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Functional and echocardiographic improvement following multisite biventricular pacing for congestive heart failure
Kwan-Leung Chan1, Anthony S L Tang, Augusto Achilli
1University of Ottawa Heart Institute, Ontario, Canada. kchan@ottawaheart.ca
Background:
Heart failure remains a major cause of morbidity and mortality despite advances in pharmacological treatment. Recently, multisite biventricular pacing has been used in the treatment of patients with heart failure.
Objectives And Methods:
The short and medium term effects of this treatment modality were assessed, and the association between baseline clinical characteristics and the positive response to treatment was investigated. Consecutive patients who received this treatment modality were included. They underwent comprehensive clinical and echocardiographic assessment including a 6 min walk at baseline, one month and three months.
Results:
Between January 1998 and June 1999, 95 patients received multisite biventricular pacing therapy in the three participating hospitals. In 63 patients with complete three-month follow-ups, there were improvements from baseline to three-month follow-up in New York Heart Association heart failure (3.3 +/- 0.5 to 2.2 +/- 0.6, P<0.001) and 6 min walk (305 +/- 120 to 403 +/- 113 m, P<0.001). Significant salutary changes in echocardiographic measurements were also observed in left ventricular (LV) diastolic dimension, ejection fractions (EFs), interventricular contraction delay and severity of mitral regurgitation (MR). The 63 patients were categorized into responders (n=42) and nonresponders (n=21) based on the clinical response. Clinical characteristics were similar between the two groups. The responders had a more pronounced decrease in QRS width. An increase in LVEF and a reduction in LV diastolic dimension, interventricular mechanical delay and severity of MR were observed in the responders but not in the nonresponders. Furthermore, there was a positive association between the reduction in QRS width and the increase in LVEF.
Conclusions:
Cardiac resynchronization by means of multisite pacing appears to be a promising therapy in the treatment of heart failure. The salutary clinical response is associated with echocardiographic improvement.