Medical cardioversion of atrial fibrillation and flutter with class IC antiarrhythmic drugs in young patients with and without congenital heart disease

INTRODUCTION

The use of flecainide and propafenone for medical cardioversion of atrial fibrillation (AF) and atrial flutter/intra-atrial reentrant tachycardia (IART) is well-described in adults without congenital heart disease (CHD). Data are sparse regarding their use for the same purpose in adults with CHD and in adolescent patients with anatomically normal hearts and we sought to describe the use of class IC drugs in this population and identify factors associated with decreased likelihood of success.

METHODS

Single center retrospective cohort study of patients who received oral flecainide or propafenone for medical cardioversion of AF or IART from 2000 to 2022. The unit of analysis was each episode of AF/IART. We performed a time-to-sinus rhythm analysis using a Cox proportional hazards model clustering on the patient to identify factors associated with increased likelihood of success.

RESULTS

We identified 45 episodes involving 41 patients. As only episodes of AF were successfully cardioverted with medical therapy, episodes of IART were excluded from our analyses. Use of flecainide was the only factor associated with increased likelihood of success. There was a statistically insignificant trend toward decreased likelihood of success in patients with CHD.

CONCLUSIONS

Flecainide was more effective than propafenone. We did not detect a difference in rate of conversion to sinus rhythm between patients with and without CHD and were likely underpowered to do so, however, there was a trend toward decreased likelihood of success in patients with CHD. That said, medical therapy was effective in >50% of patients with CHD with AF.

Antiarrhythmic drugs for pharmacological cardioversion of atrial fibrillation and sex differences: Insights from the CANT II Study

BACKGROUND

Data on sex differences in terms of action of antiarrhythmic agents (AADs) are limited. This study aimed to evaluate the clinical profile of patients with atrial fibrillation (AF), and efficacy and safety of AADs used for pharmacological cardioversion (PCV) of AF.

METHODS

This research was a sub-analysis of the retrospective multicenter Cardioversion with ANTazoline II (CANT) registry, which comprised 1365 patients with short-duration AF referred for urgent PCV with the use of AAD. Patients were categorized according to and compared in terms of clinical parameters and PCV outcomes. The primary endpoint was return of sinus rhythm within 12 hours after drug infusion, and the composite safety endpoint involved bradycardia <45 bpm, hypotension, syncope, or death.

RESULTS

The sex distribution of patients qualified for PCV was even (men, n = 725; 53.1%). Females were older and more symptomatic and had higher CHA2DS2-VASc scores, higher prevalence of tachyarrhythmia, and higher use of chronic anticoagulation. The overall efficacy (71.4% vs. 70.1%; P = 0.59) and safety (5.2% vs. 4.6%; P = 0.60) of PCV was comparable in men and women. Amiodarone (68.3% vs. 65.9%; P = 0.66) and antazoline (77.1% vs. 80.0%; P = 0.19) had similar efficacy in men and women, but propafenone had a lower rate of rhythm conversion in men (64.7% vs. 79.3%; P = 0.046). None of the assessed AADs differed in terms of safety profile in both sexes.

CONCLUSION

Female patients with AF have different clinical profiles but similar efficacy and safety of AADs as compared to male participants. Propafenone has significantly lower efficacy in men, which requires further investigation.

Idiopathic premature ventricular complexes treatment: Comparison of flecainide, propafenone, and sotalol

BACKGROUND

Beta-blockers (BB) or dihydropyridine calcium channel blockers (CCBs) are still the first choices in the treatment of idiopathic premature ventricular complexes (PVCs), with low-modest efficacy. Antiarrhythmic drugs (AADs) of Ic class are moderate to highly efficient but the evidence on their benefits is still limited.

AIM

To compare effectiveness and safety of flecainide, propafenone, and sotalol in the treatment of symptomatic idiopathic PVCs.

METHODS

Our single-center retrospective study analyzed 104 consecutive patients with 130 medication episodes of frequent idiopathic PVCs treated with AADs flecainide, propafenone (Ic class) or sotalol (III class). The primary outcome was complete/near complete reduction of PVCs after medication episode (PVCs burden reduction >99%), and the secondary outcome was significant PVC burden reduction (≥80%).

RESULTS

The complete/near complete PVCs burden reduction occurred in 31% and was significant in 43% of treated patients. A reduction of PVC burden for >99% was achieved in 56% of patients on flecainide, in 11% of patients on propafenone (p = .002), and in 21% of patients receiving sotalol (p = .031). There was no difference between propafenone and sotalol (p = .174). A reduction of PVC burden for ≥80% was achieved in 64% of patients on flecainide, in 30% of patients on propafenone (p = .009), and 33% of patients on sotalol (p = .020). There was no difference between propafenone and sotalol (p = .661).

CONCLUSIONS

The efficacy of AADs class Ic and III in the treatment of idiopathic PVCs was modest. Flecainide was the most effective AAD in the achievement of complete/near complete or significant PVC burden reduction, compared to propafenone and sotalol.

A Mechanistic Clinical Trial Using (R)- Versus (S)-Propafenone to Test RyR2 (Ryanodine Receptor) Inhibition for the Prevention of Atrial Fibrillation Induction

BACKGROUND

Experimental data suggest ryanodine receptor-mediated intracellular calcium leak is a mechanism for atrial fibrillation (AF), but evidence in humans is still needed. Propafenone is composed of two enantiomers that are equally potent sodium-channel blockers; however, (R)-propafenone is an ryanodine receptor inhibitor whereas (S)-propafenone is not. This study tested the hypothesis that ryanodine receptor inhibition with (R)-propafenone prevents induction of AF compared to (S)-propafenone or placebo in patients referred for AF ablation.

