Long Term Exercise Capacity in Patients with Hypertrophic Cardiomyopathy Treated with Percutaneous Transluminal Septal Myocardial Ablation

Background In hypertrophic obstructive cardiomyopathy, percutaneous transluminal septal myocardial ablation (PTSMA) improves functional capacity in the short term. However, long term functional capacity is unknown. Aim To assess the long term exercise capacity of patients with hypertrophic obstructive cardiomyopathy undergoing PTSMA. Methods Twenty three patients (56.5% male, mean age 44.5±13.6 years) who underwent PTSMA were included. All patients had also undergone a symptom limited cardiopulmonary exercise treadmill test before the procedure, then after 3 months (early follow-up) and after a mean 7.2±1.0 years (long term follow-up). Results Before PTSMA, mean maximal pressure gradient in the left outflow tract (LVOTGmax) was 82±29 mmHg, 17 patients had NYHA functional class ≥ III and peak oxygen uptake (pVO2) was 18±4 ml/kg/min. PTSMA led to a reduction in mean LVOTGmax (to 29 ± 19 mmHg. p<.0001), improvement of heart failure symptoms (NYHA≥III in 1 patient, p<.0001) and an increase of pVO2 (to 22±6 ml/kg/min, p =.0002) at short term. LVOTGmax, functional class and pVO2 did not change significantly during long term follow-up compared to early follow-up. However, there was a continuous improvement in percentage predicted pVO2 over time. Conclusions In patients with hypertrophic obstructive cardiomyopathy and symptoms of heart failure, PTSMA leads to stable long term improvement of objectively measured exercise capacity.