Carl A.P.L. Ascoop

Exercise test, history, and serum lipid levels in patients with chest pain and normal electrocardiogram at rest: Comparison to findings at coronary arteriography

In a series of 96 patients with chest pain, and a normal ECG at rest, the results of a GXT, the history, and the serum lipid levels were compared to the findings at coronary arteriography. In addition, in 91 subjects a modified two-step test was performed. To characterize quantitatively and in one number the relation to the coronary arteriogram, use was made of the index of merit (T) which ranges from 0 to 1. The following indices were found: history, 0.59; GXT, 0.53; serum β-lipoprotein, 0.37; serum cholesterol, 0.28; and two-step test, 0.26. In 30 subjects the statements of the history, the GXT, and serum β-lipoprotein were concordant. In this category the agreement with the coronary arteriogram was excellent (T = 0.93). In 64 subjects the statements by the history and the GXT were concordant, but the serum β-lipoprotein level was at variance. For this group T = 0.82. For the entire series the best result was obtained if the decision was made according to two or three identical statements, which resulted in an index of merit of 0.67.

Dipyridamole thallium testing: noncardiac side effects, cardiac effects, electrocardiographic changes and hemodynamic changes after dipyridamole infusion with and without exercise

Thallium-201 scintigraphy in combination with intravenous dipyridamole has been reported to be useful in patients who are unable to perform maximal exercise stress testing. Few reports have dealt with side effects in large numbers of patients. For that reason noncardiac side effects, cardiac effects, electrocardiographic changes, as well as hemodynamic changes were studied in 301 consecutive patients, examined by dipyridamole thallium-201 imaging because of suspected coronary artery disease. The patients were divided into two groups (A and B). Patients in group A (101 patients) received an infusion of 0.14 mg/kg per minute dipyridamole for four minutes. Patients in group B (200 patients) received the same dose of dipyridamole followed by low level exercise (60 rpm/30 Watts) for three minutes to achieve maximal coronary blood flow and to diminish thallium-201 uptake in the gastrointestinal organs. The likelihood of having hemodynamically significant coronary artery disease was the same in both groups. Patients in group B experienced significantly less side effects than patients in group A (11% vs 43%, P less than 0.05). In group B changes in systolic blood pressure (P less than 0.05), heart rate (P less than 0.05), and rate pressure product (P less than 0.05) were more distinct. The occurrence of angina was the same in both groups (47% vs 44%, NS), but ischemic ST segment changes were significantly more frequent in group B than in group A (25% vs 12%, P less than 0.05). Thus, exercise added to dipyridamole infusion compared to dipyridamole infusion alone results in fewer noncardiac side effects, the same prevalence of angina pectoris, and a higher incidence of ST segment changes.

Exercise capacity after His bundle ablation and rate response ventricular pacing for drug refractory chronic atrial fibrillation

OBJECTIVE: To evaluate exercise capacity of patients with chronic atrial fibrillation in whom His bundle ablation followed by ventricular rate response pacing (VVIR) was carried out because of drug refractoriness. DESIGN: Prospective study. PATIENTS: 25 consecutive patients, all with chronic symptomatic drug refractory atrial fibrillation, underwent His bundle ablation. Before this intervention all patients were on antiarrhythmic drugs to attain acceptable heart rate control and to relief symptoms. MAIN OUTCOME MEASURES: Exercise capacity, including measurements of VO2, was examined before and after a mean interval of seven months following His bundle ablation. RESULTS: Exercise capacity after His bundle ablation increased from a mean of 109 (SD 49) W to 118 (46) W (P < 0.002), but VO2 at peak exercise did not change significantly. Maximum exercise capacity was achieved with a significantly lower maximum driven heart rate than the spontaneous heart rate before ablation. CONCLUSIONS: Exercise capacity of patients who underwent His bundle ablation followed by VVIR pacing remained unchanged or improved during a mean follow up of seven months. Larger patient populations with longer follow up are necessary to examine determinants of improved exercise capacity.

Combined assessment of technetium-99m SESTAMIBI planar myocardial perfusion images at rest and during exercise with rest/exercise left ventricular wall motion studies evaluated from gated myocardial perfusion studies

The favorable physical characteristics of technetium-99m-labeled 2-methoxy-2-methylisopropyl-1-isonitril (Tc-SESTAMIBI) enable the combined evaluation of both myocardial perfusion and left ventricular wall motion. To assess the potential of rest and exercise regional myocardial function as an adjunct to planar myocardial perfusion imaging, 60 patients with coronary artery disease and documented arteriographic findings were studied with both protocols during a single study. Exact segmental concordance between myocardial perfusion and wall motion studies was 77% (701/900 segments). Overall sensitivity and specificity to detect hemodynamically significant coronary artery disease with Tc-SESTAMIBI myocardial perfusion imaging were 89% and 79%, respectively, with resting wall motion studies 83% and 71%, respectively, and with rest/exercise wall motion studies, 85% and 71%, respectively. If the results of both perfusion and rest/exercise studies were combined, sensitivity increased to 96% and specificity decreased to 64%. The differences with perfusion studies alone were not statistically significant. Thus despite a good correlation between regional left ventricular function and perfusion, no statistically significant incremental diagnostic value was found when the results of both perfusion and wall motion studies were combined.

