Patient characteristics and underlying heart disease as predictors of recurrent atrial fibrillation after internal and external cardioversion in patients treated with oral sotalol

Predicting the Outcomes of External Direct Current Cardioversion for Atrial Fibrillation: A Narrative Review of Current Evidence

Atrial fibrillation (AF) is the most common sustained arrhythmia associated with significant morbidity and mortality. External direct current cardioversion (DCCV) is a cornerstone intervention for rhythm control in AF; however, its success is influenced by various patient-specific and procedural factors. This review examines the predictors of DCCV success and AF recurrence with specific focus upon demographics, biochemical, cardiovascular imaging, and P-wave parameters and their likely ability to predict procedural outcomes. Demographic factors such as age, sex, and comorbidities influence DCCV outcomes, with prolonged AF duration, obesity, and heart failure being associated with higher failure rates. Elevated biochemical markers of inflammation and fibrosis, including C-reactive protein, galectin-3, and Type III procollagen-N-peptide, were predictive of poor outcomes. Imaging parameters, particularly left atrial (LA) volume and strain, emerged as critical indicators of atrial remodelling and DCCV failure. Increased P-wave duration and dispersion on electrocardiography were associated with an increased risk of recurrence. Biphasic waveforms and antiarrhythmic drugs, such as amiodarone and flecainide, improved cardioversion success. The predictors of DCCV success and recurrence reflect the interplay of structural, biochemical, and electrical remodelling in AF. Integrating these parameters into clinical practice can guide individualised patient management and improve outcomes. Further research is needed to validate these predictors and enhance precision medicine approaches in DCCV.

Body surface mapping of P-waves in sinus rhythm to predict recurrence following cardioversion for atrial fibrillation

Background

Direct current cardioversion (DCCV) is used as elective and emergency rhythm control for atrial fibrillation (AF). We aimed to explore the role of P-wave parameters measured during sinus rhythm using body surface mapping (BSM) in predicting successful DCCV for persistent atrial fibrillation (persAF) at 12 months.

Methods

This case-control study included 56 males >18 years old who underwent DCCV for persAF. P-wave parameter collection after DCCV for AF was done using 128 unipolar leads. A band-pass filter of 1-50 Hz was utilised. Corrected P-wave duration (PWDc), P-wave amplitude, and P-wave dispersion were measured to predict 12-month outcomes and time of recurrence.

Results

The mean age was 64 ± 4 years, and 23 patients (44%) were on amiodarone. The 12-month success rate was 44% (n = 23), while the rest reverted to AF after 2.6 ± 0.4 months. The parameters were comparable between successful and failed DCCV in the entire cohort and patients not on amiodarone. In patients on amiodarone, patients with failed arms had higher PWDc than those with successful arms (188 vs. 150 ms, P = 0.04). Receiver operator characteristic curve analysis for PWDc in the amiodarone cohort showed an area under the curve (AUC) of 0.75 and P = 0.049. A recurrence cut-off >161 ms had a sensitivity of 69% and a specificity of 100%, with a hazard ratio of 10.7, P = 0.004. The parameters were not predictive of the time of recurrence.

Conclusion

In patients on amiodarone, increased PWDc measured using BSM was associated with higher AF recurrence at 12 months following DCCV for persAF.

Atrial Fibrillation Management: A Comprehensive Review with a Focus on Pharmacotherapy, Rate, and Rhythm Control Strategies

Atrial fibrillation (AF) is an increasingly common arrhythmia encountered in clinical practice that leads to a substantial increase in utilization of healthcare services and a decrease in the quality of life of patients. The prevalence of AF will continue to increase as the population ages and develops cardiac comorbidities; thus, prompt and effective treatment is important to help mitigate systemic resource utilization. Treatment of AF involves two tenets: prevention of stroke and systemic embolism and symptom control with either a rate or a rhythm control strategy. Historically, due to the safe nature of medications like beta-blockers and non-dihydropyridine calcium channel blockers, used in rate control, it has been the initial strategy used for symptom control in AF. Newer data suggest that a rhythm control strategy with antiarrhythmic medications with or without catheter ablation may lead to a reduction in major adverse cardiovascular events, particularly in patients newly diagnosed with AF. Modulation of factors that promote AF or its complications is another important aspect of the overall holistic management of AF. This review provides a comprehensive focus on the management of patients with AF and an in-depth review of pharmacotherapy of AF in the rate and rhythm control strategies.

Is there any Link Between Vitamin D and Recurrence of Atrial Fibrillation after Cardioversion?

Introduction

Atrial fibrillation (AF) is the most common chronic arrhythmia in the elderly population. In symptomatic patients, restoration and maintenance of sinus rhythm improve quality of life. Unfortunately, AF recurrence still occurs in a considerable number of patients after cardioversion (CV). In this study, we aimed to evaluate the association between vitamin D (VitD) and AF recurrence after electrical or medical CV.

Method

A total of 51 patients who underwent CV for symptomatic AF were included in the study. AF recurrence was defined as an AF pattern in 12-lead electrocardiography (ECG) recording after CV within 6 months or ECG Holter recording of AF lasting more than 30 seconds at 6-month follow-up.

Results

Mean vitD level was 21.4 ng/ml in our study population. VitD level was lower in the AF recurrence group than in the non-recurrence group (18 ng/ml vs. 26.3 ng/ml, respectively; P=0.001). Additionally, left atrial diameter was larger in the AF recurrence group compared to the non-recurrence group (4.4 vs. 4.1, P=0.025). Patients with AF recurrence were older than patients without AF recurrence, and, although the prevalence of hypertension is higher in the AF recurrence group, there was no statistically significant difference (P=0.107, P=0.867).

Conclusion

In our study, there is a strong association between vitD level and AF recurrence after CV. VitD deficiency might be a predictor of high risk of AF recurrence after CV and vitD supplementation during the follow-up might help the maintenance of sinus rhythm.

Peak Early Diastolic Transmitral Velocity As A Surrogate Marker Of Short-Term Atrial Fibrillation Recurrence After Electrical Cardioversion

OBJECTIVES

The aim of this study was to assess if peak early diastolic transmitral velocity (E-wave) can be used as a surrogate marker of short-term atrial fibrillation (AF) recurrence.

METHODS

We prospectively studied 57 consecutive patients who underwent electrical cardioversion (ECV) for AF and successfully converted to sinus rhythm. N-terminal brain natriuretic peptide levels (BNP) before and after ECV was measured in all patients. The follow-up included physical examination and a 12-lead electrocardiogram 14 days and one month after the ECV.

