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Intravenous propafenone: efficacy and safety in the conversion to sinus rhythm of recent onset atrial fibrillation--a single-blind placebo-controlled study.

The effectiveness of intravenous propafenone for conversion to sinus rhythm (SR) of paroxysmal atrial fibrillation (AF), lasting less than 7 days, was evaluated with a single-blind, randomized, placebo-controlled study, given the possible spontaneous conversion of this arrhythmia. Group 1 (98 patients) received intravenous propafenone (2 mg/kg iv over 10 minutes followed by 0.007 mg/kg/min); and group 2 (84 patients) received intravenous placebo (0.9% saline solution). The infusion was continued until restoration of SR but no longer than 24 hours. Eight-nine patients (90.8%) received propafenone and 27 patients (32%) receiving placebo were converted to SR (p < 0.005). The mean conversion time was 2.46 +/- 2.59 hours in group 1 and 17.15 +/- 5.78 hours in group 2 (p < 0.005). In patients treated with propafenone, conversion of SR mostly occurred in the first 4 hours (86.5%), considered to be the optimal infusion time in our experience. In both groups, the left atrial size was significantly larger in nonconverted than in converted patients. Similarly, the duration of the arrhythmia was significantly longer in nonconverted patients. In nonconverted patients, the mean ventricular rate decreased from 143 +/- 16 beats/min to 101 +/- 18 beats/ min after propafenone and from 135 +/- 19 beats/min to 119 +/- 16 beats/min after placebo (group 1 vs. group 2: p < 0.005). Two episodes of sinus standstill (3.4 and 3.8, seconds, respectively) occurred at SR restoration obtained with propafenone. Intravenous propafenone is an effective, safe, and usually rapid drug for AF treatment. Moreover, it produces a real and significant reduction in the mean ventricular rate in nonconverted patients.

Adult↗

Are there stereoselective electrophysiologic effects of intravenously administered (S)- or (R)-propafenone hydrochloride in patients with supraventricular tachycardia?

OBJECTIVE: The electrophysiological effects of intravenously administered pure (S)- and (R)-propafenone hydrochloride has been determined for the first time in humans-12 patients with supraventricular tachycardia. METHODS: Measurements were performed before and during drug therapy. RESULTS: (S)- and (R)-propafenone prolonged the AH interval from 82 to 107 ms and 75 to 84 ms, respectively, and significantly increased the V nodal Wenckebach cycle length by 58 ms and 37 ms, respectively. The AV nodal effective refractory period in both groups was increased significantly to the same extent (45 vs 42 ms). Sinus node recovery times were not significantly influenced by either enantiomers. Both (S)- and (R)-propafenone significantly prolonged the HV interval to the same extent (from 41 to 51 ms, and 42 to 53 ms). Changes in the electrophysiological characteristics of the myocardium were more pronounced in the atria than in the ventricles. Only (S)-propafenone significantly increased the atrial effective refractory period from 204 to 230 ms, and the ventricular effective refractory period from 225 to 241 ms compared to (R)-propafenone (from 221 to 239 ms, and from 219 to 222 ms, respectively). There was a more pronounced electrophysiological effect on AV nodal conduction of (S)- than (R)-propafenone, probably as a result of its beta-blocking activity. CONCLUSION: The electrophysiological effects of (S)-compared to (R)-propafenone were not very pronounced, so it still remains questionable whether one of the enantiomers might be clinically superior to the other, or to the racemic mixture.

Adult↗

Effects of propafenone on ventricular arrhythmias: double-blind, parallel, randomized, placebo-controlled dose-ranging study.

