Publications by authors named "Narula O"

Hypoxia in the setting of liver disease is often multifactorial. Obstructive or restrictive lung disease, pleural effusions, and tense ascites are common underlying disorders. Less often observed and frequently unrecognized is hypoxia related to diffuse intrapulmonary shunting--the hepatopulmonary syndrome.

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Selective modification of atrioventricular (AV) nodal conduction, that is, induction of varying degrees of AV nodal delays or block (second or third degree), or both, was achieved with a pervenous laser catheter technique. In six adult mongrel dogs anesthetized with pentobarbital (Nembutal), 5F leads were placed through femoral and external jugular veins and placed into the right atrium and His bundle region. Through another femoral vein, a 200 micron optical fiber was inserted by way of a 7F catheter with a preformed curved tip.

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This study describes microtransection of the His bundle with a pervenous laser catheter in a live dog. In an adult mongrel dog anesthetized with Nembutol , administered intravenously, electrode catheters (No. 5Fr and 6Fr ) were inserted through a femoral vein and positioned in the high right atrium for atrial pacing and in the His bundle region for recording of His bundle electrograms.

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The role of provocation tests for the assessment of amiodarone therapy in patients with ventricular tachycardia remains a subject of controversy: recent studies seem to show that the ability to initiate VT in patients on amiodarone is compatible with a good long-term result. Eighteen patients, 16 male and 2 female, average age 56 years, were treated with amiodarone (600 mg/day in 15 cases, and 400 mg/day in 3 cases) and submitted to provocative tests before and after treatment. The mean follow-up period was 14 +/- 4 months.

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Encainide is an antiarrhythmic agent under evaluation; it is effective in ventricular and supraventricular arrhythmias. Its electrophysiological effects seem to differ according to the route of administration, oral or intravenous, probably because of the effects of active metabolites. Two electrophysiological studies were carried out in 20 patients, under basal conditions, and after 4 to 10 days oral administration at doses ranging from 75 to 300 mg/day.

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Thirty six patients (21 coronary artery disease, 8 cardiomyopathy, 3 mitral valve prolapse and 4 apparently normal) underwent endocavitary stimulation studies. The protocol consisted in delivering one or two right ventricular extrastimuli and twice the diastolic threshold either during spontaneous rhythm (S2 and S2-S3) or a paced ventricular rhythm (S1-S2 and S1-S2-S3). In 9 patients overdrive ventricular pacing at 150-200 bpm was required.

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The functional dissociation (FD) of conduction within the AV-node is characterized by sudden prolongations and/or shortenings of the AH-time during stimulation. Examples for FD are presented during regular atrial stimulation and atrial extrastimulus technique. The appearance of FD is no proof for functional impairment of the AV-node.

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In 35 patients aged 18 to 69 years (mean 48) with clinical, electrocardiographic, or electrophysiological evidence of normal sinus node function, the effect of intravenous propranolol (0.1 mg/kg) was assessed on 3 indices of sinus node function. The drug significantly prolonged sinus node cycle length (12%), slightly prolonged the corrected sinus node recovery time (15%), and slightly but insignificantly lengthened sinuatrial conduction time.

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This study describes a new method (NM) for estimation of sinoatrial conduction time (SACT), which utilizes constant atrial pacing (AP) instead of the premature atrial beats (PABs) used in the method reported in 1973 by Strauss et al. The SACTs were obtained by both methods in 20 patients. The SACT by the Strauss method (SM) was calculated as A2A3 minus A1A1.

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This study analyzes the response to overdrive suppression of junctional pacemakers (JP) and correlates it with symptoms in 21 patients. Junctional rhythm (JR) was seen in 5 patients with intact A-V conduction, and in 16 with complete heart block, the JPs were located proximal to or within the His bundle (BH). Junctional recovery time (JRT) was measured following atrial or ventricular pacing during control and after atropine (2-2.

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The functional behaviour of the healthy and sick human AV-node under various clinical-experimental conditions is described with special reference to (1) AV-nodal conduction, (2) AV-nodel refractoriness, (3) influence of autonomic tone and (4) role of the AV-node in the initiation of rhythm disturbances.

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32 patients were studied by His-bundle-electrocardiogram and programmed atrial stimulation to examine to which extent frequency and autonomic tone participate in influencing the effective (ERP) and functional (FRP) refractory periods of the atrium and AV-node. The measurements were performed during three electrically induced atrial frequencies before and after intravenous injection of 1 mg Atropine (15 patients) and 0.4 mg Visken (17 patients).

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32 patients were studied by His-bundle recordings to examine the extent to which frequency and autonomic nervous system influence the conduction velocity in the subdivisions (atrium, AV-node, His-Purkinje system) of the normal PR-interval. The measurements were performed during sinus rhythm and three electrically induced atrial frequencies before and after intravenous administration of 1 mg Atropine (15 patients) and 0.4 mg Visken (17 patients).

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