Relationship Between Procedural Right Bundle Branch Block and 1-Year Outcome After Alcohol Septal Ablation for
Junya Matsuda1, Hitoshi Takano2, Masaki Morooka2
1Division of Cardiovascular Intensive Care, Nippon Medical School Hospital.
Insights
Alcohol septal ablation (ASA) for hypertrophic obstructive cardiomyopathy (HOCM) often causes right bundle branch block (RBBB). This study found that procedural RBBB does not worsen outcomes and may reduce repeat procedures.
Area of Science:
- Cardiology
- Interventional Cardiology
- Cardiac Electrophysiology
Background:
- Alcohol septal ablation (ASA) is a treatment for drug-refractory symptomatic hypertrophic obstructive cardiomyopathy (HOCM).
- Right bundle branch block (RBBB) frequently develops during ASA due to septal artery supply to the right bundle branch.
- The clinical significance of procedural RBBB in HOCM patients undergoing ASA is not well-established.
Purpose of the Study:
- To investigate the clinical significance and outcomes associated with new-onset right bundle branch block (RBBB) following alcohol septal ablation (ASA) in patients with hypertrophic obstructive cardiomyopathy (HOCM).
Main Methods:
- Retrospective review of 144 patients with HOCM who underwent ASA.
- Patients were categorized into two groups: those who developed RBBB during the procedure (n=95) and those who did not (n=49).
- Comparison of left ventricular pressure gradient (LVPG) reduction, conduction disturbances, pacemaker implantation rates, and need for repeat ASA between the groups.
Main Results:
- ASA significantly reduced LVPG in both RBBB and no-RBBB groups.
- Patients developing RBBB showed a significantly greater percentage reduction in LVPG at 1 year compared to the no-RBBB group.
- Procedural RBBB was not associated with increased pacemaker implantation but was linked to a reduced need for repeat ASA.
Conclusions:
- New-onset right bundle branch block (RBBB) during alcohol septal ablation (ASA) for hypertrophic obstructive cardiomyopathy (HOCM) is common.
- Procedural RBBB does not appear to have adverse clinical consequences.
- RBBB may be associated with improved long-term outcomes and reduced need for repeat procedures.
Background:
Alcohol septal ablation (ASA) is a treatment option in patients with drug-refractory symptomatic hypertrophic obstructive cardiomyopathy (HOCM). In many patients, right bundle branch block (RBBB) develops during ASA because septal branches supply the right bundle branch. However, the clinical significance of procedural RBBB is uncertain.
Methods And Results:
We retrospectively reviewed 184 consecutive patients with HOCM who underwent ASA. We excluded 40 patients with pre-existing RBBB (n=10), prior pacemaker implantation (n=15), mid-ventricular obstruction type (n=10), and those lost to follow-up (n=5), leaving 144 patients for analysis. Patients were divided into 2 groups according to the development (n=95) or not (n=49) of procedural RBBB. ASA conferred significant decreases in the left ventricular pressure gradient (LVPG) in both the RBBB and no-RBBB group (from 74±48 to 27±27 mmHg [P<0.001] and from 75±45 to 31±33 mmHg [P<0.001], respectively). None of the RBBB patients developed further conduction system disturbances. The percentage reduction in LVPG at 1 year after the procedure was significantly greater in the RBBB than no-RBBB group (66±24% vs. 49±45%; P=0.035). Procedural RBBB was not associated with pacemaker implantation after ASA, but was associated with reduction in repeat ASA (odds ratio 0.34; 95% confidence interval 0.13-0.92; P=0.045).
Conclusions:
Although RBBB frequently occurs during the ASA procedure, it does not adversely affect clinical outcomes.
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