Propafenone is a new class Ic antiarrhythmic compound with a broad pharmacologic profile. In this study, its dose-response relationship was examined in a double-blind, randomized, placebo-controlled five treatment parallel design protocol. Patients enrolled had heart disease with Lown grade 2 premature ventricular contractions (PVCs) (greater than or equal to 30/hr) documented on 24-hour Holter recordings. Propafenone was compared in four doses (337.5, 450, 675, and 900 mg/day) to placebo. The double-blind phase lasted 2 weeks. Two hundred twenty-six patients were enrolled, of whom 171 were men and 55 were women; their mean age was 59.8 years and 85% were Caucasian and 4% were black. The arrhythmias were symptomatic in 173. Twenty (8.8%) withdrew from the study before completion: 15 had adverse reactions, two had intercurrent illnesses, and three withdrew for administrative reasons. In one patient, the density of arrhythmia appeared to increase with propafenone. Side effects were of central nervous system or gastrointestinal origin; less than 5% of patients developed first-degree atrioventricular block or intraventricular conduction defect. There were no deaths in the study. The occurrence of side effects was not related to dose. Propafenone had no effect on heart rate. It increased the PR interval at all doses (9% to 22% compared to placebo at baseline; p less than 0.01) at 450 to 900 mg/day after 2 weeks of therapy. The drug increased the QRS duration at all doses, highly significantly at 675 mg/day (8.5 msec; p less than 0.01) and at 900 mg/day (15.7 msec; p less than 0.01) after 2 weeks of therapy. Only at the highest dose was the QTc slightly but significantly (14.3 msec; p less than 0.01) increased. Propafenone exerted a dose-dependent effect on PVCs recorded on serial 24-hour Holter recordings: compared to placebo, at 2 weeks 337.5 mg/day reduced PVCs by 70.8% (p less than 0.05), 450 mg/day reduced PVCs by 82.0% (p less than 0.01), 675 mg/day reduced PVCs by 90.2% (p less than 0.01) and 900 mg/day reduced PVCs by 95.3% (p less than 0.01). The effects of the two highest doses of propafenone were significantly greater than those of 337.5 mg/day. In 68% of the patients receiving 900 mg/day, 80% or greater reduction in total PVCs was found. In addition, there was a greater than 90% decrease in ventricular couplets, and 96% decrease in ventricular tachycardia (VT) beats. Propafenone eliminated PVCs in 8% of all patients, ventricular couplets in 58%, and VT beats in 91%.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗

Effects of acute and prolonged administration of propafenone on internal defibrillation in the pig.

Some antiarrhythmic sodium channel blocking drugs have been found to increase the energy necessary for internal defibrillation. Propafenone is a new drug that has been shown to be efficacious in the therapy of supraventricular and ventricular arrhythmias, and is of potential use in patients with defibrillators. The effects of short-term and prolonged propafenone administration on the internal defibrillation threshold (DFT) were determined in 43 pigs randomized to one of four groups: saline infusion (n = 10); propafenone infusion (n = 10); placebo administration for 8 days (n = 10); or propafenone administration for 8 days (n = 13). Two mesh electrodes were sutured on the right lateral and left lateral epicardial surface and current was delivered from the right electrode to the left electrode. Triplicate DFTs were obtained before and at 40 and 80 minutes after infusion of drug or placebo. In pigs receiving long-term administration, after baseline DFTs were obtained the electrodes were removed and the chest was closed. Following 8 days of drug or placebo administration, DFTs were redetermined. No changes were observed in the short- or long-term control groups. DFTs were lower after propafenone administration: either short-term infusion (20 +/- 6.2 joules at baseline; 15.6 +/- 5 joules at 40 minutes, p less than 0.05; 10.2 +/- 6 joules at 80 minutes, p less than 0.001) or long-term administration (17.8 +/- 2.6 joules at baseline versus 12 +/- 3.2 joules on drug, p less than 0.002). Decreased ventricular cycle lengths were found with acute administration of propafenone. Three pigs died during long-term administration of propafenone.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

Efficacy of propafenone compared with quinidine in chronic ventricular arrhythmias.