METHODS

Participants were randomized 4:4:1 to a one-time intravenous dose of (R)-propafenone, (S)-propafenone, or placebo. The study drug was given at the start of the procedure and an AF induction protocol using rapid atrial pacing was performed before ablation. The primary endpoint was 30 s of AF or atrial flutter.

RESULTS

A total of 193 participants were enrolled and 165 (85%) completed the study protocol (median age: 63 years, 58% male, 95% paroxysmal AF). Sustained AF and/or atrial flutter was induced in 60 participants (84.5%) receiving (R)-propafenone, 60 (80.0%) receiving (S)-propafenone group, and 12 (63.2%) receiving placebo. Atrial flutter occurred significantly more often in the (R)-propafenone (N=23, 32.4%) and (S)-propafenone (N=26, 34.7%) groups compared to placebo (N=1, 5.3%, P=0.029). There was no significant difference between (R)-propafenone and (S)-propafenone for the primary outcome of AF and/or atrial flutter induction in univariable (P=0.522) or multivariable analysis (P=0.199, adjusted for age and serum drug level).

CONCLUSIONS

There is no difference in AF inducibility between (R)-propafenone and (S)-propafenone at clinically relevant concentrations. These results are confounded by a high rate of inducible atrial flutter due to sodium-channel blockade.

REGISTRATION

https://clinicaltrials.gov; Unique Identifier: NCT02710669.

Efficacy and safety in pharmacological cardioversion of recent-onset atrial fibrillation: a propensity score matching to compare amiodarone vs class IC antiarrhythmic drugs

The acute management of recent-onset (<48 h) atrial fibrillation (AF) is still debated. Aim of our study was to compare efficacy and safety of intravenously administered class IC antidysrhythmic agents vs amiodarone in a propensity score matched series of patients acutely treated for AF in the emergency department. During a 3-year period, we retrospectively evaluated all episodes of recent-onset (<48 h) AF pharmacologically treated for sinus rhythm restoration in the emergency department. By means of a propensity score matching considering the main statistically different covariates, we selected two accurately matched treatment groups. We analysed the differences between amiodarone and class IC group in terms of efficacy and safety that is conversion to sinus rhythm rates within 12 and 48 h after starting treatment, time to conversion, and adverse drug effects. An overall number of 817 episodes of recent-onset AF were collected (amiodarone group = 406, class IC group = 411). After matching, we obtained 358 episodes equally divided (amiodarone group = 179 and class IC group = 179). Conversion rates within 12 h were 139 (53.1 %) in amiodarone group and 95 (72.6 %) in class IC group (p < 0.05). Median time for cardioversion was 420 min (331.6-508.3 CI 95 %) in amiodarone and 55 min (44.9-65.1 CI 95 %) in class IC group (p < 0.05). The incidence of adverse events in both groups was very low and equally distributed (p = ns). Intravenously administration of class IC agents, when compared with amiodarone, proved to be more rapid and effective, and equally safe in the acute management of recent-onset AF.

Propafenone-Induced Liver Injury

OBJECTIVE:

To describe propafenone-induced liver injury.

DESIGN:

Retrospective case report.

SETTING:

Referred care in a large tertiary care center. Laboratory tests were performed at the auxiliary site and the tertiary care center.

PATIENT:

A 71-year-old woman with atrial fibrillation developed elevations of greater than two times the upper limit of normal in alkaline phosphatase (ALK), alanine aminotransferase (ALT), aspartate aminotransferase (AST), and gamma glutamyltransferase (GGT) after initiation of propafenone therapy.

INTERVENTIONS:

Studies included serial measurements of ALK, ALT, AST, and GGT.

RESULTS:

The patient developed elevations of greater than two times the upper limit of normal in ALK, ALT, and AST, one month after initiating propafenone therapy. The propafenone dose was decreased from 900 to 675 mg/d and, ten days later, the ALK, ALT, and AST were decreased slightly, but still above the upper limit of normal. One month later, serum transaminases had returned to baseline, but propafenone therapy was discontinued because of recurrent atrial fibrillation, persistent elevation in ALK, and elevation in GGT. Two months after discontinuing propafenone, serum aminotransaminase and ALK concentrations had normalized and GGT had decreased and remained only slightly elevated.

CONCLUSIONS:

The occurrence of liver injury secondary to propafenone therapy is rare. Reported cases appear to be secondary to hepatocellular injury, cholestasis, or a combination of the two. In this case, the pattern demonstrated by elevations in liver enzymes may be classified as acute cholestatic liver injury. Because the reported incidence is 0.1–0.2 percent and there are no known fatalities secondary to propafenone liver injury, routine monitoring of liver function tests in all patients receiving propafenone cannot be recommended at this time. Baseline liver function tests prior to initiating propafenone therapy with follow-up laboratory studies one month later are recommended in patients with known liver dysfunction. If elevations are noted, a reduction in dose may result in lower liver enzyme concentrations, although discontinuation of therapy may be required in some cases.

