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Biomedical subjects

S Laniado

Publications and source records attributed to S Laniado.

At least 91 records · Page 5Linked to original sources
PubMed1989

High frequency electrocardiography of three orthogonal leads in dogs during a coronary artery occlusion.

The ability to detect cardiac ischemia in dogs was studied using high frequency electrocardiography and signal averaging technique. Ischemia was induced via a balloon occluding cuff placed around the left anterior descending coronary artery. Three surface orthogonal bipolar leads (X, Y, and Z) were recorded prior to inflation of the occluding cuff. The cuff was then inflated, causing a complete occlusion of the coronary artery. The surface electrocardiogram was recorded before and during ligation and during reperfusion. The recorded waveforms were divided into sequential 10-15 second segments representing different stages of the ischemic state and were aligned using cross-correlation scheme, averaged and band pass filtered between 150-250 Hz. Analysis of the filtered high frequency QRS complexes revealed that coronary ligation was accompanied by changes in waveform morphology including the appearance of zones of reduced amplitude. In seven out of ten experiments reduced amplitude zones were absent before the ligation, present during the occlusion and absent following reperfusion. In two experiments, reduced amplitude zones that were present prior to ligation became wider during occlusion. In one experiment no reduced amplitude zone was present during any stage of the experiment. Such zones may represent slow conduction in regions of the heart rendered ischemia during coronary ligation. Therefore, the morphology of the high frequency QRS complex, as determined by analysis of the signal averaged electrocardiogram, may provide useful information regarding the presence of myocardial ischemia.

Animals↗
PubMed1989

Traumatic heart block.

Penetrating chest wounds have only occasionally been reported as a cause of permanent atrioventricular block. A case is presented in which a nail, fired from a power operated device, passed through the chest, causing complete atrioventricular block and requiring permanent pacing.

Electrocardiography↗
PubMed1989

Diagnosis of dual accessory pathways by ajmaline test.

In a patient with the Wolff-Parkinson-White syndrome, the existence of dual accessory pathways, both right-sided, was suspected during ajmaline test and confirmed during electrophysiologic study. The first accessory pathway was manifest in sinus rhythm while the second was obscured and revealed during low right atrial pacing. Ajmaline abolished conduction over the first pathway which most probably had a long refractory period allowing manifestation of the second pathway which had a very short refractory period. A longer conduction time over the second accessory pathway was suggested to explain its concealment during sinus rhythm.

Adult↗
PubMed1989

Failure of corticosteroid therapy to prevent induction of ventricular tachycardia in sarcoidosis.

Programmed ventricular stimulation was performed in a patient with sarcoidosis who exhibited an episode of sustained ventricular tachycardia. Sustained rapid ventricular tachyarrhythmias requiring cardioversion for termination were induced by double right ventricular apical extrastimuli during control, and treatment with disopyramide, quinidine, and fluocortolone. In contrast, only four repetitive ventricular complexes were induced during combined therapy with quinidine, mexiletine and amiodarone. While receiving the latter regimen, the patient has been asymptomatic during 28 months of follow-up.

Adult↗
PubMed1988

Comparison of nalbuphine hydrochloride versus morphine sulfate for acute myocardial infarction with elevated pulmonary artery wedge pressure.

The hemodynamic and respiratory effects of intravenous nalbuphine hydrochloride and morphine sulfate were compared in a randomized fashion in 20 patients (age 65 +/- 11 years) with acute myocardial infarction and elevated pulmonary artery wedge pressure. Titration of the nalbuphine dose to lower pulmonary artery wedge pressure by greater than or equal to 25% resulted in a decrease of this parameter from 22 +/- 3 to 15 +/- 4 mm Hg, and was associated with a reduction in heart rate from 106 +/- 20 to 96 +/- 19 beats/min (p less than 0.05) and decreases in mean blood pressure (78 +/- 8 to 70 +/- 12 mm Hg, p less than 0.05) and mean pulmonary artery pressure (31 +/- 4 to 22 +/- 5 mm Hg, p less than 0.05), without any remarkable change seen in cardiac index (2.21 +/- 0.43 to 2.22 +/- 0.50 liter/min/m2, difference not significant), stroke volume index (22 +/- 7 to 23 +/- 4 ml/m2, difference not significant), stroke work index (17 +/- 7 to 18 +/- 7 g.m/m2), or systemic and pulmonary vascular resistances (1,675 +/- 333 to 1,513 +/- 508 and 191 +/- 78 to 170 +/- 109 dynes.s.cm-5 respectively, all differences not significant). Nalbuphine also significantly reduced respiratory rate (32 +/- 8 to 26 +/- 8 resp/min, p less than 0.05) and pH (7.45 +/- 0.04 to 7.41 +/- 0.03, p less than 0.05) and increased arterial PCO2 (32 +/- 6 to 35 +/- 6 mm Hg, p less than 0.05) without any major change in arterial PO2 (63 +/- 13 to 66 +/- 17 mm Hg, difference not significant).(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1988

The effect of metal detector gates on implanted permanent pacemakers.