A double-blind, randomized study was designed to evaluate the efficacy of oral propafenone and oral quinidine in suppressing premature ventricular complexes (PVCs). Twenty-five men were studied for 3 weeks. Twelve were randomized to the quinidine group and 13 to the propafenone group. Small doses of the drugs were administered for 1 week (200 mg of quinidine every 6 hours or 300 mg of propafenone every 12 hours) and large doses were administered for another week (400 mg of quinidine every 6 hours or 300 mg of propafenone every 8 hours). Strict criteria were used to define responders to antiarrhythmic therapy. For more than 85% reduction in total PVCs per hour: During the low-dose week, 36% in the quinidine group and 50% in the propafenone group were responders (difference not significant [NS]), while during the high-dose week 33% and 64% were responders (NS). For more than 95% reduction of ventricular couplets per hour: During the low-dose week, 45% in each group were responders, while during the high-dose week, 56% and 60% were responders (NS). For 100% abolition of ventricular tachycardia (VT) beats per 24 hours: During the low-dose week, 60% in the quinidine group and 56% in the propafenone group were responders (NS); during the high-dose week 80% and 67% were responders (NS). There was no significant difference in the 2 groups in incidence of side effects. This study shows comparable efficacy and tolerance of propafenone and quinidine for the control of ventricular arrhythmias in ambulatory patients with diverse forms of heart diseases.

Adult↗

Usefulness of programmed stimulation in predicting efficacy of propafenone in long-term antiarrhythmic therapy for paroxysmal supraventricular tachycardia.

The electrophysiologic effects of intravenous (i.v.) and oral propafenone were evaluated in 14 patients with Wolff-Parkinson-White syndrome and in 10 patients with atrioventricular (AV) nodal reentrant tachycardia. The effective refractory periods of the right atrium and the AV node increased after both preparations. In patients with Wolff-Parkinson-White syndrome, i.v. propafenone blocked anterograde accessory pathway conduction in 2 patients and retrograde conduction in 1; during oral therapy, accessory pathway conduction block occurred in 2 additional patients. The mean cycle length of the supraventricular tachycardia (SVT) increased from 338 +/- 60 ms to 387 +/- 56 ms (p less than 0.05) after i.v. application, and from 336 +/- 65 ms to 367 +/- 65 ms (p less than 0.05) during oral propafenone. The shortest pacing interval maintaining a 1:1 AV conduction increased from 325 +/- 65 ms to 368 +/- 81 ms (p less than 0.05) after i.v. infusion, and from 333 +/- 57 ms to 369 +/- 75 ms (p less than 0.05) during oral therapy. There was no difference in the electrophysiologic effects between i.v. and oral propafenone. The induction of SVT was prevented by i.v. propafenone in 10 of 20 patients and in 4 additional patients with oral propafenone. During follow-up, 6 of 7 patients, whose SVT could not be initiated by electrophysiologic drug testing, remained free from recurrences, whereas 5 of 7 patients with inducible tachycardia had recurrences of SVT. Thus, in patients with SVT, propafenone prolonged accessory pathway and AV nodal conduction and had a beneficial effect on circus movement tachycardia.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Oral↗

A controlled study on oral propafenone versus digoxin plus quinidine in converting recent onset atrial fibrillation to sinus rhythm.

UNLABELLED: Eighty-seven patients with recent onset atrial fibrillation (< or = 8 days) without clinical signs of heart failure were randomly allocated to one of the following treatments: (i) oral propafenone (600 mg as a loading dose followed after 8 h by 300 mg t.i.d.); (ii) intravenous digoxin as acute scheme (up to 1.125 mg/24 h) followed after 6 h by hydroquinidine chlorhydrate (total dose, 1350 mg); or (iii) placebo. The patients were submitted to Holter monitoring for 48 h. RESULTS: propafenone achieved higher successful conversion rates at 6, 12 and 24 h compared either with placebo (62% vs. 17%, 83% vs. 34%; 86% vs. 55%; P < 0.01, respectively) or with digoxin at 6 h (62% vs. 38%; P < 0.05) and digoxin plus quinidine at 12 h (83% vs. 48%; P < 0.05). At 48 h, a placebo conversion rate of 76% was observed with consequent lack of any significant difference with the active treatments. Mean conversion times within 48 h were 267 +/- 238 min for propafenone, 648 +/- 631 min for digoxin plus quinidine (P < 0.01 vs. propafenone) and 893 +/- 622 min for placebo (P < 0.001 vs. propafenone). Propafenone and digoxin plasma levels were within the therapeutic range. Asymptomatic phases of atrial flutter with > or = 2:1 atrio-ventricular conduction ratio were observed during Holter monitoring, before conversion to sinus rhythm, in four patients treated with propafenone, in one patient taking digoxin plus quinidine and in four patients with placebo.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Oral↗

Effects of propafenone and its main metabolite, 5-hydroxypropafenone, on HERG channels.

