Clinical introduction

A man in his 70s with a left bundle branch block and advanced valvular systolic heart failure (HF) presented with a subacute HF and low cardiac output (CO) (peripheral hypoperfusion, high lactic levels, symptomatic hypotension). Echocardiography confirmed severe reduction in left ventricular ejection fraction, global longitudinal strain and stroke volume, as assessed by outflow tract pulse Doppler. Acute HF therapy with dobutamine and levosimendan was started, leading to progressive haemodynamic improvement.

After suspension of inotropes, under conditions of haemodynamic stability, a cardiopulmonary ramp-protocol maximal exercise test (CPET) was performed, showing a peculiar breathing during the exercise (figure 1).