Restrictive physiology in tetralogy of Fallot: exercise and arrhythmogenesis

The effect of right ventricular restrictive physiology on exercise capacity and arrhythmogenesis after correction of tetralogy of Fallot was assessed in 80 patients aged 7.9 +/- 3.6 years. Right ventricular restrictive physiology was defined as the presence of an A wave across the pulmonary artery on 2-dimensional echocardiography. At the 6 month follow-up, 52 patients had restrictive physiology (group 1). A transannular patch was used in 36 patients in group 1 (62%) and in 19 (86%) of the 28 patients without restrictive physiology (group 2). Maximum heart rate attained (69% vs. 77%), maximum predicted heart rate (211 +/- 12.6 vs. 226 +/- 24.2 beats x min(-1)), and metabolic equivalents (7.6 +/- 3.2 vs. 8.1 +/- 2.6) were higher in group 2, but not significantly. The chronotropic index was similar in both groups. In group 1, 14% of patients presented with ventricular premature complexes at 6 months. No effect on exercise capacity and arrhythmogenesis could be attributed to restrictive physiology, but both groups had chronotropic incompetence compared to normal children.