J.Richard Warbasse

Transthoracic electrical impedance: Quantitative evaluation of a non-invasive measure of thoracic fluid volume

Abstract Transthoracic electrical impedance (TEI) measurements have previously been proposed as a sensitive non-invasive measure of fluid shifts in the thorax. The present study compares measured changes in TEI to measured thoracic intra- and extravascular fluid volumes in 22 experimental animals during production of pulmonary edema, phlebotomy, pleural effusion, pneumothorax, and pulmonary artery obstruction. Insignificant shifts in TEI and thoracic fluid volume were observed in control animals. In all animals increased intrathoracic fluid volumes were associated with significantly decreased TEI while decreases in thoracic fluid volume were associated with significant increases in TEI. Alterations in pleural, pulmonary extravascular, and intrathoracic blood volume were quantifiable by TEI measurements at statistically significant levels. Certain limitations in the clinical application of this method are discussed.

Quantitative evaluation of vitamin E in the treatment of angina pectoris

Because of previous reports of the beneficial effect of vitamin E in angina pectoris patients, 48 patients, with both stable angina and positive (chest pain plus ishemic ST depression) maximal exercise treadmill tests, participated in a double-blind cross-over study of 6 months of vitamin E and 6 months of placebo therapy, separated by a 2 month no treatment period. All 48 patients had positive selective coronary arteriograms (75 per cent obstruction of at least a major coronary artery) and/or Q wave ECG evidence of previous myocardial infarction (Minnesota criteria). Evaluation of drug effectiveness was based on performance of serial maximal exercise treadmill tests, serial systolic time interval measurements, and daily angina diaries. No statistically significant differences between the two treatment studied. It is concluded that a large dose of vitamin E (1,600 I.U. of d-alpha-tocopherol succinate daily) for 6 months in patients with stable angina pectoris fails to increase the exercise capacity, improve left ventricular function, or reduce the frequency of chest pain.

Diagnosis of Obstructive Coronary Disease by Maximal Exercise and Atrial Pacing

The reliability of graded maximal exercise treadmill testing and right atrial pacing in diagnosing significant obstructive coronary artery disease was evaluated in 74 consecutive patients referred to a cardiac unit with chest pain consistent with angina pectoris. The results of maximal exercise testing and right atrial pacing, with regard to the presence or absence of the patients characteristic chest pain or discomfort and ischemic ST segment depression, were compared with the findings determined by selective coronary arteriography. Ischemic ST segment depression was defined as a downward displacement of one full mm or more of a horizontal or downward sagging ST segment.Forty-nine of the 74 patients studied were found to have significant coronary arteriographic obstruction, i.e., greater than 75% obstruction of one major coronary artery. The occurrence of the patients characteristic chest pain or discomfort during maximal exercise testing or right atrial pacing is an excellent indicator of the presence of obstructive coronary artery disease, since all of the 41 patients developing their characteristic pain on maximal exercise testing had coronary arteriograms positive for obstructive coronary disease (no false positives), and 46 of 47 patients with characteristic chest pain on right atrial pacing had selective coronary arteriograms positive for obstructive coronary disease. When present, one mm ST depression during maximal exercise treadmill testing also reliably indicates arteriographic obstructive coronary disease (26 of 27 patients). However, the presence or absence of ischemic ST depression during right atrial pacing is a particularly unreliable indication of the presence or absence of arteriographic obstructive coronary disease: 15 of 25 false positive tests, and 13 of 49 false negative tests.

Congenital dextrocardia with anterior wall myocardial infarction

Abstract A case of anterior wall myocardial infarction in a patient with congenital dextrocardia with situs inversus is presented. The clinical, electrocardiographic, and vectorcardiographic findings are discussed with reference to the pertinent literature.

Aortic regurgitation and aneurysm of sinus of Valsalva associated with osteogenesis imperfecta

Abstract A case of osteogenesis imperfecta with aortic regurgitation is described. The patient is the first whose aortic root abnormalities accounting for the aortic regurgitation were characterized by cardiac catheterization and angiography. The patient had a dilated aortic valve ring and an aneurysm of the sinus of Valsalva. The similarity of these findings to the cardiovascular abnormalities found in other types of connective tissue disorders is discussed and a common cause is suggested.

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.

Physiologic evaluation of a catheter tip electromagnetic velocity probe. A new instrument.

