His Bundle Pacing via the Atrial Port of a Dual‐Chamber ICD: Programming Solution for Undersensing
Thai Duy Vo, Le Uyen Phuong Tran, Thi Van Khanh Nguyen, Ngoc Dung KieuABSTRACT
Background
His‐bundle pacing connected to the atrial port of a dual‐chamber ICD may lead to sensing failure and unsafe pacing.
Case Summary
A 67‐year‐old man with permanent atrial fibrillation, alternating rapid and slow ventricular rates despite medication, symptomatic pauses longer than 6s, and a dual chamber ICD (His lead in the RA port; DF4 lead in the RV port) presented with palpitations. ECG and 24‐hour Holter demonstrated intermittent His‐channel undersensing with pacing on the T‐wave peak. Interrogation showed small His electrograms followed by a prominent, constant ventricular far‐field signal on the atrial channel. We turned off far‐field protection after V‐sense, intentionally used the ventricular far‐field signal for sensing of His lead, and disabled related discrimination algorithms.
Conclusion
A dual‐chamber ICD with a His‐bundle pacing lead may be associated with complex programming challenges, and targeted reprogramming can avoid lead revision or reimplantation.