Potential candidates for cardiac resynchronization therapy in Japanese patients with idiopathic dilated cardiomyopathy--a Niigata multicenter study of DCM--.

Background: The purpose of this study was to assess the candidates suitable for cardiac resynchronization therapy (CRT) and to examine the significance of the QRS duration in Japanese patients with idiopathic dilated cardiomyopathy (DCM).

Methods And Results: The study population consisted of 357 patients. The selection criteria for candidates suitable for CRT were QRS duration =130 ms, left ventricular ejection fraction (LVEF) =35% and New York Heart Association (NYHA) functional class III or IV by ACC/AHA/NASPE 2002 guidelines. We divided the study population into 2 groups: group A with a QRS duration <130 ms, and group B with a QRS duration =130 ms. In 25 of the 375 patients (7.0%), all the criteria were fulfilled. Group B had a significantly larger left ventricular diameter end-diastole and end-systole than group A (P<0.0001). Group B had a lower LVEF (P<0.0001). There was a fair inverse correlation (r=-0.58, P<0.0001) between the length of the QRS duration and LVEF.

Conclusion: Approximately 7% of the Japanese patients with DCM are CRT candidates. In the present study, we found that prolonged QRS duration was associated with poor systolic function.