RESULTS

In 42.1% patients AF recurred during one-month follow-up period. Gender, presence of mitral regurgitation, treatment with angiotensin II receptor blocker and left atrium diameter independently influenced E-wave velocity before ECV. E-wave velocity fell immediately after successful ECV (94.0±27 cm/s vs 79.7±23 cm/s, P<0.0001). E-wave velocity before ECV>94 cm/s and E-wave velocity after ECV >80 cm/s were predictors of one-month AF recurrence [(Hazard Ratio) HR=3.62 with 95% CI=1.49-8.78 and HR=3.76 with 95% CI=1.40-10.10, respectively]. E-wave velocity before and E-wave velocity after ECV remained predictors of AF recurrence but only in non-hypertensive patients (HR=1.01 with 95% C.I=1.01-1.03 and HR=1.03 with 95% C.I=1.01-1.06, respectively). Similarly, BNP levels before and after ECV were associated with an increased the risk of AF recurrence (HR=1.14 with 95% C.I 1.01-1.28 and HR= 1.16 with 95% C.I 1.03- 1.31, respectively). The addition of BNP levels to E-wave velocity before ECV appeared to have incremental value on short-term AF recurrence but at a marginally statistical significance (LR chi2=3.28, p=0.07).

CONCLUSIONS

E-wave velocity before and after ECV appears to be a marker of short-term recurrence of AF.

Efficacy of dronedarone versus propafenone in the maintenance of sinus rhythm in patients with atrial fibrillation after electrical cardioversion

PURPOSE

Our objective was to compare the efficacy of dronedarone and propafenone in maintaining sinus rhythm in patients with atrial fibrillation (AF) after electrical cardioversion.

METHODS

In this single-center, open-label, randomized trial, we randomly assigned patients with AF after electrical cardioversion to receive dronedarone 400 mg BID or propafenone 150 mg TID. Follow-up clinical evaluations were conducted at 1, 2, 3, and 6 months of treatment. The primary end point was the time to the first recurrence of AF.

FINDINGS

A total of 98 patients were enrolled (79 men; mean age, 59.2 years; n = 49 per group). The median times to first recurrence of AF were 31 days in the dronedarone group and 32 days in the propafenone group (P = 0.715). The median (interquartile range) ventricular rates at first recurrence of AF were 76.5 (67.3-86.5) beats/min in the dronedarone group and 83.0 (71.0-96.0) beats/min in the propafenone group (P = 0.059).

IMPLICATIONS

Dronedarone and propafenone had similar efficacies in maintaining sinus rhythm in patients with AF after electrical cardioversion. The ventricular rate at the first recurrence of AF was numerically but not statistically significantly lower in the dronedarone group than in the propafenone group. ClinicalTrials.gov identifier: NCT01991119.

Noninvasive time and frequency predictors of long-standing atrial fibrillation early recurrence after electrical cardioversion

BACKGROUND

Several clinical factors have been studied to predict atrial fibrillation (AF) recurrence after electrical cardioversion (ECV) with limited predictive value.

METHODS

 A method able to predict robustly long-standing AF early recurrence by characterizing noninvasively the electrical atrial activity (AA) with parameters related to its time course and spectral features is presented. To this respect, 63 patients (20 men and 43 women; mean age 73.4 ± 9.0 years; under antiarrhythmic drug treatment with amiodarone) who were referred for ECV of persistent AF were studied. During a 4-week follow-up, AF recurrence was observed in 41 patients (65.1%).

RESULTS

 RR variability and the studied AA spectral features, including dominant atrial frequency (DAF), its first harmonic and their amplitude, provided poor statistical differences between groups. On the contrary, f waves power (fWP) and Sample Entropy (SampEn) of the AA behaved as very good predictors. Patients who relapsed to AF presented lower fWP (0.036 ± 0.019 vs 0.081 ± 0.029 n.u.(2) , P < 0.001) and higher SampEn (0.107 ± 0.022 vs 0.086 ± 0.033, P < 0.01). Furthermore, fWP presented the highest predictive accuracy of 82.5%, whereas SampEn provided a 79.4%. The remaining features revealed accuracies lower than 70%. A stepwise discriminant analysis (SDA) provided a model based on fWP and SampEn with 90.5% of accuracy.

CONCLUSIONS

 The fWP has proved to predict long-standing AF early recurrence after ECV and can be combined with SampEn to improve its diagnostic ability. Furthermore, a thorough analysis of the results allowed outlining possible associations between these two features and the concomitant status of atrial remodeling.

Time and frequency recurrence analysis of persistent atrial fibrillation after electrical cardioversion

Electrical cardioversion (ECV) has become a mainstay of therapy for the treatment of persistent atrial fibrillation (AF), which is an arrhythmia that affects up to 1% of the general population. The procedure is initially effective, but it is also characterized by a high rate of AF recurrence. As a consequence, it would be clinically useful to predict normal sinus rhythm (NSR) maintenance after ECV before it is attempted. In this respect, several clinical, echocardiographic and demographic parameters have been analyzed by other authors. However, these indices are weak predictors of ECV outcome. In this work, surface electrocardiographic (ECG) recordings were used to extract the atrial activity (AA) signal and parametrize the fibrillatory (f) waves, both in time and frequency, to obtain AF recurrence predictors. Parameters as f waves amplitude (fWA), AA mean power, dominant atrial frequency (DAF), its first harmonic, etc were studied. Obtained results showed that fWA was the most significant predictor of AF recurrence 1 month later. Concretely, 72.73% of the patients resulting in NSR, 83.87% relapsing to AF and 80.0% with unsuccessful ECV, were correctly identified. Therefore, fWA classified satisfactorily 79.37% of the analyzed patients. In addition, a forward stepwise discriminant analysis, with a leave-one-out cross validation approach, proved that fWA and DAF combination provided an improved diagnostic ability of 85.71%. In this case 86.36%, 83.87% and 90% of the patients who resulted in NSR, relapsed to AF and with unsuccessful ECV, were correctly discerned, respectively. In conclusion, fWA could be considered as a promising predictor of ECV outcome during the first month following the procedure. Additionally, time and frequency indices could yield complementary information useful to predict the cardioversion outcome. Finally, further studies are needed to validate the robustness of these parameters and the repeatability of the obtained results on wider databases.

Atrial premature complexes and heart rate have prognostic significance in 1-month atrial fibrillation recurrence after electrical cardioversion

AIMS

The aim of this study was to investigate the significance of simple 24-h Holter (24H) data after electrical cardioversion (CV) for atrial fibrillation (AF) recurrence.

METHODS

We prospectively studied 47 consecutive patients subjected to CV, who successfully converted to sinus rhythm. All underwent echocardiography and 24H after CV. AF recurrence was studied at 14 days and 1 month by second 24H or by interim report of AF.

RESULTS

About 53.2% remained in sinus rhythm (group I) and the rest recurred to AF (group II). Group I had fewer atrial premature complexes per hour (APC/h) (P = 0.002) and lower maximum (max HR), average, and minimum heart rates compared with group II (all Ps < 0.05). The optimal value of APC/h and max HR with best sensitivity and specificity was 32 APC/h and 90 bpm, respectively. These findings were the predictors of AF recurrence [hazard ratio (HR) = 4.5 with 95% CI = 1.7-11.7 and HR = 4.3 with 95% CI = 1.7-10.9, respectively]. Patients with the combination of both predictors had greater HR of AF recurrence compared with those with < 32 APC/h and max HR < 90 bpm (HR = 8.8 with 95% CI = 2.5-31.4).

