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Biomedical subjects

D Tzivoni

Publications and source records attributed to D Tzivoni.

At least 91 records · Page 5Linked to original sources
PubMed1988

Sinus node and atrioventricular nodal function in 220 patients recovering from acute myocardial infarction.

Sinus node and atriventricular (A-V) nodal functions were evaluated by right atrial pacing in 220 consecutive patients recovering from acute myocardial infarction (AMI), 10-28 days after the infarct (mean = 14 days). In the 188 patients in whom a pacing rate of 120 beats/min could be achieved, sinus node recovery time, corrected sinus node recovery time (CSNRT) and total recovery time were correlated to infarct site and the presence or absence of myocardial ischemia. Sinus node recovery time and total recovery time were significantly longer in patients with inferior (1,153 + 28 and 3,129 + 179 ms, respectively) or non-Q-wave infarct (1,112 + 28 and 3,730 + 266 ms, respectively), than in patients with anterior infarct (1,044 + 20 and 1,153 + 28 ms, respectively). The parameters were within the reported normal range. When corrected for heart rate (CSNRT), these differences were no longer present. The presence or site of residual ischemia during right atrial pacing did not affect the sinus nodes parameters. A-V nodal function, studied in all 220 patients, was assessed by the appearance of second-degree A-V block at pacing rates below 120 beats/min and by measuring the shortest atrially paced cycle length with 1:1 A-V conduction. Second-degree A-V block appeared at a similar frequency in different AMI locations. Thus, sinus and A-V node functional status in patients recovering from AMI are not affected by infarct site or by the presence or absence of residual myocardial ischemia.

Adult↗
PubMed1988

Use of streptokinase for lysis of a mobile left ventricular thrombus--report of a case and review of the literature.

One-third of patients with acute anterior wall infarction develop left ventricular apical thrombi. Mobile thrombi carry the highest risk of systemic embolization, particularly in the early phase after the acute infarction. We report here on a young patient in whom a protruding and mobile left ventricular thrombus was detected on two-dimensional echocardiogram 1 week after an acute antero-septal infarction. Intravenous administration of relatively low doses of streptokinase was followed within 14 h by complication-free resolution and disappearance of the thrombus.

Echocardiography↗
PubMed1988

Treatment of torsade de pointes with magnesium sulfate.

Twelve consecutive patients who developed torsade de pointes (polymorphous ventricular tachycardia with marked QT prolongation, TdP) over a 4 year period were treated with intravenous injections of magnesium sulfate. In nine of the patients a single bolus of 2 g completely abolished the TdP within 1 to 5 min, and in three others complete abolition of the TdP was achieved after a second bolus was given 5 to 15 min later. Nine of the patients also received continuous infusion of MgSO4 (3 to 20 mg/min) for 7 to 48 hr until the QT interval was below 0.50 sec. In nine of the 12 patients the TdP was induced by antiarrhythmic agents. The QT interval preceding TdP ranged from 0.54 to 0.72 sec. After the MgSO4 bolus, which prevented the recurrence of TdP, no significant changes were observed in the QT interval. There were no side effects of this treatment. In eight of the 12 patients potassium levels before the TdP were below 3.5 meq/liter; magnesium levels were available in eight patients before TdP, and were normal in all. Five additional patients with polymorphous ventricular tachycardia but normal QT intervals (non-TdP patients) received two to three boluses of MgSO4. This treatment was ineffective in all, but they responded to conventional antiarrhythmic therapy. Thus, MgSO4 is a very effective and safe treatment for TdP, and its application is rapid and simple. Its use is therefore recommended as the first line of therapy for TdP.

Aged↗
PubMed1987

Day-to-day variability of myocardial ischemic episodes in coronary artery disease.

