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Biomedical subjects

D Tzivoni

Publications and source records attributed to D Tzivoni.

At least 145 records · Page 8Linked to original sources
PubMed1980

Prinzmetal's angina. Aternating ST-segment deviation in anterior and inferior electrocardiographic leads during the same episode of pain.

A 60-year-old man had recurrent episodes of spontaneously occurring pain in the chest which were associated with ST-segment elevation consistent with Prinzmetal's angina. The simultaneous elevation of the S-T segment in anterior and inferior electrocardiographic leads with initial ST-segment depression followed by elevation in high lateral leads suggested that heightened vascular reactivity in variant angina may involve multiple coronary vessels during the same episode of vasospasm.

Aged↗
PubMed1980

Hypertrophic nonobstructive cardiomyopathy as a cause of angina pectoris.

Four patients with severe classic angina pectoris and no evidence of myocardial infarction are described. All had ECG changes compatible with myocardial ischemia. Coronary arteriography showed normal coronary arteries (except for minor narrowing in one patient) and marked hypertrophy of the left ventricle without left ventricular outflow tract obstruction. The diagnosis of hypertrophic nonobstructive cardiomyopathy was confirmed by the presence of small left ventricular diastolic and systolic volumes with a supernormal ejection fraction indicative of a hypercontractile state of the left ventricle. Treatment with beta-blocking agents reduced myocardial work, improved diastolic compliance and decreased patients' anginal symptoms. Hypertrophic nonobstructive cardiomyopathy is an important cause of typical angina pectoris in patients who have normal coronary arteries on coronary angiography.

Adult↗
PubMed1980

Right atrial pacing soon after myocardial infarction for assessment of residual myocardial ischemia.

To assess the presence of residual myocardial ischemia, right atrial pacing was performed in 30 patients with 31 episodes of acute myocardial infarction (AMI) on the day before their discharge from the hospital. Ten patients had anterior, 11 inferior, and 10 subendocardial AMI. The atrial pacing was performed in the intensive care unit. The electrode was introduced by direct puncture of the antecubital vein and positioned under intracavitary ECG control. No complications occurred in any of the patients. Ischemic ST depression was observed in 14 patients. Only 1 of 10 with anterior AMI had a positive test, compared with 7 of 11 with inferior AMI and 6 of 10 with subendocardial AMI. It is concluded that right atrial pacing can be performed safely in patients soon after AMI, and that the procedure is sensitive in detecting residual myocardial ischemia. It is expected that this method will provide a tool for identifying high-risk patients, thus enabling better treatment and possibly a reduction in the rates of reinfarction and sudden death.

Adult↗
PubMed1980

Evaluation of myocardial perfusion by thallium-201 imaging at rest and during exercise. Comparison with ECG stress testing.

In order to assess the accuracy of thallium-201 cardiac imaging at rest or during exercise in detecting permanent or transient myocardial damage, we studied 49 patients with angiographically documented coronary disease (31 with previous myocardial infarction) and 29 patients with normal coronary arteries. The resting thallium scan was significantly more accurate in detecting previous myocardial infarction (31 patients) than the resting ECG (22 patients) (P < 0.01). The combination of thallium imaging and ECG stress testing revealed reversible myocardial ischemia in 41 of the 49 patients (84%), compared with 28 of 49 (57%) detected by ECG stress testing alone (P < 0.01). Thallium imaging was more accurate in ruling out coronary disease (26 of 29 patients, 90%) than ECG stress testing (19 of 29 patients, 65%) (P < 0.05). In patients with previous myocardial infarction, thallium imaging alone or in combination with ECG stress testing was not significantly more sensitive than ECG stress testing alone.

Coronary Circulation↗
PubMed1979

Photokymography: a noninvasive method of detecting ischemic segmental myocardial wall motion abnormalities.