CONCLUSION

Patients with frequent APC/h and high max HR are at high risk for 1-month AF recurrence after electrical CV.

Prospective randomized trial of transthoracic versus low-energy internal cardioversion in persistent atrial fibrillation: long term follow-up

Low energy internal cardioversion (ICV) is a relatively new method. This report describes the long-term follow-up results of a prospective randomized comparison of low energy ICV and transthoracic cardioversion (TT CV) in patients with persistent atrial fibrillation (AF). Fifty-two patients (mean age, 60.6 +/- 10.1 years, 23 males) with persistent AF were randomly assigned to either TT (n = 26) or ICV (n = 26). The baseline characteristics of the 2 groups were similar. Transthoracic CV was performed under sedation with hand-held electrodes in the apex-anterior position and high energy (100-360 J) monophasic shocks. ICV was performed by a dedicated balloon-directed catheter utilizing truncated, biphasic shocks of low energy (1-15 J). Sinus rhythm (SR) was restored in 24/26 (92%) patients in the ICV group and in 22/26 (85%) patients in the TT CV group (P > 0.05). Immediate recurrence of AF (IRAF), defined as reappearance of AF within 2 minutes of successful CV, occurred in 5 patients (21%) in the ICV group and in 1 patient (4.5%) in the TT group (P > 0.05). Successfully cardioverted patients in whom no IRAF occurred were followed-up for 18 months under both warfarin and Class 1 or 3 antiarrhythmic drugs, as guided by the current ACC/AHA/ESC Guidelines. The rate of SR at 1, 3, 6, 12, and 18 months of follow-up was not significantly different between the 2 groups, and in an intention-to-treat analysis at 18 months, SR was present in 6 patients (23%) in the ICV group and in 10 patients (38%) in the TT group (P > 0.05). The majority of AF recurrences occurred within a month of successful CV in both groups (8/12 [67%] in the TT group and 15/18 [83%] in the ICV group, P > 0.05). The mortality, thromboembolic, and bleeding complication rates were similar in the 2 groups. In this prospective randomized comparison of TT and low energy ICV in patients with persistent AF, the 18-month rates of SR and major adverse clinical events were found to be similar.

Long-term outcome after cardioversion of atrial fibrillation: Prediction of recurrence with P wave signal averaged ECG and chemoreflexsensitivity

AIM

The recurrence of atrial fibrillation after cardioversion was a general problem in medical practice.

METHODS

We wanted to test the hypothesis that the recurrence of atrial fibrillation could be predicted by measurements of P wave triggered P wave signal averaged ECG and chemoreflexsensitivity (CHRS) in 118 consecutive patients one day after successful electrical cardioversion. We measured the filtered P wave duration (FPD) and the root mean square voltage of the last 20 ms of the P wave (RMS 20) with P wave triggered P wave signal averaged ECG. The CHRS was calculated of a ratio between the difference of RR intervals in ECG and venous pO2 before and after 5-min oxygen inhalation. The pathologic CHRS was predefined as a CHRS below 3.0 ms/mm Hg.

RESULTS

A recurrence of atrial fibrillation was observed in 57 patients (48%) during a 9.3-month follow-up. The left atrial size (41.9+/-4.0 vs. 39.3+/-3.1 mm, P<0.0003) was larger, the FPD (139.6+/-16.0 vs. 118.2+/-14.1 ms, P<0.0001) was longer, the RMS 20 (2.57+/-0.77 vs. 3.90+/-0.99 muV, P<0.0001) and the CHRS (2.66+/-1.18 vs. 4.01+/-1.66 ms/mm Hg, P<0.0001) were lower in patients with recurrence of atrial fibrillation. A cut-off point was defined with FPD > or =126 ms and RMS 20 < or =3.1 muV and could predict atrial fibrillation with a specificity of 77%, a sensitivity of 72%, a positive value of 75%, a negative predictive value of 75% and an accuracy of 75%. Patients with FPD > or =126 ms and RMS 20 < or =3.1 muV had nearly a 7-fold increase risk for recurrence of atrial fibrillation.

CONCLUSION

The recurrence of atrial fibrillation after cardioversion could be detected by P wave signal averaged ECG and an analysis of CHRS. These methods seem to be appropriate to show a delayed atrial conduction and a neurovegetative imbalance which might be possible trigger mechanisms of reinitiating of atrial fibrillation.

Electrical cardioversion of atrial fibrillation: different methods for a safe and effective technique

Atrial fibrillation is the most common cardiac arrhythmia observed in clinical practice. Many different therapeutic approaches are available at present but none may be considered the gold standard treatment. Antiarrhythmic drugs are not very effective agents to cardiovert persistent atrial fibrillation and, therefore, the technique most frequently used to restore sinus rhythm is external direct current cardioversion, which has proved to be safe and very effective. Esophageal cardioversion is an alternative method that could obviate some of the limitations of the external technique, such as the high energy required, need for anesthesia and longer hospital stay. Another technique performed during the last two decades is internal cardioversion, but at present, the advantage of this technique is limited to the small proportion of cases of unsuccessful external cardioversion.

The effect of patient sex on recurrence of atrial fibrillation following successful direct current cardioversion

BACKGROUND

The effect of patient sex on recurrence of atrial fibrillation after a successful direct current cardioversion is unknown.

METHODS

This prospective study included 773 patients (486 [63%] men and 287 [37%] women) undergoing successful direct current cardioversion of atrial fibrillation between May 2000 and July 2003. Patient characteristics at presentation were recorded. The primary end point was the time between cardioversion and the first documented recurrence of arrhythmia.

RESULTS

At presentation, women were older and had a higher prevalence of hypertension and valvular disease compared with men. In addition, women had worse mechanical left atrial appendage function. Arrhythmia recurrence was more prevalent in women (50.0% at 1 year compared with 43.4% in men, and 75.8% at 2 years compared with 67.0% in men; P = .03). On the basis of multivariate analysis, patient sex was a significant predictor of arrhythmia recurrence. There was no significant difference in overall mortality between men and women.

CONCLUSIONS

Women were more likely than men to have recurrence of atrial fibrillation after successful direct current cardioversion. Patient sex should be taken into account with other clinical factors when making the decision about cardioversion for atrial fibrillation.

Supraventricular ectopy and recurrence of atrial fibrillation after electrical cardioversion

AIMS

Paroxysmal atrial fibrillation (AF) is usually preceded by a premature atrial complex (PAC). We hypothesized that patients with a high frequency of atrial ectopic activity after restoration of sinus rhythm following direct current cardioversion would be more likely to experience recurrence of AF.

METHODS AND RESULTS

Forty-four patients with documented persistent AF were studied. A 24 h Holter recording was performed from the day of external direct current cardioversion. Patients were reviewed at 1 week, 1 month, and 6 months. After 6 months, 59% of patients had experienced a recurrence of AF. Neither the frequency of PACs nor the frequency or duration of supraventricular tachycardia (SVT) episodes predicted AF recurrence (P=0.60, 0.30, and 0.42, respectively). There was a trend towards maximum rate of SVT predicting recurrence of AF (P=0.08).