OBJECTIVES: Propafenone is a class Ic antiarrhythmic drug used to maintain sinus rhythm in patients with atrial fibrillation. During chronic therapy, it undergoes extensive first-pass hepatic metabolism to 5-hydroxypropafenone. In the present study we have analysed the effects of propafenone and 5-hydroxypropafenone on HERG current. METHODS: The whole-cell configuration of the patch-clamp technique was used in CHO cells stably transfected with the gene encoding HERG channels. RESULTS: Propafenone and 5-hydroxypropafenone (2 microM) inhibited HERG current by 78.7+/-2.3% (n=7) and 71.1+/-4.1% (n=7, P>0.05) when measured at the end of 5-s depolarizing pulses to -10 mV. Block measured at the maximum peak of tail currents recorded at -60 mV was similar for propafenone (78.3+/-2.0%, n=7, P>0.05) and higher for 5-hydroxypropafenone (79.3+/-1.5%, n=7, P<0.05). Propafenone and 5-hydroxypropafenone shifted the midpoint of the activation curve by -10.2+/-0.9 mV (n=7, P<0.01) and -7.4+/-1.1 mV (n=10, P<0.01), respectively. Both drugs accelerated the deactivation and the inactivation process of HERG current. Propafenone, but not 5-hydroxypropafenone, inhibited to a higher extent HERG current at the end of 5-s depolarizing pulses to 0 mV than after promoting the transition of HERG channels from the inactivated to the opened state. CONCLUSIONS: These results indicate that propafenone and its main active metabolite, 5-hydroxypropafenone, block HERG channels to a similar extent by binding predominantly to the open state of the channel.

Animals↗

Effects of pilsicainide and propafenone on vagally induced atrial fibrillation: role of suppressant effect in conductivity.

The effects of pilsicainide on vagally induced atrial fibrillation and on electrophysiological parameters were compared with those of propafenone in alpha-chloralose-anesthetized dogs. Conduction velocity, effective refractory period, wavelength, averaged atrial fibrillation cycle length and activation sequence in the right atrial free wall were determined before and after drug administration. Pilsicainide (2 mg/kg/5 min and 3 mg/kg/h)(n=10) or propafenone (2 mg/kg/15 min and 4 mg/kg/h)(n=10) was intravenously infused during stable atrial fibrillation sustaining > 30 min. Pilsicainide terminated atrial fibrillation in nine dogs, while propafenone did so in three (p < 0.01). After the drug, conduction velocity was suppressed more in the pilsicainide than in the propafenone group(p < 0.01). There was no difference in effective refractory period after drug between the two groups. Mean wavelength was prolonged from 46.0 to 70.4 mm in the pilsicainide group and from 45.0 to 110.8 mm in the propafenone (p < 0.01 vs. pilsicainide). Activation mapping during atrial fibrillation showed Type II or III atrial fibrillation as previously defined [Konings, K.T.S., Kirchhof, C.J.H.J., Smeets, J.R.L.M., Wellens, H.J.J., Penn, O.C., Allessie, M.A., 1994. High-density mapping of electrically induced atrial fibrillation in humans. Circulation. Vol. 89, pp. 511-521.] before the drug, and changed to Type I before atrial fibrillation termination. Thus, pilsicainide was more effective to terminate vagally induced atrial fibrillation than was propafenone despite a greater effect of propafenone than of pilsicainide on wavelength. In this canine atrial fibrillation model, the suppression of conduction velocity may play an important role in changing the activation pattern of atrial fibrillation and thus, terminating atrial fibrillation.

