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.