The InSync italian registry: Analysis of clinical outcome and considerations on the selection of candidates to left ventricular resynchronization

Biventricular pacing improves the functional status of patients with congestive heart failure and interventricular conduction delay. The aim of this report is to describe the clinical outcome in the large cohort of patients of the InSync Italian Registry. Since January 1998, 190 patients with dilated cardiomyopathy of ischaemic (47%), idiopathic (38%) or other aetiology (15%) were implanted with a biventricular stimulation system. Paired data analysis, over a mean ± SD follow-up of 10 ± 5 months, showed a decrease of QRS duration (172 ± 34 ms vs 135 ± 22 ms, P 3, left ventricular ejection fraction 120 ms), a significant improvement was also obtained in patients with QRS 35% or QRS <120 ms), only left ventricular ejection fraction and quality of life changed significantly during follow-up (29 ± 10% vs 33 ± 9%, P=0.02, and 44 ± 25 vs 17 ± 16, P=0.001) with no changes of QRS duration (146 ± 46 ms vs 130 ± 24 ms). These observational data confirm the promising role of biventricular pacing in improving the functional status of patients with severe, drug-refractory congestive heart failure and interventricular conduction delay, that does not appear to be influenced by the degree of QRS shortening or by the presence of chronic atrial fibrillation. A more modest improvement was observed in patients with less advanced heart failure or QRS prolongation, justifying the need for large, controlled studies before expanding the clinical application of this technique.