Animals↗

Amiodarone versus propafenone for conversion of chronic atrial fibrillation: results of a randomized, controlled study.

OBJECTIVES: The purpose of this study was to investigate the efficacy and safety of amiodarone and propafenone in the conversion of chronic atrial fibrillation in a prospective, randomized, placebo-controlled study. BACKGROUND: The effectiveness of amiodarone and propafenone in the treatment of patients with chronic atrial fibrillation has not been adequately studied. METHODS: One hundred one patients (48 men, mean age 64 +/- 9 years) with atrial fibrillation lasting >3 weeks participated in the study. Thirty-four patients received amiodarone (300 mg intravenously over 1 h, followed by 20 mg/kg over the next 24 h plus 600 mg orally, in three doses, for 1 week, then 400 mg/day orally, for three weeks), 32 received propafenone (2 mg/kg intravenously over 15 min, followed by 10 mg/kg over 24 h and then 450 mg/day orally, for one month) and the remaining 35 served as control subjects. All patients received digoxin and anticoagulant treatment as indicated (International Normalized Ratio 2 to 3). RESULTS: Conversion to sinus rhythm was achieved in 16 (47.05%) patients who received amiodarone, in 13 (40.62%) who received propafenone and in none of the control subjects (p < 0.001 for both groups vs. control subjects). Those who converted had smaller atria than those who did not and atrial fibrillation of shorter duration in both the amiodarone and propafenone groups. Treatment was discontinued in one patient of the propafenone group because of significant QRS widening. CONCLUSIONS: Amiodarone and propafenone appear to be safe and equally effective in the termination of chronic atrial fibrillation. Left atrial diameter and arrhythmia duration are independent predictors of conversion.

Aged↗

The efficacy and safety of intravenous propafenone versus intravenous amiodarone in the conversion of atrial fibrillation or flutter after cardiac surgery.

OBJECTIVE: The primary objective was to evaluate the efficacy of propafenone compared with amiodarone in the reversion of atrial fibrillation or flutter. The secondary objective was the assessment of the tolerance of propafenone versus amiodarone. DESIGN: An open, randomized trial. SETTING: A single university hospital. PARTICIPANTS: Forty patients who gave their informed consent. INTERVENTIONS: These patients underwent cardiac bypass surgery or aortic valvular replacement. For treatment of postsurgical arrhythmias, they either received intravenous propafenone, 1 to 2 mg/kg in a 10-minute bolus, followed by an infusion of 420 mg in 24 hours, or amiodarone, 2.5 to 5 mg/kg, in a 10-minute bolus followed by an infusion of 900 mg in 24 hours. MEASUREMENTS AND MAIN RESULTS: Sinus rhythm was restored in 12 of 18 (67%) propafenone patients and in 17 of 22 (77%) amiodarone patients. If the early success time-limit had been fixed at 60 minutes, the proportion would have been 41% (7/17) for propafenone versus 14% (3/22) for amiodarone, and that difference is nearly significant (p = 0.07 Fisher's exact test). However, after 210 minutes, 50% of the propafenone patients regained sinus rhythm versus only 25% of the amiodarone patients. Hemodynamic parameters improved with time in both groups without showing any statistically significant difference. CONCLUSIONS: The results suggest that propafenone produces a more prompt effect in converting patients from atrial fibrillation or flutter to normal sinus rhythm.

Adolescent↗

Metabolite cumulation during chronic propafenone dosing in arrhythmia.

