Prognostic value of dipyridamole thallium-201 imaging in elderly patients.

The prognostic value of intravenous dipyridamole myocardial perfusion imaging has not been studied in a large series of elderly patients. Patients greater than or equal to 70 years of age with known or suspected coronary artery disease were evaluated to determine the predictive value of intravenous dipyridamole thallium-201 imaging for subsequent cardiac death or nonfatal myocardial infarction. Of the 348 patients, 207 were symptomatic and 141 were asymptomatic; 52% of the asymptomatic group had documented coronary artery disease. During 23 +/- 15 months of follow-up, there were 52 cardiac deaths, 24 nonfatal myocardial infarctions and 42 revascularization procedures (percutaneous transluminal coronary angioplasty in 20; coronary artery bypass surgery in 22). Clinical univariate predictors of a cardiac event included previous myocardial infarction, congestive heart failure symptoms, hypercholesterolemia and diabetes (all p less than 0.05). The presence of a fixed, reversible or combined thallium-201 defect was significantly associated with the occurrence of cardiac death or myocardial infarction during follow-up (p less than 0.05). Cardiac death or nonfatal myocardial infarction occurred in only 7 (5%) of 150 patients with a normal dipyridamole thallium-201 study (p less than 0.001). Stepwise logistic regression analysis of clinical and radionuclide variables revealed that an abnormal (reversible or fixed) dipyridamole thallium-201 study was the single best predictor of cardiac events (relative risk 7.2, p less than 0.001). As has been demonstrated in younger patients, previous myocardial infarction (relative risk 1.8, p less than 0.001) and symptoms of congestive heart failure at presentation (relative risk 1.6, p = 0.02) were also significant independent clinical predictors of cardiac death or myocardial infarction.(ABSTRACT TRUNCATED AT 250 WORDS)

Effectiveness of increasing hours of continuous ambulatory electrocardiography in detecting maximal ventricular ectopy. Continuous 48 hour study of patients with coronary heart disease and normal subjects.

The effectiveness of 1, 6, 12, 24, 36 and 48 hours of continuous ambulatory electrocardiographic examination in detecting maximal ventricular ectopy was studied in 67 patients with coronary heart disease (45 with myocardial infarction, 22 with angina pectoris) and 23 normal subjects. Two consecutive 24 hour Holter recording examinations provided 48 hours of continuous examination. Ventricular ectopy was detected in 87 percent of patients and 35 percent of normal subjects. Complex forms (multifocal or repetitive patterns) were found in 62 percent and high frequency ectopy (greater than 60/hour) in 30 percent of the patients with coronary heart disease. Examination of either the initial hour of study or an hour of dynamic activity frequently failed to reveal the maximal ventricular ectopy present, particularly with regard to complex types and high frequency. Continuous 6 and 12 hour examinations were less effective than the 24 hour examination, which detected the maximal grade of ventricular ectopy in 71 to 74 percent and the maximal frequency in 58 to 83 percent of patients with coronary heart disease. Detection of maximal complex types and high frequency of ventricular ectopy was one to three times greater with a continuous 24 hour examination than with studies of shorter duration. Patient-recorded diaries showed that 50 to 80 percent of patients were engaged in mild to moderate activity during ventricular ectopy and only 9 percent indicated symptoms during the hours of maximal ventricular ectopy.

Systolic functional response of normal older and younger adult left ventricles to dobutamine.

To determine the systolic functional response of the aged left ventricle to catecholamines, 16 healthy, physically active subjects aged 62 to 72 years (group A) and 19 healthy adults aged 18 to 28 years (group B) were evaluated before and during infusion of 8 micrograms/kg/min of dobutamine. Phonocardiograms, electrocardiograms and M-mode echocardiograms were recorded simultaneously with a carotid pulse tracing. End-diastolic dimension and end-systolic pressure remained unchanged in the 2 groups. End-systolic dimension decreased 0.3 cm (p less than 0.001) in group A and 0.5 cm (p less than 0.001) in group B. Fractional shortening increased (p less than 0.001) from 34 +/- 4% to 38 +/- 5% in group A and from 34 +/- 4% to 43 +/- 4% in group B. Mean velocity of circumferential fiber shortening (Vcf) increased 0.6 circ/s (p less than 0.001) in group A and 1 circ/s (p less than 0.001) in group B. End-systolic pressure/dimension ratio increased 3 mm Hg/cm (p less than 0.001) in group A and 8 mm Hg/cm (p less than 0.001) in group B. The changes in end-systolic dimension, fractional shortening, Vcf and end-systolic pressure/dimension ratio were more significant in group B (p less than 0.001). Thus, the left ventricular systolic functional response to dobutamine is diminished in healthy older persons.

