A systematic review 1 including 21 studies with a total of 1 181 subjects was abstracted in DARE. The aim was to quantify the effects of ablation and pacing therapy on measures of clinical outcome and survival, in people with medically refractory atrial tachyarrhythmias. Fifteen studies (642 patients) were used in the outcome analysis, and 16 (1 073 patients) in the mortality analysis. An improvement was shown for each of the 19 outcome measures, with the exception of fractional shortening. Cardiac symptom scores, quality of life measures and health care use showed improvement in all individual studies. Fractional shortening was improved in 2 of the 3 studies. Exercise duration and ejection fraction were unchanged in 4 out of 7 studies and 5 out of 11 studies, respectively. However, the meta-analysis showed improvement in both measures. Effect sizes and 95% CIs were illustrated graphically for all clinical outcomes.
The overall monthly and 1-year total mortality rates calculated for patients in the intervention group were 1.4% (95% CI 0.04 to 2.4) and 6.3% (95% CI 5.5 to 7.2), respectively. The authors concluded that in patients with refractory atrial tachyarrhythmia, ablation and pacing therapy reduces cardiac symptoms and health care use while improving exercise duration, quality of life and ejection fraction. Mortality rates were comparable with findings from other studies and do not seem to be disproportionate for the characteristics of the study group.
Comment: The quality of evidence is downgraded by review quality. No primary hypotheses were stated for the 19 outcome measures, and little information was provided on the meta-analyses of these outcomes. Results of before- and-after studies were pooled with non-randomised and randomised trials, heterogeneity was not discussed and no adjustments for significance were made for multiple testing. The authors did not draw attention to the better quality evidence from the RCTs.
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