The influence of anatomic evolution of coronary artery disease on left ventricular contraction: An angiographic follow-up study of 300 nonoperated patients

The impact of the evolution of obstructive coronary artery disease (CAD) on left ventricular (LV) function was studied in 300 nonoperated patients who had had two angiographic studies. The interval between studies ranged from 6 months to 10 years (mean 29.6 months). Quantitative analysis of LV contractions in right anterior oblique projections was performed with the use of a computer program for calculation of ejection fraction (EF) and regional wall motion (RWM) according to the method of Leighton. No progression of CAD was found in 131 patients. Progression of CAD was found in 169 patients. In the patients without progression and in 75 patients who had progression to less than total obstruction, no changes in EF and RWM were found. In the 67 patients in whom progression from less than 90% narrowing to occlusion had occurred a significant decrease in EF and RWM was found. In the 27 patients with progression from subtotal narrowing to occlusion, however, no change in LV function was found. A myocardial protective value of angiographically visible preexistent collaterals could not be demonstrated. We conclude that absence of progression of CAD implies that LV function does not deteriorate and that slow progression to occlusion, via a stage of subtotal narrowing, generally does not influence LV function.

The accuracy of 1-day dual-isotope myocardial SPECT in a population with high prevalence of coronary artery disease

Background: In order to evaluate the diagnostic efficacy of the 1-day separate acquisition dual-isotope single-photon emission computed tomography (SPECT) protocol, using 201Tl for the rest and 99mTc-tetrofosmin for the stress images, a consecutive series of patients with suspected or known coronary artery disease (CAD) was studied that also underwent coronary angiography. Methods: The results of myocardial SPECT, using a semi-quantitative visual analysis, were acquired in 123 patients and compared with the results of coronary angiography. Sensitivity and specificity were calculated, using thresholds of ≥50 and ≥70% stenosis. As an alternative for specificity, the normalcy rate was determined in a separate group of 87 patients with a <5% pre-test likelihood of CAD. Results: The prevalence of CAD using ≥50 and ≥70% stenosis was 88 and 78%, respectively. The sensitivity for detection of patients with ≥50 and ≥70% stenosis was 94 and 97%, respectively while specificity was 62 and 59%, respectively. The high rate of false positive perfusion defects resulting in a low specificity could be explained by specific clinical issues. However, the routine assessment with additional clinical and electrocardiographic data resulted in a correct interpretation of most of the false positive perfusion defects. The positive predictive value was 92 and 85% and the negative predictive value 46 and 77%, using thresholds of ≥50 and ≥70% stenosis, respectively. The normalcy rate was 91%. Conclusion: The one-day separate acquisition rest 201Tl/stress 99mTc-tetrofosmin SPECT protocol is an efficient procedure for myocardial perfusion scintigraphy with high sensitivity for detection of CAD. Specific clinical issues caused a low value for specificity. Therefore, clinical information and knowledge of the electrocardiogram is essential for a correct interpretation of SPECT images.

99Tcm-SESTAMIBI for planar myocardial perfusion imaging; not as ideal as the physical properties

99Tcm-methoxyisobutyl isonitrile (Tc-SESTAMIBI) has recently been introduced as a new myocardial perfusion agent which exhibits ideal physical properties for imaging with the gamma camera. To assess the diagnostic accuracy of planar Tc-SESTAMIBI, myocardial perfusion imaging was performed in 60 consecutive patients at rest and during exercise. The results were compared with coronary angiographie findings, obtained within 3 months of the exercise test. Planar 201Tl images were also performed on the same day and to the same level of stress as the Tc-SESTAMIBI exercise. Exact segmentai agreement between Tc-SESTAMIBI and 201Tl was 77%. Nineteen per cent of all 900 segments demonstrated ischaemia with Tc-SESTAMIBI and 20% with 201Tl.The overall sensitivity for detecting haemodynamically significant coronary artery disease with Tc-SESTAMIBI was 86% and specificity was 78%; with 201Tl the values were 89 and 78%, respectively (differences not significant). Vessel-specific comparative detection rates revealed no statistical significant differences between both radiopharmaceuticals. Intra-observer variability for Tc-SESTAMIBI images was 12% and for 201Tl it was 14%. Inter-observer variability for Tc-SESTAMIBI was 14% and for 2O1T117%.Although the physical characteristics of Tc-SESTAMIBI allow crisp and clear high-count density imaging, no significant differences are found when planar images are compared with 201Tl and are well within observer variabilities.