Comparative effectiveness and safety of antazoline‑based and propafenone‑based strategies for pharmacological cardioversion of short‑duration atrial fibrillation in the emergency department

INTRODUCTION    Numerous studies described the effectiveness and safety of antazoline in pharmacological cardioversion of short‑duration atrial fibrillation (AF). However, there are no data on the comparison of antazoline and antiarrhythmic drugs listed in clinical guidelines. OBJECTIVES    The aim of the study was to assess the comparative effectiveness and safety of antazoline‑based and propafenone‑based strategies in pharmacological cardioversion of short‑duration AF performed in our emergency department. PATIENTS AND METHODS    We conducted a retrospective case‑control study based on the analysis of medical records of patients undergoing pharmacological cardioversion of short‑duration AF with intravenous antazoline or propafenone at our department in the years 2008-2012. The primary endpoint was the successful cardioversion of AF. The primary safety endpoint was hospitalization due to the adverse effects of the treatment. RESULTS    We analyzed 432 cases of cardioversion. The mean age of patients was 68.9 ±9.8 years; 65% of the patients were male; 90% of the patients had a history of AF. Antazoline was administered 334 times and propafenone-98 times. The mean dose of antazoline was 172 ±65 mg, while all patients in the propafenone group received the drug at a fixed dose of 70 mg (1 vial). Cardioversion with antazoline was successful in 239 cases (71.6%) and with propafenone-in 54 patients (55.1%) (relative risk [RR], 1.30; 95% confidence interval [CI], 1.07-1.57). The rate of hospitalization due to the adverse effects of the treatment were low and similar between the study groups: 10 (3.0%) for antazoline and 4 (4.1%) for propafenone (RR, 0.73; 95% CI, 0.23-2.27). CONCLUSIONS    The antazoline‑based strategy was more effective and safer in comparison with propafenone‑based strategy in the pharmacological cardioversion of short‑duration AF in our emergency department.

Electric cardioversion of atrial fibrillation resulting in pulmonary oedema in patient with apical hypertrophic cardiomyopathy

The direct-current electric shock is considered to be safe treatment of arrhythmias and rarely leads to serious hemodynamic complications. A 62-year-old patient was admitted to the hospital due to a first symptomatic episode of atrial fibrillation. Patient was diagnosed with apical hypertrophic cardiomyopathy 20 years ago. Transoesophageal echocardiography was performed to exclude an atrial thrombus followed by electrical cardioversion with restoration of sinus rhythm. After 6 hours symptoms of pulmonary oedema developed. The patient's condition improved after furosemide administration. As the possible cause of the oedema, inotropic effect of administered propafenone and atrial stunning were considered. The atria seem to be responsible for important part of forward cardiac output even during AF, especially in cardiomyopathies. Contractility deterioration of the left atrium (stunning) along with earlier resumption of the right atrium contractile function could be associated with hemodynamic instability causing pulmonary oedema in subjects with hypertrophied myocardium. It is necessary to take into consideration the atrial function while administrating antiarrhythmic drugs, especially those with negative inotropic effect.

Propafenone associated severe central nervous system and cardiovascular toxicity due to mirtazapine: a case of severe drug interaction

We describe a rare case of severe drug-drug interaction between propafenone and mirtazapine leading to propafenone toxicity. A 69-year-old Caucasian male taking propafenone for atrial fibrillation was prescribed mirtazapine for insomnia. Subsequent to the first dose of mirtazapine the patient experienced seizures, bradycardia and prolonged QRS as well as QTc intervals on EKG. The patient was admitted to the ICU and recovered after supportive management. Propafenone is an established class IC antiarrhythmic drug commonly used in the treatment of atrial fibrillation. It is metabolized through the CYP4502D6 pathway. Five to 10 percent of Caucasians are poor metabolizers. Mirtazapine is a commonly prescribed antidepressant drug, which is also metabolized through and may modulate the CYP4502D6 pathway leading to altered metabolism of propafenone and possible adverse effects. In this case, toxicity was reversed once the offending drugs were discontinued. An extensive review of the literature revealed this to be the first described case of drug interaction between propafenone and mirtazapine.

Radiofrequency ablation as initial therapy in paroxysmal atrial fibrillation

BACKGROUND

There are limited data comparing radiofrequency catheter ablation with antiarrhythmic drug therapy as first-line treatment in patients with paroxysmal atrial fibrillation.

METHODS

We randomly assigned 294 patients with paroxysmal atrial fibrillation and no history of antiarrhythmic drug use to an initial treatment strategy of either radiofrequency catheter ablation (146 patients) or therapy with class IC or class III antiarrhythmic agents (148 patients). Follow-up included 7-day Holter-monitor recording at 3, 6, 12, 18, and 24 months. Primary end points were the cumulative and per-visit burden of atrial fibrillation (i.e., percentage of time in atrial fibrillation on Holter-monitor recordings). Analyses were performed on an intention-to-treat basis.

RESULTS

There was no significant difference between the ablation and drug-therapy groups in the cumulative burden of atrial fibrillation (90th percentile of arrhythmia burden, 13% and 19%, respectively; P=0.10) or the burden at 3, 6, 12, or 18 months. At 24 months, the burden of atrial fibrillation was significantly lower in the ablation group than in the drug-therapy group (90th percentile, 9% vs. 18%; P=0.007), and more patients in the ablation group were free from any atrial fibrillation (85% vs. 71%, P=0.004) and from symptomatic atrial fibrillation (93% vs. 84%, P=0.01). One death in the ablation group was due to a procedure-related stroke; there were three cases of cardiac tamponade in the ablation group. In the drug-therapy group, 54 patients (36%) underwent supplementary ablation.

CONCLUSIONS

In comparing radiofrequency ablation with antiarrhythmic drug therapy as first-line treatment in patients with paroxysmal atrial fibrillation, we found no significant difference between the treatment groups in the cumulative burden of atrial fibrillation over a period of 2 years. (Funded by the Danish Heart Foundation and others; MANTRA-PAF ClinicalTrials.gov number, NCT00133211.).

[The efficacy of propafenon in the case of supraventricular atrioventricular tachycardia]

One of the main methods the treatment of patients with supraventricular paroxysmal tachycardia remains drug therapy, which involves the prevention attacks of cardiac arrhythmias. Drugs of choice for termination and prevention of paroxysmal supraventricular tachycardia in the absence of pronounced signs structural myocardial damage is an antiarrhythmic with I C class (propafenon - propanorm). Efficacy of propafenon and its influence on the functional state of heart in patients with paroxysmal antrioventricular tachycardias was studied. It was found that propafenon is highly effective in preventing paroxysmal antrioventricular reciprocating tachycardia and atrioventricular nodal tachycardia. The drug has no negative effect on the functional state of heart.

