| Summary: | 博士 === 中國醫藥大學 === 臨床醫學研究所博士班 === 100 === Objects: The purpose of this study was to evaluate atrial and ventricular function and synchrony in patients undergoing cardiac resynchronization therapy.
Background: Right atrial pacing in cardiac resynchronization therapy induces dyssynchrony in electrical and mechanical activation of the left atrium. The impact of atrial sensing versus atrial pacing on left ventricular performance in cardiac resynchronization therapy and the underlying mechanisms leading to differences between these two pacing modes in cardiac resynchronization therapy have not been fully elucidated.
Methods: Fifty-five patients with heart failure undergoing cardiac resynchronization therapy for 9± 12.5 months and 22 control subjects with dual pacemaker for conduction disorders were enrolled. Conventional and tissue Doppler echocardiography was performed to examine atrial and ventricular mechanics and hemodynamic status.
Results: Left ventricular (LV) outflow tract time-velocity integral (22± 7 cm vs. 20± 7 cm, p= 0.001), diastolic filling period (468± 124 ms vs. 380± 93 ms, p= 0.001), and global strain (-32± 24% vs. -27± 22%, p= 0.001) were greater in atrial sensing compared with atrial pacing mode. Atrial strain was higher in atrial sensing compared with atrial pacing mode in the right atrium (-28.2± 8.6% vs. -22.6± 7.6%, p= 0.0007), interatrial septum (-17.1± 6.5% vs. -13.2± 5.4%, p= 0.002), and left atrium (-16.4± 11.0% vs. -13.6± 8.5%, p= 0.02). There was no difference in intra-ventricular dyssynchrony but significantly lower atrial dyssynchrony in atrial sensing compared with atrial pacing mode (31± 19 ms vs. 42 ± 24 ms, p= 0.0002).
Conclusion: Atrial sensing is associated with preserved atrial contractility and synchrony, with the results of optimal LV diastolic filling, stroke volume, and LV systolic mechanics consequently. This pacing mode maximizes LV performance and the hemodynamic benefit of cardiac resynchronization therapy in patients with heart failure.
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