CONCLUSION

Frequency of supraventricular ectopy or the number and length of SVT runs in the 24 h after restoration of sinus rhythm are not strong predictors of recurrence of AF after electrical cardioversion. A larger study would be required to detect a small predictive effect.

Electrical cardioversion for persistent or chronic atrial fibrillation: Outcome and clinical factors predicting short and long term success rate

AIMS

To assess the effectiveness and to identify predictors for successful electrical cardioversion (ECV) and maintenance of sinus rhythm, in long term follow up of patients with persistent (PAF) and chronic atrial fibrillation (CAF).

METHODS AND RESULTS

Retrospective analysis of medical records of 68 patients with PAF or CAF, who underwent 91 cardioversions. ECV was successful in 86 attempts (94.5%). In obese (body mass index>30) and hypertensive patients (blood pressure >140/90 mm Hg), ECV was less successful in restoring sinus rhythm (p<0.05, p<0.021, respectively). Sinus rhythm was maintained more than half a year in 42 cardioversions (61%). Treatment with beta blockers prior to cardioversion and age younger than 75 were independent factors predicting long term success (p<0.013, p<0.034, respectively). Mild or moderate enlargement of left atrium (<6 cm) did not predict relapse of the arrhythmia. Second ECV was as or more effective than the first in 82.3% of patients that underwent more than one cardioversion.

CONCLUSIONS

Conversion of atrial fibrillation by DC shock was found to be safe and effective procedure. Patients should be treated with beta blockers prior to cardioversion, if possible. Mild or moderate enlargement of left atrium is not contraindication to cardioversion. Recurrent cardioversions may be recommended.

Are transthoracic echocardiographic parameters associated with atrial fibrillation recurrence or stroke? Results from the Atrial Fibrillation Follow-Up Investigation of Rhythm Management (AFFIRM) study

OBJECTIVES

The purpose of this study was to evaluate the associations of transthoracic echocardiographic parameters with recurrent atrial fibrillation (AF) and/or stroke.

BACKGROUND

The Atrial Fibrillation Follow-up Investigation of Rhythm Management (AFFIRM) study, an evaluation of elderly patients with AF at risk for stroke, provided an opportunity to evaluate the implications of echocardiographic parameters in patients with AF.

METHODS

Transthoracic echocardiographic measures of mitral regurgitation (MR), left atrial (LA) diameter, and left ventricular (LV) function were evaluated in the AFFIRM rate- and rhythm-control patients who had sinus rhythm resume and had these data available. Risk for recurrent AF or stroke was evaluated with respect to transthoracic echocardiographic measures.

RESULTS

Of 2,474 patients studied, 457 had > or =2(+)/4(+) MR, and 726 had a LA diameter >4.5 cm. The LV ejection fraction was abnormal in 543 patients. The cumulative probabilities of at least one AF recurrence/stroke were 46%/1% after 1 year and 84%/5% by the end of the trial (> 5 years), respectively. Multivariate analysis showed that randomization to the rhythm-control arm (hazard ratio [HR] = 0.64; p < 0.0001) and a qualifying episode of AF being the first known episode (HR = 0.70; p < 0.0001) were associated with decreased risk. Duration of qualifying AF episode >48 h (HR = 1.55; p < 0.0001) and LA diameter (p = 0.008) were associated with an increased risk of recurrent AF. Recurrent AF was more likely with larger LA diameters (HR = 1.21, 1.16, and 1.32 for mild, moderate, and severe enlargement, respectively). No transthoracic echocardiographic measures were associated with risk of stroke.

CONCLUSIONS

In the AFFIRM study, large transthoracic echocardiographic LA diameters were associated with recurrent AF, but no measured echocardiographic parameter was associated with stroke.

Recurrence of Atrial Fibrillation After Internal Cardioversion of Persistent Atrial Fibrillation Prognostic Importance of Electrophysiologic Parameters

BACKGROUND

The purpose of this study was to determine whether the extent of atrial electrical remodeling affects the recurrence of atrial fibrillation (AF) after cardioversion of persistent AF (PAF).

METHODS AND RESULTS

Internal atrial cardioversion was performed in 47 patients with PAF. The right atrial monophasic action potential duration (RA-MAPD) at pacing cycle lengths (PCLs) of 800-300 ms and P wave signal-averaged electrocardiogram were recorded after cardioversion. Bepridil (150-200 mg/day) and carvedilol (10 mg/day) were administered to all patients after cardioversion. Of the 47 patients, 20 had recurrent AF within 3 months. No relation was observed between age, left atrial dimension, left ventricular ejection fraction, and AF recurrence. The AF duration was significantly longer (p<0.05) and RA-MAPD at PCLs of 800 to 300 ms were significantly shorter (p<0.05) in patients with AF recurrence than in those without recurrence. The mean slope of the RA-MAPD for PCLs between 600 and 300 ms did not differ between the patients with and without AF recurrence. The filtered P-wave duration (FPD) was significantly longer in the patients with AF recurrence than in those without (p<0.05). Multivariate analysis also showed that the RA-MAPD at a PCL of 300 ms and FPD were predictors of AF recurrence (RAMAPD: p=0.038; FPD: p=0.052).

CONCLUSION

These results suggest that electrical remodeling related to the repolarization and depolarization may be the main contributors to early AF recurrence after cardioversion under the administration of bepridil and carvedilol.

Overview of the management of atrial fibrillation: what is the current state of the art?

Management of Atrial Fibrillation. There are three fundamental approaches to the management of atrial fibrillation (AF): rate control, rhythm control, and anticoagulation. Selecting a course of treatment requires a thorough knowledge of these therapeutic alternatives. This article explores treatment options, including the relative benefits of rate control versus rhythm control, which are complicated by the lack of highly effective and safe antiarrhythmic drugs. Anticoagulation is also an important issue in AF management, and warfarin effectively reduces the incidence of thromboembolic events in AF patients. The use of warfarin, however, presents its own complications. We conclude that individualization of therapy is paramount when treating AF.

Pharmacologic reversion of persistent atrial fibrillation with amiodarone predicts long-term sinus rhythm maintenance

OBJECTIVE

The study analyzed the role of different variables that determine long-term sinus rhythm maintenance in patients with persistent atrial fibrillation who are treated with amiodarone.

BACKGROUND

It has been recognized that different factors influence long-term sinus rhythm preservation after the conversion of persistent atrial fibrillation. Although the duration of the arrhythmia appears to be the most important factor, consistent information regarding the role of the mode of arrhythmia conversion (pharmacologic or electric) is still lacking.