A miniature catheter electromagnetic velocity probe has been designed and enclosed within the tip of a No. 8 F cardiac catheter, 2.67 mm. in external diameter. Peak systolic blood flow rates from 3 to 338 cm.3/sec. as measured by the catheter probe agreed closely with simultaneous measurements by the perivascular electromagnetic flowmeter probe, in the ascending, descending thoracic and abdominal aorta of 12 anesthetized dogs (r = 0.97 to 0.99). Catheter and perivascular probe measurements of blood flow, made every 1100 of a second throughout the cardiac cycle, correlated well with each other in these 12 experimental animals (r = 0.94 to 0.99). In vitro studies utilizing measured steady blood flow in the physiologic range, 13 to 473 cm.3/sec., demonstrated that the electrical output of the catheter probe was linear (r = 0.998). Therefore, the catheter probe can be utilized to record and measure accurately the instantaneous blood velocity and flow in the systemic arterial circulation. In comparison to the perivascular flow probe, the catheter probe has the advantage of (1) not requiring surgical exposure of the blood vessels; (2) not restricting pulsatile expansion of the blood vessel; (3) readily allowing the recording of blood velocity in the larger arteries and veins of the systemic and pulmonary circulation; and (4) having the velocity sensing electrodes in direct contact with the blood.

Management of Type IV Hyperlipoproteinemia: Evaluation of Practical Clinical Approaches

A lipid intervention clinic screened 4000 employees (89% participation) and identified 150 type IV subjects (top 5 percentile triglyceride values, 100% initial participation, 6% drop out). The 150 healthy type IV subjects, ages 20 to 49, were randomly divided into treatment subgroups: A, treatment by clinic nutritionist and physician with the National Heart and Lung Institutes type IV diet for 6 weeks, then diet plus clofibrate for 18 weeks; B, same treatment by private physician; C, no intervention for 24 weeks, subjects advised of abnormality. The group A mean fasting serum triglyceride of 407 mg/dl declined 50% at 6 weeks, 61% at 12 weeks, and was unchanged at 24 weeks (P less than 0.0005 at 6, 12, 24 weeks). Group B triglyceride decreased 42%, 50%, 41% (P less than 0.0005 at 6, 12, 24 weeks). Group C triglyceride declined 20%, 1st to 24th week. Body weight decreased 8% (A) and 4% (B) at 6 weeks (P less than 0.0005) and was unchanged at 24 weeks. The maximum cholesterol decrease (A) was 11% (P less than 0.0005). Type IV hyperlipoproteinemia can readily be identified in a working population; treatment by clinic or private physician will markedly lower fasting serum triglyceride values in apparently healthy type IV subjects for at least 24 weeks.

Digital filtering of left ventricular heart volume and calculation of aortic valve blood flow

Abstract The volume of the left ventricle of the heart can be calculated from measurements taken from cine angiocardiograms. During normal systole, blood leaves the left ventricle via the aortic valve; therefore, the first derivative of left ventricular volume with respect to time (during systole) is equal to aortic valve blood flow. Since a curve of left ventricular volume versus time contains significant scatter, it must be filtered, or smoothed, prior to differentiation. This paper describes three methods of digitally filtering left ventricular volume, and discusses methods of calculating aortic valve blood flow. All three methods of smoothing volume give similar results.

Lactic dehydrogenase isoenzymes after electroshock treatment of cardiac arrhythmias

The serum enzyme concentrations measured in this study can be used to differentiate injury of heart muscle, skeletal muscle, lung and liver tissue. Serum lactic dehydrogenase (SLDH) isoenzymes, total SLDH, serum glutamic oxalacetic transaminase (SGOT) and serum glutamic pyruvic transaminase (SGPT) were measured in 29 patients on the day before, the day of but before and the three days after treatment of atrial fibrillation by D.C. electroshock. All patients selected were men aged 50 or older with some evidence of atherosclerotic heart disease. Identical enzyme measurements were also made concurrently in a control group of 19 untreated subjects who were matched to the treated subjects by sex, age and disease. n nThe SGOT levels increased significantly after D.C. electroshock in a minority of patients. These changes are statistically significant for the group as a whole (p values < 0.02 and < 0.05). No significant changes occurred in SLDH alpha 1 and 2 and beta isoenzymes, in total SLDH, or in SGPT. No evidence was found that the enzyme changes observed after D.C. electroshock are due to myocardial injury. The statistically significant rise in SGOT appears to originate from tissues other than those of the heart. Reasons are presented for implicating the skeletal muscle of the chest wall as the source of these changes in serum enzyme concentrations.