Exercise thallium-201 scintigraphy in the localization of myocardial ischaemia

We performed a retrospective study in order to study the ability of thallium-201 exercise scintigraphy to detect and to localize coronary artery perfusion defects (in comparison with a recent coronary angiogram). We studied 81 patients (67 males); their average age was 52.3 years (men 50.5 and women 54.1 years). They performed a pulse-conducted cycle exercise test, and 2 min before end of exercise 75 MBq of thallium-201 was infused intravenously, and tomographic images were reconstructed by using a Siemens-Rota SPECT gamma camera immediately and 4 h after exercise. The thallium-201 uptake defects were attributed to different coronary arteries, and the results were compared with a coronary angiogram made afterwards in 48 patients. The groups of one-, two- and three-vessel disease were 27, 21, and 21 patients, and only 12 patients did not have significant (over 50%) stenoses. The latter had the highest ejection fraction and working capacity. Sensitivity of thallium-201 exercise scintigraphy was 65%, whereas that of exercise ECG was 41% in patients with a low ejection fraction, while in the whole material the sensitivity of thallium-201 scintigraphy was 91% and that of exercise ECG was 54%. A stenosis in the right coronary artery was best localized by the thallium-201 scintigram (86% correctly); a stenosis in the left anterior descending artery was localized correctly in 75% of the cases, but a stenosis in left circumflex artery was localized correctly only in 44%. We conclude that exercise thallium-201 scintigraphy is a useful method not only in detecting but also in localizing coronary artery disease.     

Computerized two-lead resting ECG analysis for the detection of coronary artery stenosis

BACKGROUND: Resting electrocardiogram (ECG) shows limited sensitivity and specificity for the detection of coronary artery disease (CAD). Several methods exist to enhance sensitivity and specificity of resting ECG for diagnosis of CAD, but such methods are not better than a specialist's judgement. We compared a new computer-enhanced, resting ECG analysis device, 3DMP, to coronary angiography to evaluate the device's accuracy in detecting hemodynamically relevant CAD. METHODS: A convenience sample of 423 patients without prior coronary revascularization was evaluated with 3DMP before coronary angiography. 3DMP's sensitivity and specificity in detecting hemodynamically relevant coronary stenosis as diagnosed with coronary angiography were calculated as well as odds ratios for the 3DMP severity score and coronary artery disease risk factors. RESULTS: 3DMP identified 179 of 201 patients with hemodynamically relevant stenosis (sensitivity 89.1%, specificity 81.1%). The positive and negative predictive values for identification of coronary stenosis as diagnosed in coronary angiograms were 79% and 90% respectively. CAD risk factors in a logistic regression model had markedly lower predictive power for the presence of coronary stenosis in patients than did 3DMP severity score (odds ratio 3.35 [2.24-5.01] vs. 34.87 [20.00-60.79]). Logistic regression combining severity score with risk factors did not add significantly to the prediction quality (odds ratio 36.73 [20.92-64.51]). CONCLUSIONS: 3DMP's computer-based, mathematically derived analysis of resting two-lead ECG data provides detection of hemodynamically relevant CAD with high sensitivity and specificity that appears to be at least as good as those reported for other resting and/or stress ECG methods currently used in clinical practice.     

Computerized two-lead resting ECG analysis for the detection of coronary artery stenosis after coronary revascularization