METHODS

One hundred and forty one anticoagulated patients with persistent atrial fibrillation (median duration 8 months, percentiles 25 and 75: 2-24) were treated for 4 weeks with oral amiodarone (600 mg/day). Those in whom the arrhythmia persisted underwent electric cardioversion. After restoration of normal sinus rhythm (either pharmacologic or electric), all patients received a daily dose of amiodarone (200 mg) and were followed for a median of 19 months (percentiles 25 and 75: 8-34 months).

RESULTS

Sixty eight patients (48.22%) regained sinus rhythm during the initial period of amiodarone treatment with 600 mg/day (Group I) and 73 (51.78%) required electric cardioversion (Group II). During the entire follow-up, atrial fibrillation relapsed in 63 patients: 17 (25%) in Group I and 46 (63%) in Group II. Recurrences of the arrhythmia were strikingly less frequent in patients whose atrial fibrillation lasted 12 months or less (33/103, 32.3%) than in those whose atrial fibrillation lasted more than 12 months (30/38, 78.94%). In the multivariate analysis, the mode of reversion (HR, 0.37; CI, 0.21-0.65) and the duration of the arrhythmia (HR, 2.55; CI, 1.54-4.20) were the determinants for long-term sinus rhythm maintenance. Age, sex, left atrium size, left ventricle diameter, and the shortening fraction did not significantly influence the rate of arrhythmia recurrence. Among the 141 patients included in the study, 113 patients were followed for at least 1 year, and cardiac rhythm was assessed at this time. Of these, only 1 of 48 patients (2.1%) in Group I was in atrial fibrillation, in marked contrast with 18 of 65 patients (27.8%) in Group II (RR, 0.075; 95% CI, 0.01-0.54).

CONCLUSIONS

In patients with persistent atrial fibrillation, long-term preservation of sinus rhythm under chronic amiodarone treatment may be anticipated when the arrhythmia lasts 12 months or less and/or its reversion is obtained pharmacologically. We may confidently assume that these two factors have a beneficial additive influence on the outcome.

Persistent atrial fibrillation: a population based study of patients with their first cardioversion

BACKGROUND

Electrical cardioversion is effective in terminating even long standing atrial fibrillation (AF), but the relapse risk of AF is high. Data on long-term success of cardioversion in real life clinical practice are scant.

METHODS

Restoration and maintenance of sinus rhythm as well as acceptance of permanent AF was studied in a population based cohort (catchment area with a population of 440,000) of patients with persistent AF after first elective cardioversion.

RESULTS

Of the 183 patients having their first electrical cardioversion during the 1-year study period, sinus rhythm was restored in 153 patients (84%). Only 39 of these (25%) maintained sinus rhythm for 1 year, even though 108 (71%) patients had anti-arrhythmic medication. Age, hypertension, coronary artery disease, heart failure and valvular disease, or absence of these known risk factors for AF were not associated with the outcome. The outcome was better if the cardioversion was performed earlier than the median delay (78 days) from the diagnosis of AF to cardioversion compared to longer delay (P=0.022 in multivariate modelling). The decision of acceptance of permanent AF was made in 74 cases (40%) during 1 year of follow-up.

CONCLUSIONS

Patients with persistent AF had a high tendency to remain in or relapse into AF, even though most patients had anti-arrhythmic medication after first cardioversion. Short history of arrhythmia was associated with better outcome. Acceptance of permanent AF was made in almost half of the cases during 1 year of follow-up.

Clinical predictors and time course of arrhythmia recurrence in patients with early reinitiation of atrial fibrillation after successful internal cardioversion

Early reinitiation of atrial fibrillation (ERAF) was commonly observed after successful electrical cardioversion, however, the effect of ERAF on the subsequent time course of arrhythmia recurrence remains unclear. The aim of this study was to evaluate the clinical predictors and time course of AF recurrence with respect to the occurrence of ERAF after successful cardioversion. The clinical predictors and time course of AF recurrence were prospectively evaluated in 124 patients (94 men, 30 women; mean age 65 +/- 9 years) with persistent AF (mean AF duration 36 +/- 40 months), who underwent internal cardioversion. After cardioversion, all patients received treatment with sotalol and were monitored for AF recurrence. Successful restoration of sinus rhythm was achieved in 104 (84%) of 124 patients. ERAF was observed in 28 (27%) of 104 patients in whom 26 of them were successfully treated acutely with intravenous sotalol and repeated cardioversion. After a mean follow-up of 26 months, 29 (28%) of 104 patients remained in sinus rhythm. Kaplan-Meier analysis revealed a significantly poorer outcome with regard to the recurrence of AF in patients with ERAF (hazard ratio 1.7,P = 0.03) and in those with AF for more than 3 years (hazard ratio 1.6,P = 0.03). Despite treatment with sotalol, patients with ERAF had a significantly higher AF recurrence rate within the first day (13/26 [50%] vs 12/76 [16%],P < 0.01), but not during long-term follow-up (21/26 [81%] vs 52/76 [68%],P = 0.3). In contrast, patients with AF for more than 3 years had a similar AF recurrence rate within the first day (7/29 [24%] vs 18/73 [25%],P = 1.0), but a significantly higher recurrence rate during long-term follow-up (27/29 [93%] vs 46/73 [37%],P < 0.01). In conclusion, the occurrence of ERAF and long AF duration were independent predictors for AF recurrence after successful internal cardioversion. The difference in the time course of AF recurrence in patients with ERAF from those with long AF duration suggests distinct arrhythmogenic mechanisms.

External Cardioversion in Patients With Persistent Atrial Fibrillation A Reappraisal of the Effects of Electrode Pad Position and Transthoracic Impedance on Cardioversion Success

The optimal methods to perform external cardioversion of atrial fibrillation (AF) have yet to be conclusively determined. This study was performed to examine the relative efficacy of different pad positions on cardioversion success and the relationship between the transthoracic impedance (TTI) and energy requirement for AF cardioversion. Seventy patients with persistent AF undergoing elective cardioversion were randomly assigned to an electrode pad position situated either over the ventricular apex-right infraclavicular area (AL group, n = 31 ) or over the right lower sternal border-left infrascapular area close to the spine (AP group, n = 39). Energy was delivered at an initial 100 joules (J) and then increased to 150 J, 200 J, 300 J, and 360 J if needed. Energy and TTI readings were recorded. Mean TTI was significantly lower in the AP group than in the AL group. However, the cumulative success rates at each energy level were similar in the two groups (23% vs 19.4%, 41% vs 45.2%, 66.7% vs 74.2%, 79.5% vs 77.4%, and 84.6% vs 83.9% at 100 J, 150 J, 200 J, 300 J and 360 J, respectively). In the AP group, converters showed slightly lower TTI compared to nonconverters. In the AL group, converters showed significantly lower TTI compared to nonconverters. However, for all patients as a group, TTI was the only predictor for cardioversion success and showed a significant relationship to the energy required for cardioversion, which can be described by a quadratic equation. Rather than pad position. TTI is the single factor that significantly affects cardioversion and correlates with energy requirement. The relationship between energy requirement and TTI further allows estimation of energy requirements to achieve a successfil cardioversion.

