Feasibility, Safety, and Mid-Term Efficacy of Cardiac Resynchronization Therapy in Patients with Severe Heart Failure and Ventricular Conduction Delay: Chulalongkorn Experience
Buncha Sunsaneewitayakul MD*, Surapun Sitthisook MD**, Somkiat Sangwatanaroj MD**, Somchai Prechawat MD*, Smonporn Boonyaratavej Songmuang MD**
Affiliation : * Cardiac Center, King Chulalongkorn Memorial Hospital, Thai Red Cross Society ** Division of Cardiology, Department of Medicine, Faculty of Medicine, Chulalongkorn University
Background : Heart failure is a major and growing public health problem in developed and developing
countries. Despite major advances in medical therapy, morbidity and mortality remain high. Cardiac
resynchronization therapy (CRT) has been proposed as an adjunctive therapy in patients with drug-refractory
heart failure and ventricular conduction delay. Short and long-term studies have demonstrated the clinical
benefits of CRT.
Objective : The present study was designed to assess the feasibility, safety, and mid-term efficacy of CRT in
patients with severe heart failure and ventricular conduction delay in the institute.
Materials and Methods : Ten patients with severe heart failure in New York Heart Association (NYHA) functional
class III or IV with left ventricular ejection fraction (LVEF) < 35%, QRS duration > 120 ms with left bundle
branch block morphology received CRT. At baseline, and 6 months after implantation, the following param-
eters were evaluated: NYHA class, QRS duration, LVEF, N-terminal pro-brain natriuretic peptide (NT-pro
BNP) level, 6-minute walking distance, SF-36 quality-of-life (QOL) score, and number of heart failure visit.
Results : All clinical parameters improved significantly at 6 months. NYHA class decreased from 3.5 + 0.5 to
2.4 + 0.7 (p < 0.01). QRS duration decreased from 145 + 22 ms to 126 + 6 ms (p < 0.01). LVEF increased from
21 + 6% to 31 + 12% ( p < 0.01). NT-pro BNP level decreased from 2503 + 1953 pg/ml to 767 + 342 pg/ml
(p < 0.01). The 6-minute walking distance increased from 153 + 122 m to 278 + 128 m (p < 0.01). QOL score
improved from 66 + 14 to 98 + 25 (p < 0.01). The number of heart failure visits was reduced from 3.8 + 3.7 per
year to 0.5 + 0.8 visit per year (p < 0.01). Seventy percent of patients were free of heart failure visit for one year
after implantation. One patient had sudden cardiac death eleven months after implantation. There was no
procedure-related mortality. One patient had left ventricular lead dislodgement 3 months after implantation.
Conclusion : In the present study, CRT was safe and effective in improving heart failure symptom, functional
status, LV function, and quality of life. CRT also reduced heart failure hospitalization in the presented severe
heart failure and ventricular conduction delay patients.
Keywords : Cardiac resynchronization therapy, Heart failure, Ventricular conduction delay, Biventricular pacing
