Abnormal left ventricular exercise stress echocardiography response in the absence of obstructive coronary disease: is subclinical left ventricular myocardial dysfunction another aetiology?

Abstract

Purpose: Failure of left ventricular (LV) contractile reserve or reduced ejection fraction (EF) post-exercise is an abnormal stress echocardiography (ESE) response. The aetiology of this response in the absence of obstructive coronary artery disease (CAD) is often unclear. We sought to determine the resting echocardiogram characteristics of patients with an abnormal ESE with no known aetiology compared to patients with a normal ESE. Methods: Of 4,542 consecutive patients who underwent ESE for suspected CAD between 2009 and 2012, 521 underwent angiography within 90 days. Having excluded those with obstructive (≥50%) CAD, hypertensive response (>210/105 in men, >190/105 in women), failure to achieve >85% age-predicted heart rate, resting LVEF<50% or >mild valve disease, we identified 110 patients with an abnormal LV contractile response to exercise (abnormal ESE group). These were compared to 90 consecutive patients without obstructive (≥50%) CAD and a normal ESE (normal ESE group) during the same period. LV mass, early diastolic annular velocities (e'), left atrial volume and transmitral Doppler were measured. LVEF was calculated using Simpson's method. Results: Demographic and echocardiogram parameters are summarised in table. In the abnormal ESE group, LVEF decreased post-exercise in 85 (77%) patients and was unchanged in 23 (25%). Comparing normal ESE group vs abnormal ESE group, septal and lateral e' were abnormally reduced in 42 (47%) vs 86 (78%) and 27 (30%) vs 51 (47%) patients (both P<0.001), respectively (defined as >2 standard deviations below age-predicted mean). Demographic & echocardiogram parameters Conclusions: An abnormal LV contractile response to exercise in the absence of obstructive CAD or other established aetiologies is associated with subclinical LV myocardial dysfunction and occurs more commonly in females.