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Biomedical subjects

A Keren

Publications and source records attributed to A Keren.

At least 73 records · Page 4Linked to original sources
PubMed1989

[Ischemic episodes during daily activities and progression of ischemic heart disease].

In patients with coronary artery disease, ischemic episodes, the majority of which are silent, can be detected electrocardiographically during daily activities by Holter ambulatory monitoring. We here summarize our experience with the prognostic significance of such ischemic episodes, silent or symptomatic. In 356 patients the progression of ischemic heart disease was evaluated by clinical follow-up averaging 2 years. Death, infarction, unstable angina, referral for coronary bypass surgery or balloon angioplasty were significantly more common in those with ischemic episodes on Holter monitoring than in those without. Thus, in addition to the results of the treadmill exercise test and determinations of left ventricular ejection fraction, the appearance of ischemic episodes is also of prognostic significance.

Activities of Daily Living↗
PubMed1989

Residual left ventricular function and prognosis of patients with asymmetric septal hypertrophy recovering from acute myocardial infarction.

The prognosis of patients recovering from acute myocardial infarction (MI) depends mainly on their residual left ventricular (LV) function. In patients with asymmetric septal hypertrophy (ASH) who are recovering from MI, a larger functioning myocardial mass may remain. However, the frequency of ASH in these patients has not yet been described. Predischarge echocardiography, radionuclide ventriculography, and treadmill stress tests were performed in 403 consecutive patients who had recovered from acute MI. Eighty-eight patients (22%) had ASH with septal thickness greater than or equal to 1.3, and 32 (8%) had septal thickness greater than or equal to 1.5 cm. One hundred thirty-six patients who had recovered from a first MI and had no ASH served as control subjects. Left ventricular ejection fraction (LVEF) in the group with ASH was significantly higher than in control subjects (61% vs 50%; p = 0.0001). LV end-diastolic diameter (LVD(d] and E point septal separation (EPSS) were smaller in the group with ASH (4.9 cm and 5.4 mm) than in the control group (5.5 cm and 10.5 mm). The frequency of positive treadmill test results, angina pectoris, recurrent MI, heart failure, and death during a 22-month follow-up period was similar in both groups. Fifty subjects in the control group were matched with 50 patients from the group with ASH on the basis of maximal level of creatine phosphokinase, location of infarct, and presence or absence of hypertension, and the difference between the two groups was even more marked (LVEF 48% vs 61%, respectively; p = 0.0004).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

The etiology of tumor plop in a patient with huge right atrial myxoma.

In a patient with a large atrial myxoma, the phonocardiographic timing of the tumor plop has been correlated with the two-dimensional echocardiographic motion pattern of the cardiac mass. The tumor plop occurred at the time when the mass stopped its diastolic forward motion into the ventricle and made a strong impact on the interventricular septum and right ventricular posterior wall. Occurrence of tumor plop may require a large mass or long enough tumor stalk to allow the impact of the mass on the ventricular wall.

Adult↗
PubMed1988

Prognostic significance of ischemic episodes in patients with previous myocardial infarction.

This study assessed the prognostic significance of ischemic changes during daily activity as recorded by ambulatory electrocardiographic monitoring in a group of 224 low-risk postinfarction patients. Of the 224 patients studied, 74 (33%) had transient ischemic episodes on Holter monitoring. During the 28 months of follow-up the frequency of cardiac events (cardiac death, reinfarction, hospitalization for unstable angina, balloon angioplasty or coronary bypass surgery) was 51% among those with ischemic episodes on Holter monitoring, compared with 12% in those without such changes (p less than 0.0001). The 74 patients with positive results in their exercise tests and Holter monitoring had a 51% event rate, compared with 20% among the 44 patients with a positive exercise test result but negative Holter results (p less than 0.001). The event rate in those without ischemic changes either on the exercise test or on Holter was only 8.5%. Among patients with good (greater than 40%) or reduced (less than 40%) left ventricular ejection fraction, those with transient ST depression on Holter had a significantly higher cardiac event rate compared with those without it. A similar event rate was found in patients with only silent, only symptomatic and with silent and symptomatic ischemic episodes.

Activities of Daily Living↗
PubMed1988

Characteristics of silent and symptomatic myocardial ischemia during daily activities.

In 191 patients with proven coronary artery disease, 24-hour Holter monitoring detected 587 transient episodes of ST depression during daily activities. Of that total, 424 episodes were silent (72.3%) and 163 were symptomatic (27.7%). There were no statistically significant differences between silent and symptomatic episodes as to their mean duration (15.1 vs 14.3 minutes, respectively), heart rate at onset of ST depression (93 vs 96 beats/min, respectively), heart rate at the time of maximal ST depression (114 beats/min, both) and mean maximal ST depression (1.9 vs 2.0 mm, respectively). Of the 191 patients, 104 (55%) had only silent episodes, 33 (17%) only symptomatic episodes and 54 (28%) had both types ("mixed"). All patients, regardless of episode type, were of similar age, received comparable medical therapy, had a similar extent of angiographically documented coronary artery disease and similar episode characteristics. However, mixed-episode patients had significantly more ischemic episodes per day (4.8) than silent-episode (2.6) and symptomatic-episode (1.9) patients (p less than 0.001 for both) and a longer total period of daily ischemia (60 minutes), than the other 2 groups (36 and 28 minutes, respectively, p less than 0.001 for both). Of the 191 patients, 97 (51%) had had a previous myocardial infarction. The characteristics of their silent and symptomatic episodes were similar to the 94 (49%) patients without infarction, except for a longer duration of the silent episodes.(ABSTRACT TRUNCATED AT 250 WORDS)

Activities of Daily Living↗
PubMed1988

Effects of magnesium on ischemic and reperfusion arrhythmias in the rat heart and electrophysiologic effects of hypermagnesemia in the anesthetized dog.

