Incidence and prognostic significance of intraventricular conduction abnormalities after coronary bypass surgery.

To determine the incidence and prognostic significance of new postoperative conduction disturbances, 2,000 consecutive patients who underwent primary elective coronary bypass surgery were evaluated. One hundred eleven (5.5%) of the 2,000 patients developed a new intraventricular conduction defect that persisted to hospital discharge. Right bundle branch block occurred in 86 (85%), left bundle branch block in 5 (4%) and nonspecific intraventricular conduction defect in 9 (11%). One hundred of these 111 patients were successfully matched with others in the study population who had maintained normal intraventricular conduction during the operative period. Patients were matched on the basis of age, gender, absence of preoperative conduction disturbances, left ventricular function and bypass grafts to the same vessels. Follow-up of the two groups for a period of 1 to 76 months (mean 60 months) failed to show any difference in survival or cardiac events such as myocardial infarction, repeat coronary bypass surgery, coronary angioplasty and permanent pacemaker implantation. The appearance of right or left bundle branch block or a nonspecific intraventricular conduction defect after coronary bypass surgery does not appear to have an unfavorable impact on the long-term prognosis of these patients.

Videodensitometric ejection fraction from intravenous digital subtraction right ventriculograms: correlation with first pass radionuclide ejection fraction.

Thirty-one consecutive patients undergoing intravenous blurred mask digital subtraction right ventriculography were submitted to first pass radionuclide angiography. Second order mask resubtraction of end-diastolic and end-systolic right ventricular digital image frames was executed using preinjection end-diastolic and end-systolic frames to rid the digital subtraction images of mis-registration artifact. End-diastolic and end-systolic perimeters were drawn manually by two independent observers with a light pen. Ejection fractions calculated from the integrated videodensitometric counts within these perimeters correlated well with those derived from the first pass radionuclide right ventriculogram (r = 0.84) and the interobserver correlation was acceptable (r = 0.91). Interobserver differences occurred more frequently in patients with atrial fibrillation and in those whose tricuspid valve planes were difficult to discern on the digital subtraction right ventriculograms. These results suggest that videodensitometric analysis of digital subtraction right ventriculograms is an accurate method of determining right ventricular ejection fraction and may find wide clinical applicability.

Acute myocardial infarction and complete bundle branch block at hospital admission: clinical characteristics and outcome in the thrombolytic era. GUSTO-I Investigators. Global Utilization of Streptokinase and t-PA [tissue-type plasminogen activator] for Occluded Coronary Arteries.

OBJECTIVES: We sought to assess the outcome of patients with acute myocardial infarction (MI) and bundle branch block in the thrombolytic era. BACKGROUND: Studies of patients with acute MI and bundle branch block have reported high mortality rates and poor overall prognosis. METHODS: The North American population with acute MI and bundle branch block enrolled in the Global Utilization of Streptokinase and t-PA [tissue-type plasminogen activator] for Occluded Coronary Arteries (GUSTO-I) trial was matched by age and Killip class with an equal number of GUSTO-I patients without conduction defects. RESULTS: Of all 26,003 North American patients in GUSTO-I, 420 (1.6%) had left (n = 131) or right (n = 289) bundle branch block. These patients had higher 30-day mortality rates than matched control subjects (18% vs. 11%, p = 0.003, odds ratio [OR] 1.8) and were more likely to experience cardiogenic shock (19% vs. 11%, p = 0.008, OR 1.78) or atrioventricular block/asystole (30% vs. 19%, p < 0.012, OR 1.57) and to require ventricular pacing (18% vs. 11%, p = 0.006, OR 1.73). Bundle branch block also carried an independent 53% higher risk for 30-day mortality. Thirty-day mortality rates for patients with complete, partial and no reversion of the bundle branch block were 8%, 12% and 20%, respectively (two-tailed chi-square test for trend 5.61, p = 0.02, OR 0.34 for complete reversion, OR 0.55 for partial reversion). CONCLUSIONS: Bundle branch block at hospital admission in patients with acute MI predicts in-hospital complications and poor short-term survival.

Ineffectiveness of dipyridamole SPECT thallium imaging as a screening technique for coronary artery disease in patients with end-stage renal failure.

