chagasic and non-chagasic people. Other observational investigations focused on the description and follow-up of hospital-based cohorts of chagasic patients 7,[38][39][40][41] .…”