The photokymograph is a new and simple noninvasive device for assessing epicardial segmental myocardial wall motion utilizing cardiac fluoroscopy and image intensification. The validity of this technique in detecting wall motion changes occurring with ischemia was assessed in seven closed chest dogs undergoing acute balloon occlusion of the left circumflex coronary artery. Acute occlusion resulted in a prompt change in the analog signal of the photokymogram, characterized first by a decreased systolic inward motion and late systolic outward movement that later became akinetic and dyskinetic. Systolic amplitude decreased 18 +/- 7 percent (mean +/- standard error of the mean) within 5 seconds of occlusion and progressed to systolic outward motion (- 106 +/- 24 percent) at 2 minutes. The time course and type of morphologic changes observed after occlusion were similar to those previously described using invasive methods. Furthermore, such changes preceded electrocardiographic S-T segment elevation. These data suggest that photokymography is a sensitive technique for noninvasive detection of acute ischemic segmental wall motion abnormalities and holds promise as a simple method of detecting ischemic heart disease in man.

Animals↗
PubMed1979

Analysis of regional ischemic left ventricular dysfunction by quantitative cineangiography.

The ability of left ventricular angiography to detect regional ischemic dysfunction was assessed in 10 closed-chest dogs during the course of acute balloon occlusion of the anterior descending coronary artery. During the 2-minute period of occlusion, serial cineangiography revealed a sequence of wall motion abnormalities over the anteroapical region almost identical to that observed using directly implanted gauges. This sequence consisted of progressive reduction in regional systolic shortening with eventual replacement by systolic expansion. These changes preceded both electrocardiographic ST-segment and hemodynamic alterations, and were readily observed by gross subjective inspection of the cineangiograms, but with an intraobserver variability of 22%. Frame-by-frame motional analysis of the ventricular perimeter relative to its centroid of mass allowed more precise characterization of regional dysfunction. These data are consistent with previous studies demonstrating that regional wall motion abnormalities are both sensitive and specific markers of acute ischemia, and support the use of computerized left ventricular angiography for the quantitative assessment of clinical ischemic dysfunction.

Animals↗
PubMed1978

Preservation of myocardial contractility in hemorrhagic shock with methylprednisolone.

The left anterior descending or left circumflex coronary artery was cannulated selectively in 10 dogs. Methylprednisolone, 1 mg per kilogram of body weight, was injected into the artery and the cannula was withdrawn. The animals were then subjected to hemorrhagic shock for 90 minutes. Retransfusion to prestudy blood pressure was then accomplished. The electrocardiogram, arterial blood pressure, contractile force, and first derivative of contractile force were recorded continously both from the areas that were pretreated and those that were not, the controls. Contractile force in the control area was reduced to 32 +/- 3.2% of the preshock period after 90 minutes of shock, whereas in the pretreated area it was twice as high at the same time. Ten minutes after transfusion, the contractile force of the pretreated area exceeded the preshock level, whereas the recovery of contractile force in the control area reached only 70% of the preshock level. This study shows that intracoronary infusion of methylpredisolone can afford myocardial protection in hemorrhagic shock to a significant degree.

Animals↗
PubMed1978

Ambulatory ECG monitoring and bicycle ergometry: correlation with findings on coronary arteriography.

Ambulatory ECG monitoring during everyday activities (AEM) and a multistage submaximal bicycle ergometric test (BET) was performed on a series of 48 patients suffering from precordial symptoms or pain. The results of these tests were compared with the results of coronary arteriography. In 20 subjects with a negative AEM and BET the coronary arteriography was normal in 18, moderately pathological (30-60% narrowing) in 1, and severely pathological (greater than 60% narrowing) in another. In 23 subjects in whom both AEM and BET disclosed ST-T alterations, 20 had severely pathological and 1 moderately pathological coronary arteriograms; normal coronary arteries were found in only 2 subjects. Only 5 of the total of 48 patients of the series showed a discrepancy between the results of AEM and BET. The findings on coronary arteriography confirmed that patients with a normal AEM and BET have a very high probability of having normal coronary arteries, while if both tests are positive the patient will most likely have advanced coronary pathology. When the two tests were concordant, the number of false positive and false negative results were slightly less than if ergometry was performed alone. Although AEM does not provide the quantitative aspect of effort testing, it does have the advantage of avoiding the risk of unusual physical effort for the patient.

Activities of Daily Living↗
PubMed1978

The marked myocardial depressant effect of verapamil.

