Reduced Cardioversion Thresholds for Atrial Fibrillation and Flutter Using the Rectilinear Biphasic Waveform

Background: The RLB waveform has been shown to be superior in overall efficacy to the MDS waveform for cardioversion of AF in one prospective study and one large retrospective analysis. However, little is known about the efficacy of the RLB waveform at lower energies.Objective: This study was undertaken to define the cardioversion thresholds for atrial fibrillation (AF) and flutter (FL) using the rectilinear biphasic (RLB) waveform and compare these to the cardioversion threshold using the conventional monophasic damped sine (MDS) waveform.Methods: All patients underwent transthoracic cardioversion of persistent AF and FL. We performed step-up cardioversion thresholds for AF in 180 RLB patients and 38 MDS patients and compared those results. We also performed cardioversion threshold determinations in 39 RLB patients with typical right atrial FL. For the RLB patients, an initial energy setting of 5 Joules (J) was selected, with increasing energy steps until success, up to 200J. The MDS energy sequence was 50 up to 360J.Results: The average selected energy threshold for AF using the RLB waveform was 70.6 J (median = 50 J) versus 193.4 J (median=150 J) for the MDS waveform (p < 0.001). For FL, the average cardioversion threshold using the RLB waveform was 33.2 J (median = 20 J; p < 0.001 vs. AF with the RLB waveform).Conclusions: Our results show that the transthoracic AF cardioversion threshold using the RLB waveform is significantly lower than the MDS waveform. As expected, the cardioversion threshold for FL was significantly lower than that of AF using the RLB waveform.     

Internal Cardioversion of Persistent Atrial Fibrillation Using Rectilinear Biphasic Waveform

Internal electrical cardioversion is currently used in patients with persistent atrial fibrillation resistant to external electrical cardioversion. In external cardioversion, biphasic waveforms have shown a greater efficacy than monomorphic waveforms. The present study aimed to test the safety and efficacy of rectilinear biphasic waveform in converting patients with persistent atrial fibrillation to sinus rhythm using internal electrical cardioversion, and to compare it with that of classical monophasic waveform. Twenty-seven consecutive patients with persistent AF received 31 internal cardioversions, using monophasic waveform in 11 (group I), and rectilinear biphasic waveform in 20 cases (group II). Baseline patients characteristics were similar in both groups. Multipolar catheters were positioned in the distal coronary sinus and in the high right atrium. Synchronised shocks were delivered using an escalating protocol of 2, 5, 10, 15, 20, 30, and 50 Joules. In group I, 1 patient was resistant to maximal energy (success rate 91%). The mean energy of the maximal shock was 18 ± 13 J. In group II, all patients were converted to sinus rhythm. The mean energy of the maximal shock was 9 ± 5 J (p < 0.01 vs. group I). No significant complications occurred. At 3 months follow-up, 45% of group I and 60% of group II patients remained in sinus rhythm (p = NS).We conclude that internal cardioversion using rectilinear biphasic waveform is feasible and safe, and requires less energy than classical monophasic waveforms.     

Atrial Burst Pacing with Biphasic and Monophasic Waveforms for Atrial Fibrillation

Background: Biphasic pacing is a novel mode of pacing that was suggested to increase cardiac conduction velocity as compared with cathodal monophasic pacing. We aimed to evaluate the safety and efficacy of rapid atrial pacing to convert atrial fibrillation (AF) to normal sinus rhythm. Methods: Multiple biphasic (anodal/cathodal), reverse biphasic (cathodal/anodal), and monophasic (cathodal) atrial pacing therapies were performed among 12 patients undergoing left atrial catheter ablation for AF. The efficacy end point was successful conversion of AF to sinus rhythm, and safety end point no induction of ventricular arrhythmias. Patients were paced at three cycle lengths (100, 200, and 333 msec) for 60 seconds at three locations (right and left atrial appendages and coronary sinus). Results: Among the 66 biphasic (anodal/cathodal) pacing procedures one procedure in a patient with chronic AF, which involved pacing at the left atrial appendage with a cycle length of 200 msec, led to conversion of AF to sinus rhythm. None of the 66 monophasic pacing procedures or the 66 reverse biphasic (cathodal/anodal) pacing procedures was associated with AF termination. None of the biphasic pacing procedures was associated with induction of ventricular arrhythmias. Conclusions: Rapid atrial pacing using a variety of waveforms at the cycle length and output used in the current study was found to be safe. There was a single success in converting a chronic AF to sinus rhythm. Ann Noninvasive Electrocardiol 2012;17(1):22–27     