Twenty patients with chronic stable angina pectoris, proved coronary artery disease, positive treadmill stress test response, and at least 2 episodes of ischemia per day underwent 72 hours of Holter monitoring during daily activities. During this period they had 389 ischemic episodes: 104 (27%) symptomatic and 285 (73%) silent. Marked variability was observed between patients in the number of ischemic episodes (range 2 to 15 per day, mean 6.5), duration of ischemia (range 6 to 419 minutes/day, mean 76.5), maximal ST depression (range 1 to 6 mm, mean 3.4) and heart rate at the beginning of ST depression (range 75 to 105 beat/min, mean 91). The day-to-day variability in individual patients between the different days in the number of ischemic episodes was 36%, in duration 51%, and in maximal degree of ST depression 31%. Only 9% variability was noted in heart rate at the beginning of ST depression. Similar day-to-day variability in individual patients was noted in the symptomatic and silent episodes. For clinical purposes of evaluation of ischemia during daily activities, 1 day of monitoring appears to be sufficient because within the first day, 78% of the maximal number of ischemic episodes, 64% of their duration, and 84% of the maximal degree of ST depression were detected. However, for evaluation of anti-ischemic drugs at least 2 monitoring days are required.

Aged↗
PubMed1987

Silent myocardial ischemia: diagnosis, clinical significance and management.

With the inception of continuous ECG monitoring with high-fidelity reproduction of the ST-segment, silent myocardial ischemia has been regarded with increasing importance in the detection and management of coronary artery disease. With the aid of a variety of invasive and noninvasive methods, the validity of ST-segment depression as indicative of myocardial ischemia, even in the absence of symptoms, has been adequately documented. In completely asymptomatic subjects with positive evidence of silent ischemia in the exercise ECG or Holter monitoring, the risk of developing a future manifestation of coronary artery disease may be up to ten-fold higher than in individuals with negative tests In patients with established coronary artery disease, concomitant use of continuous ECG monitoring and exercise testing, methods which complement each other rather than being mutually exclusive, a substantial number of patients with otherwise typical angina pectoris may be found to have silent ischemic episodes. An adequate differentiation between those with symptomatic and those who are asymptomatic based on characterization with respect to age, sex, hypertension, coronary anatomy, etc., has not been successful. Patients with silent ischemia during exercise may also exhibit more episodes of silent ischemia during daily activities and up to 75% of ischemic episodes may be asymptomatic. In general, however, silent ischemia during exercise appears more common than silent ischemia only during daily activities. In the latter case, since there is usually no increase in heart rate, the pathophysiology is regarded as dissimilar from that associated with exercise-induced ischemia. While the presence of silent ischemia appears quite common in patients after acute myocardial infarction, its occurrence, to date, has not been confirmed to carry additional risk, whereas in unstable angina, the association of silent ischemia is indicative of a higher probability of subsequent cardiac events.

Angina Pectoris↗
PubMed1987

The significance of ST abnormalities in myocardial infarction.

During the acute phase of myocardial infarction, elevation of the ST segment represents one of the major criteria for location of the injury. Recent studies showed that changes in the ST segment in leads remote from the infarcted area or in right precordial leads may provide additional information on the extent of the infarction and right ventricular involvement.

Electrocardiography↗
PubMed1986

Myocardial ischemia during daily activities and stress.

Twenty-four-hour, 2-channel Holter monitoring during daily activities was performed in 210 patients; during the same day a Bruce protocol treadmill test was also performed and the electrocardiogram was recorded using the same Holter system. Significant ST-segment depression was observed during daily activities in 97 patients, while similar changes were recorded during the treadmill test in 122 patients. Thus, 77% of patients with ST depression during the provocation of the treadmill test had ischemic episodes during their everyday life. On the other hand, 3 patients with proven significant coronary artery disease had spontaneous ischemic episodes during daily activities, but had a negative stress test. The ischemic changes during daily activity developed at a lower heart rate than during stress testing (94 beats/min vs 109 beats/min, respectively, p less than 0.05). A total of 351 ischemic episodes were recorded during daily activities, 241 (69%) of these were asymptomatic. In 46 patients all episodes were asymptomatic, in 15 all were symptomatic, while in 36 both symptomatic and silent episodes were detected. The mean duration of the symptomatic episodes was 13.7 minutes and that of the asymptomatic ones was 14.9 minutes (difference not significant). The degree of ST depression in these 2 groups was also similar. Because of more advanced symptomatology in 143 patients, coronary arteriography was performed; 43 had normal and 100 had pathologic coronary arteries. In this selected group, the sensitivity of Holter monitoring during daily activity was 87% and during stress 97%; the specificity during daily activity was 95% and during stress 88%.(ABSTRACT TRUNCATED AT 250 WORDS)