The cumulation of propafenone and two of its metabolites, 5-hydroxypropafenone (5-OHP) and N-depropylpropafenone (NDPP), was examined in patients with frequent ventricular ectopy. After 2 weeks of propafenone therapy (300 mg twice a day), propafenone was discontinued and blood samples were drawn for 24 hours. The mean (+/- SD) steady-state concentrations of propafenone, 5-OHP, and NDPP were 1010 +/- 411, 174 +/- 113, and 179 +/- 93 ng/ml. The concentration ratios of 5-OHP/propafenone and NDPP/propafenone were 0.177 +/- 0.049 and 0.227 +/- 0.203. Plasma concentrations of 5-OHP and NDPP did not decay in a log-linear manner during the sampling period and thus estimates of their disappearance t1/2s were not possible. At 24 hours after propafenone dosing, concentrations of 5-OHP and NDPP were 63% +/- 37% and 50% +/- 21% of their mean steady-state levels. Our data indicate that these propafenone metabolites cumulate in the plasma during chronic oral propafenone therapy, and that their clinical role needs to be elucidated.

Adult↗

Comparison of the pharmacodynamic effects of intravenous and oral propafenone.

The effect of propafenone and its major metabolite 5-hydroxy-propafenone on ECG intervals was investigated in eight healthy extensive metabolizers after single oral (300 to 450 mg) and intravenous (35 to 50 mg) doses of propafenone in a single-blind randomized trial. Peak serum concentrations were 278 +/- 233 ng/ml (oral) and 295 +/- 131 ng/ml (intravenous). After oral administration peak 5-hydroxy-propafenone levels were 194 +/- 65 ng/ml, whereas after intravenous dosing no metabolite was detected, except in one subject. Serum concentrations were related to effects by linear regression including a hypothetical effect-site compartment in a pharmacokinetic-pharmacodynamic model. Significant prolongations of ECG intervals were found in both sequences. Comparison of the two concentration-effect data sets (intravenous, oral) revealed an additive effect of 5-hydroxy-propafenone in four of eight subjects for PQ interval and seven of eight subjects for QRS duration. We conclude that 5-hydroxy-propafenone exerts pharmacologic activity and could thus contribute to the antiarrhythmic effect of propafenone.

Administration, Oral↗

Quinidine-enhanced beta-blockade during treatment with propafenone in extensive metabolizer human subjects.

Propafenone, a sodium channel blocking antiarrhythmic drug with beta-blocking properties, is metabolized to non-beta-blocking metabolites in part by cytochrome P4502D6. Subtherapeutic doses of quinidine inhibit P4502D6 and increase plasma propafenone in extensive metabolizer subjects, in whom the active enzyme is present. In this study we tested the hypothesis that quinidine would enhance beta-blockade in extensive metabolizers receiving propafenone. Seven extensive and two poor metabolizers received propafenone (225 mg orally every 8 hours) plus quinidine sulfate (60 mg orally every 8 hours) or propafenone plus placebo for 7 days in a randomized, double-blind, crossover fashion. In extensive metabolizers, the coadministration of quinidine significantly increased the extent of propafenone-induced beta-blockade, assessed by a decrease in exercise heart rate and by sensitivity to isoproterenol. We conclude that low-dose quinidine enhances propafenone-induced beta-blockade in extensive metabolizers. Thus the polymorphic patterns of drug metabolism can result in clinically significant drug interactions on a genetic basis.

Adrenergic beta-Antagonists↗

Beta-adrenergic stimulation modulates the sodium current block by propafenone in rat ventricular myocardium.

Propafenone is a class I antiarrhythmic drug used to suppress cardiac arrhythmia both of atrial and ventricular origin. We measured fast sodium current (I(Na)+) directly with the loose-patch-clamp technique and confirm the frequency-dependent block of this current. Effects on steady-state current kinetics were small or even in the opposite direction. Since propafenone interacts with the beta-adrenergic receptor and stimulation of this receptor itself increases I(Na)+, propafenone was combined with isoproterenol (100 nmol/L). Now we found an augmentation of the frequency-dependent block of I(Na)+. Together with the beta-receptor antagonist atenolol, propafenone exhibited more class I potency but the frequency-dependent block of propafenone was only slightly increased. We conclude that the augmentation of the frequency-dependent effect was predominantly due to phosphorylation of the sodium channel and not due to displacement of propafenone from the beta-receptor. Nevertheless, in clinical settings with various states of the sympathetic tone one has to be aware of different propafenone effects.