Atrial mechanical performance after internal and external cardioversion of atrial fibrillation: an echocardiographic study

OBJECTIVES

To compare the time course of resumption of mechanical performance of the left and right atrium after the novel method of internal low-energy cardioversion (CV) and conventional external CV of atrial fibrillation (AF).

BACKGROUND

Right atrial performance has been shown to normalize before the left atrium after external CV. However, no data on atrial function after internal CV are available.

PATIENTS AND INTERVENTIONS

Sixty-three patients with chronic AF were randomized to participate in either external or internal CV.

MEASUREMENTS

Echocardiographic examinations were carried out before as well as immediately after CV (day 0), and at days 1, 7, and 28 thereafter for the determination of cardiac dimensions, volumes, and transvalvular flow patterns.

RESULTS

After randomized internal CV or external CV, stable sinus rhythm was restored in 59 patients. Irrespective of the mode of CV, the right atrium resumed its mechanical function immediately after CV, whereas the left atrium was stunned beyond day 7. The mode of CV, internal or external, had no influence on the recovery of atrial mechanical function.

CONCLUSIONS

The right atrium resumes its normal function immediately after internal as well as external CV, whereas left atrium function is delayed. In contrast to the assumption that low-energy internal CV would impact less on atrial mechanical recovery, the type of method of CV used has no effect on such recovery.

Long-term efficacy and safety of propafenone and sotalol for the maintenance of sinus rhythm after conversion of recurrent symptomatic atrial fibrillation

This study was performed to evaluate, using a randomized double-blind, placebo-controlled protocol, the long-term efficacy and safety of propafenone and sotalol in maintaining sinus rhythm after conversion of recurrent symptomatic atrial fibrillation (AF). The maintenance of sinus rhythm in patients with recurrent AF has several potential benefits, the most important being a reduced risk of thromboembolic events. Three hundred patients with recurrent AF (> or = 4 episodes in the last year) and AF at enrollment lasting < 48 hours were randomized to receive either propafenone (mean daily dose 13 +/- 1.5 mg/kg; 102 patients), sotalol (mean daily dose 3 +/- 0.4 mg/kg; 106 patients), or placebo (92 patients). After 1-year follow-up, Kaplan-Meier estimates of the proportion of patients remaining in sinus rhythm were comparable between propafenone (63%) and sotalol (73%) and superior to placebo (35%; p = 0.001 vs both drugs). Symptomatic recurrences occurred later with propafenone and sotalol than with placebo. Nine patients (9%) in the propafenone group, 11 (10%) in the sotalol group, and 3 (3%) in the placebo group discontinued therapy due to adverse effects. Malignant nonfatal arrhythmias due to proarrhythmic effects were documented with sotalol only, and occurred < 72 hours from the beginning of therapy in 4 patients (4%). During recurrences, the ventricular rate was significantly reduced in patients taking propafenone and sotalol (p = 0.001 for both drugs vs placebo). The likelihood of remaining in sinus rhythm during follow-up was higher in younger patients with smaller left atrial size and without concomitant heart disease. In patients with recurrent symptomatic AF, propafenone and sotalol are not significantly different from each other and are superior to placebo in maintaining sinus rhythm at 1 year. Recurrences occur later and tend to be less symptomatic with propafenone and sotalol compared with placebo.

[Independent predictive factors of acute and first year success after electrical cardioversion in patients with chronic atrial fibrillation]

OBJECTIVES

We retrospectively analyzed the predictive factors of successfully electrical cardioversion in patients with chronic atrial fibrillation.

METHODS

We included 118 patients, 68 men and 50 women, with a mean age of 65.1 years and a length of arrhythmia evolution of 83.3 days. These patients consecutively underwent electrical cardioversion in our Cardiology Department with a follow-up of one year to determine relapses. Structural cardiopathy was observed in 63.6% of the patients and 43.7% presented a left atrium between 4 and 5 cms. We analyzed the clinical and echocardiographic factors which predict the acute and first year success of electrical cardioversion.

RESULTS

The cardioversion was effective in 73.7% (CI 95%, 64.6%-81.1%) of the patients and 35.6% (CI 95%, 25.8%-46.6%) had a relapse within the first year. The inexistence of cardiomyopathy and therapy with amiodarone were predictive of acute success (p < 0.04 and p < 0.03, respectively). The length of arrhythmia evolution did not predict acute success but did so when relapses were analyzed. The size of the left atrium is predictive of both acute and long term success (p < 0.02 and p < 0.001, respectively). Logistic regression showed that the size of the left atrium and the patient's age were the only predictive factors of acute and first year success.

CONCLUSIONS

Electrical cardioversion is very efficient in the short-term, despite numerous relapses. Patient age and the size of left atrium are associated with acute and long-term success of cardioversion.

Prevalence and significance of focal sources of atrial arrhythmia in patients undergoing cardioversion of persistent atrial fibrillation

INTRODUCTION

Recent reports have high-lighted the importance of focal atrial arrhythmias as a curable cause for a group of patients with frequently recurrent paroxysmal atrial fibrillation (AF). The importance of this arrhythmia mechanism in the general population of patients with persistent AF is unknown.

METHODS AND RESULTS

After successful internal cardioversion of 50 consecutive patients with persistent AF (mean age 60 years, mean duration of AF 26 months), endocardial activity in the immediate postcardioversion period was analyzed for the presence of focal atrial activity. Postcardioversion atrial arrhythmias were considered to be focal if there was evidence of a localized source of repetitive early atrial activation, either in the form of (1) self-terminating monomorphic atrial tachycardia (at least five beats) or (2) recurrences of AF with an initial atrial activation sequence (first five beats) that was both monomorphic and reproducible with repeated recurrences. Evidence for a focal atrial arrhythmia was present in 20 of the total group of 50 patients (40%). Multivariate analysis of clinical characteristics revealed the diagnosis of lone AF as the only independent predictor of a focal source of AF (P = 0.028). Thirty-nine patients were discharged from hospital in sinus rhythm. At 1-month follow-up, 25 (64%) of these 39 patients had suffered AF recurrence. The only significant predictor of AF recurrence was evidence of a focal source of atrial arrhythmia immediately after cardioversion, with a relative risk of 1.73 (range 1.1 to 2.7; P = 0.015).

CONCLUSION

Focal atrial arrhythmias are common in patients presenting with "idiopathic" persistent AF, suggesting a possible causative role in the generation of this common arrhythmia.