Activities of Daily Living↗
PubMed1986

Analysis of risk factors in 532 survivors of first myocardial infarction hospitalized in Jerusalem.

During the period January 1979-March 1983, we have conducted in Jerusalem a case control study of all patients under the age of 65 surviving their first diagnosed myocardial infarction, in order to evaluate the importance of the conventional risk factors and to detect additional factors through quantifying plasma apolipoprotein concentrations. As a control group, we have chosen a sample from a previously studied Jewish population (LRC study), representative of the adult Jerusalemite population, parents of children born during 1958-1961. To complete the younger age group missing in the LRC population, we added a population studied in the Kiryat Yovel district of Jerusalem. We report here the results obtained from interviews and analysis of 532 cases (448 males and 84 females), and 869 controls (457 males and 412 females). In order to overcome the effects of age and ethnic origin on the risk factors, we have divided our populations according to age and country of origin of their fathers. Age, sex, smoking, history of high blood pressure, diabetes, elevated plasma triglycerides and/or cholesterol, and decrease in plasma HDL cholesterol, emerged as the most powerful and significant risk factors in this study. Other putative risk factors such as socioeconomic status, dietary habits, physical activity and obesity index were not found to be significantly different between cases and controls. It is noteworthy that smoking was more important as a risk factor in the younger age groups, whereas hypertension and diabetes were more important in the older age groups, particularly in females. The differences in lipid levels were considerably more prominent in the young age groups in both sexes. Myocardial infarction was observed more frequently in patients of European or American extractions. Apolipoproteins A-I, A-II, E and B determined in this study were shown to be affected partly by age and country of origin. Apo E and apo B levels were significantly higher and Apo A-I significantly lower in patients with myocardial infarction when compared to controls.

Aged↗
PubMed1986

Usefulness of predischarge echocardiographic criteria in predicting complications following acute myocardial infarction.

In 103 patients who recovered from an acute myocardial infarction (AMI) we evaluated the usefulness of predischarge clinical, routine laboratory and M-mode echocardiographic (echo) criteria in predicting cardiac complications during a period of 12-41 months (25.0 +/- 10.7 months) follow-up. The echo parameters evaluated were: left ventricular diastolic diameter, left ventricular percent fractional shortening and the mitral valve E point septal separation. The combination of these three echo criteria was defined as an echo-index, which was considered abnormal if at least two of the three single parameters were pathological. Congestive heart failure occurred in 35 (34%) patients, with significantly higher prevalence among those older than 65 years, with previous AMI and with predischarge findings of heart failure. However, the sensitivity of these clinical parameters was unsatisfactory (34-69%). The sensitivity, specificity and positive predictive value of the echo-index for future heart failure were 89, 88 and 80%, respectively. Chest pain prior to hospital discharge was the only criteria predicting high risk of reinfarction (p = 0.001). The risk of cardiac death was related to age older than 65 years (p = 0.03) and an abnormal echo-index (p = 0.01). The overall mortality rate was 13%, but only 6% among those with normal and 26% among those with pathologic echo-index. In conclusion, in patients who recovered from an AMI, a simple and easily measured echo-index was superior to most clinical and routine laboratory criteria in predicting future heart failure and cardiac death.

Angina Pectoris↗
PubMed1985

Reciprocal electrocardiographic changes in acute myocardial infarction.