Acute propafenone toxicity after two exposures at standard dosing

A 72-year-old woman presented with a decreased level of consciousness and hypotension. The initial electrocardiogram demonstrated atrial fibrillation with a wide QRS complex. Her medical history revealed that she had just been started on propafenone. A diagnosis of propafenone toxicity was made and sodium bicarbonate was administered. A rare phenomenon in which toxicity occurred at therapeutic dosing is reported. Acute propafenone toxicity manifests in a wide range of organ systems; in particular, cardiovascular compromise in the form of hypotension, bradycardia and QRS widening can occur. Sodium bicarbonate therapy is advocated to directly counteract the toxic effects of propafenone. In the case described, this treatment resulted in rapid normalization of the QRS duration and stabilization of the hemodynamic profile.

Syncope, widened QRS interval, and left ventricular systolic depression: coincident with propafenone therapy for atrial fibrillation

We report the case of a 46-year-old man who developed syncope, a widened QRS interval, and depressed left ventricular systolic function during propafenone therapy for atrial fibrillation. These acute findings may have been consequent to an increased dosage of propafenone combined with heavy alcohol consumption that led to decreased metabolism of propafenone. In addition, propafenone is known to interfere with liver function, although this patient's test results showed scant evidence of liver abnormalities. Yet another possible factor is the genetic spectrum in the metabolism of propafenone and other class I antiarrhythmic agents. When propafenone is prescribed, we recommend advising patients that alcohol consumption and interactions with other drugs can lead to increased levels of the antiarrhythmic agent, with resultant toxicity that can lead to adverse cardiovascular effects. Patients taking propafenone should also undergo periodic liver function testing. Finally, attention should be paid to voluntary or official recalls of specific antiarrhythmic medications that are of unreliable quality or potency.

[Life-threatening ventricular arrhythmia during simultaneous administration of propafenone and sotatol]

A case of a patient treated with antiarrhythmic drugs for ventricular arrhythmia occurring after viral infection of the respiratory tract is presented. In the course of preliminary cardiologic examination no organic heart disease was diagnosed. Due to numerous ventricular extrasystolic beats (16,500 per day) and short runs of non-sustained ventricular tachycardia (maximum of 4 subsequent beats) propafenone was introduced. Persistent arrhythmia was a reason for adding sotalol to that treatment in an outpatient clinic. After three weeks of such treatment the patient presented cardiac arrest in the mechanism of ventricular tachycardia and fibrillation. Successful resuscitation and drug discontinuation led to complete resolution of the life-threatening arrhythmia. No inducible complex ventricular arrhythmia was observed during electrophysiologic examination.

Propafenone-induced drug fever in the absence of agranulocytosis

Propafenone is an antiarrhythmic drug used in the treatment of life-threatening ventricular tachyarrhythmias. Adverse reactions necessitating discontinuation of the medication are common. Propafenone-induced drug fever has not been definitively proven. We present a case report of drug fever secondary to propafenone, confirmed with rechallenge.

Efficacy and tolerability of oral propafenone versus quinidine in the treatment of recent onset atrial fibrillation: A randomized, prospective study

BACKGROUND

A prospective, randomized study was conducted to evaluate the efficacy and tolerability of oral propafenone and quinidine for the conversion of paroxysmal atrial fibrillation (AF).

METHODS

Eighty one consecutive patients (female/male 46/35; mean age 64.0 +/- 11.6), admitted to hospital with AF lasting no longer than 48 hours, were randomized in terms of their pharmacological therapy. Forty three patients (55%) were randomly assigned to Group I and received propafenone 600 mg orally as the initial therapy, with an additional dose of 300 mg after eight hours, if the sinus rhythm had not been restored by then. Thirty eight patients (45%) (Group II) received 1 mg digoxin IV followed by an oral loading of quinidine (400 mg followed by 200 mg every two hours).

RESULTS

The conversion rate assessed after 24 hours was the same in both groups (Gr. I vs. Gr. II: 90.7 vs. 91.4%), with the same number of mild side effects (Gr. I vs. Gr. II: 37.2% vs. 45.7%). No life-threatening adverse events were reported. Propafenone achieved a higher efficacy rate during the first eight hours (83.3 vs. 54.3%; p = 0.01), with a significantly shorter time required to sinus rhythm recovery throughout the study period, with a median time of 165 min (95% confidence interval 120-278) vs. 360 min (95% confidence interval 298-650; p < 0.05). There was some indication of greater effectiveness of propafenone than quinidine in early sinus rhythm restoration in patients with: no structural heart disease, in those with an AF duration shorter than 12 hours, and in patients with an ejection fraction > 55%.

CONCLUSIONS

Although both drugs revealed the same effectiveness, the conversion to sinus rhythm in the group treated with propafenone was observed more quickly despite the longer paroxysmal AF episode duration.

[Proarrhythmic effect of propafenone in patients with atrial fibrillation and atrial flutter]

We present two cases of proarrhythmia after propafenone treatment. In the first case slowing of the flutter cycle length from 205 ms to 290 ms resulted in a change from well tolerated two to one atrioventricular conduction to one to one conduction with hypotension and presyncope. In the second case organization of atrial fibrillation to atypical atrial flutter and use-dependent left bundle branch block resulted in fast broad QRS tachycardia that mimicked ventricular tachycardia.

