Biomedical subjects
Publications and source records attributed to W Steinbrunn.
Clinical diagnosis is easily established at bedside or in the doctor's cabinet. Four clinical symptoms have to be considered: 1) functional impairment of the left ventricle, 2) intolerance to physical stress, 3) congestion and 4) ventricular arrhythmia (not covered in this paper). History provides the keys for 1, 2 and 3, physical examination for 1 and 3, electrocardiography under exercise for 2 and chest X-ray for 3.
A computer algorithm for estimating probabilities of any significant coronary obstruction and triple vessel/left main obstructions was derived, validated, and compared with the assessments of cardiac clinician angiographers. The algorithm performed at least as well as the clinicians when the latter knew the identity of the patients whose angiograms they had decided to perform. The clinicians were more accurate when they did not know the identity of the subjects but worked from tabulated objective data. Referral and value induced bias may affect physician judgment in assessing disease probability. Application of computer aids or consultation with cardiologists not directly involved with patient management may assist in more rational assessments and decision making.
The aim of this investigation was to determine the difference in accuracy between two frequently published noninvasive indicators of severity of coronary artery disease (exercise-induced ST segment depression and heart rate-adjusted ST depression [ST/HR index]). The study was designed as a survey of consecutive patients undergoing exercise electrocardiography and coronary angiography. There were a total of 2,270 patients without prior myocardial infarction or cardiac valvular disease referred for angiography from eight institutions in three countries; 401 of these patients had triple-vessel or left main coronary artery disease. The sensitivities of ST depression and ST/HR index in detecting triple-vessel or left main coronary artery disease were, respectively, 75% and 78% (p = 0.08) at cut point values where their specificities were equal (64%). This small increase in the accuracy of the ST/HR index was evident only at peak exercise heart rates below the median value of 132 beats/min, where the sensitivities of ST depression and ST/HR index were 73% and 76% (p = 0.03), respectively, at cut point values corresponding to a specificity of 60%. These results were consistent at all eight participating institutions. The increase in accuracy achieved by dividing exercise-induced ST depression by heart rate is small and confined exclusively to a low exercise heart rate. This lack of superiority cannot be generalized to all methods of heart rate adjustment.
Logistic regression was applied to the clinical, risk factor, and exercise data of consecutive angiographic referrals without prior myocardial infarction to determine an algorithm predicting the probability of triple-vessel/left main coronary artery disease. These data were obtained from a total of 1,074 such subjects from patient populations at four centers (Cleveland Clinic Foundation, Cleveland, Ohio; Hungarian Institute of Cardiology, Budapest, Hungary; the university hospitals, Zurich and Basel, Switzerland; and the Veterans Administration Medical Center, Long Beach, Calif.) and used to derive four separate probability algorithms. Each algorithm is based on patient data from study samples at three of the four centers and consists of 272 logistic functions, which are related to linear combinations of 13 variables (age, sex, type of chest pain, systolic blood pressure, resting electrocardiogram, serum cholesterol, fasting blood sugar, achieved exercise work load, achieved heart rate, exercise-induced angina and hypotension, heart rate-adjusted resting ST depression, and exercise ST slope). The four algorithms were cross validated by testing them on the populations not involved in their derivation. The resulting probabilities in the four test groups were then compared with the angiographic findings of triple-vessel/left main coronary artery disease. The discriminatory power of all the algorithms was fair to good (area under receiver operating characteristic curve, 0.68, 0.75, 0.82, 0.85) in the test groups. The algorithm did not significantly underestimate or overestimate disease probability except in one center (Long Beach).(ABSTRACT TRUNCATED AT 250 WORDS)
Spontaneous coronary artery dissection is a rare cause of myocardial infarction. It occurs most commonly in young, otherwise healthy women, especially in the peripartum period. Dissections are most often located in the proximal part of the left coronary artery. Histologically a hematoma is found in the media with compression of the true lumen and usually a localized periadventitial inflammation. The etiology of the disease is unknown; hormonal influences and defective collagen metabolism are discussed. Prognosis is poor; only one third of patients survive the first 24 hours after acute onset of symptoms, and mortality is high in the following days and weeks. Surgery may prevent extension of infarction, and for this reason early diagnosis by coronary angiography is essential in patients at risk for this disease. Two cases of coronary dissection are described, followed by a review of the literature and discussion of etiology, prognosis and management.
