Long-term cardiac resynchronization therapy at 6 months significantly improved left ventricular ejection fraction from 29% to 40% (P<0.01) and maintained acute hemodynamic improvements.
Observational (n=22)
Absolute Event Rate: 40% vs 29%
p-value: p=<0.01
Background— Acute hemodynamic effects of cardiac resynchronization therapy (CRT) were reported previously, but detailed invasive studies showing hemodynamic consequences of long-term CRT are not available. Methods and Results— We studied 22 patients scheduled for implantation of a CRT device based on conventional criteria (New York Heart Association class III or IV, left ventricular LV ejection fraction 120 ms). During diagnostic catheterization before CRT, we acquired pressure-volume loops using conductance catheters during atrial pacing at 80, 100, 120, and 140 bpm. Studies were repeated during biventricular pacing at the same heart rates after 6 months of CRT. Our data show a significant clinical benefit of CRT (New York Heart Association class change from 3.1±0.5 to 2.1±0.8; quality-of-life score change from 44±12 to 31±16; and 6-minute hall-walk distance increased from 260±149 to 396±129 m; all P <0.001), improved LV ejection fraction (from 29±10% to 40±13%, P <0.01), decreased end-diastolic pressure (from 18±8 to 13±6 mm Hg, P <0.05), and reverse remodeling (end-diastolic volume decreased from 257±67 to 205±54 mL, P <0.01). Previously reported acute improvements in LV function remained present at 6 months: dP/dt max increased 18%, −dP/dt min increased 13%, and stroke work increased 34% (all P <0.01). Effects of increased heart rate were improved toward more physiological responses for LV ejection fraction, cardiac output, and dP/dt max . Moreover, our study showed improved ventricular-arterial coupling (69% increase, P <0.01) and improved mechanical efficiency (44% increase, P <0.01). Conclusions— Hemodynamic improvements with CRT, previously shown in acute invasive studies, are maintained chronically. In addition, ventricular-arterial coupling, mechanical efficiency, and chronotropic responses are improved after 6 months of CRT. These findings may help to explain the improved functional status and exercise tolerance in patients treated with CRT.
Steendijk et al. (Mon,) conducted a observational in Heart failure (n=22). Cardiac resynchronization therapy (CRT) vs. Baseline was evaluated on Left ventricular ejection fraction (p=<0.01). Long-term cardiac resynchronization therapy at 6 months significantly improved left ventricular ejection fraction from 29% to 40% (P<0.01) and maintained acute hemodynamic improvements.