The effect of metal detector security gates, such as are used in airports, was tested in 103 nonselected pacemaker patients. Various types of single and dual chamber units were examined, using telemetry during the test. Pulse rate and duration were measured immediately before and after the procedure. No ill effect was seen on any of the units tested, pacemaker inhibition was not observed, and programmability was not affected. Metal detector security gates have no effect on implanted permanent pacemakers.

Electrocardiography↗
PubMed1988

Transcatheter electrical shock ablation of a concealed accessory pathway.

Transcatheter electrical shock ablation of a concealed posteroseptal accessory pathway was performed on a 57-year-old man with drug-refractory paroxysmal supraventricular tachycardia. A single 300-joules shock delivered at the ostium of the coronary sinus abolished conduction in the accessory pathway and resulted in long-term cure of the arrhythmia. No complications were observed during the procedure.

Electrocoagulation↗
PubMed1988

Recurrent sustained ventricular tachycardia solely responsive to verapamil in a patient with a remote myocardial infarction.

A 49-year-old man with a silent remote postero-inferior wall myocardial infarction exhibited recurrent episodes of sustained ventricular tachycardia which was hemodynamically well tolerated. Ventricular tachycardia was neither terminated nor prevented by therapy with multiple class I and class III antiarrhythmic drugs. In contrast, ventricular tachycardia was repeatedly terminated within a few minutes following intravenous administration of 10 mg verapamil and did not recur during oral therapy with verapamil (360 mg daily). Electrophysiologic study suggested that ventricular tachycardia was due to a reentrant mechanism rather than to triggered or abnormal automaticity. Thus, in contrast to previous reports, findings in this patient indicate that verapamil may be very effective and safe in certain types of ventricular tachycardia occurring late after a myocardial infarction.

Heart Ventricles↗
PubMed1988

Comparative clinical and electrophysiologic effects of adenosine triphosphate and verapamil on paroxysmal reciprocating junctional tachycardia.

The efficacy, electrophysiologic effects, and side effects of adenosine triphosphate (ATP) and verapamil in the short-term management of paroxysmal reciprocating junctional tachycardia (PRJT) were compared in 20 patients. All patients had inducible sustained PRJT during control electrophysiologic study. Fourteen patients had PRJT involving a retrograde accessory pathway, and six patients had atrioventricular (AV) nodal reentrant tachycardia ("slow-fast" type). ATP, which has a very short half-life, was first administered (10 mg iv over 1 sec) during sustained PRJT. If PRJT did not terminate within 2 min, a bolus of 20 mg ATP was given. Verapamil (5 mg iv over 15 sec) was subsequently administered during sustained PRJT, and if the latter did not terminate within 3 min another bolus of 5 mg verapamil was given. The cycle lengths of PRJT before administration of 10 or 20 mg ATP and 5 mg verapamil were similar. The 10 mg dose of ATP terminated PRJT in 17 of the 20 patients, and 20 mg ATP was required to terminate PRJT in the three remaining patients. The 5 mg dose of verapamil terminated PRJT in 15 patients, whereas an additional bolus of 5 mg terminated PRJT in one of the remaining five patients. The overall efficacy of ATP (20/20, 100%) was significantly greater than that of verapamil (16/20, 80%) (p less than .05); however, there was no significant difference between the conversion rate of PRJT after administration of 10 mg ATP (17/20) and 5 mg verapamil (15/20). ATP terminated PRJT more quickly than verapamil (mean 24 sec vs mean 51 sec; p less than .01). Termination of PRJT by either ATP or verapamil was mainly related to a block in the AV node in patients with accessory pathways and to a block in the antegrade slow pathway in patients with AV nodal reentry. Cycle length alternans before termination of tachycardia was observed more frequently after verapamil than after ATP (7/16 vs 1/20; p less than .01). The total incidence of transient second-degree AV nodal block and various cardiac supraventricular and ventricular arrhythmias was higher after termination of PRJT by ATP than after verapamil (17/20 vs 5/16; p less than .001). A higher incidence of transient but frequently uncomfortable noncardiac side effects was observed after ATP. We conclude that ATP (10 to 20 mg) is more effective and more rapid than verapamil (5 or 5 + 5 mg) in terminating PRJT but results in a higher incidence of cardiac and noncardiac side effects.(ABSTRACT TRUNCATED AT 400 WORDS)

Adenosine Triphosphate↗
PubMed1987

Bidirectional flow in congenital ventricular septal defect: a Doppler echocardiographic study.

