piperidines and Tachycardia--Paroxysmal

Intracardiac electrophysiological effects and antiarrhythmic activity of novel domestic class III antiarrhythmogenic drug niferidil has been studied in a group of 25 patients with paroxismal supraventricular tachycardia (PSVT) diagnosis. The drug was administered in a dose of 20 mg/kg (i.v.). Niferidil injections increased the refractory periods in both right and left atrium (by 22 and 20%, respectively, p < 0.001), right ventricle (12%, p < 0.01), and the His-Purkinje system (34%, p < 0.001) and improved additional anterograde and retrograde conduction (by 22 and 31%, respectively, p < 0.001), while not influencing the conduction via excitable cardiac tissues. Elongation of the QTc interval (22%, p <0.05) in one case was accompanied by an arrythmogenic effect (induction of short-term polymorphous ventricular tachycardia of the "torsade de pointes" type. Niferidil arrested PSVT in 78% cases and prevented PSVT development in response to endocardial stimulation in 86% of patients.

Topics: Adult; Aged; Anti-Arrhythmia Agents; Electrocardiography; Female; Heart; Humans; Male; Middle Aged; Piperidines; Refractory Period, Electrophysiological; Tachycardia, Paroxysmal; Tachycardia, Supraventricular

Topics: Adult; Anesthesia, Intravenous; Anesthesia, Obstetrical; Anesthetics, Intravenous; Cardiomyopathies; Female; Humans; Infant, Newborn; Male; Piperidines; Pregnancy; Remifentanil; Tachycardia, Paroxysmal; Tachycardia, Supraventricular

The electrophysiologic effects and therapeutic efficacy of intravenous and oral flecainide were studied in 15 patients with spontaneous and inducible sustained paroxysmal supraventricular tachycardia (SVT). Twelve patients had atrioventricular (AV) reentrance using an accessory pathway for retrograde conduction and 3 had AV nodal reentrance. Fourteen patients received intravenous flecainide (2 mg/kg body weight over 15 minutes) during an initial electrophysiologic study. Nine patients were restudied during oral flecainide administration (200 to 400 mg/day). After intravenous or oral flecainide therapy, reentrant SVT was noninducible in 6 patients with AV reentrance and in the 3 with AV nodal reentrance. In these 9 patients, intravenous flecainide prevented induction of reentrant SVT by depressing conduction over the retrograde limb of the reentry circuits. In the 6 patients with inducible sustained AV reentrant SVT before and after flecainide therapy, the cycle length of tachycardia increased significantly, mainly as the result of an increase in ventriculoatrial conduction time. There was concordance between the intravenous and the oral effects of flecainide on the mechanism of the SVT. Twelve patients continued oral flecainide treatment for a mean of 16 months (range 5 to 28). Tachycardia recurred in 3 of 4 patients whose arrhythmia remained inducible after flecainide therapy and in 1 of 8 patients whose SVT was suppressed. It is concluded that flecainide is an effective and convenient antiarrhythmic agent to treat patients who have AV nodal or AV reentrant SVT.

Topics: Administration, Oral; Adult; Aged; Anti-Arrhythmia Agents; Cardiac Pacing, Artificial; Female; Flecainide; Follow-Up Studies; Heart Conduction System; Humans; Injections, Intravenous; Male; Middle Aged; Piperidines; Refractory Period, Electrophysiological; Tachycardia, Paroxysmal; Time Factors

An assessment was made of the effect of pirmenol in the termination of paroxysmal supraventricular tachycardia (SVT). Sinus rhythm was restored by intravenous administration in 11 of 17 patients during a spontaneous attack. Another 8 patients were studied electrophysiologically. Pirmenol terminated an induced SVT in 3 of 5 patients having an atrioventricular (AV) intranodal re-entry mechanism but in none of 3 patients having an atrioventricular bypass tract as one re-entrant limb. The overall success in restoring sinus rhythm was 14 of 25 patients (56%). The drug was hemodynamically well tolerated even in cases of continued SVT. Pirmenol increased the atrial effective refractory period and had no obvious effect on AH and HV intervals. The functional refractory period of the AV node was decreased, probably by an anticholinergic effect. The effective and functional refractory periods of retrograde atrioventricular conduction via the AV node and bypass tract were increased in some patients. The mechanism terminating the AV intranodal SVT was a block in the retrograde part of the dual AV nodal pathway, a typical antiarrhythmic Class I effect.