Action Potentials↗

Utility of adjunctive single oral bolus propafenone therapy in patients with atrial defibrillators.

AIMS: Previous studies have demonstrated that ambulatory atrial defibrillation shocks delivered by an implantable cardioverter-defibrillator (ICD) are safe and effective, but poorly tolerated. Separate studies have demonstrated the utility of single oral bolus propafenone for conversion of recent-onset atrial fibrillation (AF); however, most patients were hospitalized, had no structural heart disease, were taking no other antiarrhythmic drugs, and were not exposed to concomitant shock. We hypothesized that a single oral bolus dose of propafenone given early after onset would be a safe and effective adjunct to ICD-based AF therapy and improve overall therapy tolerance. METHODS AND RESULTS: A randomized three-way crossover study design was used to compare three strategies, deployed in the ambulatory setting early after AF episode onset in 35 ICD patients with advanced, drug refractory episodic/persistent syndromes, many of whom had structural heart disease and were taking other antiarrhythmic drugs: (i) single oral bolus propafenone (600 mg), followed by ICD shock if necessary; (ii) single oral bolus placebo, followed by ICD shock if necessary; and (iii) no oral bolus therapy and ICD shock if necessary (no bolus). Antiarrhythmic efficacy, defined by the restoration of sinus rhythm within 24 h, was similar during propafenone (81%) and no-bolus strategies (84%); both were significantly higher than during placebo strategy (62%). Propafenone was well tolerated and not associated with proarrhythmia. Shock use was significantly lower during propafenone strategy (19%) than during no-bolus strategy (55%); this was correlated with improved patient tolerance. CONCLUSION: Adjunctive use of single oral bolus propafenone is safe and effective in patients with an ICD and improves patient tolerance of device-based AF therapy.

Administration, Oral↗

Fatal propafenone overdoses: case reports and a review of the literature.

First synthesized in 1970, propafenone is a frequently used 1C antiarrhythmic drug metabolized into two major metabolites, 5-hydroxypropafenone and norpropafenone. Paradoxically, fatal intoxication is rarely described, and only six cases have been reported in the literature. We report our experience with two patients found dead of self-inflicted poisoning where the propafenone blood concentration was very high (one concentration to our knowledge is one of the highest reported in the literature). At autopsy, no evidence of significant pathological disease were found. Propafenone was detected in blood by gas chromatography-mass spectrometry and by high-performance liquid chromatography using a diode-array detector, respectively, as propafenone artifact and propafenone. Blood propafenone concentrations were 4180 ng/mL and 9123 ng/mL. The literature regarding propafenone pharmacokinetic and intoxication is reviewed, and we discuss the low death rate attributed to this drug in contrast to its frequent use.

Adult↗

Effects of propafenone on pacing-induced ventricular fibrillation and intracellular calcium in rat hearts.

Propafenone is an antiarrhythmic agent with fast sodium channel, calcium channel, and beta-adrenergic receptor blocking properties. The effects of propafenone on arrhythmias, free intracellular calcium and left ventricular performance were studied using perfused rat hearts during (i) pacing-induced ventricular fibrillation and (ii) infusion with 2.65 x 10(-6) M, 5.3 x 10(-6) M and 7.9 x 10(-6) M propafenone hydrochloride (corresponding to approximately 1, 2 and 3 mg kg-1 body weight). A bolus of 1 mg kg-1 propafenone during ventricular fibrillation resulted in a decrease in intracellular calcium, with subsequent conversion to sinus rhythm. In perfused hearts with sinus rhythm propafenone produced a dose-dependent decrease in heart rate and myocardial oxygen consumption together with a rise in left ventricular diastolic pressure, and diastolic [Ca2+]i, indicative of depression of left ventricular function. We conclude that a bolus of propafenone during ventricular fibrillation leads to a decrease in [Ca2+]i preceding conversion to sinus rhythm. In rat hearts with sinus rhythm the depressive effects of propafenone on [Ca2+]i are dose dependent.

Animals↗