Prognostic value of exercise thallium scintigraphy in patients with good exercise tolerance and a normal or abnormal exercise electrocardiogram and suspected or confirmed coronary artery disease.

Exercise thallium scintigraphy is widely used to assess prognosis in patients with suspected or proven coronary artery disease. The incremental prognostic value of this technique in patients who have good exercise tolerance has not been well studied. Two hundred ninety-nine patients with known or suspected coronary artery disease without prior myocardial infarction or revascularization procedure referred for exercise myocardial perfusion imaging and able to exercise to greater than or equal to stage III of the Bruce protocol were included. After a mean follow-up of 50 +/- 10 months, there were 15 cardiac events (5%). The incidence of cardiac events was 10 versus 3% (p less than 0.001) in patients with an abnormal versus normal thallium-201 scan, and 9 versus 3% (p = 0.03) for an abnormal versus normal exercise electrocardiogram. When the 185 patients with a normal exercise electrocardiogram were examined, the incidence of cardiac events was 3% (5 of 150) in patients with a normal scan versus 0% (0 of 35) in patients with an abnormal scan. In the 114 patients with an abnormal exercise electrocardiogram, an abnormal thallium-201 scan was predictive of cardiac events (18% [8 of 44] versus 3% [2 of 70]; p = 0.006). Stepwise logistic regression analysis selected an abnormal thallium-201 scan and abnormal exercise electrocardiogram, low peak exercise heart rate, and male gender as independent variables associated with a significant increased risk of cardiac events. Thus, in patients with known or suspected coronary artery disease and good exercise tolerance, the addition of thallium-201 imaging in patients with an abnormal exercise electrocardiogram provides useful prognostic information.(ABSTRACT TRUNCATED AT 250 WORDS)

Detection of pulmonary edema in acute myocardial infarction.

To evaluate methods for detecting pulmonary edema, pulmonary extravascular water volume was measured at 24 hour intervals (total 72 hours) in 25 patients with acute myocardial infarction. Measured lung water was compared with results of clinical, blood gas, X-ray and hemodynamic methods for detecting pulmonary edema. Increased pulmonary extravascular water volume on one or more measurements was observed in 18 of the 25 patients and was associated with an abnormal chest radiograph and increased pulmonary arterial wedge, pulmonary arterial diastolic and right atrial pressures. It was associated less well with clinical, blood gas and other hemodynamic measurements. Pulmonary arterial diastolic or pulmonary wedge pressure was a significant predictor of lung water 24 hours later. Both "preclinical pulmonary edema" and the "therapeutic phase lag" could be predicted from the pulmonary wedge pressure. Clinical, blood gas, radiographic and other hemodynamic measurements were not predictive.

Detection of ventricular ectopy in patients with coronary heart disease and normal subjects by exercise testing and ambulatory electrocardiography.

Maximal exercise testing and 24-hour ambulatory electrocardiographic recording (Holter monitor) were utilized in the detection of ventricular ectopy in 90 patients with stable chronic coronary heart disease and in 30 normal subjects. Although the occurrence of any ventricular ectopic activity, as detected by either or both methods, was common, the incidence was significantly higher (P less than 0.001) in patients with coronary heart disease (86 percent; 77/90), as compared to that in normal subjects (40 percent; 12/30). Ventricular arrhythmia was more frequently detected by the 24-hour continuous electrocardiographic recording, being found in 70 of the 90 patients with coronary heart disease and in ten of the 30 normal subjects. In comparison, exercise testing disclosed ventricular ectopy in 56 of the 90 patients with coronary heart disease and in two of the 30 normal subjects. Multiform and repetitive patterns of ventricular ectopy were detected twice as commonly by continuous electrocardiographic recording than with exercise testing, and these patterns were present in one-half of the patients with coronary heart disease. Both methods of examination adjunctively disclosed more ventricular ectopy than either method alone.

Primary right cardiac tumor. Detection by echocardiographic and radioisotopic studies.

A primary tumor of the right atrium and right ventricle was detected in a 17-year-old male patient by noninvasive techniques, ie, M-mode echocardiograms and gated blood-pool cardiac scan combined with myocardial imaging with radioactive 201thallium. The clinical presentation was unusual, and validation of the echocardiographic and isotopic findings was obtained by contrast angiograms. Surgical pathologic findings defined the tumor as a poorly differentiated sarcoma.

A unique left-to-right shunt characterized by multimodality cardiac imaging.

We describe the first reported patient with a persistent left superior vena cava that communicates directly with the left atrium as an isolated congenital defect. She developed mitral stenosis and physiologic conditions that favored left-to-right shunting--a modified Lutembacher's syndrome. Noninvasive cardiac imaging completely elucidated her cardiac anatomy and physiology.