Cardiac memory induced by QRS widening due to propafenone toxicity

Propafenone toxicity can cause significant QRS widening and markedly abnormal ventricular activation pattern. Aberrant ventricular activation upon its resolution is known to produce persistent T-wave changes known as "cardiac memory" (CM). A 74-year-old woman presented with a severely abnormal electrocardiogram consistent with propafenone toxicity. As her QRS complex narrowed, T-wave inversions developed with the T-wave axis and resolution kinetics consistent with CM. Abnormal ventricular activation due to propafenone toxicity can result in CM development.

Brugada type electrocardiographic changes induced by concomitant use of lithium and propafenone in patient with Wolff-Parkinson-White syndrome

We report a case of ST elevation in right precordial leads compatible with type 1 Brugada syndrome following administration of propafenone in a patient with Wolff-Parkinson-White syndrome who was receiving lithium at concentrations within therapeutic levels. The mechanism of the electrocardiogram changes was considered to be caused by the two drugs synergistic sodium channel blocking effects.

A comparative study of the efficacy and safety of procainamide versus propafenone versus amiodarone for the conversion of recent-onset atrial fibrillation

The appropriate treatment for the restoration of sinus rhythm in patients with atrial fibrillation (AF) of recent onset is still the subject of controversy. In this prospective, randomized, single-blind, placebo-controlled clinical study, we investigated the effectiveness and safety of procainamide, propafenone, and amiodarone, administered intravenously, for the conversion of recent-onset AF. We enrolled 362 consecutive patients (183 men; age 34 to 86 years; mean 65+/-10) with AF duration of no >48 hours. Of these patients, 89 were given procainamide, 91 propafenone, 92 amiodarone, and 90 placebo. Treatment was considered successful if conversion to sinus rhythm was achieved within the 24-hour study period. Baseline clinical characteristics were similar in the 4 groups. The treatment was successful in 61 of the 89 patients who received procainamide (68.53%; median time 3 hours), 73 of the 91 patients who received propafenone (80.21%; median time 1 hour), 82 of the 92 patients who received amiodarone (89.13%; median time 9 hours), and 55 of the 90 patients who received placebo (61.11%; median time 17 hours; p<0.05 for all medicated groups vs placebo; p<0.05 for amiodarone and propafenone vs procainamide). In conclusion, all 3 medications, when administered intravenously, are effective in the restoration of sinus rhythm in recent-onset AF. Amiodarone and propafenone are more effective whereas procainamide and propafenone are faster.

Further evidence of inherited long QT syndrome gene mutations in antiarrhythmic drug-associated torsades de pointes

BACKGROUND

Pathophysiologically significant ion-channel mutations have been detected in only a minority of cases of acquired long QT syndrome (LQTS).

OBJECTIVE

The aim of this study was to clarify the putative role of subclinical inherited LQTS in drug-associated torsades de pointes (TdP) and to assess the concomitant proarrhythmic factors.

METHODS

We evaluated 16 consecutive cases with documented, antiarrhythmic drug-induced TdP who were referred to the Laboratory of Molecular Medicine at Helsinki University for LQTS genetic testing between September 2000 and August 2005.

RESULTS

A prolonged QTc interval was observed in 56% of the patients before administration of the drug. TdP was associated with amiodarone in seven, sotalol in six, flecainide in two, and propafenone in one of the cases. Except for the culprit drug, one or more risk factors such as female sex, congestive heart failure, and atrial fibrillation were present in each drug-associated TdP. DNA samples were screened for the four common Finnish founder mutations (KCNQ1 G589D and IVS7-2A-->G, HERG L552S, and R176W), which are known to account for the majority of inherited LQTS in Finland. A total of three (19%) individuals carried one of these four mutations.

CONCLUSIONS

Our data show that previously unsuspected LQTS mutations may be present in patients with antiarrhythmic drug-associated TdPs. A normal QTc interval does not exclude the risk of proarrhythmia.

Pharmacogenetics of antiarrhythmic therapy

Individuals vary widely in their responses to therapy with most drugs. Indeed, responses to antiarrhythmic drugs are so highly variable that study of the underlying mechanisms has elucidated important lessons for understanding variable responses to drug therapy in general. Variability in drug response may reflect variability in the relationship between a drug dose and the concentrations of the drug and metabolite(s) at relevant target sites; this is termed pharmacokinetic variability. Another mechanism is that individuals vary in their response to identical exposures to a drug (pharmacodynamic variability). In this case, there may be variability in the target molecule(s) with which a drug interacts or, more generally, in the broad biological context in which the drug-target interaction occurs. Variants (polymorphisms and mutations) in the genes that encode proteins that are important for pharmacokinetics or for pharmacodynamics have now been described as important contributors to variable drug actions, including proarrhythmia, and these are described in this review. However, the translation of pharmacogenetics into clinical practice has been slow. To this end, the creation of large, well-characterised DNA databases and appropriate control groups, as well as large prospective trials to evaluate the impact of genetic variation on drug therapy, may hasten the impact of pharmacogenetics and pharmacogenomics in terms of delivering personalised drug therapy and to avoid therapeutic failure and serious side effects.

Drug therapy of paroxysmal atrial fibrillation in the elderly over 75 years old

OBJECTIVE

To investigate the effectiveness and safety of various agents on paroxysmal atrial fibrillation in the elderly over 75 years old.

METHODS

Totally 264 in-patients (75-91 years old, 185 males and 79 females) with atrial fibrillation history of less than 7 days were enrolled in this study. A total of 611 atrial fibrillation episodes were recorded, but 130 episodes (22.3%) of atrial fibrillation were auto-converted to sinus rhythm. The rest 481 episodes of atrial fibrillation were divided into six groups based on the drug used.

RESULTS

The cardioversion ratio of atrial fibrillation were 9.5%, 46.9%, 71.7%, 55.9%, 32.7%, and 73.6% in control, cedilanid, amiodarone, propafenone, verapamil, and quinidine groups, respectively. Ventricular rate control were 5.4%, 83.6%, 84.9%, 77.9%, 78.8%, and 11.3% in those groups, respectively. The total effective rates of amiodarone and cedilanid groups were the highest. When the ventricular rate was controlled to below 90 bpm, the patients would almost complain of no discomfort. No severe side-effect was observed in each group.

