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Linde et al. (1)reported in the Journalthat biventricular pacing significantly improves clinical parameters in patients with congestive heart failure. In their study, the 6-min walking distance, New York Heart Association class, and quality of life improved with biventricular pacing. Objective measures of function, including the maximal O2consumption, left ventricular end-diastolic diameter, left ventricular end-systolic diameter, and left ventricular ejection fraction did not improve significantly. The investigators were only able to demonstrate subjective improvement but not any objective improvement with the biventricular pacing. Subjective improvement was previously shown by Linde et al. (2)to improve with sham pacing, suggesting that a significant placebo effect is associated with the insertion of a pacemaker. It is therefore possible that the subjective improvement in this group was a result of the placebo effect of pacemaker implantation rather than of the mode of pacing utilized.
- American College of Cardiology Foundation