If reciprocal electrocardiographic changes during acute myocardial infarction (AMI) are a result of ischemia of the wall opposite the AMI, a stress test is expected to induce similar changes in the corresponding electrocardiographic leads. Right atrial pacing was used as a myocardial stress method in 137 consecutive patients recovering from a transmural AMI, and the appearance of pacing-provoked ischemia before hospital discharge was correlated to the presence of absence of ST depression in the opposite wall during the initial 48 hours. Of the 137 patients, 83 (61%) had reciprocal changes; they were more common in inferior (87%) than in anterior (37%) AMI (p less than 0.01). Of 54 patients without reciprocal changes, only 5 (9%) had ST depression during predischarge pacing; however, of the 83 patients with reciprocal changes, 41 had pacing-induced ischemia (p less than 0.01) and 42 did not, indicating that in half of this group the reciprocal changes represent ischemia of the opposite wall. In the other half of the group, without ST depression during pacing, these changes may be a "mirror image" phenomenon. Follow-up showed that angina pectoris, positive treadmill test response 6 months later, or recurrent AMI all consequences of impaired myocardial blood supply, were significantly more frequent in patients with reciprocal changes. This group could be further separated according to the results of right atrial pacing, because angina pectoris or recurrent AMI were infrequent among those with reciprocal changes and negative pacing responses, but was frequent among those with reciprocal changes and positive pacing responses.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1985

Holter recording during treadmill testing in assessing myocardial ischemic changes.

One hundred forty-four patients underwent a Bruce protocol treadmill exercise test during which an electrocardiogram (ECG) was recorded simultaneously with a 2-channel Holter recorder with bipolar V3- and V5-like leads and by a conventional 12-lead system. Sixty-eight patients had no ST depression on either the Holter or on the 12-lead ECG during the exercise test, whereas in 70 patients ischemic changes were recorded by both methods; thus, in 138 of the 144 patients (96%), the results of the 2 tests were concordant. The severity of ST depression, as judged by the heart rate at which ischemic changes were first noted and the maximal ST depression observed, were similar on both recording systems. The Holter system identified 6 of the 7 patients whose ischemic changes were confined to the inferior wall on the 12-lead ECG. The addition of the V3 lead as a second ischemic lead increased the ischemia detection by 10%. Ninety-five patients also underwent coronary arteriography. In these patients the sensitivity of the Holter system during exercise in detecting significant coronary artery disease was 81% and that of 12-lead ECG was 84%, the specificity was 85% and 85%, respectively, and the positive predictive value 91% and 91%, respectively. Thus, the 2-channel Holter recording system with bipolar V3- and V5-like leads was as accurate as the 12-lead system in detecting ischemic changes during exercise and proved that ambulatory monitoring system can reliably reproduce ST segment.

Adult↗
PubMed1984

Early right atrial pacing after myocardial infarction. I. Comparison with early treadmill testing.

Right atrial (RA) pacing and modified treadmill testing (TT) were performed in 111 patients recovering from acute myocardial infarction (MI) before hospital discharge to determine whether ischemic responses are more common with RA pacing than with TT and whether the prognosis could be better determined by the results of 1 test compared with the other. Patients with predischarge congestive heart failure, chest pain, physical disability or age older than 70 years were excluded. Ischemic responses were significantly more frequent during RA pacing than during TT (41% vs 34%, p = 0.02). The results of the 2 tests were concordant in 102 patients (92%): Both were positive in 37 and both negative in 65. In 8 patients, results of RA pacing were positive and results of TT were negative; only 1 patient had positive TT and negative RA pacing responses. The higher percentage of positive responses during RA pacing than during TT can be attributed to the significantly higher pressure-rate product achieved during pacing (18,773 vs 16,831 mm Hg/min, p less than 0.001). The ischemic threshold, defined as the pressure-rate product at which an ischemic change was first noted in a particular patient, was almost identical in both tests. During a mean follow-up period of 16 months, 10 patients had recurrent MI; 8 had positive predischarge RA pacing but only 5 had positive TT responses (p = 0.008). Six patients died; in 3 RA pacing responses were positive and in 2 TT responses were positive.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