Defibrillation Threshold Testing and Long-term Follow-up in Chagas Disease.

Area of Science:

• Cardiology
• Electrophysiology
• Chagas Disease Research

Background:

• Sudden cardiac death is a primary cause of mortality in chronic Chagas cardiomyopathy (CCC).
• Implantable cardioverter-defibrillators (ICDs) are considered for CCC patients, often with high defibrillation threshold (DFT) values, suggesting a need for defibrillator threshold testing (DTT).

Purpose of the Study:

• To evaluate the utility of DTT in CCC patients undergoing ICD implantation.
• To analyze the relationship between DTT, ICD performance, arrhythmic events, and long-term outcomes in CCC.

Main Methods:

• Retrospective analysis of 133 CCC patients who received an ICD, primarily for secondary prevention.
• Collection of demographic, clinical, laboratory, Rassi score, and DTT data.
• Statistical significance set at p < 0.05.

Main Results:

• No in-hospital deaths or ICD failures occurred during DTT.
• Higher baseline Rassi scores correlated with higher DTT values (p=0.007).
• Most ventricular tachycardia episodes resolved spontaneously or with antitachycardia pacing; ICD shocks were required in only 35% of cases.
• Over a mean follow-up of 1728 days, 43 deaths occurred, predominantly from heart failure progression and sepsis.

Conclusions:

• Routine DTT may not be necessary for CCC patients receiving ICDs for secondary prevention.
• Elevated DTT values appear infrequent in this population and may be associated with higher Rassi scores.