Clinical and electrocardiographic predictors of recurrent atrial fibrillation

Patients with frequent episodes of paroxysmal atrial fibrillation (AF) are prone to develop permanent AF and have an increased thromboembolic risk. We have previously shown that P wave dispersion (P dispersion), defined as the difference between the maximum and the minimum P wave duration, and maximum P wave duration (P maximum) can distinguish patients with paroxysmal lone AF. The ability of those ECG markers and of other clinical and ECG variables to detect patients at risk for recurrent AF was tested in 88 patients, aged 64 +/- 12 years. All patients had a history of symptomatic episodes of AF during the last 2 years and had not previously received any antiarrhythmic prophylaxis. P maximum and P dispersion were calculated from a 12-lead surface ECG recorded in all patients during sinus rhythm. A computerized ECG system was used and P maximum and P dispersion were calculated on screen from the averaged complexes of all 12 leads. Age (P = 0.01), history of organic heart disease (P = 0.03), P maximum (P < 0.001), minimum P wave duration (P = 0.05), and P dispersion (P < 0.001) were found to be significant univariate predictors of recurrent AF, whereas only P maximum (P < 0.001) and age (P = 0.037) remained significant independent predictors of frequent AF paroxysms in the multivariate analysis. It is concluded that advanced age and prolonged P wave duration may be used as predictors of frequently relapsing AF. Therefore, simple AF predictors exist that could possibly distinguish the patients in whom prophylaxis with antiarrhythmic medicines should be instituted.

Signal-averaged P wave duration predicts early recurrence of atrial fibrillation after cardioversion

Thirty-two patients had signal-averaged P wave duration measured after electrical cardioversion of AF, and were followed for 1 year or until there was a recurrence. The use of antiarrhythmic medications was left to the discretion of the attending physician. Among 20 patients not taking antiarrhythmic medication, the 11 patients who had a recurrence of AF within 3 months of cardioversion had a significantly longer signal-averaged P wave duration compared to the 9 patients who did not (148 +/- 17 vs 135 +/- 20 ms, P = 0.005). There was no difference in clinical parameters or left atrial diameter. A signal-averaged P wave duration cutoff anywhere between 130 and 135 ms correctly classified 85% of patients with a sensitivity of 81% and a specificity of 89%. In patients taking antiarrhythmic medications, signal-averaged P wave duration did not correlate with the risk of recurrence. In patients not taking antiarrhythmic medications, signal-averaged P wave duration can be used to predict the risk of an early recurrence of AF after cardioversion. The poor predictive value in patients taking antiarrhythmics may be due to changes in the atrial refractory period, which are not reflected in P wave duration.

Marked reduction in atrial defibrillation thresholds with repeated internal cardioversion

OBJECTIVES

This study was performed to assess the atrial defibrillation threshold in patients with recurrent atrial fibrillation (AF) using repeated internal cardioversion.

BACKGROUND

Previous studies in patients with chronic AF undergoing internal cardioversion have shown this method to be effective and safe. However, current energy requirements might preclude patients with longer-lasting AF from being eligible for an implantable atrial defibrillator.

METHODS

Internal shocks were delivered via defibrillation electrodes placed in the right atrium (cathode) and the coronary sinus (anode) or the right atrium (cathode) and the left pulmonary artery. After cardioversion, patients were orally treated with sotalol (mean 189 +/- 63 mg/day). Eighty consecutive patients with chronic AF (mean duration 291 +/- 237 days) underwent internal cardioversion, and sinus rhythm was restored in 74 patients. Eighteen patients underwent repeated internal cardioversion using the same electrode position and shock configuration after recurrence of AF (mean duration 34 +/- 25 days).

RESULTS

In these 18 patients, the overall mean defibrillation threshold was 6.67 +/- 3.09 J for the first cardioversion and 3.83 +/- 2.62 J for the second (p = 0.003). Mean lead impedance was 55.6 +/- 5.1 ohms and 57.1 +/- 3.7 ohms, respectively (not significant). For sedation, 6.7 +/- 2.9 mg and 3.9 +/- 2.2 mg midazolam were administered intravenously (p = 0.003), and the pain score (0 = not felt, 10 = intolerable) was 5.1 +/- 1.9 and 2.7 +/- 1.8 (p = 0.001). Uni- and multivariate analyses revealed only the duration of AF before cardioversion to be of relevance, lasting 175 +/- 113 days before the first and 34 +/- 25 days before the second cardioversion in these 18 patients (p = 0.002).

CONCLUSIONS

If the duration of AF is reduced, a significant reduction in defibrillation energy requirements for internal cardioversion ensues. This might extend the group of patients eligible for an implantable atrial defibrillator despite relatively high initial defibrillation thresholds.

Efficacy and safety of sotalol versus quinidine for the maintenance of sinus rhythm after conversion of atrial fibrillation. SOCESP Investigators. The Cardiology Society of São Paulo

To compare the efficacy and safety of sotalol and quinidine after conversion of atrial fibrillation (AF) of <6 months, a prospective multicenter trial enrolled 121 patients who were randomized to receive dl-sotalol (160 to 320 mg/day, 58 patients) or quinidine sulfate (600 to 800 mg/day, 63 patients). Patients with left ventricular ejection fraction of <0.40 or left atrial diameter >5.2 cm were excluded. After 6 months of follow-up, using the Kaplan-Meier method, the probabilities of success were comparable between sotalol (74%) and quinidine (68%), but recurrences occurred later with sotalol than with quinidine (69 vs 10 days, p <0.05). Four patients developed proarrhythmic events, 3 (5%) with sotalol and 1 (2%) with quinidine, which were all associated with diuretic therapy. In patients converted from recent-onset AF (< or = 72 hours), sotalol was more effective than quinidine (93% vs 64%, p = 0.01), whereas in chronic AF (> 72 hours), quinidine was more effective than sotalol (68% vs 33%, p <0.05). During recurrences, the ventricular rate was significantly reduced in patients taking sotalol (98 to 82 beats/min, p <0.05). Independent predictors of therapeutic success were recent-onset AF in the sotalol group (p <0.001) and absence of hypertension in the quinidine group (p <0.05). In conclusion, sotalol and quinidine have comparable efficacy and safety for the maintenance of sinus rhythm in the overall group. In recent-onset AF, sotalol was more effective, whereas in chronic AF, quinidine had a better result. Recurrences occurred later with sotalol when compared with quinidine. Because of proarrhythmia, these drugs should be used judiciously in patients on diuretic therapy.

Transvenous atrial defibrillation--techniques and clinical applications

Atrial fibrillation (AF) is the most common arrhythmia requiring treatment. The most desirable therapy may be restoration and maintenance of sinus rhythm. Limitations of the current methods for cardioversion of AF have prompted the development of transvenous atrial defibrillation (TADF) as an alternative and more effective technique for converting AF. Recent advances in the technique of TADF, particularly in the design and configuration of the electrodes, and the use of an optimal biphasic shock waveform have dramatically improved the efficacy of TADF for the termination of all types of AF. The reduction in voltage and energy requirements for cardioversion by TADF may allow the procedure to be performed with little or no sedation and the risk of general anesthesia may be avoided. Both experimental and clinical studies have demonstrated the feasibility, safety, and efficacy of using TADF as a new temporary or "permanent" mode of electrical therapy for AF. It has several potential applications, from acute termination of AF in the electrophysiology laboratory and in patients who have failed to respond to external cardioversion, to its use as an implantable device for treating recurrent AF. This article reviews the current technique and clinical applications of TADF for treatment of AF.