Background: Resting electrocardiogram (ECG) shows limited sensitivity and specificity for the detection of coronary artery disease (CAD), where patients with a history of coronary revascularization may pose special challenges. Several methods exist to enhance sensitivity and specificity of resting ECG for diagnosis of CAD, but such methods are not better than a specialist''s judgement. We compared a new computer-enhanced, resting ECG analysis device, 3DMP, to coronary angiography to evaluate the device''s accuracy in detecting hemodynamically relevant CAD.Methods: A convenience sample of 172 patients with a history of coronary revascularization scheduled for coronary angiography was evaluated with 3DMP before coronary angiography. 3DMP''s sensitivity and specificity in detecting hemodynamically relevant coronary stenosis as diagnosed with coronary angiography were calculated as well as odds ratios for the 3DMP severity score and coronary artery disease risk factors.Results: The 3DMP system accurately identified 50 of 55 patients as having hemodynamically relevant stenosis (sensitivity 90.9%, specificity 88.0%). Positive and negative predictive values for the identification of coronary stenosis as diagnosed in coronary angiograms were 62.7% and 97.8% respectively. Risk and demographic factors in a logistic regression model had a markedly lower predictive power for the presence of coronary stenosis in these patients than did 3DMP severity score (odds ratio 2.04 [0.74-5.62] vs. 73.57 [25.10-215.68]). A logistic regression combining severity score with risk and demographic factors did not add significantly to the prediction quality (odds ratio 80.00 [27.03-236.79]).Conclusions: 3DMP''s computer-based, mathematically derived analysis of resting two-lead ECG data provides detection of hemodynamically relevant CAD in patients with a history of coronary revascularization with high sensitivity and specificity that appears to be at least as good as those reported for other resting and/or stress ECG methods currently used in clinical practice.     

Electrocardiographic prediction of the severity of aortic valvular stenosis

The ECG at rest and at 4 min after a symptom-limited exercise test was studied in 52 patients who were catheterized because a significant aortic valvular stenosis was suspected. The calculated valve area ranged from 0.2 to 1.1 cm2/m2 BSA. QRS amplitude criteria did not discriminate between slight and severe stenoses but a negative or biphasic T wave in lead V6 did, especially after exercise. Thirty-three of the 37 patients with an area of less than or equal to 0.5 cm2/m2 BSA showed negative/biphasic TV6 after exercise but only 4 of the 15 with an area of greater than or equal to 0.6 cm2/m2 BSA. Thus, this criterion had a sensitivity for stenoses less than or equal to 0.5 cm2/m2 BSA of 89%, a specificity of 73% and a predictive value of a positive test of 89% (the pre-test likelihood being 71%). The left ventricular pressures measured during supine exercise in 38 patients did not correlate to the TV6 patterns after exercise.     

Comparison of 18F SPECT with PET in myocardial imaging: A realistic thorax-cardiac phantom study

Background

Cardiac syndrome X is defined by a typical angina pectoris with normal or near normal (stenosis <40%) coronary angiogram with or without electrocardiogram (ECG) change or atypical angina pectoris with normal or near normal coronary angiogram plus a positive none-invasive test (exercise tolerance test or myocardial perfusion scan) with or without ECG change. Studies with myocardial perfusion imaging on this syndrome have indicated some abnormal perfusion scan. We evaluated the role of myocardial perfusion imaging (MPI) and also the severity and extent of perfusion abnormality using Tc-99m MIBI Single Photon Emission Computed Tomography (SPECT) in these patients.

Methods

The study group consisted of 36 patients with cardiac syndrome X. The semiquantitative perfusion analysis was performed using exercise Tc-99m MIBI SPECT. The MPI results were analyzed by the number, location and severity of perfusion defects.

Results

Abnormal perfusion defects were detected in 13 (36.10%) cases, while the remaining 23 (63.90%) had normal cardiac imaging. Five of 13 (38.4%) abnormal studies showed multiple perfusion defects. The defects were localized in the apex in 3, apical segments in 4, midventricular segments in 12 and basal segments in 6 cases. Fourteen (56%) of all abnormal segments revealed mild, 7(28%) moderate and 4 (16%) severe reduction of tracer uptake. No fixed defects were identified. The vessel territories were approximately the same in all subjects. The Exercise treadmill test (ETT) was positive in 25(69%) and negative in 11(30%) patients. There was no consistent pattern as related to the extent of MPI defects or exercise test results.

