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> or = 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> or =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.