A comparison of the diagnostic performance of the ST/HR hysteresis with cardiopulmonary stress testing parameters in detecting exercise-induced myocardial ischemia.

Abstract

BACKGROUND:

Because ST segment depression has limited diagnostic performance at exercise electrocardiography (ECG), ST segment depression/heart rate (ST/HR) hysteresis and cardiopulmonary exercise test (CPET)-derived parameters have been proposed as alternatives to diagnose exercise-induced myocardial ischemia. We compared the diagnostic performance of such parameters.

METHODS:

We studied 56 subjects (45 men, 11 women, age 59.7 ± 13.6 years) referred for suspected exercise-induced myocardial ischemia with an equivocal ECG exercise test. All subjects serially underwent CPET and a myocardial single-photon emission computerized tomography (SPECT) perfusion imaging (as the gold standard for ischemia). Maximum ST depression at peak exercise (ST-max), the ST/HR hysteresis, ΔVO2/ΔWR b-b1 slope, ΔVO2/ΔWR (aa1-bb1), VO2/HR flattening duration and other CPET parameters were derived in all subjects.

RESULTS:

On the basis of SPECT, 23 subjects (41%) were considered ischemic and 33 subjects (59%) non-ischemic. ST/HR hysteresis was higher (0.026 mV; 95% CI: 0.003 to 0.049 vs -0.016 mV; 95% CI: -0.031 to -0.001 mV) and ST-max was lower (-0.105 mV; 95% CI: -0.158 to -0.052 vs 0.032 mV; 95% CI: -0.001 to -0.066 mV) in ischemic vs non-ischemic subjects (P=0.004 and P=0.001, respectively). Among CPET parameters, ΔVO2/ΔWR b-b(1) slope was lower (9.4 ± 3.8) and ΔVO2/ΔWR (aa(1)-bb(1)) was higher (2.1 ± 2.6) in ischemic vs non-ischemic subjects (11.4 ± 2.3, P=0.005, and 1.1 ± 1.5, P=0.001, respectively). The ST/HR hysteresis had the highest area under the curve value, better (P<0.05) than any other parameters tested, thus showing the highest overall diagnostic performance.

CONCLUSION:

The ST/HR hysteresis is superior to CPET-derived parameters for detecting exercise-induced myocardial ischemia in patients with equivocal ECG exercise test results.

• Authors: Marco Zimarino, Luca Barnabei, Rosalinda Madonna, Giuseppe Palmieri, Francesco Radico, Alfonso Tatasciore, Francesco Iachini Bellisarii, Gianni Mauro Perrucci, Alessandro Corazzini, Raffaele De Caterina
• Journal: International journal of cardiology (Int J Cardiol) Vol. 168 Issue 2 Pg. 1274-9 (Sep 30 2013) ISSN: 1874-1754 [Electronic] Netherlands
• PMID: 23260751 (Publication Type: Comparative Study, Journal Article)
• Copyright: Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

Topics

• Aged
• Cardiac-Gated Single-Photon Emission Computer-Assisted Tomography (methods, standards)
• Electrocardiography (methods, standards)
• Exercise Test (methods, standards)
• Female
• Heart Rate (physiology)
• Humans
• Male
• Middle Aged
• Myocardial Ischemia (diagnostic imaging, physiopathology)