Zoi D. Psomadaki

Improved Detection of Coronary Artery Disease by Exercise Electrocardiography with the Use of Right Precordial Leads

BACKGROUND Exercise electrocardiography is an perfect test for the detection of coronary artery disease. We attempted to improve the diagnostic accuracy of exercise testing as a noninvasive method for the detection of coronary artery disease by using a combination of the left and right precordial leads. METHODS We studied 245 patients (218 men and 27 women) ranging from 32 to 74 years of age (mean [+/-SD], 52+/-8) who underwent treadmill exercise testing, thallium-201 scintigraphy, and coronary arteriography. During exercise testing, each patient had one electrocardiogram recorded with the standard 12 leads and 3 right precordial leads (V3R, V4R, and V5R), with the results for each set of leads recorded and analyzed separately. RESULTS On the basis of coronary arteriography, 34 patients had normal coronary arteries, 85 had single-vessel disease, 84 had two-vessel disease, and 42 had three-vessel disease. The sensitivities of the standard 12-lead exercise electrocardiogram, exercise electrocardiography incorporating right precordial leads, and thallium-201 scintigraphy were 52 percent, 89 percent, and 87 percent, respectively, for the detection of single-vessel disease; 71 percent, 94 percent, and 96 percent for the detection of two-vessel disease; 83 percent, 95 percent, and 98 percent for the detection of three-vessel disease; and 66 percent, 92 percent, and 93 percent for the detection of any coronary artery disease. The specificities of the three methods for the detection of any coronary artery disease were 88 percent, 88 percent, and 82 percent, respectively. CONCLUSIONS Use of right precordial leads along with the standard six left precordial leads during exercise electrocardiography greatly improves the sensitivity of exercise testing for the diagnosis of coronary artery disease.

Significance of exercise-induced simultaneous ST-segment changes in lead aVR and V5

This study was undertaken to investigate the ability of the exercise-induced ST depression in lead V5 and concomitant ST elevation in lead aVR for the identification of the significantly narrowed coronary artery in patients with single vessel disease. We studied 229 consecutive patients who developed the aforementioned exercise-induced electrocardiographic changes. All underwent Thallium-201 scintigraphy and coronary arteriography. Patients were divided into three groups. In group A, 58 patients with ST depression in V5 and ST elevation in aVR, in group B 149 patients with ST depression in V5 without ST elevation in aVR, and in group C 22 patients with ST elevation in aVR without ST depression in V5 induced with exercise, were included. In group A, 81% of the patients while in group B, 29% and in group C only 18% of the patients had left anterior descending artery disease. According to Thallium-201 scintigraphy, 80% of the group A, 27% of the group B and 12% of the group C patients developed myocardial ischemia in areas supplied by the left anterior descending artery. Thus, exercise-induced ST depression in V5 and concomitant ST elevation in aVR, may detect left anterior descending artery significant stenosis in patients with single vessel disease.

Exercise-induced ST-segment changes in lead V1 identify the significantly narrowed coronary artery in patients with single-vessel disease correlation with thallium-201 scintigraphy and coronary arteriography data

We investigated the correlation of exercise-induced ST-segment changes in lead V1, with the detection of the significantly narrowed vessel that induced ischemia during exercise in myocardial areas supplied by this vessel. We studied 198 patients who underwent exercise testing, thallium-201 scintigraphy, and coronary arteriography. The patients were divided into three groups. In group 1 (ST-segment elevation in lead V1), 84% had left anterior descending coronary artery disease (P<.001); in group 2 (ST-segment depression in lead V1), 76% had right coronary artery disease (P<.001); and in group 3 (no ST-segment changes in lead V1), there were no significant differences concerning the narrowed vessel. Thallium-201 scintigraphy data confirmed the existence of the reversible perfusion defect(s) in an area(s) of myocardium supplied by the respective coronary arteries (P<.001). Exercise-induced ST-segment elevation or depression in V1 may identify the obstructed vessel in patients with single-vessel disease and without prior myocardial infarction.

QRS score improves diagnostic ability of treadmill exercise testing in women.

ObjectiveThe accuracy of treadmill exercise testing to detect coronary artery disease is limited in women. This study was undertaken to evaluate whether QRS score can improve the accuracy of treadmill exercise testing in women. MethodsThe study population consisted of 114 women with angina-like symptoms, who underwent both treadmill exercise testing and coronary angiography. The impact of QRS score on the standard ST-segment based diagnostic ability of treadmill exercise testing to detect coronary artery disease was studied. ResultsIncorporation of QRS score in standard ST-segment diagnostic criteria significantly enhanced sensitivity (from 59 to 80%), specificity (from 40 to 94%) and diagnostic accuracy (from 50 to 87%) of treadmill exercise testing. The QRS score was shown to reduce significantly the false-positive results from 60 to 6%. Furthermore, QRS score accuracy was correlated with the extent of coronary artery disease. The diagnostic ability of QRS score was greater both among patients with normal and impaired systolic function of the left ventricle. ConclusionsQRS score can improve the limited diagnostic accuracy of treadmill exercise testing in women, by predominantly decreasing the high prevalence of false-positive results.