Topics: Adolescent; Adult; Aged; Anti-Arrhythmia Agents; Atrioventricular Node; Blood Pressure; Drug Evaluation; Electrocardiography; Humans; Middle Aged; Piperidines; Refractory Period, Electrophysiological; Tachycardia, Paroxysmal

Flecainide acetate is a recently introduced, class 1 antiarrhythmic agent that is highly effective in the treatment of ventricular and atrioventricular/nodal reentrant tachycardias. Although both intravenous and orally administered flecainide are known to cause an increase in the pacing threshold, an abrupt and potentially lethal rise in threshold causing failure of a properly functioning, newly implanted pacing system has not to our knowledge been described. We report such a case to stress the need for caution when using this drug in elderly pacemaker patients.

Topics: Aged; Arrhythmias, Cardiac; Cardiac Pacing, Artificial; Flecainide; Humans; Male; Piperidines; Tachycardia, Paroxysmal

The acute effects of intravenous flecainide on electrically-induced paroxysmal supraventricular tachycardia and the safety and efficacy of long term prophylaxis with orally administered flecainide were assessed in 37 patients with paroxysmal supraventricular tachycardia refractory to treatment with 'conventional' antiarrhythmic drugs. Over a mean treatment period of 14.2 months, flecainide 200 to 400mg daily completely suppressed paroxysmal supraventricular tachycardia in 9 of 20 patients with paroxysmal supraventricular tachycardia due to Wolff-Parkinson-White syndrome, while 3 patients reported only transient episodes of paroxysmal supraventricular tachycardia, and 1 patient had a decreased ventricular response to chronic atrial fibrillation. Of 17 patients with paroxysmal supraventricular tachycardia due to atrioventricular nodal re-entry, flecainide 200 to 500mg daily for a mean period approaching 26 months totally prevented episodes of paroxysmal supraventricular tachycardia in 8, and reduced the frequency and duration of episodes of paroxysmal supraventricular tachycardia in 3 others. Flecainide prolonged action potential refractoriness in a few patients in each group; however, an increased frequency of occurrence of paroxysmal supraventricular tachycardia occurred due to a simultaneous decrease in the re-entry circuit conduction velocity. In both patient groups the acute electrophysiological effects of flecainide were often predictive of the long term efficacy of the drug in the prophylaxis of paroxysmal supraventricular tachycardia. Side effects usually involved the central nervous system and were most commonly manifested by disturbances in vision, balance, and taste and increased nervousness. These side effects generally subsided following 1 to 2 months' treatment with flecainide. No abnormal trends were observed in laboratory analysis of blood samples taken from patients during long term treatment with flecainide.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Adolescent; Adult; Aged; Anti-Arrhythmia Agents; Female; Flecainide; Humans; Male; Middle Aged; Piperidines; Tachycardia, Paroxysmal; Wolff-Parkinson-White Syndrome

Topics: Administration, Oral; Anti-Arrhythmia Agents; Arrhythmias, Cardiac; Flecainide; Humans; Piperidines; Tachycardia, Paroxysmal; Wolff-Parkinson-White Syndrome

Flecainide acetate depresses both the upstroke of the intracellular action potential and the rate of diastolic depolarisation in isolated tissue preparations of atrial myocardium. It produces no consistent effect on action potential duration. Predictably, in the human heart, studied by clinical cardiac electrophysiological techniques, conduction velocity through atrial myocardium, the atrioventricular (AV) node and anomalous tissue is depressed following flecainide administration. Refractoriness of normal atrial or AV nodal myocardium is not prolonged but the recovery time of anomalous or abnormal tissue is lengthened by the drug. In response to the intravenous injection of flecainide, atrial fibrillation (90%), atrial tachycardia (100%), intra-AV nodal tachycardia (89%) and atrioventricular re-entrant tachycardia (80%) are generally terminated, and although atrial flutter is slowed, only a small proportion (20%) is terminated. There is little experience of the long term treatment of supraventricular tachycardia with oral flecainide. However, preliminary results suggest that flecainide is equally effective in the treatment of both supraventricular and ventricular arrhythmias. Thus, flecainide acetate is a 'broad spectrum' antiarrhythmic agent.

Topics: Animals; Anti-Arrhythmia Agents; Arrhythmias, Cardiac; Electrocardiography; Flecainide; Guinea Pigs; Heart Conduction System; Humans; Piperidines; Refractory Period, Electrophysiological; Tachycardia, Paroxysmal

The effect of flecainide in 12 patients with the Wolff-Parkinson-White syndrome was analyzed with respect to the anterograde and retrograde conduction properties of the accessory pathway, the modes of initiation and termination of circus movement tachycardias, and the ventricular response during induced atrial fibrillation. The principal effect of this drug was to depress both anterograde and retrograde conduction of the accessory pathway. In 8/9 cases circus movement tachycardia was terminated by prolongation of the retrograde effective refractory period of the accessory pathway. Flecainide increased the shortest and the mean cycle length during induced atrial fibrillation. It is concluded that the drug may be of potential benefit in patients with paroxysmal supraventricular tachycardias in patients with the Wolff-Parkinson-White syndrome.