Towards a Consensus in Rate Versus Rhythm Control for Management of Atrial Fibrillation: Insights from the PIAF Trial

Knowledge on the pathophysiology of atrial fibrillation is rapidly expanding and identification of focally localized triggers have led to the development of new treatment options for this arrhythmia. Conversely, the clinical decision whether to restore and maintain sinus rhythm or simply control the ventricular rate has remained a matter of intense debate. The Pharmacological Intervention in Atrial Fibrillation (PIAF) trial was the first pilot-study to prospectively assess the symptomatic benefits of rate versus rhythm control in patients with persistent symptomatic AF. Since the publication of PIAF, results from three additional randomized clinical trials have confirmed and extended the PIAF notion of equivalent outcomes with regard to symptoms, quality of life, and cardiovascular events. This review summarizes the rationale and results of PIAF in an attempt to update and discuss the clinical relevance of these findings in the light of the other studies and with regard to individual treatment options.     

An Update on Electrical Cardioversion of Atrial Fibrillation

Atrial fibrillation is the most frequently encountered sustained arrhythmia in clinical practice. Electrical cardioversion of atrial fibrillation using damped sine wave shocks has been a mainstay of therapy for nearly 4 decades; its limitation remains a failure rate that approaches 20%. Although several alternatives have been proposed, including delivering 720 J shocks using dual monophasic defibrillators, ibutilide pretreatment and internal cardioversion, each of these approaches has significant limitations, which preclude its routine use. Recent data demonstrate that routine use of biphasic shocks for cardioversion of atrial fibrillation is associated with a marked improvement in cardioversion efficacy and suggest that biphasic shocks may be the preferred method for the transthoracic electrical cardioversion of atrial fibrillation.     

Higher Energy Monophasic DC Cardioversion for Persistent Atrial Fibrillation: Is it Time to Start at 360 Joules?

Background: Electrical direct‐current cardioversion (DCCV) has become a routine therapy for atrial fibrillation (AF), although some uncertainty remains regarding the optimal energy settings. Aims: This study examines whether the use of a higher initial energy monophasic shock of 360 joules (J) for external DCCV, in patients with persistent AF would prove more effective, yet as safe, as the use of a lower initial energy 200 J shock. Methods: A cohort of 107 patients with persistent AF was prospectively randomized to an initial synchronized DCCV shock of 360 J versus 200 J (n = 50 vs 57), followed by a similar shock sequence thereafter of four further shocks of 360 J for the two groups. In all patients the levels of troponin I (cTnI) were measured precardioversion and 18–20 hours later, the following day. In a subgroup of 36 patients in each group, the levels of creatine kinase (CK) and aspartate transaminase (AST) were measured pre‐ and 18–20 hours postcardioversion. Results: The success rate for DCCV was significantly higher in the 360 J group compared to the 200 J group (96.0% vs 75.4%, P = 0.003 ). The mean CK IU/L levels (1137.5.0 vs 2411.8, P = 0.014 ) and AST levels (39.83 vs 52.86, P = 0.010 ) were significantly lower in the 360 J group compared to the 200 J group. There was no statistical rise in cTnI (μg/L) in either group (P = 1.00 ). The average number of shocks delivered (1.84 vs 2.56, P = 0.006) was significantly less in the 360 J group than in the 200 J group, although total energy requirements for DCCV were similar for the two groups (662.4 J vs 762.4 J, P = 0.67 ). Conclusion: For patients with persistent AF the use of a higher initial‐energy monophasic shock of 360 J achieves a significantly greater success rate, with less skeletal muscle damage (and no cardiac muscle damage) as compared with the traditional starting energy of a 200 J DC shock.     