Assessment of Time Domain and Spectral Components of Heart Rate Variability Immediately Before Ischemic ST Segment Depression Episodes

In an attempt to study autonomic function during the 5‐minute period preceding ischemic ST segment depression (↓ST) episodes, we selected 138 ↓ST episodes, without preceding ↓ST during the last 15 minutes before each episode, from the Holler tapes of 35 patients with multivessel coronary artery disease. For the 5‐minute period preceding each ↓ST episode, we calculated the following heart rate variability (HRV) indices; the mean RR interval (RR5), the standard deviation of all RR intervals (SD Index5), the corresponding coefficient of variation (CV5), and the natural log (Ln) of the spectral components, total power at 0.000 to 0.400 Hz (TP5), low frequency power at 0.040 to 0.150 Hz (LF5), high frequency power at 0.150 to 0.400 Hz (HF5), and the ratio of the low to high frequency power (LF5/HF5). As HRV indices of the 24‐hour period, we calculated the respective RR, SD Index, CV, LnTP, LnLF, LnHF, and Ln LF/HF. RR5, SD Index5, CV5, and LnTP5 were all significantly lower than RR (t =−5.343, p = 3.7 × 10−7), SD Index (t =−19.091, p = 1.99 × 10−40), CV(t ‐15.780, p = 1.28 × 10−32), and LnTP (t =−3.210, p = 0.0016), respectively. LnHF5 was inversely correlated with the magnitude of the ↓ST; r =−0.174, P < 0.05, and CV5 was inversely correlated with the natural log (Ln) of the ischemic event duration; r =−0.183, P < 0.05. Analogous results were obtained for both the painful and silent ↓ST episodes. It is concluded that HRV is decreased during the 5‐minute period preceding ↓ST episodes, and is inversely related with the magnitude and the duration of the ↓ST.

Role of right-sided chest leads in the detection of multivessel coronary artery disease in patients with extended Q-wave anterior myocardial infarction.

ObjectiveTo evaluate the improvement of diagnostic ability of exercise testing to detect multivessel coronary artery disease in patients with extended Q-wave anterior myocardial infarction, using additional right-sided chest leads. MethodsFifty-two consecutive patients with Q-wave anterior myocardial infarction underwent exercise testing, using the standard 12 and the additional right-sided (V3R, V4R, V5R) chest leads, thallium-201 scintigraphy and coronary arteriography. ResultsTwenty-one (40%) patients had one-vessel disease, 18 (35%) had two-vessel disease and 13 (25%) had three-vessel disease. The sensitivities of the standard 12-lead exercise testing and its combination with the additional right-sided chest leads were 24% (5/21) versus 28% (6/21) for the detection of one-vessel disease (P: NS), 33% (6/18) versus 83% (15/18) for the detection of two-vessel disease (P<0.05) and 38% (5/13) versus 92% (12/13) for the detection of three-vessel disease (P<0.05), respectively. In thallium-201 scintigraphy, 29 of the 31 (94%) patients with multivessel coronary artery disease demonstrated reversible ischemia. The usual 12-lead exercise testing could detect ischemia in 11 (35%) of these 31 patients, while the addition of the right-sided chest leads could detect ischemia in 27 (87%) of them (P<0.05). ConclusionsThe additional right-sided chest leads significantly improve the low sensitivity of the usual exercise testing to detect multivessel coronary artery disease in patients with previous extended Q-wave anterior myocardial infarction.

Exercise-induced st-segment variability may discriminate false positive tests

The clinical value of exercise-induced variations in ST-segment depression and R wave amplitude in consecutive sinus beats was studied in 160 patients who had a positive treadmill exercise test with the Bruce protocol. The patients, all of whom underwent cardiac catheterization, included 100 with coronary artery disease (CAD) (group with true positive test) and 60 with normal coronary arteries (group with false positive test). Minimal or no exercise-induced variations in the magnitude of ST-segment depression despite variations in R wave amplitude were observed in 84 of the 100 patients with CAD and in only 9 of the 60 patients with normal coronary arteries (P < .0001). Significant exercise-induced variations in ST-segment depression were observed in only 16 of 100 patients with CAD and in 51 of 60 patients with normal coronary arteries (P < .0001). The coefficient of variation of R wave amplitude was similar in both groups (no statistical significance), while the coefficient of variation of ST-segment depression was much greater in the patients with normal coronary arteries than in those with CAD (P < .0001). It is concluded that variability of ST-segment depression at peak exercise may discriminate false positive from the true positive exercise tests, improving the diagnostic ability of the method.