Aims: Cardiac resynchronization therapy(CRT) utilizing biventricular pacing(BVP) is a promising treatment modality for symptomatic patients with chronic left ventricular(LV)systolic dysfunction and intraventricular co...Aims: Cardiac resynchronization therapy(CRT) utilizing biventricular pacing(BVP) is a promising treatment modality for symptomatic patients with chronic left ventricular(LV)systolic dysfunction and intraventricular conduction delay. Clinical studies have shown short-term improvement in contractile function and mid-term improvement in clinical status with CRT. The objective of this study was to evaluate the haemodynamic consequences of temporary interruption of CRT after long-term stimulation. Methods and results: Twenty patients(16 men, 4 women) with LV dysfunction and New York Heart Association class III or IV heart failure, despite optimal medical therapy and a QRS interval of at least 120 ms, received a transvenous BVP system at the age of 66(interquartile range, 61- 69). Patients were studied after a median duration of 427 days(interquartile range, 281- 563) of continuous CRT and again 72 h after cessation of BVP. Withdrawal of CRT resulted in a significant decline in maximal rate of LV systolic pressure rise from 711 mmHg/s(interquartile range, 640- 816) to 442 mmHg/s(interquartile range, 389- 582)(P=0.0001) and increases in mitral effective regurgitant orifice area from 4.8 mm2(interquartile range, 0.0- 7.8) to 9.1 mm2(interquartile range,5.7- 13.3)(P=0.0001), mitral regurgitant volume from 7.8 mL(interquartile range, 0.0- 11.5) to 16.0 mL(interquartile range, 10.7- 20.8)(P=0.0001) and fraction from 13.8% (interquartile range, 0.0- 19.2) to 27.7% (interquartile range, 14.6- 34.0)(P=0.0002) determined by Doppler echocardiography. Conclusion: Cessation of long-term BVP leads to a decline in LV systolic performance and an increase in functional mitral regurgitation. These results indicate a sustained benefit of long-term CRT and support the notion to maintain CRT indefinitely.展开更多
文摘Aims: Cardiac resynchronization therapy(CRT) utilizing biventricular pacing(BVP) is a promising treatment modality for symptomatic patients with chronic left ventricular(LV)systolic dysfunction and intraventricular conduction delay. Clinical studies have shown short-term improvement in contractile function and mid-term improvement in clinical status with CRT. The objective of this study was to evaluate the haemodynamic consequences of temporary interruption of CRT after long-term stimulation. Methods and results: Twenty patients(16 men, 4 women) with LV dysfunction and New York Heart Association class III or IV heart failure, despite optimal medical therapy and a QRS interval of at least 120 ms, received a transvenous BVP system at the age of 66(interquartile range, 61- 69). Patients were studied after a median duration of 427 days(interquartile range, 281- 563) of continuous CRT and again 72 h after cessation of BVP. Withdrawal of CRT resulted in a significant decline in maximal rate of LV systolic pressure rise from 711 mmHg/s(interquartile range, 640- 816) to 442 mmHg/s(interquartile range, 389- 582)(P=0.0001) and increases in mitral effective regurgitant orifice area from 4.8 mm2(interquartile range, 0.0- 7.8) to 9.1 mm2(interquartile range,5.7- 13.3)(P=0.0001), mitral regurgitant volume from 7.8 mL(interquartile range, 0.0- 11.5) to 16.0 mL(interquartile range, 10.7- 20.8)(P=0.0001) and fraction from 13.8% (interquartile range, 0.0- 19.2) to 27.7% (interquartile range, 14.6- 34.0)(P=0.0002) determined by Doppler echocardiography. Conclusion: Cessation of long-term BVP leads to a decline in LV systolic performance and an increase in functional mitral regurgitation. These results indicate a sustained benefit of long-term CRT and support the notion to maintain CRT indefinitely.