The efficacy of dipyridamole single photon emission computed tomography (SPECT) thallium as a screening test for coronary artery disease (CAD), was studied in 45 patients with end-stage renal failure undergoing evaluation for renal transplantation. Coronary arteriography, dipyridamole SPECT thallium imaging and clinical follow-up were performed in all patients. Nineteen patients (42%) had an obstruction of 50% or more in at least one coronary artery. Fourteen patients had a positive thallium scan, but 7 of these were false-positives (sensitivity 37%, specificity 73%). The sensitivity was considerably lower than that quoted for non-ESRF patients in the literature, and significantly lower than a control group of 19 patients without ESRF having comparable severity and distribution of CAD. Five of the 6 patients who died of cardiac causes over a mean follow-up period of 25 months had normal thallium imaging, but all had significant coronary artery disease at cardiac catheterization. Dipyridamole SPECT thallium imaging has not proved a useful screening test for angiographically significant CAD, and does not predict cardiac prognosis in this population.

Influence of left ventricular mass on the diagnostic accuracy of myocardial perfusion imaging using positron emission tomography with dipyridamole stress.

This study assesses the influence of left ventricular hypertrophy (LVH) on the accuracy of myocardial perfusion imaging using pharmacologic coronary vasodilation. Seventy-five patients without previous infarction, and with known coronary anatomy, were studied by echocardiography and PET. LVH (defined by mass greater than 131 g/m2 in males or greater than 100 g/m2 in females) was identified in 25 patients; this group did not differ significantly from the remainder in terms of clinical or angiographic parameters. Twenty patients with hypertrophy had significant coronary artery stenoses, which were identified correctly by PET in 11 (55%), in contrast to 29 of 34 patients (85%, p = 0.03) with coronary disease but normal LV mass. Normal perfusion images were obtained in three of five patients (60%) with hypertrophy but no coronary disease; in contrast, 14 of 16 patients without either coronary disease or hypertrophy (88%, p = ns) had normal scans. The accuracy of PET was 14/25 (56%) in those with hypertrophy, and 43/50 (86%, p = 0.01) in patients with normal LV mass. In this group, the presence of hypertrophy was associated with reduction in the diagnostic accuracy of PET using dipyridamole stress. These findings may account for the phenomenon of "dipyridamole nonresponsiveness" in some patients.

A prospective comparison of rubidium-82 PET and thallium-201 SPECT myocardial perfusion imaging utilizing a single dipyridamole stress in the diagnosis of coronary artery disease.

The purpose of the present study is to prospectively compare myocardial perfusion imaging with rubidium-82 (82Rb) by positron emission tomography (PET) with thallium-201 (201Tl) imaging by single-photon emission tomography (SPECT) by recording both studies with a single dipyridamole handgrip stress, and reading both sets of images with the same display technique. In a series of 202 patients with previous coronary arteriography, the sensitivity, specificity, and accuracy of 82Rb PET were 93%, 78%, and 90% and for 201Tl SPECT 76%, 80%, and 77%, respectively. When 70 patients with previous therapeutic interventions were excluded, the remaining 132 patients showed a sensitivity, specificity, and accuracy of 95%, 82% and 92% for 82Rb PET and 79%, 76%, and 78% for 201Tl SPECT. The improved contrast resolution of PET resulted in markedly superior images and a more confident identification of defects.

Clinical evaluation of 360 degrees and 180 degrees data sampling techniques for transaxial SPECT thallium-201 myocardial perfusion imaging.

The most serious controversy regarding the application of transaxial SPECT technology to 201Tl myocardial perfusion imaging is the choice between 360 degrees compared with 180 degrees data sampling techniques. The present study utilized the original 360 degrees sampled raw data of 25 patients who had both SPECT 201Tl myocardial perfusion imaging and coronary angio/ventriculography for back projection reprocessing to accomplish the 360 degrees/180 degrees comparison. The results show a high incidence, 36% (9/25), of false-positive segmental perfusion abnormality and a high incidence, 24% (6/25), of moderate to severe degree of image distortion with the 180 degrees data sampled reconstructed images. These were not observed in the 360 degrees data sampled reconstructed images. The above findings confirmed our previous preliminary conclusion that even though the 180 degrees data sampling technique has the advantage of providing improved image contrast and reduction in acquisition time it is not a reliable technique and should be abandoned. The 360 degrees data sampling is the technique of choice for transaxial SPECT 201Tl myocardial perfusion imaging.

Symptomatic coronary artery disease in patients aged 21 to 30 years.