Magnesium sulfate, reportedly clinically effective against some ventricular arrhythmias, has not been extensively studied for its effects on experimental ischemic and reperfusion arrhythmias. We evaluated the effects of three high extracellular concentrations of magnesium (Mg2+) 1.19, 2.38, and 4.76 mM in 70 isolated perfused rat hearts following coronary artery ligation and reperfusion, at each of three different perfusate ionized calcium (Ca2+) concentrations (0.9, 1.25, and, 2.5 mM), where 1.25 mM is close to physiologic. At 0.9 mM Ca2+, higher concentrations of Mg2+ increased the sinus node cycle length (p less than 0.02) and virtually abolished ischemic ventricular tachycardia (VT) and reperfusion ventricular fibrillation (VF) (p less than 0.01), otherwise consistently found in this model. At 1.25 and 2.5 mM Ca2+ increasing Mg2+ had no effect on the incidence of ischemic or reperfusion arrhythmias, although at 1.25 mM Ca2+ ischemic VT had longer cycle lengths and VT appeared after a longer delay (p less than 0.01). In the nonischemic dog heart, marked increases of serum Mg2+ progressively prolonged the A-H, H-V, and QR S intervals, the ventricular effective refractory period, and the sinus cycle length, while the arterial blood pressure fell. Because of its relatively modest electrophysiologic and hemodynamic effects, it is inferred that intravenous magnesium may be given therapeutically with relative safety.

Anesthesia↗
PubMed1988

Myocardial damage after a scorpion sting: long-term echocardiographic follow-up.

A seven-year-old girl, stung by a scorpion, was hospitalized in a confused state with signs of myocarditis and pulmonary edema. In spite of clinical improvement within 24 h, 14 serial echocardiograms and electrocardiograms performed during a four-month period showed severe changes. There have been no previously published reports of echocardiographic studies showing myocardial changes after a scorpion sting.

Animals↗
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↗
PubMed1988

Ventricular aberrant bands and hypertrophic trabeculations. A clinical pathological correlation.

We reviewed the clinical, hemodynamic, and pathology data of 22 patients with dilated congestive cardiomyopathy and 13 patients with ischemic heart disease who underwent heart transplantation, primarily to improve the pathological definition of left ventricular (LV) and right ventricular (RV) aberrant bands and hypertrophic trabeculations. Overall prevalence of aberrant bands was 37% in th LV and 28% in the RV. Similar values for hypertrophic trabeculations were 43% and 28%, respectively. Compared with ischemic heart disease, our patients with dilated congestive cardiomyopathy had similar ventricular size and wall thickness, but had a higher prevalence of LV aberrant bands (p = .005) and LV hypertrophic trabeculations (p = .01). Aberrant bands were associated, both in the LV and RV, with dilated cavities (p less than .05), whereas hypertrophic trabeculations were associated with more ventricular hypertrophy and smaller LV size. Following morphological and histological analysis of the aberrant bands, we propose their division into two categories: genuine or primary bands (probably congenital in origin) and secondary bands, which most probably represent trabecular structures that develop a free cavitary course following pathological changes in the ventricular wall structure and cavitary geometry. Compared with the muscular RV bands situated mostly in the distal portion of the ventricle, LV bands were usually fibrotic and had at least one point of insertion in the inflow or outflow tract. The pattern of trabecular hypertrophy was also different in the two ventricles. Ventricular arrhythmias and thrombi occurred equally in patients with and without bands or trabeculations.

Adolescent↗
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↗
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

Importance of (perimembranous) ventricular septal aneurysm in the natural history of isolated perimembranous ventricular septal defect.

Records were reviewed of 247 patients found to have isolated perimembranous ventricular septal defect (VSD) on cross-sectional echocardiography. Patients were separated into 2 groups: those in whom a perimembranous ventricular septal aneurysm (VSA) was associated with the VSD (group A, 77% of patients) and those in whom a VSA was not present (group B, 23%). The VSD was assessed by clinical (125 in group A, 24 in group B) and hemodynamic criteria (65 in group A, 33 in group B). The median follow-up period was 27 months (range 3 months to 25 years). In group A, the VSD closed spontaneously in 11% of the patients, improved clinically in 33% and required surgical closure in 11%. In group B, the VSD closed spontaneously in only 2%, improved clinically in 16% and required surgical closure in 47%. When considering larger VSDs only, 28% required surgery in group A, whereas 84% required surgery in group B (p less than 0.001). The VSA was found at the first echocardiographic examination in 94% of the studies. Thus, VSA is found in a large proportion of patients with perimembranous VSD. It occurs as an early phenomenon and is an important mechanism of closure. The presence of a VSA appears to confer a more favorable prognosis in perimembranous VSD except in patients with Down's syndrome.

Adolescent↗