Clinical effect of three-dimensional left ventricular mechanical dyssynchrony and cardiac sympathetic denervation in systolic heart failure risk-stratified by left ventricular ejection fraction and QRS duration.

Background: The left ventricular ejection fraction (LVEF) and QRS duration (QRSd) are prognostic factors in patients with systolic heart failure (HF). However, no study has evaluated the prognosis was evaluated by adding three-dimensional left ventricular mechanical dyssynchrony (LVMD) and cardiac sympathetic dysfunction.

Results: In 1011 consecutive patients with HF having LVEF < 50%, LVMD was evaluated as the phase SD of the regional onset-of-mechanical contraction phase angles on a phase histogram created by Fourier phase analysis applied to regional time-activity curves obtained by gated myocardial perfusion. ¹²³I- meta-iodobenzylguanidine scintigraphy was also performed in all cases. Patients were followed up with a primary endpoint of lethal cardiac events (CEs). During the follow-up period (44 months), CEs were documented in 315 of the patients with HF. The CE group had a greater phase SD and lower standardized late heart-to-mediastinal ratio (slHMR) than the non-CE group. Phase SD and slHMR were identified by overall multivariate analysis to be significant prognostic determinants. ROC curve analyses revealed cutoff values of 36° for phase SD and 1.89 for slHMR for identifying patients with high-risk HF. Patients with HF and both phase SD > 36° and slHMR < 1.89 showed a significantly higher CE rate than other patients in the overall population, and patients' CE rates were divided into four groups according to the cutoff values of LVEF (35%) and QRSd (130 ms).

Conclusions: The addition of three-dimensional LVMD and cardiac sympathetic function to the evaluation of LVEF and QRSd in patients with systolic HF may stratify the risk of their prognosis.