Although periodic breathing (PB) has been previously reported as a feature of right heart failure, it has never been observed in any manifestation of adult congenital heart disease. We report two cases of patients with tetralogy of Fallot (ToF) demonstrating this phenomenon late after repair. Both patients had right heart failure because of pulmonary regurgitation (PR) assessed by cardiovascular magnetic resonance imaging and exhibited PB on a background of a depressed ventilatory drive, long circulatory time, and elevated sympathetic activity. PB may be present more often than suspected in adult congenital heart disease patients with predominant right ventricular (RV) dysfunction and have noteworthy prognostic implications.

It is well documented that left ventricular failure is associated with unstable cardiorespiratory control.¹ PB is characterised by oscillations in the depth of ventilation (with or without apnoeas) paired with synchronous oscillations in heart rate and blood pressure with respect to the cardiovascular system.² PB in patients with chronic heart failure (CHF) …