One hundred one young people (88 men, 13 women) aged 30 years or younger with arteriographically proved obstructive coronary artery disease (CAD) were identified and reviewed for risk factor prevalence. The men were compared with an age and date-of-catheterization matched control group who were arteriographically normal. Significant risk factors were cigarette smoking (p = 0.001), familial CAD (p = 0.002) and familial CAD manifested by age 50 years or younger (p = 0.005). Serum cholesterol values were significantly higher in the CAD group (p = 0.0001), but in most (54%) were still less than 250 mg/dl. Arteriography showed a spectrum of CAD: 1-vessel in 57, 2-vessel in 21 and 3-vessel in 22. One patient had significant left main CAD. Follow-up was obtained for all of the 94 American subjects. One-year mortality was 3% and 5-year mortality was 20%. The causes of death were predominantly cardiac: myocardial infarction in 10 patients, congestive heart failure in 2 and sudden death in 6; 3 patients died of noncardiac causes.

Establishment of signal-averaged electrocardiographic criteria with Frank XYZ leads and spectral filter used alone and in combination with ejection fraction to predict inducible ventricular tachycardia in coronary artery disease.

Signal-averaged electrocardiographic criteria are reported for corrected Frank XYZ leads and a spectral filter. The new criteria were used alone and in combination with ejection fraction to predict inducibility of ventricular tachycardia (VT) at electrophysiologic testing. Signal-averaged electrocardiographic criteria were developed in 87 control subjects and validated in 182 patients (aged 63 +/- 10 years) with coronary artery disease and QRS duration less than 118 ms. Patients underwent electrophysiologic testing in which up to 3 extra-stimuli were used during 2 paced drives from 2 right ventricular sites. A positive finding was monomorphic VT lasting 30 seconds or needing intervention. An ejection fraction less than 40% was considered abnormal. Signal-averaged electrocardiographic variables that best characterized control subjects and separated patients with and without inducible VT were filtered QRS duration less than 120 ms, low-amplitude signal duration less than 38 ms and root-mean-square voltage greater than 20 muv. With these criteria, signal-averaged electrocardiographic and ejection fraction sensitivities were 87 and 45%, respectively, and specificities were 65 and 77%, respectively. Combining signal-averaged electrocardiography with ejection fraction improved the predictive accuracy. In conclusion, diagnostic criteria for signal-averaged electrocardiography with use of Frank XYZ leads and a spectral filter produced results similar to those reported for use of bipolar XYZ leads and a Butterworth filter. Signal-averaged electrocardiography was a better predictor of VT than was ejection fraction.

Prediction of improvement in left ventricular function after ventricular aneurysmectomy using Fourier phase and amplitude analysis of radionuclide cardiac blood pool scans.

Postoperative improvement in left ventricular (LV) function is a common objective of LV aneurysmectomy, but is difficult to predict. The first Fourier component of time-activity curves of pre- and postoperative gated radionuclide angiographic studies was evaluated for this purpose in 20 patients who had undergone aneurysmectomy. LV aneurysms had portions that characteristically exhibited marked phase delay with varying degrees of amplitude. Total aneurysmal amplitude was obtained preoperatively by summing the amplitude component of all pixels that exhibited phase delay, suggesting paradoxical motion. LV ejection fraction (EF) before and after aneurysmectomy and the absolute postoperative increase in LVEF were calculated. Nine of 20 patients had an absolute increase of EF less than 10% despite resection of large aneurysms. A strong correlation was found between the absolute increase in EF after aneurysmectomy and the total amplitude within paradoxically moving areas (r = 0.93, p less than 0.0001). Thus, preoperative measurement of the total paradoxical amplitude predicts absolute change in EF and may be important in selecting patients for aneurysmectomy. The data also suggest that the total aneurysmal amplitude reflects the stroke volume ejected into an aneurysm in systole and that paradoxical expansion of an aneurysm contributes to LV dysfunction in some of these patients.

Identification of recurrent ischemia after coronary artery bypass surgery: a comparison of positron emission tomography and single photon emission computed tomography.

