Cardiac resynchronization therapy acutely reduced functional mitral regurgitation severity, with effective regurgitant orifice area decreasing from 25 mm2 (OFF) to 13 mm2 (CRT).
Does cardiac resynchronization therapy acutely reduce functional mitral regurgitation in heart failure patients with LBBB?
CRT acutely reduces functional mitral regurgitation in heart failure patients with LBBB by increasing left ventricular closing force.
Absolute Event Rate: 13% vs 25%
OBJECTIVES: We studied the acute effects of cardiac resynchronization therapy (CRT) on functional mitral regurgitation in heart failure (HF) patients with left bundle branch block (LBBB). BACKGROUND: Both an decrease corrected in left ventricular (LV) closing force and mitral valve tethering have been implicated as mechanisms for functional mitral regurgitation (FMR) in dilated hearts. We hypothesized that an increase in LV closing force achieved by CRT could act to reduce FMR. METHODS: Twenty-four HF patients with LBBB and FMR were studied after implantation of a biventricular CRT system. Acute changes in FMR severity between intrinsic conduction (OFF) and CRT were quantified according to the proximal isovelocity surface area method by measuring the effective regurgitant orifice area (EROA). Results were compared with the changes in estimated maximal rate of left ventricular systolic pressure rise (LV+dP/dt(max)) and transmitral pressure gradients (TMP), both measured by Doppler echocardiography. RESULTS: Cardiac resynchronization therapy was associated with a significant reduction in FMR severity. Effective regurgitant orifice area decreased from 25 +/- 19 mm(2) (OFF) to 13 +/- 8 mm(2) (CRT). The change in EROA was directly related to the increase in LV+dP/dt(max) (r = -0.83, p < 0.0001). Compared with OFF, TMP increased more rapidly during CRT, and a higher maximal TMP was observed (OFF 73 +/- 24 mm Hg vs. CRT 85 +/- 26 mm Hg, p < 0.01). CONCLUSIONS: Functional mitral regurgitation is reduced by CRT in patients with HF and LBBB. This effect is directly related to the increased closing force (LV+dP/dt(max)). The results support the hypothesis that an increase in TMP, mediated by a rise in LV+dP/dt(max) due to more coordinated LV contraction, may facilitate effective mitral valve closure.
Breithardt et al. (Sat,) conducted a other in Heart failure with left bundle branch block and functional mitral regurgitation (n=24). Cardiac resynchronization therapy (CRT) vs. Intrinsic conduction (OFF) was evaluated on Effective regurgitant orifice area (EROA). Cardiac resynchronization therapy acutely reduced functional mitral regurgitation severity, with effective regurgitant orifice area decreasing from 25 mm2 (OFF) to 13 mm2 (CRT).