Topics: Adult; Electrophysiology; Female; Flecainide; Heart Conduction System; Humans; Male; Middle Aged; Piperidines; Tachycardia, Paroxysmal; Wolff-Parkinson-White Syndrome

Intravenous flecainide acetate was administered to 33 patients undergoing routine electrophysiologic study: 18 patients had a direct accessory atrioventricular (AV) pathway and 15 patients had functional longitudinal A-H dissociation (dual A-H pathways). Flecainide was given to 14 patients during sustained AV reentrant tachycardia and to 9 patients during sustained intra-AV nodal reentrant tachycardia. AV reentrant tachycardia was successfully terminated in 12 of 14 patients. Tachycardia termination was due to retrograde accessory pathway block in 11 patients and AV nodal block in 1. During flecainide administration, tachycardia cycle lengths increased (327 +/- 55 to 426 +/- 84 ms) principally because of retrograde conduction delay in the accessory pathway (127 +/- 34 to 197 +/- 67 ms). After flecainide administration, tachycardia reinitiation was not possible in 6 patients. In all 18 patients with accessory AV pathway conduction, flecainide significantly increased both anterograde and retrograde accessory pathway effective refractory periods, with anterograde accessory pathway block in 3 patients and retrograde accessory pathway block in 8. Intra-AV nodal reentrant tachycardia was successfully terminated in 8 of 9 patients. Tachycardia termination was due to retrograde "fast" A-H pathway block in 7 patients and anterograde "slow" A-H pathway block in 1 patient. During flecainide administration, tachycardia cycle lengths increased (326 +/- 50 to 433 +/- 64 ms) due to both anterograde, A-H and H-V (AV 242 +/- 97 to 343 +/- 75 ms), and retrograde, earliest ventricular to earliest atrial (51 +/- 14 to 70 +/- 23 ms) conduction delay. After flecainide administration, reinitiation of intra-AV nodal reentrant tachycardia was not possible in 4 patients. In all 15 patients with dual A-H pathways, flecainide selectively prolonged the retrograde effective refractory period of the fast A-H pathway, having little effect on anterograde fast A-H pathway refractoriness or on anterograde and retrograde slow A-H pathway refractoriness. Anterograde fast A-H pathway block occurred in 1 patient and retrograde fast A-H pathway block occurred in 6 patients. No serious adverse effects were encountered during the study. Flecainide acetate is an effective agent for the acute termination of both orthodromic AV and intra-AV nodal reentrant tachycardias. This antiarrhythmic action appears to be mediated through a predominant effect on either accessory AV pathway or retrograde fast A-

Topics: Adult; Aged; Anti-Arrhythmia Agents; Cardiac Pacing, Artificial; Electrocardiography; Female; Flecainide; Humans; Male; Middle Aged; Piperidines; Tachycardia, Paroxysmal

Both the electrophysiological and antiarrhythmic effects of some antiarrhythmic agents may differ markedly depending on their route of administration. Flecainide acetate, a new class 1 agent, was therefore administered both intravenously and orally to 13 patients with recurrent paroxysmal tachycardia to assess whether the acute response to intravenous flecainide accurately predicts the response to oral therapy. Eight patients had atrioventricular re-entrant tachycardia (AVRT) and five patients intra AV nodal re-entrant tachycardia (AVNRT). When administered by either route, flecainide markedly prolonged both the anterograde and retrograde conduction intervals during constant rate pacing and the anterograde and retrograde Wenckebach cycle lengths during incremental pacing. Five of the 13 patients developed complete retrograde block after both routes of administration of the drug. All 13 patients received intravenous flecainide during tachycardia with successful reversion to sinus rhythm in all cases. Tachycardia could be reinitiated in five of the patients with AVRT after intravenous flecainide and in one further patient after oral administration. It was not possible to reinitiate tachycardia in any of the five patients with AVNRT after either intravenous or oral flecainide. The size of the tachycardia initiation windows, by either atrial or ventricular premature stimuli, were significantly reduced by both intravenous and oral flecainide. In those patients in whom tachycardia could be reinitiated, tachycardia cycle length was significantly increased, and to a similar degree, by both routes of administration of the drug. This increase in cycle length was predominantly due to prolongation in retrograde conduction. It is concluded that flecainide acetate is a potent antiarrhythmic agent for use in patients with junctional tachycardia. The intravenous administration of flecainide reliably predicts the subsequent response to oral therapy.

Topics: Administration, Oral; Adolescent; Adult; Aged; Anti-Arrhythmia Agents; Atrioventricular Node; Bundle of His; Female; Flecainide; Humans; Injections, Intravenous; Male; Middle Aged; Piperidines; Purkinje Fibers; Tachycardia, Paroxysmal