CONCLUSION

Amiodarone and cedilanid may be the proper drugs for the treatment of paroxysmal atrial fibrillation in the elderly. The above antiarrhythmics in each therapeutic group were relatively safe and effective.

Comparison of intravenous ibutilide vs. propafenone for rapid termination of recent onset atrial fibrillation

This study was to evaluate the efficacy and safety of ibutilide and propafenone given intravenously in converting recent onset atrial fibrillation (AF). Eighty-two consecutive patients with AF (onset in 2 h to 90 days) were randomly assigned to receive two 10-min infusions, 10 min apart, of either ibutilide (1 mg) or propafenone (70 mg). The treatment was considered successful if sinus rhythm occurred within 90 min after the beginning of infusion. Ibutilide had a significantly higher rate of cardioversion than propafenone (70.73 vs. 48.78%, p = 0.043). The patients with shorter AF duration or smaller left atrium diameter had a higher success rate. Nonsustained monomorphic ventricular tachycardia was the most serious adverse effect of ibutilide in 9.76% of patients, and hypotension and heart pause were the major serious adverse events in 17.07% of patients treated with propafenone. Ibutilide is more effective than intravenous propafenone for the cardioversion of recent onset AF, and the adverse effects are rare and transient.

Propafenone added to ibutilide increases conversion rates of persistent atrial fibrillation

OBJECTIVE

To assess the effectiveness and safety of pharmacological conversion of persistent atrial fibrillation (AF) with a combined propafenone plus ibutilide regimen.

METHODS AND RESULTS

100 consecutive patients (66 men, mean (SD) age 65 (10) years) with persistent AF (mean (SD) duration 99 (92) days) admitted for elective pharmacological cardioversion were randomly assigned to treatment with either intravenous ibutilide (1 mg plus an additional 1 mg, if required; n = 51) or oral propafenone (600 mg) plus intravenous ibutilide at the same dose (n = 49). Success rates were 41.1% (21 of 51 patients) for ibutilide alone and 71.4% (35 of 49 patients) for propafenone plus ibutilide (p = 0.0044). However, cardioversion occurred earlier in the ibutilide alone group (55 (20) minutes) compared with the combination group (81 (32) minutes, p = 0.0019). A comparable increase in the QTc interval was observed in both groups but one case of sustained torsade de pointes, requiring electrical cardioversion, was observed in the propafenone plus ibutilide group. No other complications were noted during the hospitalisation period.

CONCLUSION

Concurrent administration of propafenone plus ibutilide for pharmacological cardioversion of persistent AF is safe and more effective than ibutilide alone.

Stunning of the left atrium after pharmacological cardioversion of atrial fibrillation

INTRODUCTION

Stunning of the left atrium and atrial appendage is a well known but not fully clarified phenomenon observed during the cardioversion of atrial fibrillation regardless of the cardioversion method attempted.

AIM

To assess the effects of propafenone and amiodarone on left atrium and left atrial appendage contractility.

METHODS

Forty patients with paroxysmal atrial fibrillation (20 females, 20 males), aged 60-83 (mean 72.0+/-10.1) years, were enrolled into the study. Half of these patients had sinus rhythm restored by the administration of oral propafenone (150-300 mg) and the remaining 20 patients were treated with intravenous amiodarone (150-450 mg). The control group consisted of 20 patients (10 females, 10 males) aged 52-78 (mean 61.2+/-9.3) years with sinus rhythm and no history of atrial fibrillation. All the patients had a transthoracic (TTE) and transesophageal (TEE) echocardiography performed while still in the AF, before drug administration and 1 hour after sinus rhythm restoration.

RESULTS

All haemodynamic parameters of the left atrium measured after the sinus rhythm restoration were significantly worse when compared with the control group. Left atrial fractional shortening and total atrial fraction were significantly lower after propafenone than amiodarone (8.6+/-3.6% vs 11.7+/-5.5%, p<0.05; and LA FC 16.2+/-5.3% vs 23.3 (+/-6.3)% respectively, p<0.05). Doppler echocardiographic parameters included in the analysis such as mitral flow and superior left pulmonary vein flow were significantly lower in the sinus rhythm restoration group than in the control group. Among them the end-diastolic mitral flow velocity amplitude and flow velocity integral as well as the maximum pulmonary retrograde velocity were significantly worse in the group treated with propafenone than in patients receiving amiodarone. All the atrial appendage Doppler velocity parameters were significantly reduced after the sinus rhythm restoration in both groups. In the patients treated with propafenone, values of these parameters were significantly decreased compared with the patients receiving amiodarone.

CONCLUSIONS

Successful pharmacological cardioversion of atrial fibrillation causes the left atrium and left atrial appendage contractility impairment similar to that observed with other methods of the sinus rhythm restoration. Following the AF cardioversion the level of left atrial stunning is higher in the patients treated with propafenone than in subjects receiving amiodarone.

[Pharmacogenetic study of the response to flecainide and propafenone in patients with atrial fibrillation]

We analyzed cytochrome P450 2D6 polymorphism by determining phenotype as the metabolic ratio between dextromethorphan and its main metabolite, dextrorphan. We studied 18 men and 22 women in whom mean age was 54.6+/-11.9 years. In 9 patients metabolic ratio was determined before antiarrhythmic treatment and again during treatment, with a mean increase of 0.13+/-0.15 (P=.03). We found 19 poor metabolizers and 21 extensive metabolizers. Adverse effects were more frequent in poor metabolizers (21.1%) than in extensive metabolizers (4.8%; P=.12). Antiarrhythmic treatment was effective in 27 patients (67.5%), with no difference between poor and extensive metabolizers.

