The Accuracy of the Electrocardiogram during Exercise Stress Test Based on Heart Size

BACKGROUND: Multiple studies have shown that the exercise electrocardiogram (ECG) is less accurate for predicting ischemia, especially in women, and there is additional evidence to suggest that heart size may affect its diagnostic accuracy. HYPOTHESIS: The purpose of this investigation was to assess the diagnostic accuracy of the exercise ECG based on heart size. METHODS: We evaluated 1,011 consecutive patients who were referred for an exercise nuclear stress test. Patients were divided into two groups: small heart size defined as left ventricular end diastolic volume (LVEDV) <65 mL (Group A) and normal heart size defined as LVEDV ≥65 mL (Group B) and associations between ECG outcome (false positive vs. no false positive) and heart size (small vs. normal) were analyzed using the Chi square test for independence, with a Yates continuity correction. LVEDV calculations were performed via a computer-processing algorithm. SPECT myocardial perfusion imaging was used as the gold standard for the presence of coronary artery disease (CAD). RESULTS: Small heart size was found in 142 patients, 123 female and 19 male patients. There was a significant association between ECG outcome and heart size (χ(2) = 4.7, p = 0.03), where smaller hearts were associated with a significantly greater number of false positives. CONCLUSIONS: This study suggests a possible explanation for the poor diagnostic accuracy of exercise stress testing, especially in women, as the overwhelming majority of patients with small heart size were women

Clinical application of cine-MRI in the visual assessment of mitral regurgitation compared to echocardiography and cardiac catheterization.

Detecting and quantifying the severity of mitral regurgitation is essential for risk stratification and clinical decision-making regarding timing of surgery. Our objective was to assess specific visual parameters by cine-magnetic resonance imaging (MRI) in the determination of the severity of mitral regurgitation and to compare it to previously validated imaging modalities: echocardiography and cardiac ventriculography.The study population consisted of 68 patients who underwent a cardiac MRI followed by an echocardiogram within a median time of 2.0 days and 49 of these patients who had a cardiac catheterization, median time of 2.0 days. The inter-rater agreement statistic (Kappa) was used to evaluate the agreement.There was moderate agreement between cine MRI and Doppler echocardiography in assessing mitral regurgitation severity, with a kappa value of 0.47, confidence interval (CI) 0.29-0.65. There was also fair agreement between cine MRI and cardiac catheterization with a kappa value of 0.36, CI of 0.17-0.55.Cine MRI offers a reasonable alternative to both Doppler echocardiography and, to a lesser extent, cardiac catheterization for visually assessing the severity of mitral regurgitation with specific visual parameters during routine clinical cardiac MRI

Measurement of visual assessment parameters.

<p>Measurement of visual assessment parameters.</p