Conclusion

Our study suggests that multiple perfusion abnormalities with different levels of severity are common in cardiac syndrome X, with more than 30 % of these patients having at least one abnormal perfusion segment. Our findings suggest that in these patients microvascular angina is probably more common than is generally believed.     

Detection of coronary artery disease by means of exercise ECG in patients with aortic stenosis

In a preoperative evaluation, 35 consecutive patients with aortic stenosis were examined by means of exercise ECG, Doppler and direct manometric measurements of the pressure difference over the aortic valve (delta P) and angiocardiography. Coronary artery disease (CAD) was found in 43% of the patients. Those with CAD had a lower mean maximum physical performance expressed as a percentage of the normal value (Wmax%), larger ST depressions and a higher effort angina (EA) score at the exercise test than the non-CAD group. Mean delta P was equal in the two groups. A myocardial coronary obstruction score covariated positively with a coronary insufficiency index (CT index = 100 X STdepr/Wmax%) and the EA score. There was no correlation between delta P and the EA score or the CI index. A CI index less than 3 and an EA score less than 2 were found in 49% of the patients and excluded the presence of CAD with a predictive accuracy of 88%, a better diagnostic complement to coronary arteriography than a history of EA.     

ST changes in relation to heart rate during bicycle exercise in patients with coronary artery disease

Exercise test on cycle ergometer and coronary angiography were performed on 190 patients with chest pain. Volunteers with a normal thallium scintigraphy (n = 47) served as controls. The load started at 20 W and increased at a rate of 10 W min-1 until exhaustion or symptoms. Conventional 12-lead ECGs were recorded by means of computer before, during and after exercise. Minimum ST amplitude 60 ms after the STJ point (ST60) at end of work with a cut-off level of -1.10 mm had a sensitivity of 69% (52/75) and a specificity of 89% (37/42) when individuals with a normal resting ECG were considered. ST80 and sum of ST60 in left ventricular leads had slightly lower values of sensitivity and specificity. Changes in ST60 during exercise discriminated less well between the groups. Final heart rate during exercise (less than 148 min-1) had a sensitivity of 88% (53/60) and a specificity of 89% (42/47). The change in heart rate during exercise (less than 66 min-1) had a sensitivity of 50/60 (only patients without beta-blockers were considered). The best discrimination was obtained by defining a test score (TS) according to the linear equation TS = 2.95-0.23 x HRE-0.301 X ST60 where a positive value indicates a positive test and a negative value a negative test. Sensitivity and specificity were 21/23 (91%) and 40/42 (95%), respectively. The test score was also calculated in those patients having significant coronary disease and an abnormal resting ECG (no bundle branch block, no beta-blockers) and this yielded a sensitivity of 30/34.     

运动平板心电图与24小时动态心电图在诊断冠心病中的应用价值对比

目的分析运动平板心电图和24小时动态心电图应用于冠状动脉粥样硬化性心脏病诊断的临床价值。方法选取通过冠脉造影进行确诊冠心病患者56例,分别采取运动平板心电图及24小时动态心电图检查,对比两组检查措施诊断冠状动脉粥样性心脏的特异度及敏感度。结果运动平板心电图诊断冠心病的特异度为46.2%,敏感度为86%,24小时动态心电图诊断冠心病的特异度为62.5%,敏感度为75%。两组者比较差异无统计学意义(P0.05)。结论运动平板心电图及24小时动态心电图应用于冠心病的诊断均具有较好的临床价值,为提高冠心病的临床诊断准确度,应当联合上述两种诊断手段。     

