Transient cavity dilatation during supine exercise bicycle stress testing: mechanistic insights

Cavity dilatation is occasionally observed during supine bicycle exercise stress echocardiography (SBSE). The underlying mechanisms are poorly understood.

This study aimed to characterise patients with left ventricle (LV) cavity dilatation and a decrease in the left ventricular ejection fraction (LVEF) during SBSE.

A total of 653 patients who underwent SBSE were evaluated. Those with exercise-induced cavity dilatation (defined as increased cavity size and a decrease in LVEF) were evaluated (n = 29). A control group (n = 37) of patients with a hypertensive response and a normal ESE was also evaluated.

A total of 33/653 (5.1%) patients had an abnormal LV cavity response to exercise, with 15/29 (51.7%) having significant underlying coronary artery disease (CAD). Comparisons were made between patients with CAD (n = 15) and those with nonobstructive coronary arteries (NCAs, n = 14). NCA patients had significantly higher peak diastolic blood pressure (DBP) (NCA-CD 109 ± 17 mmHg vs. CAD-CD 96 ± 16 mmHg, p = 0.044) and rate-pressure product (RPP) (NCA-CD 28,623 ± 4474 vs. CAD-CD 23,649 ± 4763, p = 0.007). There was a trend toward increased dyspnoea at peak exercise in NCA (NCA-CD 35.7% vs. CAD-CD 6.7%, p = 0.080), and CAD patients showed a higher observed frequency of severe chest pain (CAD 53.3% vs. NCA 14.3%, p = 0.050). When patients with NCA and cavity dilatation were compared with a control group of patients with a hypertensive response to exercise but no cavity dilatation, no significant differences were observed.

Cavity dilatation is observed in 5% patients undergoing SBSE and is attributable to significant CAD in approximately half of patients. NCA cavity dilatation is associated with increased RPP and DBP at peak exercise, with a trend toward increased dyspnoea. Severe chest pain at peak exercise was observed more frequently in CAD patients.