Biomedical subjects
Publications and source records attributed to S Laniado.
An atypical clinical presentation, the diagnostic procedures and a novel surgical approach are described in a 67-year-old woman with a patent ductus arteriosus.
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Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Rate dependent first degree block, which was followed by a complete block, between a pacemaker electrode and the ventricular myocardium, was observed in a patient with inferior myocardial infarction. These conduction disturbances which occurred during pacing at the postero-basal wall of the right ventricle and not during pacing at the apex, suggested that the posterior part of the right ventricle was damaged. This hypothesis was supported by hemodynamic findings which indicated a right ventricular infarction.
A 28-year-old male with recurrent episodes of ventricular fibrillation, which were initiated by very early ventricular premature depolarizations with a normal QT interval, was subjected to three consecutive electrophysiological studies. During the first study, which was carried out to test the efficacy of amiodarone treatment, no ventricular arrhythmias could be induced. While on amiodarone therapy, the patient experienced another syncopal episode and therefore a second electrophysiological study was done. In that study, ventricular fibrillation was induced by ventricular stimulation. During the third study, which was carried out in order to evaluate the effect of the addition of quinidine to the on-going amiodarone therapy, no more than three repetitive ventricular responses could be induced. The patient has been asymptomatic since the third study (fifteen months) with combined therapy of amiodarone and quinidine. The significance of the ability to induce ventricular fibrillation during an electrophysiological study is discussed as well as the value of such studies in determining the long-term efficacy of antiarrhythmic drug therapy.
A 28-year-old man is described with no demonstrable organic heart disease and recurrent paroxysmal attacks of sustained ventricular tachycardia. Lignocaine and ajmaline failed to terminate the first attack but a bolus infection of verapamil succeeded. This drug was subsequently successful on six more occasions. During electrophysiological study of the eighth attack, slow intravenous administration of verapamil significantly reduced the rate of the tachycardia and prevented its subsequent reinitiation by pacing. Two mechanisms are postulated to explain both the arrhythmia and the beneficial effects of verapamil in this case.
To examine the mechanisms of mitral valve motion in mid diastole and at closure, we simultaneously measured mitral flow (electromagnetic), valve motion (echo), and atrioventricular pressures (micromanometer). Peak valve excursion (E point) occurs early 46 +/- 7 ms) after opening and always precedes peak flow; therefore, mid-diastolic closing motion (EF slope) is not due to flow deceleration or vortex formation. Large variations in peak flow are accompanied by small variations in valve excursion (coefficient of variation 41 vs. 12%, respectively). We conclude that the valve overshoots its equilibrium position and that the chordae produce tension on the valve during diastole. This approach is supported by data from papillary muscle rupture, prolonged P-R interval, and mathematical modeling. We offer a valve-closure theory unifying chordal tension, flow deceleration, and vortices, with chordal tension as a necessary condition for the proper function of the other two. Nevertheless, prolonged periods of diastasis and ventricular premature contractions indicate that competent valve closure may occur in the absence of vortices and flow deceleration.
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An inexpensive method for obtaining simultaneous echograms from two or more cardiac areas is described. The measurement of systolic and diastolic time intervals, the identification of various auscultatory findings and the diagnosis of some valvular lesions are among the uses of such a technique.
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Paroxysmal supraventricular tachycardia results from circular movement of the depolarization wave, with or without the involvement of an accessory pathway. Two ECG signs have been proposed as indicators of such accessory pathway involvement in the retrograde limb of the circular movement: a negative retrograde atrial activity in lead I, and a paradoxical tachycardia slowdown with the onset of a functional bundle-branch block ipsilateral to the accessory pathway. Electrophysiological studies were carried out on 17 patients--12 with manifest and five with concealed preexcitation--and the data were analyzed with respect to the two above-mentioned signs. In the 14 patients with a left accessory pathway, there was a negative P wave in lead I during tachycardia. Six of them had functional left bundle-branch block; in four of these six, the tachycardia slowed down with the onset of the block and in one, the rate of the tachycardia did not change. In the sixth patient, the left bundle-branch block pattern appeared in one atrial echo beat and its effect on the rate of tachycardia could not be determined. In 6 of the 14 patients with a left accessory pathway, there was no change in the rate of tachycardia with the onset of a right bundle-branch block. It was concluded that the two ECG signs are reliable indicators of the involvement of an accessory pathway in paroxysmal supraventricular tachycardia.
M-mode echocardiography was performed in 20 asymptomatic patients undergoing chronic hemodialysis, in order to assess pericardial involvement. Six of the patients had small to moderate amounts of pericardial effusion. One of these patients and 5 others showed an echocardiographic pattern of pericardial thickening. No correlation was found between pericardial involvement and age, sex, secondary hyperthyroidism, serum levels of urea, creatinine or uric acid. The traditional diagnostic techniques commonly used for the detection of pericardial disease such as physical examination, chest X-ray and electrocardiography were not helpful in our patients. Our study demonstrates the high incidence of pericardial involvement in asymptomatic chronically dialyzed patients. Periodic echocardiographic evaluation is recommended for assessment of the presence and significance of these findings.
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M-mode echocardiography was performed in 81 patients with chronic arterial hypertension in order to determine the specificity and sensitivity of the various ECG criteria used for diagnosing left ventricular hypertrophy (LVH) in the determination of left ventricular wall thickening (LVWT). Fifteen popular ECG criteria were studied and showed to be highly specific for LVWT (90 percent to 100 percent). TV1 greater than TV6, RV8 greater than 20 mm and SV1 + Rmax V5 or V6 greater than 35 mm were the most sensitive criteria (69 percent, 54 percent, and 52 percent respectively). The popular limb lead criteria for LVH were less sensitive than the precordial lead criteria in the determination of LVWT. The Estes point system, although less sensitive than some of the other voltage criteria, showed an absolute specificity for LVWT. The ST segment deviation with strain pattern was found in 46 percent of patients with LVWT. An isolated ST segment deviation without any other voltage criterion reflected at most only mild wall thickening. Six patients with LVWT had normal ECG; all of them were categorized in the mild LVWT group. Left axis deviation was found to be a poor indicator of wall thickening in uncomplicated hypertensive patients.
A prognostic profile for patients with acute myocardial infarction (AMI) treated in a coronary care unit has been constructed by applying a modified sequential statistical analysis. The profile represents a dynamic system which enables the physician to predict hospital prognosis simply and rapidly on the basis of daily changing clinical and laboratory parameters. The procedure was tested prospectively on a population of AMI patients and was found to be a reliable prognostic tool. Comparing this scale with that of popular prognostic indices, it was found that prediction was more accurate with this technique.