Current techniques for the detection of recurrent coronary stenoses following bypass grafting have shown disappointing diagnostic accuracy. This study used the same dipyridamole-handgrip stress to compare the accuracy of rubidium-82 positron emission tomography and thallium-201 single photon emission computed tomography, in 50 consecutive post-bypass patients undergoing coronary arteriography at a mean interval of 6.5 years after surgery. Significant stenoses in native coronary vessels (greater than 50% diameter) or grafts (greater than 70% diameter) were defined by quantitative angiography. Forty-six patients had recurrent or residual stenoses, 43 (93%) had a perfusion defect identified by positron emission tomography, and 35 (76%) were identified by single photon emission computed tomography (P = 0.04). Fourteen of the 17 patients (82%) without previous Q-wave myocardial infarction were identified by positron emission tomography; 10 of the 17 (59%) were detected by single photon emission computed tomography (P = NS). Stress-induced perfusion defects were demonstrated by positron emission tomography in 19 patients; of this group, thallium imaging identified reversible defects in 11, showed no perfusion defect in 1, and portrayed a persistent defect in 7 patients. Significant graft disease was present in 33 patients; perfusion defects were identified by positron emission tomography in 30 (91%), and by single photon emission computed tomography in 24 (73%, P = NS). Four patients were fully revascularized, without significant recurrent coronary disease; normal perfusion was present in 3 (75%) by positron emission tomography, and 4 (100%) by single photon emission computed tomography.(ABSTRACT TRUNCATED AT 250 WORDS)

Dipyridamole thallium imaging may not be a reliable screening test for coronary artery disease in patients undergoing vascular surgery.

Dipyridamole thallium imaging has been proposed for cardiac risk stratification in patients undergoing peripheral vascular surgery. The purpose of this study was to define the benefit of this investigation in routine preoperative evaluation of these patients. The outcome of 86 patients undergoing vascular surgery procedures was examined in light of preoperative clinical assessment and dipyridamole SPECT thallium imaging (DST). Fifty-one patients (59%) were considered at high risk on clinical grounds, and 22 patients (26%) had perfusion defects. Ten patients suffered a perioperative coronary event, including unstable angina, myocardial infarction, or cardiac death. Seven of the patients with such events were among the 51 clinically high-risk subjects (14%). Three perioperative events occurred in the group of 19 patients with positive DST images who underwent surgery (16%), but the DST test failed to identify 7 patients who suffered coronary events. The frequency of abnormal thallium imaging was similar to the prevalence of angiographically significant coronary disease reported previously at this center, but considerably less than the rate of abnormal thallium imaging in past studies of vascular surgery patients. The application of the test to a low to moderate risk population is probably responsible for its lower predictive accuracy for coronary events. DST is not an ideal routine noninvasive technique for risk stratification in patients undergoing vascular surgery.

Prospective comparison of exercise digital subtraction and exercise first pass radionuclide ventriculography.

In order to test the comparative sensitivities of first-pass radionuclide and digital subtraction ventriculography in detecting wall motion abnormalities during exercise, 29 patients referred for coronary angiography were submitted to both types of stress ventriculograms. Resting and exercise ventriculograms by both techniques were reviewed by independent observers and the five equal ventricular wall segments were graded as normal, mildly, moderately, severely hypokinetic, akinetic, or dyskinetic. Of the 29 patients, 24 had arteriographically defined ischemic potential (at least greater than 50% obstruction of a major coronary artery supplying viable myocardium). Exercise digital subtraction ventriculography correctly identified 17 (71%) of these by a worsening of wall motion during exercise, while radionuclide ventriculography identified only eight (33%) by the wall motion response. When either a worsening of wall motion or the failure to increase ejection fraction by at least 5 points were used as criteria for an abnormal test, the sensitivities of digital and radionuclide ventriculographies were 96% and 79%, respectively. Though the number of patients without ischemic potential (5 patients) was too small to judge the relative specificities, digital subtraction ventriculography appears to be more sensitive than radionuclide ventriculography in identifying exercise-induced wall motion abnormalities and in predicting coronary occlusions.

Coronary artery disease in women: a risk-factor analysis.

BACKGROUND: Risk factor modification is important in preventing coronary artery disease; however, risk factors for coronary artery disease have been studied mostly in men, not women. OBJECTIVE: To examine risk factors for coronary artery disease in women. METHODS: We retrospectively reviewed the records of all adult women who underwent their first-ever cardiac catheterization at our institution in 1983. Risk factors in women with angiographic evidence of coronary atherosclerosis were compared with risk factors in women without angiographic evidence of coronary artery disease. RESULTS: Risk factors identified included age, diabetes mellitus, hypertension for more than 5 years, hyperlipidemia, smoking, and familial coronary artery disease. CONCLUSIONS: Risk factors for coronary artery disease in women are similar to those of men.

Temporal electrical heterogeneity for detecting coronary artery disease: results in a heterogeneous cardiac population.