缺血修饰白蛋白及肌红蛋白在急性冠脉综合征早期的诊断意义

目的:评价缺血修饰白蛋白(IMA)、肌红蛋白(Mb)及心电图(ECG)对急性冠脉综合征(ACS)的早期诊断价值。方法:115例在发病6h内就诊的ACS患者,包括不稳定性心绞痛(UA组)67例和心肌梗死(MI组)48例,均行心电图检查和血清IMA、Mb水平测定,并与对照组比较各组IMA及Mb水平差异,分析IMA、Mb和ECG单项或联合诊断ACS的敏感性。结果:UA和MI两组IMA水平均明显升高,而Mb仅在MI组升高,IMA单项诊断ACS的敏感度为88.70%,明显高于Mb(51.30%)和ECG(47.83%);IMA联合ECG或Mb以及三者联合诊断ACS的敏感度高达93.04%、94.78%及97.39%,均高于单项诊断的敏感性。结论:IMA是早期诊断ACS的敏感生化指标,尤其对UA的诊断有着较高的敏感性,IMA、Mb及ECG联合检测,可进一步提高对ACS的早期诊断价值。     

Multifocal inflammatory leukoencephalopathy: use of thallium-201 SPECT and proton MRS

In a patient receiving 5-fluorouracil and levamisole, neurologic deficits suggest the cerebral demyelinating syndrome as a differential diagnosis. The authors report a patient diagnosed as multifocal inflammatory leukoencephalopathy for which thallium-201 (201Tl) single photon emission computed tomography (SPECT) and proton magnetic resonance spectroscopy (MRS) were employed as noninvasive diagnostic tools. 201Tl SPECT study was negative and proton MRS showed an increase of choline and lactate and well preserved N-acetylaspartate. These findings support histopathologic findings of multifocal inflammatory leukoencephalopathy revealing demyelination with relative axonal sparing in the patient.     

Ergometry and long-term ECG for assessing bradycardiac and tachycardiac heart rhythm disorders in symptomatic patients over 70

The usefulness of exercise testing and long term-ECG recording in old age was evaluated in a retrospective study. During a period of 24 months 317 long-term-ECGs in 195 patients greater than 70 years and 208 exercise tests in patients greater than 70 years were performed. The mean age of the patients was 73 +/- 3 years. Long-term ECG revealed a high incidence of supraventricular arrhythmias, while PVCs were found in only 28.7% of patients and PVCs greater than 30/h in only 7.3% of patients. Complex ventricular arrhythmias occurred in 25% of patients. Long-term ECG recording appeared to be of particular value in detecting abnormal regulation of heart rate and bradycardia, although symptom correlation with arrhythmias recorded was rare. Exercise testing revealed a higher incidence of PVCs with PVCs recorded in 67% of patients and PVCs greater than 2/min in 42% of patients. The incidence of complex ventricular arrhythmias was slightly greater compared to long-term recording with 29% of all patients. Exercise testing was particularly useful in detecting complex arrhythmias in patients with additional signs of myocardial ischemia (ST-segment depression and/or angina pectoris during increasing levels of exercise). Thus comparing both exercise testing and long-term ECG both appeared to be useful methods to uncover arrhythmias in symptomic patients older than 70 years and have to be considered as complementary tools. Exercise testing is particularly useful in recovering complex ventricular arrhythmias in patients with signs of myocardial ischemia during exercise. Long-term ECG on the other hand allows better recognition of bradycardias and conduction defects that may also be present and may contribute to the patients symptoms.     

Problems of Mason-Likar lead system in treadmill exercise electrocardiography

A Mason-Likar (M-L) leads system has been widely used in the exercise electrocardiography (ECG) using treadmill for the detection of myocardial ischemia. In routine treadmill exercise ECG using M-L lead, we often observe different patterns of ST-T forms those of II, III and aVF on bipolar leads. In this study, on 213 patients, conventional 12 lead ECG and the M-L lead placement ECG were recorded both at supine and standing positions. A careful analysis was made on all the records of patterns, durations, and amplitudes of QRS and T waves. We also evaluated the ST trendgram of patients with no ischemic changes proven exercise TI-201 myocardial single photon emission tomography (SPECT). Quantitative examination showed no significant differences between those in precordial leads of the standard and the M-L lead system in any subjects. The augmented amplitude of QRS and T waves, the disappearance of abnormal Q-waves in II, III, aVF lead, the negative inversion in QRS phase in lead aVL an left axis deviation were often recognized with M-L lead placement. In treadmill exercise ECG, ST depression more than 1 mm in II, III, aVF lead was noted 14 out of 17 patients with no ischemic changes. The all ST-T changes showed "not-decrescendo" type in ST trendgram. We concluded that rigorous evaluation for electrical axis, the configuration of ST-T waves and the existence of myocardial ischemia in leads II, III, aVF was necessary on treadmill exercise ECG using M-L lead replacement.     

