Angiographic and electrophysiologic substrates of ventricular tachycardia in chronic chagasic myocarditis

Sudden death in Chagas' disease

“…According to the authors, the high percentage of torsade de pointes may be explained by the coexistence in Chagas' heart disease of multiple abnormalities, such as disorders of conduction, sinus based on observations, hypotheses, or inference 38,39 . Nevertheless, the essentially arrhythmogenic nature of chronic chagasic heart disease, which is mainly characterized by a high density and complexity of ventricular arrhythmias [40][41][42][43] , its fibrotic character, with akinetic or dyskinetic areas intermingled with preserved myocardial fibers 44,45 , and the reentrant mechanism of sustained ventricular tachycardia in a large number of cases on programmed ventricular stimulation [46][47][48][49] , strongly suggest that ventricular fibrillation constitutes the terminal event in most cases of sudden death in Chagas' disease. Less frequently, a bradyarrhythmia ( sinus (12) CS-cardiac silhouette; CS-cerebral stroke; FC-functional class; CD-Chagas' disease; ECG -electrocardiogram; VEs -ventricular extrasystoles; H -Holter; HFheart failure; CHF-congestive heart failure; mod -moderate; SD -sudden death; NR -not reported; P -patients; XR -chest X-ray; NSVT -nonsustained ventricular tachycardia.…”

“…It is worth noting that reproduction of monomorphic sustained ventricular tachycardia in chronic Chagas' heart disease has been reported in 63 to 95% of the cases [46][47][48][49] . Reentry has been considered the major electrophysiological mechanism, and focal areas of fibrosis or With the inclusion of additional risk predictors, the chagasic population becomes more selective and the risk of sudden death increases gradually.…”

Chagas' heart disease

“…Although definitive evidence of benefit is lacking, this procedure is also useful in two other subsets: survivors of sudden cardiac death; and those with sustained ventricular tachycardia to determine prognosis and to select the appropriate antiarrhythmic therapy (medical, surgical, or implantable device) 70,71 .…”

“…On clinical grounds, myocardial perfusion abnormalities have been documented by several independent reports using various types of myocardial perfusion markers (thallium-201, 99m Tc-Sestamibi, 99m Tc-microspheres), during effort and at rest, in chagasic patients with angiographically normal coronary arteries 8,47,70,[136][137][138][139][140][141][142] . Reversible, fixed and paradoxical perfusion defects, in areas with normal contraction, were found in a large proportion of patients even in the absence of other signs of myocardial involvement.…”

Ventricular arrhythmias in Chagas disease

“…The electrophysiological mechanism of VT in Chagas disease is reentry (63) , and the main goal of ablation is to identify critical isthmuses that maintain tachycardia and to destroy small portions of the myocardium, thereby preventing the electrical impulses that perpetuate arrhythmias (Figure 1).…”