Intermittent coronary spasm during graded exercise.

We report a patient with Prinzmetal's angina with nearly normal coronary angiogram who not only developed severe myocardial ischemia during exercise, documented both electrocardiographically (ST elevation) and scintigraphically (with thallium-201), but also did so intermittently as the graded exercise progressed. Diagnostic coronary angiography showed spontaneous focal spasm of the proximal left anterior descending coronary artery. This unique response to exercise in a patient with variant angina suggests that factors other than catecholamine stimulation alone are active and rapidly attenuated in some patients. This phenomenon could be overlooked without appropriate electrocardiographic monitoring.

Accelerated atrioventricular conduction in Fabry's disease: a case report.

Three unrelated men with Fabry's disease (angiokeratoma corporis diffusum universale) and accelerated atrioventricular conduction are described. AQn His bundle electrogram in one patient who reported episodes of tachycardia demonstrated a prolonged deflection preceding the ventricular complex. This deflection is thought to represent an abnormal His bundle potential, possible resulting from glycolipid deposition. In the second patient the PR interval decreased from 0.18 to 0.11 second during 10 years, and in the third patient it decreased from 0.12 to 0.10 seconds during 13 years. Accelerated atrioventricular conduction may develop in Fabry's disease.

Catheter separation during cardiac catheterization and coronary angiography. A report of four incidents and review of the literature.

Four incidents of catheter separation in three patients during left heart catheterization and coronary angiography are presented. In two cases the catheters had been used before. After the second incident, we decided to use angiography catheters once only. All catheter fragments were removed under local anesthesia, and no further complications arose. In all incidents the point of catheter fracture was near the bond between the body of the catheter and its tip. We believe that catheter separation is related to polymer aging. The catheters in the third and fourth incidents were unused, but there was no expiration date on their packages. We recommend that expiration dates be clearly stated on every catheter package, catheter manufactures issue warnings not to use catheters after expiration date, and unused angiography catheters with no expiration date not be used. We also suggest that consideration be given to using catheters once only.

Familial sinoatrial node dysfunction. Increased vagal tone a possible aetiology.

Clinical and electrophysiological studies of a 13-year-old boy with sinus bradycardia revealed sinus node dysfunction. Long-term follow-up data of members of his family indicated familial sinus node dysfucntion. Increased vagal tone was present in all patients. It is suggested that excessive vagal discharge for a pronlonged time may be the basic mechanism of sinus node dysfunction in these patients.

Preload or afterload reduction: which is more beneficial for patients with ischemic heart disease?

We studied the acute hemodynamic effects of molsidomine, a selective preload reducing agent, and nifedipine, a selective afterload reducing agent. Thirty-two patients with stable angina pectoris and angiographically significant coronary artery disease were randomized into two groups: group A patients received 4 mg of molsidomine, and group B patients received 20 mg of nifedipine orally. Molsidomine was associated with a significant reduction of the left ventricular end-diastolic pressure and an increase in Vcf. Nifedipine caused a significant reduction of the mean arterial pressure and an increase of the heart rate. Hemodynamic parameters associated with chronic exertional angina pectoris in patients with angiographically significant coronary artery disease improved more with a preload reducing agent, like molsidomine.

Ambulatory electrocardiography. A clinical perspective.

Advances in modern technology have made it possible to record and analyze the electrocardiographic data of ambulatory persons for as many as 24 h or more. This capability and an increasing awareness of cardiac dysrhythmias and myocardial ischemia as a cause of morbidity and mortality have led to the more widespread use of ambulatory electrocardiography in the examination of patients for various clinical conditions. From a clinical viewpoint, we review and summarize the present state-of-the-art of ambulatory electrocardiography and discuss when such studies are indicated, frequently warranted, or may be useful.

Serum total and free thyroxine and triiodothyronine during dynamic muscular exercise in man.

The effect of strenuous dynamic muscular exercise on serum-free thyroxine (FT4) and free triiodothyronine (FT3) concentrations has been studied in 10 healthy subjects. In the course of 7.8-19 min of treadmill exercise (protocol of R. A. Bruce), the group showed a mean increase in serum albumin concentration of 11.4% (P less than 0.01). Five subjects demonstrated an increase in FT4 concentrations (x = +54%) and five showed decreased FT4 (x = -36%). The difference in FT4 concentrations was accounted for primarily by acute alterations in dialyzable fraction T4 (DFT4) rather than total serum T4. Mean changes in DFT4 were statistically significant (P less than 0.02) when increased FT4 and decreased FT4 groups were compared. Acute exercise was accompanied by a 9% decrease in dialyzable fraction T3 (DFT3) (P less than 0.02) in the 10 subjects, but the concomitant decrease in FT3 concentration was not significant. Changes in DFT4 and DFT3 and FT4 and FT3 concentrations were not correlated. Trends in double product (heart rate times blood pressure) with maximal exercise and in double-product recovery after exercise suggested that increased FT4 concentrations developed in subjects who were physically better trained.