Compartmental multivariate analysis of exercise ECGs for accurate detection of myocardial ischaemia

An accurate computer-assisted diagnostic method for detection of myocardial ischaemia, called MUSTA, is developed. MUSTA is based on compartmental multivariate analysis of variables available in the exercise ECGs, and is definitively implemented in Prolog. It is heuristically developed by determining diagnostic criteria, which interrelate a modified ST/HR-slope, ST-segment value and shape, and maximum heart rate, so that concordance with the Tl-201 SPECT is maximised. In the learning group consisting of 47 patients, MUSTA provides a diagnostic accuracy of 98%, the detection of ischaemia being in absolute concordance with Tl-201 SPECT. MUSTA is evaluated in a similar but independent group of 60 patients. Then, accuracy is 90%, and sensitivity is 94%. The performance characteristics are significantly better than those of the standard exercise ECG, whose diagnostic accuracy in these groups is 77% and 70%, respectively. This study suggests that MUSTA is a significant improvement for computerised assessment of myocardial ischaemia.     

Compartmental multivariate analysis of exercise ECGs for accurate detection of myocardial ischaemia

An accurate computer-assisted diagnostic method for detection of myocardial ischaemia, called MUSTA, is developed. MUSTA is based on compartmental multivariate analysis of variables available in the exercise ECGs, and is definitively implemented in Prolog. It is heuristically developed by determining diagnostic criteria, which interrelate a modified ST/HR-slope, ST-segment value and shape, and maximum heart rate, so that concordance with the Tl-201 SPECT is maximised. In the learning group consisting of 47 patients, MUSTA provides a diagnostic accuracy of 98%, the detection of ischaemia being in absolute concordance with Tl-201 SPECT. MUSTA is evaluated in a similar but independent group of 60 patients. Then, accuracy is 90%, and sensitivity is 94%. The performance characteristics are significantly better than those of the standard exercise ECG, whose diagnostic accuracy in these groups is 77% and 70%, respectively. This study suggests that MUSTA is a significant improvement for computerised assessment of myocardial ischaemia.     

Coronary artery disease diagnosis based on exercise electrocardiogram indexes from repolarisation,depolarisation and heart rate variability

Several indexes have been reported to improve the accuracy of exercise test electrocardiogram (ECG) analysis in the diagnosis of coronary artery disease (CAD), compared with the classical ST depression criterion. Some of them combine repolarisation measurements with heart rate (HR) information (such as the so-called ST/HR hysteresis); others are obtained from the depolarisation period (such as the Athens QRS score); finally, there are heart rate variability (HRV) indexes that account for the nervous system activity. The aim of this study was to identify the best exercise ECG indexes for CAD diagnosis. First, a method to automatically estimate repolarisation and depolarisation indexes in the presence of noise during a stress test was developed. The method is divided into three stages: first, a preprocessing step, where QRS detection, filtering and baseline beat rejection are applied to the raw ECG, prior to a weighted averaging secondly, a post-processing step in which potentially noisy averaged beats are identified and discarded based on their noise variance; finally, the measurement step, in which ECG indexes are computed from the averaged beats. Then, a multivariate discriminant analysis was applied to classify patients referred for the exercise test into two groups: ischaemic (positive coronary angiography) and low-risk (Framingham risk index<5%). HR-corrected repolarisation indexes improved the sensitivity (SE) and specificity (SP) of the classical exercise test (SE=90%, SP-79% against SE=65%, SP=66%). Depolarisation indexes also achieved an improvement over ST depression measurements (SE=78%, SP=81%). HRV indexes obtained the best classification results in our study population (SE=94%, SP=92%) by means of the very high-frequency power (VHF) (0.4–1 Hz) at stress peak.     