External cardioversion of atrial fibrillation: role of paddle position on technical efficacy and energy requirements

AIM—To define the effect of defibrillator paddle position on technical success and dc shock energy requirements of external cardioversion of atrial fibrillation.
METHODS—301 patients (mean (SD) age 62 (11) years) with stable atrial fibrillation were randomly assigned to elective external cardioversion using anterolateral paddle position (ventricular apex-right infraclavicular area; group AL (151 patients)) or anteroposterior paddle position (sternal body-angle of the left scapula; group AP (150 patients)). A step up protocol was used, delivering a 3 J/kg body weight dc shock, then a 4 J/kg shock (maximum 360 J), and finally a second 4 J/kg shock using the alternative paddle location.
RESULTS—The two groups were comparable for the all clinical variables evaluated. The cumulative percentage of patients successfully converted to sinus rhythm was 58% in group AL and 67% in group AP with low energy dc shock (NS); this rose to 76% in group AL and to 87% in group AP with high energy dc shock (p = 0.013). Thirty seven patients in group AL and 19 in group AP experienced dc shock with the alternative paddle position; atrial fibrillation persisted in 10/37 in group AL and in 10/19 in group AP. Mean dc shock energy requirements were lower for group AP patients than for group AL patients, at 383 (235) v 451 (287) J, p = 0.025. Arrhythmia duration was the only factor that affected the technical success of external cardioversion (successful: 281 patients, 80 (109) days; unsuccessful: 20 patients, 193 (229) days; p < 0.0001). The success rate was lower if atrial fibrillation persisted for > 6 months: 29 of 37 (78%) v 252 of 264 (95%); p = 0.0001.
CONCLUSIONS—An anteroposterior defibrillator paddle position is superior to an anterolateral location with regard to technical success in external cardioversion of stable atrial fibrillation, and permits lower dc shock energy requirements. Arrhythmia duration is the only clinical variable that can limit the restoration of sinus rhythm.


Keywords: atrial fibrillation; cardioversion; electric countershock     

Maintenance of Sinus Rhythm after Cardioversion of Atrial Fibrillation in Patients with Lone Atrial Fibrillation and Patients with Hypertension

Background: The success rate and prognosis of cardioversion of atrial fibrillation (AF) in patients with organic heart disease is well known. In contrast, little data exist about cardioversion success and maintenance of sinus rhythm (SR) in patients with lone AF and in patients with hypertension as the only underlying cardiovascular disease. Methods: In a prospective cardioversion registry 148 of 181 patients (81.8%) with lone AF (age 58 ± 13 years, duration of AF 7.6 ± 19 weeks) and 120 of 148 patients (81.1%) with hypertension (age 62 ± 10 years, duration of AF 6.6 ± 21 weeks) had successful cardioversion and were followed for 7.7 ± 1.9 months. Results: At follow-up, 120 patients (81.1%) with lone AF were in SR, and 18 of these patients had had repeated cardioversion during follow-up (AF total recurrence rate 31.1%). In stepwise regression analysis, the number of previous cardioversions was predictive of rhythm at follow-up (P = 0.0453). Rhythm at follow-up did not differ between patients who were or were not on antiarrhythmic drugs. At follow-up 96 patients (80%) with hypertension were in SR, and 9 of these had had repeated cardioversion during follow-up (AF total recurrence rate 27.5%). As in lone AF, the recurrence rate of AF did not differ between patients with or without antiarrhythmic drug treatment, and in multivariate regression analysis, the number of previous cardioversions was the only clinical predictor of rhythm at follow-up (P = 0.0284). Conclusions: Even in patients with such benign conditions as lone AF or hypertension as the only underlying disease, the prognosis of cardioversion in terms of maintenance of SR is poor. Future studies of rhythm control versus rate control need to include not only patients with organic heart disease but also patients with lone AF and patients with hypertension, since the long-term benefits of these two strategies remain unclear even in these subsets of patients.     