The purpose of this study was to demonstrate the value of combined two-dimensional and pulsed Doppler echocardiography (echo) in localizing and recording bidirectional flow in congenital ventricular septal defect. Eight children, aged 8 months to 16 years, with clinical signs of a ventricular septal defect, underwent two-dimensional and pulsed Doppler echo study prior to cardiac catheterization. The ventricular septal defect was documented anatomically by two-dimensional echo in all eight patients. Flow patterns in systole and diastole through the ventricular septal defect and on both sides of the defect were carefully studied. In all eight children, systolic, high velocity, pathologic, left to right flow was documented when the sampling volume was positioned on the right ventricular side of the defect. When the sampling volume was positioned inside the defect, to and fro flow, left to right in systole and right to left in diastole, was observed. In children with moderate to large defects, the diastolic flow had a peak in early diastole. Increased pressure in the right ventricle over the left ventricle during the same period was demonstrated by cardiac catheterization and coincided with the Doppler flow. The direction of flow across the defect was affected by the size of the defect and the magnitude of the net shunt. Two-dimensional and pulsed echo Doppler were shown to be useful in demonstrating the ventricular septal defect and estimating its size and hemodynamic significance noninvasively.

Adolescent↗
PubMed1987

Atrial fibrillation and atrial enlargement in patients with mitral stenosis.

The present study was designed to assess the relative contribution of atrial fibrillation and left atrial pressure to changes in the size of the left and right atria in patients with mitral stenosis. The study included 155 subjects, 102 of whom underwent prospective echocardiography and Doppler cardiography, and 69 of whom underwent cardiac catheterization. The size of the atria was determined by two-dimensional echocardiography. There were no significant hemodynamic differences between patients with mitral stenosis who were in either sinus rhythm or atrial fibrillation. The left atrium was larger (p less than 0.001) in patients with mitral stenosis and atrial fibrillation (37.6 +/- 10.8 cm2) than in patients in sinus rhythm (27.8 +/- 7.7 cm2) or normal subjects (15 +/- 3.3 cm2). The size of the right atrium was larger (p less than 0.001) in patients with mitral stenosis and atrial fibrillation (21.7 +/- 5.2 cm2) than in patients in sinus rhythm (13.4 +/- 3.9 cm2) or normal subjects (13.8 +/- 3.7 cm2). Multiple regression analysis showed that the severity of mitral stenosis accounted for 38%, age for 7%, and atrial fibrillation for 11% of the change in the size of the left atrium. Atrial fibrillation accounted for 24%, age for 11, and mitral valve area for 3% of the change in the size of the right atrium. The analysis suggests that the onset of left atrial dilatation in mitral stenosis is the result of an early increase in left atrial pressure. Atrial fibrillation, which develops irrespective of the severity of the mitral stenosis, contributes to a further enlargement of the left and right atria.

Adult↗
PubMed1987

Are rotating tourniquets useful for left ventricular preload reduction in patients with acute myocardial infarction and heart failure?

We examined the hemodynamic effects of congesting cuffs (rotating tourniquets) in 12 patients with first acute myocardial infarction and new onset of congestive heart failure 24 to 48 hours after admission. Congesting cuffs were applied for two periods of 15 minutes each, 15 minutes apart, and inflated to 30 mm Hg and 60 mm Hg consecutively. No change was noticed in mean pulmonary artery wedge pressure, which was 20 +/- 3 mm Hg at the beginning of the study and 19 +/- 3 mm Hg at the completion (P greater than .05, NS), nor in other hemodynamic and blood gases parameters. Patients' clinical conditions remained unchanged. We conclude that application of congesting cuffs at pressures of 30 mm Hg and 60 mm Hg does not result in any change in clinical or hemodynamic data in patients with acute myocardial infarction and new onset of congestive heart failure.

Adult↗
PubMed1987

Early intervention in acute myocardial infarction: significance for myocardial salvage of immediate intravenous streptokinase therapy followed by coronary angioplasty.

Sixteen patients with acute myocardial infarction underwent treatment with streptokinase up to 3 hours after the onset of chest pain. Nine patients (group I) received streptokinase within 1 hour of the onset of pain, and seven patients (group II) received it within 2 to 3 hours. All underwent multigated radionuclide ventriculography after streptokinase therapy and 1 week later. Percutaneous transluminal coronary angioplasty of the infarct artery was performed within 24 hours in all patients. An effort-limited treadmill stress test was performed before discharge. There was no mortality or serious complication. Mean peak total creatine kinase was 521 +/- 289 mU/ml in group I, and 1,614 +/- 709 mU/ml in group II (p less than 0.05). The mean initial left ventricular ejection fraction was 47 +/- 11% in group I and 37 +/- 10% in group II. After early angioplasty (within 24 hours) and at 1 week recovery, left ventricular ejection fraction increased to 53 +/- 9% in group I (p less than 0.05) and to 40 +/- 7% in group II (p = NS). Seven of the nine patients in group I had normal radionuclide ventriculograms at discharge compared with none of the seven patients in group II. Thrombolytic therapy administered less than 1 hour after the onset of symptoms of acute myocardial infarction followed by angioplasty of the infarct artery results in preservation of left ventricular function, whereas therapy given after 2 hours has only a limited effect.

Adult↗