Long-term outcome in patients with chronic atrial fibrillation after successful internal cardioversion

Internal cardioversion is safe and effective in restoring sinus rhythm, even in patients with persistent AF of prolonged duration. Up to 40% to 50% of patients with AF lasting >1 year but <3 years could be maintained in sinus rhythm using a class III antiarrhythmic drug after successful internal cardioversion, and amiodarone appears to be more effective than sotalol in this patient population.

[Internal cardioversion with low-energy shocks in atrial fibrillation resistant to external electric cardioversion]

BACKGROUND AND OBJECTIVE

Although external electrical cardioversion is effective in most patients with atrial fibrillation, there are cases refractory to external cardioversion. This study is aimed at showing our initial experience with an internal cardioversion system in patients with previous unsuccessful external cardioversion.

PATIENTS AND METHODS

Between February, 1997 and September, 1998 nine consecutive patients with spontaneous chronic or persistent atrial fibrillation that failed external cardioversion, were included. Internal cardioversion was performed under sedation with two electrodes that had a 5.5 cm coil placed in the lateral right atrium and coronary sinus. Both electrodes were connected to an external defibrillator capable of delivering R-wave synchronized low-energy biphasic shocks following a minimum RR interval of 500 ms. Energy between 2 J and 10 J was applied until the restoration of sinus rhythm or a maximum of 2 shocks of 10 J.

RESULTS

Sinus rhythm was achieved in the nine patients, but in two of them atrial fibrillation recurred after a few beats. Both had underlying structural heart disease. The other 7 patients, 5 of them without structural heart disease, were in sinus rhythm at discharge. No mechanic complications or ventricular arrhythmias were observed. Six patients are in sinus rhythm after 4 +/- 3 months of follow-up.

CONCLUSIONS

Low-energy intracardiac cardioversion is useful in some patients with atrial fibrillation that had failed external cardioversion and can be performed without general anesthesia.

Sotalol: Current Status and Expanding Indications

BACKGROUND: The role of antiarrhythmic drug therapy continues to undergo major changes. The change is necessitated by the advent of invasive interventional procedures, such as catheter ablation of arrhythmias and the use of implantable devices for sensing and terminating life-threatening ventricular arrhythmias and symptomatically traublesome supraventricular arrhythmias. Many conventional and time-honored drugs, such as sodium channel blockers, have been found either to be ineffective or to have the potential to produce serious proarrhythmic reactions. Attention is therefore focused on compounds that prolong repolarization and reduce sympathetic stimulation. Two compounds, amiodarone and sotalol, have emerged as prototypes of drugs of the future. METHODS AND RESULTS: This review focuses on sotalol for controlling supraventricular and ventricular tachyarrhythmias. Sotalol is a major antiarrhythmic agent that combines potent class III action with nonselective beta-blocking properties. The drug's pharmacokinetics is simple. Its elimination half-life is 10-15 hours, the drug being excreted almost exclusively by the kidneys. Sotalol's pharmacokinetics allows development of optimal dosing for initiation of therapy relative to changes in creatinine clearance with further dose adjustment by monitoring the QT interval on the surface electrocardiogram. The compound exerts broad-spectrum antiarrhythmic actions in supraventricular and ventricular arrhythmias. It prevents inducible ventricular tachycardia (VT) and ventricular fibrillation (VF) in approximately 30% of patients with a higher figure for the suppression of spontaneously occurring arrhythmias documented on Holter recordings. CONCLUSIONS: The major role of sotalol is in the management of VT/VF often in conjunction with an implantable cardioverter/defibrillator, in which context it lowere the defibrillation threshold. Sotalol is superior to class I agents, especially in VT/VF and in survivors of cardiac arrest. Sotalol has emerged as a major antifibrillatory compound for the control of life-threatening ventricular arrhythmias as the main indication. Data have indicated its potential for the maintenance of stability of sinus rhythm in patients with atrial fibrillation and flutter after electrical conversion and in preventing their occurrence in a variety of clinical settings.

Initial experience with a new balloon-guided single lead catheter for internal cardioversion of atrial fibrillation and dual chamber pacing

BACKGROUND

Based on the observation that internal cardioversion (IntCV) of atrial fibrillation is effective with electrodes in the right atrium and pulmonary artery, a new balloon-guided catheter and external defibrillation device with optional dual chamber pacing was evaluated.

METHODS

IntCV was attempted in 27 patients (age: 57 +/- 10 years, duration: 14 +/- 18 months, left atrial diameter 56 +/- 8 mm) using a new defibrillation device (Alert, EP MedSystems, Inc., NJ, USA) that allows the delivery of biphasic shocks (0.5-15 J, variable tilt), atrial and ventricular pacing, and online signal recording. Pacing and defibrillation shocks were applied via a 7.5 Fr balloon-guided catheter (EP MedSystems, Inc.). Pacing, sensing, and triggering were established through the proximal atrial array and an electrode ring between both defibrillation arrays and a single ventricular electrode ring. Catheters were inserted from the antecubital vein.

RESULTS

In 25 of 27 patients sinus rhythm was restored with a mean energy of 6.7 +/- 4.5 J. In five patients, atrial postshock pacing was required for bradycardia and atrial premature beats. The mean fluoroscopy time was 2.0 +/- 1.3 minutes.

CONCLUSION

The high success rate, ease of application, and backup dual chamber pacing suggest that this system is an alternative to established methods of cardioversion. In certain indications, such as failure of prior external cardioversion and situations in which a standard pulmonary balloon catheter is needed, this system would be advantageous.

Efficacy of a new balloon catheter for internal cardioversion of chronic atrial fibrillation without anaesthesia

OBJECTIVE

To compare a new internal cardioversion system incorporated into a balloon guided catheter with a conventional two electrode system in patients with atrial fibrillation (AF).

DESIGN

Prospective study.

PATIENTS

74 patients with chronic AF treated by internal cardioversion.

MATERIALS

A 7.5 F balloon catheter with high energy electrode arrays each consisting of six 0.5 cm platinum rings. Brachial vein access enables one electrode array to be placed in the left pulmonary artery (distal pole) and the other at the lateral right atrial wall (proximal pole). The conventional two electrode system consists of 6 F electrodes placed in the proximal left pulmonary artery (anode) and the lower right atrium.

INTERVENTIONS

Internal cardioversion was performed by shocks delivered in 40 V incremental steps from an external defibrillator. Shocks were applied by the new device to 32 patients (group A) and by the conventional system to 42 patients (group B).

RESULTS

The groups differed with respect to system positioning (9.2 (7.3) upsilon 12.3 (8.1) minutes, p < 0.05) and fluoroscopy times (1.7 (1.0) v 3.3 (2.1) minutes, p < 0.01). Sinus rhythm was restored in 30 patients of group A and in 39 of group B (NS) with mean (SD) energy requirements of 8.4 (3.1) J and 7.2 (3.1) J, respectively (NS).

CONCLUSIONS

This new method of internal cardioversion has comparably high primary success rates and low sedation requirements with single and two lead systems.