AV Node Ablation and DDD Pacing in Hypertrophic Obstructive Cardiomyopathy

Clinical improvement with dual-chamber pacing has largely been reported in patients with drug-resistant hypertrophic obstructive cardiomyopathy (HOLM)1–5. This clinical improvement is mainly related to the ability to bypass the normal atrioventricular (AV) conduction system in order to obtain a complete and permanent right ventricular capture. Some patients, however, experience only minor benefits with DDD pacing. This lack of improvement is probably due to incomplete right ventricular capture and/or deleterious effects of short AV delays on AV synchrony and left ventricular filling. Instrumental AV node modulation or ablation may be indicated in this subgroup of patients. Another indication of AV node ablation in HOCM is the occurrence of atrial fibrillation in order to restore adequate and permanent right ventricular capture. This chapter will focus on the rationale, the technical problems and results of AV node ablation in HOCM.