Facilitating Electrical Cardioversion of Persistant Atrial Fibrillation by Antiarrhythmic Drugs: Update on Clinical Trial Results

Results from clinical trials suggest that antiarrhythmic drugs (AD) can facilitate electrical cardioversion (EC) for persistent atrial fibrillation (AF) (duration >48 hours, no spontaneous termination) by suppression of immediate reinitiation of AF following the procedure. Class IC agents may increase the atrial defibrillation threshold (DFT) by significantly reducing the availability of Na+-channel for depolarization. In contrast, class III agents may decrease the atrial DFT by markedly prolonging atrial refractoriness. Among all AD, ibutilide and amoidarone have been shown to be most effective in enhancing the acute outcome of EC.In patients who are over 65 years of age at high risks of stroke (e.g., atherosclerotic cardiovascular disease, diabetes, hypertension, previous thromboembolism, etc.), the rhythm control strategy offers no survival advantage over the rate control strategy and frequently subjects patients to serious adverse effects of AD therapy. It can not be overemphasized that adequate anticoagulation (INR 2.0-3.0) with warfarin is needed regardless of whichever strategy is chosen unless there are contraindications. On the other hand, in patients who are under 65 years of age without structural heart disease or other risk factors of stroke, rhythm control can be the treatment of choice. Specifically, if a patient has failed EC alone or if the patient has characteristics (e.g., duration of AF >6 months, left atrium >50 mm, etc.) that EC could fail, AD may be given before the procedure to facilitate EC. In the subgroup of patients who are symptomatic with hypertrophic cardiomyopathy and severe diastolic dysfunction requiring maintenance of sinus rhythm to have sufficient ventricular function for optimization of cardiac output, an aggressive approach for rhythm control with amiodarone along with adequate anticoagulation with warfarin should be encouraged.     

Prospective Randomized Trial of External Versus Internal Transcatheter Cardioversion in Patients with Chronic Atrial Fibrillation

To evaluate the safety and long-term efficacy of internal transcatheter cardioversion, forty patients with chronic, lone atrial fibrillation were studied. The patients were randomised to internal transcatheter cardioversion or to conventional external cardioversion. In cases where the procedure was unsuccessful, cross-over to the alternate method was performed. Oral anticoagulation therapy was started three weeks prior to the procedure and was maintained for another three weeks following successful cardioversion.Sinus rhythm was restored in 16/18 patients (88%) in the internal cardioversion group, versus 9/22 patients (40%) in the external cardioversion group (p < 0.01). In addition, 8/13 (61%) patients who were crossed-over to internal cardioversion were successfully cardioverted to sinus rhythm. In contrast, both patients who were crossed-over to external cardioversion remained in atrial fibrillation.During a mean follow-up period of 23 months, 13 (39.3%) patients maintained sinus rhythm. Using the intention to treat principle, the recurrence rate was not statistically different between the two methods.It is concluded that internal cardioversion is more effective in acutely restoring sinus rhythm compared to external cardioversion. However, both methods have similar long-term recurrence rates.     

Echocardiographic Left Atrial Dimension as a Predictor of Maintaining Sinus Rhythm after Conversion of Atrial Fibrillation

ABSTRACT Twenty-six patients with lone atrial fibrillation were studied prospectively by M-mode echocardiography less than two months before and one month after cardioversion (CV). Seven patients had reverted to atrial fibrillation (AF) one month after CV. These patients (AF group) differed significantly with regard to mean left atrial dimension (LA) from the 19 patients (73%) who maintained sinus rhythm (S group) (p<0.001). Initial LA was 38.6±4.9 mm in the S group and 47.6±2.3 mm in the AF group. These values had not changed significantly in either group when measured one month after CV. The radiological heart size index showed a closely corresponding pattern. On the other hand, the mean heart size in both groups (441±100 and 544±98 ml/m² BSA, respectively) was well below the upper normal limit (700 ml/m²) that is conventionally used as exclusion criterion from CV. In conclusion, in patients with AF and only moderate cardiac enlargement on chest X-ray, the echocardiographic LA can be used as predictor of maintaining sinus rhythm for at least one month following CV.     