Clinical Comparison of Ibutilide and Propafenone for Converting Atrial Flutter

OBJECTIVE

To evaluate the efficacy and safety of intravenous ibutilide and propafenone for immediate treatment of atrial flutter.

METHODS

Forty patients with atrial flutter with an arrhythmia duration of three hours to 90 days were randomized to receive up to two 10-minute infusions of ibutilide (1 and 1 mg) or propafenone (70 and 70 mg) with a 10-minute interval.

RESULTS

Ibutilide was superior to propafenone for treating atrial flutter (90% vs. 30%, p < 0.01). The median conversion time in the ibutilide group was 11 min (the 25th and 75th percentile was 10 and 45 min), and the median conversion time in the propafenone group was 35 min (range 20-55 min). In all patients, the duration of arrhythmia before treatment was a predictor of arrhythmia termination, although this was more obvious in the group that received ibutilide. Conversion of atrial flutter by ibutilide was characterized mainly by increased cycle length variability. Bradycardia (2/20) and hypotension (4/20) were more common side effects with propafenone. Of 20 patients given ibutilide, 8 (40%) who developed monomorphic ventricular extrasystoles or repetitive atrial flutter with aberrant conduction tachycardia, no one required any specific treatment except for the interruption of ibutilide infusion.

CONCLUSION

Ibutilide is highly effective for rapidly terminating atrial flutter. This new class III drug, under monitored conditions, is a potential alternative to currently available cardioversion options.

Outpatient treatment of recent-onset atrial fibrillation with the "pill-in-the-pocket" approach

BACKGROUND

In-hospital administration of flecainide and propafenone in a single oral loading dose has been shown to be effective and superior to placebo in terminating atrial fibrillation. We evaluated the feasibility and the safety of self-administered oral loading of flecainide and propafenone in terminating atrial fibrillation of recent onset outside the hospital.

METHODS

We administered either flecainide or propafenone orally to restore sinus rhythm in 268 patients with mild heart disease or none who came to the emergency room with atrial fibrillation of recent onset that was hemodynamically well tolerated. Of these patients, 58 (22 percent) were excluded from the study because of treatment failure or side effects. Out-of-hospital self-administration of flecainide or propafenone--the "pill-in-the-pocket" approach--after the onset of heart palpitations was evaluated in the remaining 210 patients (mean age [+/-SD], 59+/-11 years).

RESULTS

During a mean follow-up of 15+/-5 months, 165 patients (79 percent) had a total of 618 episodes of arrhythmia; of those episodes, 569 (92 percent) were treated 36+/-93 minutes after the onset of symptoms. Treatment was successful in 534 episodes (94 percent); the time to resolution of symptoms was 113+/-84 minutes. Among the 165 patients with recurrences, the drug was effective during all the arrhythmic episodes in 139 patients (84 percent). Adverse effects were reported during one or more arrhythmic episodes by 12 patients (7 percent), including atrial flutter at a rapid ventricular rate in 1 patient and noncardiac side effects in 11 patients. The numbers of monthly visits to the emergency room and hospitalizations were significantly lower during follow-up than during the year before the target episode (P<0.001 for both comparisons).

CONCLUSIONS

In a selected, risk-stratified population of patients with recurrent atrial fibrillation, pill-in-the-pocket treatment is feasible and safe, with a high rate of compliance by patients, a low rate of adverse events, and a marked reduction in emergency room visits and hospital admissions.

Atrial fibrillation: rate control often better than rhythm control

(1) The treatment aims in atrial fibrillation are to reduce patients' symptoms and to prevent both embolism and deterioration of any underlying heart disease. Therapy consists of anticoagulant or antiplatelet drugs, treatment of any underlying heart disease, and heart rate control. (2) Digoxin, betablockers, diltiazem and verapamil slow the heart rate but rarely restore sinus rhythm. Amiodarone, disopyramide, flecainide, quinidine and sotalol can be used to prevent relapse of atrial fibrillation after electrical cardioversion, but they all have potentially serious adverse effects. New trials of antiarrhythmic treatments have been published since our last review of this subject. (3) In one trial in 403 patients, amiodarone was more effective than sotalol and propafenone in restoring and maintaining sinus rhythm. After 15 months of follow-up, there were fewer strokes among patients treated with amiodarone, but there was no difference between the three drugs in the overall incidence of cardiovascular events. (4) A clinical trial with 4060 patients compared rhythm control (mainly with amiodarone, sotalol or propafenone; sometimes combined with electrical cardioversion) and rate control (with digoxin, betablocker, diltiazem or verapamil; systematically combined with anticoagulant therapy). The antiarrhythmic treatment restored sinus rhythm in more than half the patients in the long term. But rhythm control did not reduce the risk of death or serious cardiovascular events during a mean follow-up period of 3.5 years. Rhythm control caused more adverse events than rate control; subgroup analyses (weak evidence) suggest that rhythm control may also have caused more deaths among patients over 65 and among patients with coronary heart disease. (5) In another trial, electrical cardioversion followed by antiarrhythmic therapy (mainly sotalol) sustainably restored sinus rhythm in more than one-third of 522 patients. But, compared with rate control treatment plus anticoagulant therapy, rhythm control did not reduce the risk of cardiovascular events, and was associated with a larger number of serious adverse cardiac effects. (6) Other recent trials confirm the risk of serious adverse effects, including severe arrhythmia with sotalol (especially at the start of treatment), and adverse thyroid and pulmonary effects with amiodarone. (7) Combined radiofrequency ablation and cardiac stimulation improved symptoms in some patients with incapacitating atrial fibrillation who had not responded to other treatments. However, this approach carries a risk of serious adverse effects, and its impact on the risk of cardiovascular events and death is not known. (8) In practice, an attempt should be made to restore sinus rhythm with amiodarone and/or electrical cardioversion, in symptomatic, recent or paroxysmal atrial fibrillation in patients under 65 who have no signs or symptoms of coronary heart disease. In other situations, rate control is the first-line option, using digoxin, betablockers (other than sotalol) or calcium channel blockers (diltiazem or verapamil). Whatever the option, treatment must be combined with anticoagulant or antiplatelet therapy, and with treatment of any underlying heart disease.