Is quantitative analysis superior to visual analysis of planar thallium 201 myocardial exercise scintigraphy in the evaluation of coronary artery disease ? Analysis of a prospective clinical study

Quantitative analysis of myocardial exercise scintigraphy has been previously reported to be superior to visual image interpretation for detection of the presence and extent of coronary artery disease. Computer analysis of perfusion defects and washout rate of thallium 201 was performed on scintigrams from a group of 131 consecutive patients (prospective group), using criteria defined from a previous group of 72 patients (initial group), and compared with visual interpretation of scintigrams for detection and evaluation of coronary artery disease. The sensitivity of the quantitative technique with regard to overall detection of coronary artery disease was not significantly different from the visual method (69% and 74%, respectively), whereas the specificity was higher (86% and 68%). Quantitative analysis did not increase the sensitivity of thallium imaging over the visual method in the left anterior descending artery (46% vs 65%) and the right coronary artery (51% vs 72%) but did increase sensitivity in the left circumflex artery (75% vs 47%). Whereas in the initial group quantitative analysis resulted in a better identification of multivessel disease (sensitivity 81 % vs 57%), in the prospective group sensitivity decreased (54% vs 67%) without significant loss of specificity. The initial group had a 40% incidence of three-vessel disease and the prospective group, 22% (P < 0.05). One-vessel disease was higher in the prospective group (32% vs 11%,P < 0.05). Thus, assessing the quantitative technique in a larger prospective patient population, there was no improvement of detection of the presence and extent of coronary artery disease when compared with visual interpretation.

Quantitative thallium-201 myocardial exercise scintigraphy in normal subjects and patients with normal coronary arteries

Quantitative thallium-201 myocardial exercise scintigraphy was tested in two patient populations representing alternative standards for cardiac normality: group I comprised 18 male uncatheterized patients with a low likelihood of coronary artery disease (CAD); group II contained 41 patients with normal coronary arteriograms. Group I patients were younger, they achieved a higher rate-pressure product than group II patients; all had normal findings by physical examination and electrocardiography at rest and exercise. Group II patients comprised 21 females, 11 patients showed abnormal electrocardiography at rest, and five patients showed ischemic ST depression during exercise. Twelve patients had signs of minimal CAD. Twelve patients revealed abnormal visual and quantitative thallium findings, three of these patients had minimal CAD. Profiles of uptake and washout of thallium-201 were derived from both patient groups, and compared with normal limits developed by Maddahi et al. Furthermore, low likelihood and angiographically normal patients may differ substantially, and both sets of normal patients should be considered when establishing criteria for abnormality in exercise thallium imaging. When commercial software containing normal limits for quantitative analysis of exercise thallium-201 imaging is used in clinical practice, it is mandatory to compare these with normal limits of uptake and washout of thallium-201, derived from the less heterogeneous group of low-likelihood subjects, which should be used in selecting a normal population to define normality.

Quantitative thallium-201 scintigraphy after dipyridamole infusion combined with low level exercise in healthy volunteers

To establish test specific normal limits for quantitative analysis of uptake and washout of 201Tl after dipyridamole infusion combined with low level exercise, 20 healthy volunteers were studied with low likelihood of coronary artery disease (CAD) assessed by a stepwise probability analysis based on age, sex, symptoms, resting electrocardiogram, and exercise electrocardiography. Likelihood of CAD in these volunteers was calculated as ≦1%. After dipyridamole infusion combined with low level exercise, one volunteer complained of headache; no other side effects were observed. There were no chest pain complaints. Maximal hemodynamic changes were achieved during the 6th and 7th min of the test. No ST segment depression was recorded. Visual analysis of the 201Tl scintigrams was normal in all volunteers. Mean regional washout at 4 h was 44.37%±2.11%. The regional washout in the 70° LAO view (46.65%±1.10%) was significantly higher than in the anterior and 30° LAO views (43.44%±1.50% and 43.02%±1.45%, respectively). Profiles of uptake and washout of 201Tl were different after dipyridamole infusion combined with low level exercise as compared to maximal exercise. Thus, in quantitative analysis of 201Tl scintigraphy after dipyridamole infusion in conjunction with low level exercise as applied in the present study, it is mandatory to use normal limits of uptake and washout of 201Tl derived from healthy volunteers who underwent the same combined protocol.