Terminology of torsade de pointes.
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Heart Ventricles↗
Biomedical subjects
A Keren
Publications and source records attributed to A Keren.
Echocardiographic diagnosis of left anterior descending coronary artery disease and left ventricular asynergy.
Interventricular septal (IVS) motion was studied by M-mode echocardiography in 60 patients to review the value of the technique in identifying left anterior descending (LAD) coronary artery disease. Abnormalities of IVS thickening and excursion were presented in 90% of patients with proximal LAD disease, whereas septal function was essentially normal in patients with distal LAD disease and in patients with disease of the right and/or circumflex coronary arteries. Abnormalities of IVS motion were greater in patients with a history of previous anterior wall infarction and/or the presence of angiographic left ventricular (LV) asynergy. There was no difference between patients with isolated or combined LAD disease, nor was there a difference between patients with complete or partial obstruction of the LAD, when more than 75% of the lumen was occluded. The echo was also useful in identification of anterior LV asynergy. Abnormal widening of the LV near the apex and abnormal septal movement in this area detected, with high sensitivity and specificity, patients with angiographic anterior wall asynergy.
Arrhythmias, Cardiac↗
Electrocardiographic characteristics of neurocirculatory asthenia during everyday activities.
We describe the electrocardiographic changes during everyday activities recorded by ambulatory electrocardiographic monitoring in 67 patients with neurocirculatory asthenia. The findings were compared with the results of ambulatory monitoring in 33 healthy controls. We observed episodes of sinus tachycardia > 120/min unrelated to effort in 60 of the patients, 35 had frequent episodes of pronounced sinus arrhythmia, 16 showed transient ST depression, and six transient ST elevation. All these changes appeared during the patients' routine activities, without any unusual exertion and frequently at rest. Periods of sinus tachycardia and sinus arrhythmia were recorded from the patients during sleep. Cardiac arrhythmias, especially ventricular premature beats, were also much more common in those with neurocirculatory asthenia than in the control subjects. These findings indicate that ambulatory electrocardiographic monitoring provides important information on the electrocardiographic characteristics of patients with neurocirculatory asthenia and helps to establish this diagnosis in obscure cases.
Activities of Daily Living↗
Adult respiratory distress syndrome in the course of acute myocardial infarction.
The diagnosis of adult respiratory distress syndrome (ARDS) has been made in our intensive coronary care unit in four patients during the course of acute myocardial infarction (AMI). In all four patients, the syndrome manifested itself either after resuscitation or after a transient hypotensive state. In two of the patients none of the conditions known to be possible etiologies of ARDS was present; in the third, smoke inhalation preceded; and in the fourth, aspiration followed the AMI. The clinical and x-ray pictures were indistinguishable from acute left heart failure, the PaO2 levels were about 40 mm Hg, and a low pulmonary arterial wedge pressure was measured in all cases. Positive end-expiratory pressure was used successfully, combined with other therapeutic measures, and three patients recovered from the ARDS. The association of ARDS and AMI carries a grave risk in view of the additional damage that may be caused by the severe hypoxemia to the already compromised myocardium. The AMI, if complicated by circulatory arrest, cardiogenic shock, or hypotension, seems to be an etiologic factor in the development of ARDS and it should be added to the growing list of conditions that may give rise to this new syndrome.
Aged↗
Effect of methyldopa on regional cerebral blood flow in hypertensive patients.
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Adult↗
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↗
Development of carcinoma of the breast at the site of an implanted pacemaker in two patients.
We report here on two female patients who had permanent pacemakers implanted in their chests and who developed carcinoma of the breast subsequently. An association is suspected between the breast cancer and the pacemaker, which is implanted in an area which borders with the mammary gland or is even right within it. This suspicion led us lately to change in female patients the site of the subcutaneous pocket for the implantation of the pacemaker to a position higher in the chest than before. Moreover, we advocate frequent breast examinations in all female patients with implanted pacemakers.
Adenocarcinoma↗
Extreme sinus bradycardia following routine venipuncture.
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Bradycardia↗
Positive radionuclide myocardial infarction pattern after ventricular fibrillation and direct current countershock.
A patient is presented in whom direct current counter-shock was applied for primary ventricular fibrillation. He recovered uneventfully and no evidence was found of a myocardial infarction; however, a positive 99m technetium stannous diphosphate scan obtained four days after the defibrillation showed positive findings. This positive scintigram was most probably due to myocardial or skeletal muscular damage consequent to counter-schock, but myocardial necrosis induced by ventricular fibrillation may be another cause. This case demonstrates again that a transmural or subendocardial infarction is not the only circumstance under which an abnormal scintigram can be obtained.
Electric Countershock↗
Hypertrophic cardiomyopathy.
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Cardiac Pacing, Artificial↗
Pitfalls in creation of left atrial pressure-area relationships with automated border detection.
Creation of pressure-area relationships (loops) with automated border detection (ABD) involves correction for the variable inherent delay in the ABD signal relative to the pressure recording. This article summarizes (1) the results of in vitro experiments performed to define the range of, and factors that might influence, the ABD delay; (2) the difficulties encountered in evaluating a thin-walled structure like the left atrium in the dog model; and (3) the solutions to some of the difficulties found. The in vitro experiments showed that the ABD delay relative to high-fidelity pressure recordings ranges from 20 to 34 msec and 35 to 57 msec at echocardiographic frame rates of 60/sec and 33/sec, respectively. The delay was not influenced significantly by the type of transducer used, distance from the target area, or size of the target area. The delay in the ABD signal, relative to the echocardiographic image, ranges from nil to less than one frame duration, whereas it is delayed one to two frame durations relative to the electrocardiogram processed by the imaging system. In the dog model, inclusion of even small areas outside the left atrium rendered curves with apparent physiologic contour but inappropriately long delays of 90 to 130 msec. To exclude areas outside the left atrial cavity, time-gain compensation and lateral gain compensation were used much more extensively than during left ventricular ABD recording. By changing the type of sonomicrometers used in our experiments, we were able to record simultaneously ABD and ultrasonic crystal data. However, both spontaneous contrast originating from a right-sided heart bypass pump and electronic noise from the eletrocautery severely interferred with ABD recording.