Left ventricular response to graded isometric exercise in patients with coronary heart disease

The effects of graded isometric exercise on left ventricular performance were characterized in 11 male patients (53 +/- 2 years) with coronary artery disease (CAD) and in 12 normal subjects (11 male and one female 35 +/- 5 years). The echocardiographic indices of left ventricular function at rest were similar in both groups. Heart rate and blood pressure increased significantly in both groups in response to 40 and 60% of handgrip maximal voluntary contraction (MVC). Left ventricular end-diastolic dimension increased significantly (from 50 +/- 1 to 56 +/- 1 mm; P less than 0.01) with 60% of MVC in CAD group but not in the healthy subjects. The patients with CAD also exhibited significant (P less than 0.01) increases in end-systolic dimension (from 34 +/- 1 to 40 +/- 2 with 40% and to 44 +/- 1 mm with 60% MVC). End-diastolic and end-systolic dimensions did not change during isometric exercise in the healthy subjects. In the CAD group mVCF decreased significantly (from 1.08 +/- 0.06 to 0.86 +/- 0.06 with 40% and to 0.74 +/- 0.04 d . s-1 with 60% MVC; P less than 0.01). At comparable mean blood pressures, mVCF was significantly lower in the CAD group than in normal subjects. These results demonstrate that progressive deterioration of left ventricular function during increasing levels of isometric exercise in patients with CAD can be detected with echocardiography.     

Association between hepatitis B surface antibody seropositivity and coronary artery disease

BACKGROUND: Specific infectious agents have been found to be related to the pathogenesis of coronary atherosclerosis. AIMS: We assessed the possible association between angiographically proven coronary artery disease (CAD) and hepatitis B surface antibody (HBS Ab) seropositivity in a population with relatively high prevalence of hepatitis B virus (HBV) infection. SETTING AND DESIGN: This was a cross-sectional study. MATERIALS AND METHODS: We analyzed data from 830 consecutive subjects undergoing coronary angiography, including angiographic results reported by two cardiologists for inter-observer reliability and assessment of HBS Ab status determined by enzyme-linked immunosorbent assay (ELISA). STATISTICAL ANALYSIS USED: Chi-square test or Fisher's exact test, independent two-sample t test and the Pearson's Correlation Coefficient test were used, as required. Statistics were performed using SPSS software version 13 (SPSS, Chicago, IL). RESULTS: Two hundred forty-nine (30%) subjects had normal angiogram or minimal CAD, and 581 (70%) had significant CAD in at least one major coronary artery. In patients with CAD and in patients without angiographic evidence of significant atherosclerosis, 28.7% and 28.9% respectively were positive for HBV (P=0.954). Mean C-reactive protein levels in subjects with positive and negative HBS Ab were 10.77+/-8.37 mg/L versus 10.33+/-7.64 mg/L respectively (P=0.465). However, C-reactive protein levels in CAD group were significantly higher (P<0.001). CONCLUSIONS: Our results suggested hepatitis B surface antibody seropositivity has no relationship with coronary artery disease. Moreover, no significant linear correlation exists between HBS Ab and C-reactive protein levels. However, as previously shown, C-reactive protein level in patients with coronary artery disease is significantly higher than in patients with normal coronary arteries.     

