EP News: Case Reports

Risks of pacemaker-mediated cardiomyopathy and mechanical/electrical dyssynchrony have driven innovation and research into physiologic His bundle pacing (HBP) or left bundle area pacing tools and techniques. Physiologic pacing approaches in pediatric patients requires research as to its long-term efficacy, risks, and outcomes. von Alvensleben et al (https://doi.org/10.1016/j.hrcr.2022.12.010) shared 2 pediatric patients in whom multiple imaging modalities (fluoroscopy, 3-dimensional [3D] electroanatomic mapping and 3D transesophageal echocardiography [TEE]) were used to guide HBP. The first patient was a 14-year-old adolescent boy with L-transposition of the great arteries (L-TGA) and late-onset complete heart block. Electroanatomic mapping revealed a typical superiorly oriented His bundle electrogram consistent with L-TGA. The capture thresholds was 0.5 V @ 1.0 ms with R waves of 9.8 mV. TEE was used to also ensure normal valve function and lead location regarding valve closure. The second patient was a 16-year-old adolescent boy with congenital complete heart block associated with left ventricular dilation and exercise intolerance. His procedure was guided by electroanatomic mapping and 3D echocardiography to ensure normal valve function and lead location during valve closure. His capture was confirmed with a threshold of 2.0 V @ 1.0 ms with R waves of 2.1 mV. There was nonselective capture with a threshold of 0.75 V @ 1.0 ms. The second patient has persistently high thresholds, and nonselective HBP was used to improve battery longevity. Both HBP and left bundle area pacing require much more study before routine application in pediatric patients, particularly with expected higher thresholds compared to other techniques with HBP.