Baroreflex Activation Therapy and Subcutaneous ICDs: A Manageable Electrical Mismatch

Baroreflex activation therapy (BAT) improves symptoms and quality of life in patients with heart failure with reduced ejection fraction, while subcutaneous implantable cardioverter-defibrillators (S-ICDs) protect against sudden cardiac death without intravascular hardware. Unipolar BAT stimulation poses a theoretical risk of interference with S-ICD sensing.

A 52-year-old man with heart failure with reduced ejection fraction, end-stage renal disease on dialysis, and an S-ICD underwent BAT implantation. During routine hemodialysis, he experienced ventricular fibrillation arrest that the S-ICD failed to detect, misclassifying the rhythm as atrial fibrillation. Device interrogation revealed high-frequency artifact corresponding to BAT output at 6 mA. BAT output was reduced to 1 mA, and S-ICD vectors were reprogrammed. Three months later, the S-ICD appropriately detected and terminated sustained monomorphic ventricular tachycardia.

BAT-S-ICD interference can result in arrhythmia undersensing. With increasing adoption of both therapies, structured compatibility testing, individualized programming, and multidisciplinary follow-up are critical.

Concurrent S-ICD and BAT use is feasible with careful testing and output optimization.