Introduction: Cardiac Resynchronization Therapy (CRT) has resulted an effective treatment for heart failure (HF) in patients with systolic dysfunction and ventricular dyssynchrony. In Chagas disease (CD)however this teraphy dont have large studies and the records in the literature are limited to a few series cases .We present a cohort of 82 patients (pts) of our experience with CRT in CD.
Methods: Between January 1992 and May 2012, 112 pts with CD and HF were submitted to CRT. Clinical records of 82 pts were analyzed retrospectively: 47 males (57.3%) and 35 females (42.6%) with a mean age of 54.25 years. Preoperatively, 27 pts (33%) were in NYHA class IV, 50 pts (61%) in NYHA III, 5 pts (6%) in NYHA II and none in NYHA I. All pts had intraventricular conduction disturbances: 50 pts (60.9%) with Right Bundle Branch Block (RBBB) + Left Anterior Fascicular Block (LAFB) and 32 pts (39%) with Left Bundle Branch Block (LBBB). Mean width of QRS complex was 186.1±31.31 ms. The echocardiogram showed important systolic dysfunction in all pts with mean Ejection Fraction (EF) of 27.71±10.44%. All 82 pts were submitted to CRT, 69 pts (84.14%) received a CRT pacemaker (CRT-P) and 13 pts (15%) a CRT defibrillator (CRT-D). The statistical analysis of data was performed using the program SPSS Statistics v. 20.0. In mean follow-up of 24.5±39.7 months we observed clinical benefits in 80% of pts. 19 pts (23%) were in NYHA class I, 47 pts (57%) in NYHA class II, and 16 (20%) remained in NYHA class III or IV (p < 0.0001). There was a significant reduction of the mean width of QRS complex after CRT (110.55±9.72 ms, p<0.0001). The PR interval decreased from 202.9 ms to 133.45 ms (p<0.0001). The number of hospitalizations also showed a significant reduction from 2.84 to 0.89 post intervention (p<0.0001).
Results: In terms of medications, we found a significant reduction in the average doses of diuretics (from 60mg before to 35mg after surgery, p<0.0001) and a significant increase in the average doses of Beta Blockers (from 22.2 mg to 35 mg after surgery, p<0.0001). There was also a considerable improvement in EF from 27.71±10.44% pre implantation to 35.77±9.72% post treatment (p< 0.0001). We observed a total of 29 (35.36%) deaths, all in patients with CRT-P. 25 deaths (86.2%) were from cardiac causes and 13 (52%) were sudden. There no episodes of sudden death in the CRTD arm, but all patients in this arm had appropriate therapies for ventricular arrhytmias.
Conclusions: There was no difference in results among patients with LBBB and RBBB+LAFB. The position of the left ventricular lead and the distance between the left and righ leads show significative diference in the acute response to the theraphy.CRT proved to be useful in the treatment of refractory HF of CD in the cases studied. Considering the high mortality for sudden cardiac death, even in the group of good responders with CRT-P, we should always consider the indication of CRT-D for those pts.