Selective Interventricular Septal Ablation in Patients with Hypertrophic
Obstructive Cardiomyopathy: Who can benefit?
Introduction: Septal mass reduction is beneficial for hypertrophic
obstructive cardiomyopathy (HOCM) patients with severe left ventricular
outflow (LVOT) gradient and symptoms, with surgical myectomy or alcohol
septal ablation (ASA) currently recommended in selected patients.
Radiofrequency (RF) ablation of hypertrophied septum has been published
as a novel method to alleviate LVOT obstruction in small populations.
This study aims to investigate factors influencing clinical outcomes of
radiofrequency septum ablation. Methods and results: In this study,
twenty patients with HOCM who underwent endocardial ablation were
included. Echocardiography and cardiac MRI (CMR) data was collected and
analyzed pre- and (or) post- procedure. Nineteen patients underwent
ablation successfully, while ablation was aborted in one patient with
prior RBBB due to transient complete atrioventricular block (AVB). After
six months of follow-up, NYHA heart functional class improved from III
(2 - 3) to II (1 - 2) (p < 0.001), and resting LVOT gradient
was significantly reduced (87.6 ± 29.5 mmHg vs. 48.1 ± 29.7, p
< 0.001). LVOT gradient reduction was significantly higher in
patients with limited basal septal hypertrophy (60.9 ± 8.3 vs. 27.9 ±
7.1, p = 0.01), shorter anterior mitral leaflet (56.1 ± 6.4 vs. 20.4 ±
5.0, p<0.01) and normally positioned papillary muscle (36.9 ±
7.1 vs. 75.0 ± 6.3, p <0.05). Conclusions: Endocardial septal
ablation appears to be a safe and effective procedure for alleviating
LVOT gradient in patients with HOCM, especially in those with limited
basal septal hypertrophy, shorter anterior mitral leaflet and normal
positioned papillary muscle.