BACKGROUND: A new 22-lead electrocardiographic test has been advocated as a screening tool for coronary artery disease and has been shown to have accuracy similar to stress electrocardiography in specific patient populations. OBJECTIVE: To determine the accuracy of this test for detecting coronary artery disease in patients undergoing coronary angiography for a variety of cardiac conditions. METHODS: We prospectively determined the temporal electrical heterogeneity (TEH) index at rest in 70 patients who had no angina or Q waves on the resting 12-lead electrocardiogram before they underwent coronary angiography. RESULTS: Twenty-six of the 70 patients had significant coronary artery disease, defined as 70% stenosis or greater in at least one major epicardial coronary artery. A TEH index of 80 or more had a sensitivity of 58%, a specificity of 75%, and a positive predictive value of 58%. The group with significant coronary disease had a mean TEH index of 77.2, and the group without coronary disease had a mean index of 65.5 (P = .02), despite similar clinical characteristics and indications for angiography. CONCLUSION: The TEH index shows promise as a screening tool for coronary artery disease in a heterogeneous cardiac population. However, larger studies are needed before it can be endorsed for widespread clinical use.

Signal-averaged electrocardiography for detection of ventricular tachycardia using fast Fourier transform filtering on a standard ECG cart.

Signal-averaged electrocardiography has been advocated as a technique to predict the occurrence of ventricular tachycardia, especially in patients with ischemic heart disease. We studied a heterogeneous population of 77 patients referred for electrophysiologic testing using a recently developed fast Fourier transform filtering system available as part of a standard electrocardiography cart. The sensitivity, specificity, and positive predictive accuracy of this system were consistent with those previously determined using bidirectional Butterworth filters or finite impulse response filtering techniques. This new filtering approach in generation of signal-averaged ECG data for detection of ventricular tachycardia has promise but will require use in larger groups to establish its true clinical value.

Electrocardiographic criteria for anterior myocardial infarction.

In a two-stage review, electrocardiographic patterns associated with anterior infarction were determined in 135 patients whose diagnoses were established by contrast ventriculography. The five most common findings were tested in 1,324 consecutive patients to assess sensitivity, specificity, and predictive accuracies for anterior myocardial infarction. The criteria were shown to have high positive predictive accuracy and specificity levels, and confirmed the value of the standard 12-lead electrocardiogram for detecting anterior myocardial injury.

Early exercise testing following percutaneous transluminal coronary angioplasty.

The value of early symptom-limited stress electrocardiography following percutaneous transluminal coronary angioplasty in assessing late outcome was evaluated in 218 patients. All subjects were tested using the Bruce or Sheffield Protocols, 2.5 +/- 1.3 days after percutaneous transluminal coronary angioplasty. Repeat coronary angiography was performed after percutaneous transluminal coronary angioplasty because of symptoms (58%) or as routine follow-up (42%). Stress electrocardiography results were compared to coronary angiography. The sensitivity and specificity were 35.3% and 52.6%, respectively. The positive and negative predictive values were 39.6% and 48.0%. Two acute myocardial infarctions and one coronary angiographic-proven restenosis occurred within hours of the stress electrocardiogram in three patients (1.4%). It is concluded that symptom-limited stress testing immediately following percutaneous transluminal coronary angioplasty has no prognostic value and may carry increased risk for immediate negative coronary events.

Failure of dipyridamole-thallium myocardial imaging to detect severe coronary disease.

Three patients referred for peripheral vascular surgery who died of coronary artery disease complications despite normal dipyridamole-thallium scans are discussed. Although recent literature has shown enthusiasm for this test in this clinical setting, the dipyridamole-thallium scans are not absolute and patients remain at risk for major coronary artery events. Careful clinical screening and awareness of the signs of left main coronary disease on thallium images are important in the evaluation of these patients.

Cardiac rhythm and conduction disturbances in patients undergoing mitral valve surgery.

The occurrence and course of supraventricular rhythm and atrioventricular conduction disturbances were retrospectively compared in 206 patients with isolated mitral valve disease undergoing either valve replacement or ring annuloplasty (mitral repair) between January 1, 1985 and December 31, 1986. The replacement and repair groups were the same size and had approximately equal numbers of patients in sinus rhythm and atrial fibrillation preoperatively. The type of mitral valve operation did not affect the short-term outcome in terms of cardiac rhythm. For both groups, the incidence of patients crossing from sinus rhythm to atrial fibrillation and vice versa on the pre-discharge electrocardiography was equal, and both groups had a low incidence of clinically significant atrioventricular block.