An experiment was designed to measure accurately the primary effect of verapamil on myocardial contractility by infusion of the drug directly into the coronary artery of open-chested anesthetized dogs. A marked myocardial depressant effect, which was dose and time dependent, was noted during verapamil infusion at the infused area only. The percent decrease in contractile force ranged from 8.8 at an infusion rate (mg/min) of 0.55 X 10(-2) to 36.8 at 5.5 X 10(-2). Similar changes were observed in the first derivative of the contractile force. No changes were observed in the left ventricular systolic or end-diastolic pressure and only a mild increase in contractile force was noted in the control (noninfused) area. The depressant effect of verapamil was sustained. Recovery time after 5 min of verapamil infusion was dose dependent, ranging from 10 to 45 min. During the recovery period, an overshoot of the contractile force was observed in dogs on the higher doses only. We concluded that verapamil in clinically relevant doses has a marked negative inotropic effect of long duration and therefore should be used with caution in patients with depressed left ventricular function. Cessation of the verapamil treatment may cause a transient increase in myocardial contractility, which might be hazardous in patients with angina pectoris who have compromised coronary blood flow.

Animals↗
PubMed1978

[Cardiokymography: noninvasive assessment of the regional myocardial wall motion in the detection of coronary artery disease (author's transl)].

Cardiokymography is a technique to assess myocardial wall motion by means of an electromagnetic field induced over the left precordium. The normal cardiokymogram (CKG) is characterized predominantly by systolic inward movement. An abnormal contraction pattern--either at rest or provoked by a stress test--reveals a different tracing with decreased or absent systolic inward motion and/or systolic outward motion (bulging). In 50 patients with suspected coronary artery disease (CAD) the CKG was recorded before and after treadmill exercise test and the results compared to coronary angiography. Out of 33 patients with angiographically documented CAD (more than 50% luminal narrowing) 25 showed an abnormal CKG after exercise. There was one false positive postexercise CKG in the group of 17 patients without angiographically documented CAD. The CKG allows the qualitative assessment of regional myocardial wall motion, which is a sensitive and specific marker of ischemia. In conjunction with an ECG-stress test the CKG helps to detect the evolving ischemic abnormalities of myocardial contraction. The CKG represents a marker of ischemia independent of the ECG and helps to improve the diagnostic accuracy of stress testing for detection of CAD. The stress CKG is especially advantageous in those cases in which the interpretation of the stress ECG is difficult or even not possible. Its simple and inexpensive technique makes it a useful adjunct to the stress ECG in the diagnosis of CAD.

Aged↗
PubMed1977

High fidelity ECG in the diagnosis of occult coronary artery disease: a study of patients with normal conventional ECG.

High fidelity (HF) electrocardiography (ECGY) was performed on four groups of patients with a normal resting electrocardiogram (ECG). Two groups (A and B) consisted of normal subjects over or under the age of 40, while the other two groups of patients (C and D) underwent coronary arteriography because of chest pain. HR ECG components within the initial portion of the QRS complex were significantly more common among patients with advanced coronary disease. The difference between the normal groups and the group with documented coronary artery disease (CAD) became more significant when the number of leads showing the HF ECG components was counted. Precordial leads were more sensitive in predicting the presence or absence of CAD than limb leads. HF ECG components in the terminal portion of the QRS complex did not differentiate between normals and patients with coronary artery disease, unless the number of leads showing these HF ECG components was considered. It seems that abnormal HF ECG components can point to minor areas of fibrosis caused by coronary artery disease even if the resting conventional ECG is normal.

Adult↗
PubMed1977

Complete heart block following therapeutic irradiation of the left side of the chest.

Two female patients had received therapeutic irradiation of the left side of the chest for adenocarcinoma of the left breast and 18 and 23 years later, respectively, developed atrioventricular block. Both patients had early and late cutaneous reactions, as well as fibrosis of the left lung, lymphedema of the left arm, and pathologic rib fractures but had no signs of recurrence of the carcinoma. One patient developed signs of congestive heart failure while the electrocardiogram revealed second and third degree atrioventricular block; subsequent pacemaker implantation relieved the congestive heart failure. In the second patient, fatigue was the only symptom leading to the diagnosis of transient second and third degree atrioventricular block; this symptom subsided after pacemaker implantation. Based on reports of radiation-induced cardiac damage, it is assumed that the heart block in these two patients might have been due to postirradiation fibrosis of the atrioventricular node, either direct or mediated by fibro-occlusive changes in the coronary vessels.

Adenocarcinoma↗