Permanent Pacing in Patients with Recurrence of Symptoms and Relapse of Left Ventricular Obstruction at Midcavity Level after Alcohol Septal Ablation

Abstract

Treatment of symptom recurrence after initially successful alcohol septal ablation (ASA) in hypertrophic obstructive cardiomyopathy (HOCM) when accompanied by relapse of intracavitary left ventricular pressure gradient (LVG) is guided by the underlying mechanism. We describe our experience with permanent pacing in three patients with relapse of both LVG and symptoms 7 to 12 months after successful ASA. Even though pressure gradient recurrence was observed at midventricular level, we were able to achieve symptomatic improvement and LVG reduction after right ventricular apex pacing in all three cases. The effect on symptoms was long lasting—the 6-month followup echo-stress tests confirmed good exercise capacity and lack of provocable LVG. We found pacing to be a safe and effective treatment option in this clinical scenario. Based on our overall observations, we propose pacing as a niche treatment for patients with recurrence of LVG at midventricular level after ASA.

Late Complications after Alcohol Septal Ablation in a Patient with Hypertrophic Obstructive Cardiomyopathy

“…The recurrence of the pressure gradient after ASA was described in about 10% of cases in the first two years after the procedure. This complication may be explained by an incomplete scar formation, an irregular form of the scar with recovery of the periinfarct tissue-often hibernating myocardium, patchy instead of dense fibrosis, a non-proper location of the scar, an incomplete interventricular septum remodeling or a midventricular migration of the obstruction [19]. In our patient, it is possible for the scarring to have migrated in the direction of the AV node, and also for a part of the hibernating myocardium near the infarction zone to have recovered instead of developing necrosis with subsequent fibrosis and scar.…”

“…Implantation of a dual chamber pacemaker programmed with a short AV delay, combined with the maximal tolerated betablocker therapy solved the problem in the acute phase. Right ventricular apical pacing with a short AV delay is known as a good method to reduce the LVOT pressure gradient by inducing interventricular septum contraction dyssynchrony [1], but for some reasons, the studies show that it is less efficient alone, compared with the other two septal reduction therapies [1,19]. On the other hand, many authors recommend the use of the dual chamber pacemaker when one of these techniques fails, instead of repeating the procedure [5].…”

“…Lee et al reported a patient with significant pressure gradient recurrence seven years after the procedure, for which they repeated SAA and implanted a permanent pacemaker, as the procedure resulted in an acute complete AV block [20]. Velchev et al reported three patients with symptomatic midventricular obstruction, several months after the procedure of ASA, which was properly resolved by pacemaker implantation [19].…”

Permanent Pacing in a Patient with Left Ventricular Mid-Cavity Obstruction and Apical Aneurysm

“…13) Velchev et al reported the effectiveness of permanent pacing in patients with LV mid-cavity obstruction after alcohol septal ablation for LV outflow tract obstruction. 14) The mechanism of LV mid-cavity obstruction improvement in the absence of subaortic obstruction by SAM may be associated with the dyssynchronous contraction of the septum and posterior wall caused by pacing of the RV apex. 15) Because pacing is relatively noninvasive compared to surgical therapy, permanent pacing is a good option, especially for the elderly patients with LV mid-cavity obstruction and apical aneurysm.…”