A new discriminant function model for estimating probabilities of angiographic coronary disease was tested for reliability and clinical utility in 3 patient test groups. This model, derived from the clinical and noninvasive test results of 303 patients undergoing angiography at the Cleveland Clinic in Cleveland, Ohio, was applied to a group of 425 patients undergoing angiography at the Hungarian Institute of Cardiology in Budapest, Hungary (disease prevalence 38%); 200 patients undergoing angiography at the Veterans Administration Medical Center in Long Beach, California (disease prevalence 75%); and 143 such patients from the University Hospitals in Zurich and Basel, Switzerland (disease prevalence 84%). The probabilities that resulted from the application of the Cleveland algorithm were compared with those derived by applying a Bayesian algorithm derived from published medical studies called CADENZA to the same 3 patient test groups. Both algorithms overpredicted the probability of disease at the Hungarian and American centers. Overprediction was more pronounced with the use of CADENZA (average overestimation 16 vs 10% and 11 vs 5%, p less than 0.001). In the Swiss group, the discriminant function underestimated (by 7%) and CADENZA slightly overestimated (by 2%) disease probability. Clinical utility, assessed as the percentage of patients correctly classified, was modestly superior for the new discriminant function as compared with CADENZA in the Hungarian group and similar in the American and Swiss groups. It was concluded that coronary disease probabilities derived from discriminant functions are reliable and clinically useful when applied to patients with chest pain syndromes and intermediate disease prevalence.
We report the results of i.v. fibrinolysis in patients with acute myocardial infarction treated in four major hospitals in Zürich. Between 1986 and 1988 only 96 (9%) of 1069 patients admitted to intensive care units with acute myocardial infarction received thrombolytic therapy (less than 3 hours after onset of symptoms), 7% (50/703) during the first treatment period (streptokinase for 14 months), 13% (46/306) during the second treatment period (rt-PA for 8 months). The hospital mortality was 4% and severe complications of fibrinolytic therapy occurred in 4%. Coronary angiography was performed in 60% of patients in 1986/87 and in 87% in 1987/88. Despite this significant increase in invasive diagnostic procedures the percentage of patients after thrombolysis qualifying for invasive therapy remained unchanged at 53%. The indications for PTCA or bypass surgery were postinfarct angina in 41%, silent ischemia in 5%, left main coronary artery stenosis or multivessel disease with reduced left ventricular ejection fraction in 16%, and residual high grade stenosis with preserved contractility of the infarct-related myocardium in 38%. The mean in-hospital stay was 16 days, with significant variation from 13 to 22 days between the different hospitals (p less than 0.05). In the follow-up of 65 men aged below 65 years, 75% of the patients undergoing invasive therapy and 65% of those treated medically had returned to work 6 months after myocardial infarction. Due to the limited possibility of detecting viable myocardium by non-invasive methods, and the high rate of invasive therapy necessary in our patients, further management after thrombolysis should generally include large scale coronary angiography.(ABSTRACT TRUNCATED AT 250 WORDS)
Maximal vectors of depolarization (QRS) and repolarization (ST/T), and the initial QRS-vector of CGM, were measured simultaneously with conventional ECG at rest and during exercise in a population of 85 patients with suspected coronary artery disease (CAD). Coronary angiography served as standard, luminal narrowing of at least 50% in a proximal segment of one or more major coronary arteries being taken to define CAD. CGM showed sensitivity of 0.89 and specificity of 0.64 (vs 0.76 and 0.18 for conventional stress ECG).
Cardiogoniometry (CGM), an orthogonal lead system using four chest leads, was performed in a population of 120 healthy volunteers. The measurements were taken simultaneously with the conventional ECG at rest, after upright bicycle exercise at 50 watts, and immediately and 6 minutes after maximal symptom limited exercise. The results of these tests are the normal values for CGM. The normal values are located in a narrow band on the spherical surface of the coordinate system.
In a retrospective study we analyzed the long-term course in 77 patients (71 males and 6 females) with symptomatic ventricular tachycardias. Initially all patients had undergone an electrophysiological examination. 56/77 patients received drug therapy and 19/77 underwent surgery (implantation of an automatic defibrillator in 2 patients). Two patients received no therapy. After an observation period of 30 (5-81) months, 60% of the patients who had received drug therapy and 77% who had undergone surgery were free of tachycardia. 16/56 (29%) of the patients under drug management and 6/19 (32%) of the surgically treated had died in the meantime. In the whole group the mortality rate was 9.6 times higher than in an age and sex matched control group. In younger subjects (16-50 years) the mortality rate was 4 times greater than in those aged 51-81 years. The highest mortality was observed in the first year. The most important prognostic parameter was the left ventricular ejection fraction, which was significantly higher in survivors. We conclude that ventricular arrhythmias can be effectively controlled, and quality of life enhanced, with drug therapy or surgery.
The authors report on the longterm follow-up after PTCA in 130/165 (79%) patients seen approximately 3 years after angioplasty. Primary success rate in the years 1980-84 was 79%. Emergency bypass surgery was necessary in 7%. In-hospital mortality was 0%. Recurrences of angina were seen in the first 6 months in 18 and after 1 year in 3 patients. 13 of 18 had a recurrence of the dilated lesion (10%). At 3 years there had been 4 cardiac deaths, 76% were asymptomatic, 8% were improved and 83% were working full time.
