Late benefits of dual-chamber pacing in obstructive hypertrophic cardiomyopathy. A 10-year follow-up study

Enrique Galve ^1*, Antonia Sambola ¹, German Saldaña ¹, Ivan Quispe ¹, Elsa Nieto ¹, Anna Diaz ¹, Arturo Evangelista ¹ and Jaume Candell-Riera ¹

¹ Hospital Vall D'Hebron, Spain

^* To whom correspondence should be addressed. E-mail: egalve{at}vhebron.net.

Accepted 10 March 2009

Abstract

Objective: To examine the mid and long term outcomes in patients with obstructive hypertrophic cardiomyopathy (HCM) submitted to pacing.

Design: Prospective, observational study.

Setting: Single, non-referral centre.

Patients and intervention: Fifty patients (62±11years) with HCM refractory to medical therapy, all in NYHA class III or IV, and with a rest gradient >50mmHg underwent a dual-chamber pacemaker implantation. Patients were followed-up up to 10 years (mean 5.0±2.9, range 0.6-10.1).

Results: During the first year of follow-up, rest gradients decreased (baseline 86±29mmHg; 3-months 55±37; l-year 41±26; p=0.0001). NYHA class improved (p<0.0001), as well as exercise tolerance (p<0.0001). The physical and mental components of the quality of life instrument SF-36 improved as well (p=0.0001). Left ventricular wall thickness remained unchanged, while ejection fraction decreased (p=0.002). During the long-term follow-up, an additional reduction in obstruction was found (final rest gradient 28±24mmHg, p<0.02). Those patients that did not improved to NYHA class I or II and remained with obstruction were submitted to other therapies (6 to alcohol ablation, 3 to surgical myectomy).

Conclusions: Pacing in HCM results in a significant reduction in obstruction, improvement of symptoms and exercise capacity that is progressive and may be achieved after a long period of time. In our series, only 18% of cases needed a more aggressive therapy to relieve residual obstruction and obtain a satisfactory symptomatic status. In conclusion, these results emphasize the necessity of new controlled studies of pacing with a longer follow-up.