Transient platypnea-orthodeoxia-like syndrome induced by propafenone overdose in a young woman with Ebstein's anomaly

In this report we describe the case of a 37-year-old white woman with Ebstein's anomaly, who developed a rare syndrome called platypnea-orthodeoxia, characterized by massive right-to-left interatrial shunting with transient profound hypoxia and cyanosis. This shunt of blood via a patent foramen ovale occurred in the presence of a normal pulmonary artery pressure, and was probably precipitated by a propafenone overdose. This drug caused biventricular dysfunction, due to its negative inotropic effect, and hypotension, due to its peripheral vasodilatory effect. These effects gave rise to an increase in the right atrial pressure and a decrease in the left one with a consequent stretching of the foramen ovale and the creation of massive right-to-left shunting. In our case this interatrial shunt was very accurately detected at bubble contrast echocardiography.

Pharmacological treatment of young children with permanent junctional reciprocating tachycardia

Our objective was to assess the efficacy of pharmacological treatment in reducing the incidence of permanent junctional reciprocating tachycardia in young children, or to bring the mean heart rate over 24 h to a normal level. We included 21 children with a median age of 0.05 year seen with permanent junctional reciprocating tachycardia over the period 1990 through 2001. Of these children, two had abnormal left ventricular function. Follow-up visits were made at least every 6 months. We registered the presence of the tachycardia over 24 h, the mean heart rate over 24 h, and cardiac function. Treatment was started with propafenone alone, or in combination with digoxin as the first choice. Treatment was effective in 14 cases (67%), with either complete disappearance of the tachycardia after discontinuation of medication, or continuation in sinus rhythm with medication; partially effective in 4 cases (20%) when the mean heart rate over 24 h on the last Holter recording was less than 1 standard deviation above the normal for age; but was not effective in the remaining 3 cases (14%). In 3 patients treated with propafenone, or 13 given propafenone and digoxin, treatment was effective in 12 (75%), partially effective in 2 (13%), and ineffective in the other 2 (13%). All 21 children had a normal left ventricular function at the end of follow-up. The median duration of follow-up was 2.4 years. Permanent junctional reciprocating tachycardia had disappeared spontaneously in one-third of the children, 5 being less than 1 year old. Adverse effects, seen in 5 cases, were mild or asymptomatic. No signs of proarrhythmia were registered. Pharmacological treatment, either with propafenone alone, or in combination with digoxin, is safe and effective in young children with permanent junctional reciprocating tachycardia. The mean heart rate is normalized, and cardiac function is restored and preserved. Radiofrequency ablation may be delayed to a safer age, with the arrhythmia disappearing spontaneously in one-third.

Propafenone hepatotoxicity: report of two new cases

Two patients developed acute cholestatic hepatitis during treatment with propafenone. Viral infections, alcohol abuse, hepatotoxicity by other drugs, and biliary obstruction were excluded as causes. In one patient, liver biopsy showed changes consistent with a drug-associated injury. Another patient had autoimmune antibodies (ANA) in the serum. Following propafenone withdrawal, the clinical and biochemical profiles of both patients improved. Hepatic toxicity from the antiarrhythmic drug propafenone is highly uncommon. Moreover, the drug produces hepatocellular injury by an unknown mechanism. Most of the seven cases reported here had acute cholestatic hepatitis after a latency period of two to four weeks.

[Hepatic toxicity of propafenone: a case description]

A case of acute liver injury associated with the use of the antiarrhythmic drug propafenone in a 62-year-old woman undergoing clinical observation for recurrent atrial fibrillation is reported. Propafenone hydrochloride, a class 1C antiarrhythmic drug widely used in the clinical practice for the treatment of supraventricular and ventricular arrhythmias, rarely (0.1-0.2% of incidence) causes liver injury characterized by a rise in hepatic cell enzymes or cholestatic enzymes or both. Within 2 months of the discontinuation of therapy the liver function tests return to normal, therefore there are no known fatalities secondary to propafenone liver injury including fulminant hepatitis and death. The close temporal relationship between the administration of the drug and the acute onset of signs of liver injury, the marked rise in liver function tests following the increase of the drug dosage and their gradual normalization after its withdrawal strongly suggest that propafenone is involved in the pathogenesis of this syndrome. Although rare, hepatotoxicity due to this widely used antiarrhythmic drug should be borne in mind in the differential diagnosis of sudden hepatocellular or cholestatic syndrome of obscure origin. It seems prudent to obtain baseline liver function before starting therapy with propafenone and then follow up laboratory tests some months later at least in patients with known liver disease.

Propafenone-related cholestatic hepatitis in an elderly patient

Hepatic toxicity caused by propafenone is extremely rare. We here describe a case of acute cholestasis secondary to propafenone treatment in an elderly male with no history of preexistent liver disease. The clinical picture and time course of the symptoms seem to be compatible with a direct toxic reaction. Age-related delays in hepatic drug metabolism should explain the hazardous increase in the bioavailability of this drug. Despite the rarity of this complication, propafenone should be considered as a potential cause of drug-induced cholestasis in elderly patients. The literature on the hepatotoxicity of propafenone is also reviewed.