Usefulness of biventricular pacing to improve cardiac symptoms, exercise capacity and sympathetic nerve activity in patients with moderate to severe chronic heart failure.

Background: Although cardiac resynchronization using biventricular pacing (BVP) results in significant clinical improvement in patients with chronic heart failure (CHF), there is no evidence of improvement in sympathetic nerve activity (SNA).

Methods And Results: Eighteen patients with CHF (dilated cardiomyopathy/ischemic cardiomyopathy =14/4) and left ventricular (LV) ejection fraction <40%, QRS duration >160 ms and dyssynchronous LV wall motion were classified into 2 groups based on the findings of (99m)Tc-methoxyisobutyl isonitrile (MIBI) quantitative gated single-photon emission computed tomography (SPECT) (QGS). Resynchronization was considered to be present when the difference between the QGS frame number for end-systole for the LV septal and lateral walls (dyssynchrony index) disappeared. Group A achieved resynchronization after BVP, but not Group B. In group A, New York Heart Association functional class (p=0.0002), specific activity scale (p=0.0001), total defect score (p<0.05), and the heart/mediastinum ratio of delayed (123)I-metaiodobenzylguanidine imaging (p<0.05) were significantly improved after resynchronization. However, there was no significant change in group B.

Conclusions: Cardiac resynchronization after BVP can improve cardiac symptoms, exercise capacity, and SNA in patients with moderate to severe CHF.