Animals↗
Findings of automatic border detection in subjects with left ventricular diastolic dysfunction by Doppler echocardiography.
Left ventricular automatic border detection (ABD) patterns were defined in the parasternal short-axis and the apical four-chamber views and were compared with pulsed-wave diastolic Doppler flow-velocity patterns of the mitral valve in 49 subjects (aged 39 to 87 years), 10 selected normal individuals, and 39 consecutive patients with high-quality echocardiographic Doppler studies and relaxation abnormalities (Doppler peak early diastolic velocity/peak late velocity ratio < 1). Both short-axis and apical four-chamber views were useful in the assessment of diastolic function by ABD. However, in subjects with high-quality two-dimensional echocardiographic Doppler studies, ABD was technically more feasible in the apical four-chamber view (97%; 38/39 subjects) than in the short-axis view (64%; 25/39 subjects) and correlated better with Doppler parameters. Compared with normal subjects, patients with abnormal Doppler relaxation patterns showed significant differences in diastolic filling indexes obtained by the ABD technique. The ratio of peak rapid filling rate/peak atrial filling rate (PRFR/PAFR) obtained from the dA/dt waveform in the apical four-chamber view had the highest correlation with Doppler indexes (r = 0.79). A PRFR/PAFR ratio of 1.5 best discriminated between normal individuals and subjects with relaxation abnormalities, with high sensitivity and specificity (95% and 100%, respectively). The PRFR/PAFR ratio obtained from the dA/dt waveform seemed to be a simple and useful method to distinguish between normal and abnormal left ventricular diastolic filling, as defined by Doppler echocardiography.
Blood Flow Velocity↗
Features of mildly dilated congestive cardiomyopathy compared with idiopathic restrictive cardiomyopathy and typical dilated cardiomyopathy.
Congestive cardiomyopathy was recognized in eight patients with only mildly dilated ventricles (an echocardiographic ventricular diastolic dimension index of less than 10% to 15% above the normal range) but with other features typical of end-stage congestive cardiomyopathy. Such patients with mildly dilated cardiomyopathy (MDCM) represented 5% of heart transplant recipients with cardiomyopathy, who were analyzed by us. The clinical, echocardiographic, and hemodynamic data, as well as the gross and microscopic pathologic findings of the hearts in this group were compared with similar data in five patients with idiopathic restrictive cardiomyopathy (IRCM) and 10 patients with typical dilated cardiomyopathy (DCM). Compared with IRCM and DCM, patients with MDCM had a higher incidence of familial cardiomyopathy (p less than 0.009). The echocardiographic features of patients with MDCM and DCM were virtually identical, showing globular hearts with predominant left ventricular dilation and diffuse poor left ventricular contraction. Patients with IRCM had marked atrial dilation but less abnormality of left ventricular size and contraction parameters. On the basis of echocardiographic data, patients with IRCM and MDCM could be well segregated. Cardiac index and light microscopic examinations were similar in the three groups. However, electron microscopy showed a lack of myofibrillar loss in patients with IRCM, little or no myofibrillar loss in those with MDCM, and almost total myofibrillar loss in those with DCM. Patients with MDCM have a high prevalence of familial cardiomyopathy. Absolute heart size and electron microscopic features of the MDCM group were intermediate between IRCM and DCM, but other clinical, echocardiographic and hemodynamic findings were similar to typical DCM.
Adolescent↗
Effect of chronic atrial fibrillation on regional cerebral blood flow.
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Adult↗
The effect of chronic propranolol therapy on regional cerebral blood flow in hypertensive patients.
In 31 hypertensive patients the effect of chronic oral administration of the beta blocking agent propranolol on regional cerebral blood flow (rCBF) was studied, using the non-invasive 133Xenon inhalation technique. The results of the measurements were compared to the rCBF obtained in an age-matched normal control group. Our study shows that during long-term therapy with low doses of propranolol (less than 120 mg/daily) the rCBF is unaffected, but it is increased significantly if higher doses (greater than 120 mg/daily) are used. In all six patients who served as their own control, as they had basic rCBF measurements before or during low-dose propranolol, the rCBF on high-dose propranolol became significantly increased. The possible mechanisms which may cause the increased rCBF on high-dose propranolol are discussed.
Administration, Oral↗
Radionuclide imaging of the heart in myocardial infarction and acute ischemia by 99mtechnetium diphosphonate.
99mtechnetium diphosphonate was used in 81 patients for myocardial imaging. 46 of the patients suffered, 2-6 days prior to the test, from an acute transmural infarction provided by clinical, ECG, and enzymatic evidence; the scintigram was definitely positive in 43, equivocal in 2, and negative in 1. In 16 patients with subendocardial infarctions, in 9 the scintigram showed a positive result, in 1 it was equivocal, and in6 patients negative. In 6 other patients who suffered from acute chest pain, followed by enzyme changes, but no ECG evidence of infarction throughout the hospitalization period, the scan was positive in all. In 13 patients with acute ischemia (unstable 'crescendo' angina), 9 had a positive, 1 an equivocal, and 3 a negative scan. We conclude that radionuclide imaging is a valuable addition to the methods already available for diagnosis of myocardial infarction. With the use of diphosphonate as the tracer, we found that acutely ischemic myocardium that later may recover, gives also positive imaging.
Adult↗