Cardiopulmonary Exercise Test Parameters at Three Months After Alcohol Septal Ablation in Hypertrophic Obstructive Cardiomyopathy Are Associated With Late Clinical Outcome.

BACKGROUND: Alcohol septal ablation (ASA) is an established interventional treatment for hypertrophic obstructive cardiomyopathy (HOCM) patients with drug refractory symptoms. This study investigated the prognostic value of cardiopulmonary exercise test (CPET) in relation to the late clinical outcome. METHODS: Twenty-one (21) HOCM patients underwent CPET before and 3 months after ASA and were followed yearly thereafter. Clinical success was considered to be a decrease of ≥1 (New York Heart Association or Canadian Cardiovascular Society) functional class. Cardiopulmonary exercise test parameters [maximal oxygen uptake (PeakVO2), % predicted VO2 (PeakVO2%), oxygen uptake at anaerobic threshold (AT), maximal workload (W), % predicted W (W%), ventilation (VE), % predicted VE (VE%), ventilation to maximal carbon dioxide production slope (VE/VCO2), % predicted maximal heart rate (HR%), and maximal systolic blood pressure (SBP)] were compared before and 3 months after ASA. RESULTS: After follow-up of 29 ± 13 months, 16 patients had a good clinical results (clinical responders), while five did not improve (clinical non-responders). The CPET parameters did not change in non-responders, while clinical responders showed significant improvement in VO2, VO2%, W, VE/VCO2, VE, VE%, as well as an increase in HR% and SBP at 3 months. CONCLUSIONS: The data confirmed a good association between the improvement in CPET parameters and the clinical results 3 months after ASA. This may therefore serve as an early marker of HOCM-ASA treatment success.

Low occurrence of ventricular arrhythmias after alcohol septal ablation in high-risk patients with hypertrophic obstructive cardiomyopathy.

INTRODUCTION: Percutaneous alcohol septal ablation (PTSMA) is an established treatment for symptomatic patients with hypertrophic obstructive cardiomyopathy (HOCM). However, there is concern of a higher risk for ventricular tachyarrhythmias and sudden death due to the myocardial scar created after PTSMA. We investigated the possibility of increased ventricular arrhythmias and risk of sudden death after PTSMA in a subgroup of patients with an already implanted ICD. METHODS AND RESULTS: Between 2009 and 2012, 239 PTSMAs were performed in 212 patients with HOCM. In 32 of those an ICD had already been implanted before PTSMA for primary (31 patients) or secondary (1 patient) prevention of sudden death. The maximum left ventricular outflow tract gradient (LVOTG) was reduced from 114 ± 39 mmHg before PTSMA to 23 ± 19 mmHg (P < 0.0001). Among clinical risk factors for sudden death, nonsustained ventricular tachycardia (VT), syncope and family history for sudden death were most common. After a median follow-up of 5.3 (IQR 4.3-5.7) years after PTSMA only one patient had ICD shocks (annual ICD discharge 0.6 %). In another 3 patients, with already documented nonsustained VTs as risk factor before ICD implantation, VT episodes that activated antitachycardic pacing were recorded. The annual appropriate ICD intervention including all events was 2.5 % and involved only patients with a very high estimated 5-year sudden death risk before PTSMA (>14.3 %). CONCLUSIONS: In a selected high-risk patient cohort with HOCM ominous arrhythmic events seem to be rare and predominantly occur in patients with a very high estimated risk of sudden death before PTSMA.