Exercise test in patients with sarcoidosis. The importance of repolarization disturbances

The study population comprises 28 patients with sarcoidosis who all had repolarization disturbances in their exercise ECGs. None of the patients had hypertension or known cardiovascular disease, and all but two were non-smokers. The mean age was 45 years. Exercise test with beta-adrenergic blockade was performed within one month of the first examination. Persisting abnormal ST-T changes in exercise ECGs after beta-blockade were seen in 12 (43%) patients. No significant relationship was found between persisting ST-T changes and age, sex, chest X-ray stage, lung function or working capacity. In an earlier study, we found ST-T abnormalities in exercise ECG in 56 of 127 individuals (44%) in a consecutive 5-year study of patients with newly detected sarcoidosis. From this and the present report we postulate that, in our region, as much as 20% of the patients with newly detected sarcoidosis might have organic myocardial disease, possibly of sarcoid origin, as shown by repolarization disturbances in exercise ECG. If ECG abnormalities in the ST-T region are present in patients with sarcoidosis, exercise ECG with beta-blockade is a simple way of establishing suspicion of organic myocardial lesions. If exercise ECG abnormalities in the ST-T region persist after beta-blockade, careful clinical follow-up is recommended, and, in some patients early steroid therapy should be considered.     

The association between coronary arterial dominancy and extent of coronary artery disease in angiography and paraclinical studies

The association between coronary arterial dominance patterns and the coronary artery diameter, length, and valvular heart diseases were previously studied. However, its association with coronary artery disease (CAD) is unclear. We investigated to determine whether the extent and localization of CAD differ in right, left, or codominant coronary arterial patterns. Twelve thousand five hundred fifty-eight patients admitted to Tehran Heart Center for coronary angiography were studied retrospectively (2004-2006). The extent and localization of CAD and the dominant artery were determined. There were 62.7% males. The mean age was 57.6 +/- 10.3. 84.2% [95% confidence interval (CI); 83.6-84.8%], 10.9% (95% CI; 10.4-11.4%), and 4.8% (95% CI; 4.4-5.2%) of the patients were right, left, and codominant, respectively; No significant difference considering age, sex, positive family history, hypertension, hyperlipidemia, electrocardiography, exercise treadmill stress test, and perfusion scan were seen in the groups. The right-dominant patients tend to have three-vessel disease (33.1% vs. 27%, P < 0.0001), stenosis of more than 50% in right coronary artery (65.9% vs. 57.9%, P < 0.0001) and left circumflex territories (64% vs. 59.4%, P = 0.01), more than the left-dominant patients. The involvements of the left main coronary artery, left anterior descending artery territory, and posterior descending artery were not significantly different. This study demonstrates a relationship between angiographic CAD severity, and the involved arterial territory and dominancy patterns.     

Exercise stress testing in angina patients with positive response to hyperventilation testing: influence of the coronary artery tone

We studied the exercise stress test and the coronary artery tone in two groups of angina patients with comparable coronary atherosclerosis. Group I (20 males and 5 females, mean age 53.5 years) with a positive, and group II (22 males and 3 females, mean age 52.5 years) with a negative response to the hyperventilation test (HVT). A positive exercise stress test (ST depression greater than or equal to 1 mm) was found in 24 patients in group I vs. 15 in group II (p less than 0.01), despite a lower maximal rate pressure product (198 +/- 11.2 vs. 236 +/- 10.1, p less than 0.05) and maximal work load (110 W +/- 7.1 vs. 136 +/- 7.4 W, p less than 0.02) in group I. A high coronary artery tone (dilatation (DIL%) of the coronary arteries after nitroglycerin greater than or equal to 10%) was found in 18 patients in group I and in 4 in group II (p less than 0.01). DIL% was 22.6 +/- 3.8 vs. 5.8 +/- 1.4 in groups I and II, respectively (p less than 0.005). DIL% was significantly related to persistence of ST depression after exercise (r = 0.36, p less than 0.05), and 21 of 22 patients with high tone had a positive exercise stress test vs. 18 of 28 with low tone (p less than 0.05). These findings suggest that the coronary artery tone influences the response to exercise in some patients with angina. Since the patients in group I were identified by HVT, our results underline the clinical relevance of this test.