073: Very long-term effects of pacing therapy in Hypertrophic Obstructive Cardiomyopathy (HOCM)

The clinical value of DDD pacing as primary treatment of HOCM remains controversial. Very long-term data are lacking.Aimssingle-centre observational study aimed at describing the very long term effects on symptoms, clinical and echocardiographic outcomesPatients54 patients (59±14 years) with symptomatic (NYHA Class >2) drug-refractory HOCM implanted with a DDD pacemaker with or without defibrillator between 1991 and 2007 and followed up to 20 years (mean 11.5; range 0,4-21,8).Main resultsare summarised in table. No patient had myomectomy or septal ablation during follow-up (f/u). NYHA functional class and other symptoms were significantly improved at 1-2 years and at the end of f/u. Left ventricular outflow tract (LVOT) gradient decreased by a mean of 78% at 1-2 years and 89% at end f/u consistent with SAM resolution. LV ejection fraction decreased over time with a mean value of 56% at end f/u without evidence of cavity dilatation. The actuarial survival rate was 90% at 5-yrs and 65% at 10-yrs. 24 patients died, 19 from non cardiac cause and 5 cardiovascular. 2 patients had heart transplant after 8 and 13yrs.ConclusionThe clinical and echocardiographic outcome of HOCM patients treated by DDD pacing seems favourable, inviting to re-evaluate the exact value of the therapy in further controlled studiesTable – Main results.Baseline3 months1-2 yearsEnd f/uP valueNYHA functional class, (%)<0,0001Grade 10313536Grade 243535957Grade 3521667Grade 45000Syncope/nearsyncope (%)76/482/22/22/2<0,0001Angina (%)57444<0,0001LVOT gradient (mmHg)79±3620±2411±158±21<0,0001SAM (%)96383016<0,0001LVEF (%)63,5±7,561±759±756±90,05LVEDD (%)47±5NANA43±120,3