Smoking is a risk factor for coronary spasm in young women.

BACKGROUND: Risk factors for pure coronary spasm are not known. Clinical observations have pointed to cigarette smoking, a known risk factor for obstructive coronary artery disease. METHODS AND RESULTS: We conducted a case-neighborhood control study of premenopausal women, a population segment with the lowest prevalence of obstructive coronary artery disease. The cases were 21 premenopausal women (age range, 36-41 years) with angiographically proven coronary spasm. All coronary arteriograms were analyzed by two independent experienced cardiologists on two occasions. There were no differences between analyses; all cases had normal baseline coronary angiogram except for two, who had less than 20% coronary luminal stenosis in segments other than the site of the focal vasospasm. All cases had normal hemodynamics at rest, normal left ventricular function, and were in sinus rhythm. Ascertainment of the cases was done by angiographic demonstration of focal coronary spasm spontaneously or by ergonovine provocation. Six cases developed spontaneous coronary spasm before catheter engagement, and in 15, coronary spasm was induced by ergonovine provocation. Each case was asked to name as many as possible female neighborhood acquaintances of similar age and racial background who were willing to answer the same standardized questionnaire. The same standardized questionnaire was completed for each case and each control (n = 63). The standardized questionnaire was designed to obtain information on health characteristics, habits, socioeconomic status, and education. Only cigarette smoking was significantly more prevalent among coronary spasm cases. Cigarette smokers were 13 cases (62%) and 11 controls (17.5%) (p less than 0.001). The odds ratio was 7.7, with a 95% confidence interval of 2.6-23.1. CONCLUSIONS: These findings suggest that there is a very strong association between cigarette smoking and pure coronary spasm in young women.

Thallium-201 myocardial imaging in evaluation of asymptomatic individuals with ischaemic ST segment depression on exercise electrocardiogram.

Asymptomatic adults with normal physical examination, normal resting electrocardiogram, and normal routine laboratory evaluation who have a positive exercise electrocardiogram and abnormal exercise thallium-201 myocardial image have a very high probability of angiographically significant coronary artery disease. If, on the other hand, the exercise electrocardiogram is positive for "ischaemic" ST segment changes, but the exercise thallium image is normal, the probability for coronary disease is low. The exercise electrocardiogram combined with thallium-201 myocardial image are safe non-invasive methods which can be performed on an out-patient basis.

Application of computerized exercise ECG digitization. Interpretation in large clinical trials.

The authors report on a semiautomated program that incorporates both visual identification of fiducial points and digital determination of the ST-segment at 60 ms and 80 ms from the J point, ST slope, changes in R wave, and baseline drift. The off-line program can enhance the accuracy of detecting electrocardiographic (ECG) changes, as well as reproducibility of the exercise and postexercise ECG, as a marker of myocardial ischemia. The analysis program is written in Microsoft QuickBASIC 2.0 for an IBM personal computer interfaced to a Summagraphics mm1201 microgrid II digitizer. The program consists of the following components: (1) alphanumeric data entry, (2) ECG wave form digitization, (2) calculation of test results, (4) physician overread, and (5) editor function for remeasurements. This computerized exercise ECG digitization-interpretation program is accurate and reproducible for the quantitative assessment of ST changes and requires minimal time allotment for physician overread. The program is suitable for analysis and interpretation of large volumes of exercise tests in multicenter clinical trials and is currently utilized in the TIMI II, TIMI III, and BARI studies sponsored by the National Institutes of Health.

Ventricular arrhythmia 24 hours before and after maximal treadmill testing.

To determine if maximal exercise treadmill testing influences the occurence of ventricular arrhythmia in the hours after exercise, 45 myocardial infarction and 22 angina pectoris patients (New York Heart Association Class I-II), and 23 normal subjects were examined with 24-hour ambulatory electrocardiographic Holter recordings before and after exercise testing. Comparison of qualitative and quantitative ventricular arrhythmia detected during identical chronological two-, four-, and 20- or more hour periods, before and after exercise testing in each patient, revealed no statistically significant difference in any patient group. The prevalence of ventricular ectopy in 80 per cent of ischemic heart disease patients and 30 per cent of normal subjects as detected by 24-hour Holter recordings was similar to previous studies. It is concluded that in ambulatory ischemic heart disease patients (New York Heart Association Class I-II) and normal subjects, maximal treadmill testing does not significantly affect the occurrence of ventricular arrhythmia in the hours after exercise.