In this study, betathromboglobulin (BTG) and fibrinopeptide A (FPA) in peripheral venous blood were measured in 20 patients with stable angina pectoris before and immediately after exercise-induced myocardial ischaemia; in 5 of the 20 patients stable angina was associated with typical peripheral artery disease. A total of 10 patients with angiographically documented peripheral artery disease without angina and 10 normal volunteers were taken as control groups. BTG and FPA in the 15 patients with stable angina before exercise were 41 +/- 14 ng ml-1 and 2.3 +/- 0.9 ng ml-1 and were not statistically different from the values in normal controls; after exercise-induced myocardial ischaemia no significant increase occurred in these patients. Conversely, in the 5 patients with stable angina associated with peripheral artery disease BTG and FPA before exercise were 61 +/- 10 ng ml-1 and 3.5 +/- 0.8 ng ml-1 and increased to 114 +/- 14 ng ml-1 (P less than 0.001) and 4.1 +/- 0.5 ng ml-1 (P less than 0.01): These results were similar to those found in the 10 patients with isolated peripheral artery disease. We conclude that BTG and FPA in peripheral venous blood in patients with stable angina are not elevated either at rest or after exercise-induced myocardial ischaemia. Elevated values of BTG and FPA in patients with stable angina may reflect a major interaction between blood and atherosclerotic vessel wall, suggesting the presence of associated atherosclerotic lesions in peripheral artery disease.
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By retrospective analysis of 1415 bicycle ergometer exercise stress tests, 108 patients were selected for coronary angiography and left ventriculograms at least 3 months after acute anterior wall myocardial infarction. The ECG of 55/108 showed elevation of the ST-segment of 1 mm or more during exercise. 82% displayed an aneurysm defined by diastolic and/or systolic bulge (dyskinesis) of the anterior ventricular wall: sensitivity 82%, specificity 96%, positive predictive value 97%. The bicycle exercise stress test is a strong, noninvasive predictor of left ventricular aneurysm.
In contrast to ST-segment depression during exercise, the mechanism for ST-segment elevation - a more unusual finding - is controversial and poorly understood. Exercise induced ST-segment elevation of 2 mm and more was observed in 80 of 3000 consecutive patients (2.6%) undergoing bicycle exercise testing using 6 of 12 ECG leads. This abnormality was detected in 70 of 777 patients (9%) with documented previous myocardial infarction and in 10 of 2223 (0.5%) patients without a history of myocardial necrosis and with normal resting ECG. The substantial differences in exercise induced ST-segment elevation between these two groups are: patients with previous myocardial infarction and angiographically documented left ventricular aneurysm revealed progressive asymptomatic ST-segment elevation on an average of 3.4 +/- 1.2 mm persisting for a long time (greater than 3 minutes) during the recovery period. The extent of ST-segment elevation appears to correlate with LV EF and LV volume. These patients should be treated medically (as in 73% of our patients), and cardiac catheterization is indicated only in the presence of severe angina, congestive LV failure and arrhythmias. Patients with normal ECG at rest showed ST-elevation at maximal exercise. ST-segment elevation was associated with chest pain, which was more pronounced and shorter in duration than in the other group (9.1 +/- 2.8 mm, less than 30 sec). ST-elevation was abrupt and not preceded by ST-segment depression. 8 of 10 patients with anterior ST-segment elevation had a left anterior descending artery (LAD) lesion. Therefore, exercise testing in this group predicts significant proximal LAD obstruction accessible for PTCA.
The effect of nitroglycerin ointment (30 mg) and isosorbide dinitrate ointment (100 mg) versus placebo on exercise capacity has been investigated in 12 patients. All had angina pectoris and coronary artery disease documented by coronary angiography. Nitroglycerin and isosorbide dinitrate ointment produced a significant increase in exercise capacity, without any significant difference in the beneficial effect of the two. Stress-induced changes of the ST-segment in the electrocardiogram decreased by 65% after nitroglycerin ointment and by 41% after isosorbide dinitrate ointment, compared to placebo. These results indicate that nitroglycerin and isosorbide dinitrate ointment reduce stress-induced myocardial ischemia at similar work loads.
Removal of catheter tip or guide wire emboli is needed for most cases with this complication. An alternative to surgery is transvenous retrieval. The authors present their experience with a simple self-made loop-catheter, which in 11 of 12 cases proved successful for extraction of 9 catheter tips and 3 guide wires located in the central venous system, the right ventricle and the pulmonary artery in 10 patients, and in the aorta in 2. No further complications were caused by this procedure. Due to the serious hazards of embolized foreign bodies there is a need to remove them, and the authors believe that the transluminal route, preferably with the loop catheter, should be the primary approach to this iatrogenic complication.
Natural history of an aneurysm at the bifurcation of the left coronary artery is reported. A gradual increase in its size occurred over an 18-year period until it was a huge and partially thrombosed sac. It was associated with ectasia of the right coronary artery, aneurysms of the left subclavian artery and thoracic aorta, and calcified dilatations of the branches of the celiac trunk.