Low-Energy Transvenous Cardioversion of Atrial Fibrillation Using a Single Atrial Lead System

Atrial Cardioversion Using a Single Atrial Lead System. Introduction: Clinical studies have shown that electrical conversion of atrial fibrillation (AF) is feasible with transvenous catheter electrodes at low energies. We developed a single atrial lead system that allows atrial pacing, sensing, and defibrillation to improve and facilitate this new therapeutic option. Methods and Results: The lead consists of a tripolar sensing, pacing, and defibrillation system. Two defibrillation coil electrodes are positioned on a stylet-guided lead. A ring electrode located between the two coils serves as the cathode for atrial sensing and pacing. We used this lead to cardiovert patients with acute or chronic AE. The distal coil was positioned in the coronary sinus, and the proximal coil and the ring electrode in the right atrium. R wave synchronized biphasic shocks were delivered between the two coils. Atrial signal detection and pacing were performed using the proximal coil and the ring electrode. Eight patients with acute AF (38 ± 9 min) and eight patients with chronic AF (6.6 ± 5 months) were included. The fluoroscopy time for lead placement was 3.5 ± 4.3 minutes. The atrial defibrillation threshold was 2.0 ± 1.4 J for patients with acute AE and 9.2 ± 5.9 J for patients with chronic AF (P < 0.01). The signal amplitude detected was 1.7 ± 1.1 mV during AF and 4.0 ± 2.9 mV after restoration of sinus rhythm (P < 0.001). Atrial pacing was feasible at a threshold of 4.4 ± 3.3 V (0.5-msec pulse width). Conclusions: Atrial signal detection, atrial pacing, and low-energy atrial defibrillation using this single atrial lead system is feasible in various clinical settings. Tbis system might lead to a simpler, less invasive approach for internal atrial cardioversion.     

Effect of the Implantable Atrial Defibrillator on the Natural History of Atrial Fibrillation

INTRODUCTION: The purpose of our study was to evaluate the effect of repeated cardioversion with an implantable atrial defibrillator on the clinical outcome of patients with atrial fibrillation. METHODS AND RESULTS: The effects of the implantable atrial defibrillator on the total duration of atrial fibrillation, number of atrial fibrillation recurrences, and left atrial size were evaluated prospectively in 16 patients with atrial fibrillation (13 men and 3 women; mean age 58 +/- 11 years). Seven patients had no cardiovascular disease, 5 patients had hypertension, 3 patients had coronary heart disease, and 1 patient had congenital heart disease. Eight patients had paroxysmal atrial fibrillation for a mean duration of 80 +/- 61 months, and eight patients had persistent atrial fibrillation for a mean duration of 68 +/- 119 months. Except for one patient who received digoxin throughout the study, all patients received the same Class I or III antiarrhythmic agent throughout the study. The implantable atrial defibrillator successfully converted 50 (93%) of 54 spontaneous episodes of atrial fibrillation in 12 patients. During the initial 3 months of clinical follow-up, the atrial defibrillator documented 261 +/- 270 hours of atrial fibrillation compared with 126 +/- 172 hours (P = 0.01) during the subsequent 3 months. The left atrial size decreased from 4.4 +/- 0.7 cm at the time of atrial defibrillator implantation to 4.1 +/- 0.6 cm (P = 0.02) 6 months later. The number of atrial fibrillation recurrences did not change. These findings were observed in the absence of changes in drug therapy. No complications were observed. CONCLUSION: Restoration and maintenance of sinus rhythm in patients with atrial fibrillation by repeated cardioversion with an implantable atrial defibrillator was associated with a reduction in the total arrhythmia duration and a reduction in left atrial size. These results suggest that maintenance of sinus rhythm with the atrial defibrillator may reverse the remodeling process associated with atrial fibrillation.     

Evaluation of Atrial Refractoriness and Atrial Fibrillation Inducibility Immediately after Internal Cardioversion in Patients with Chronic Persistent Atrial Fibrillation

Summary. Objective: To prospectively evaluate right atrial refractoriness and sustained atrial fibrillation (AF) inducibility at programmed electrical stimulation in two groups of patient: a series of patients with chronic persistent AF, studied immediately after successful low energy internal atrial cardioversion, and a group of control patients without history of supraventricular arrhythmias.Patients: Nineteen patients with chronic persistent AF (mean AF duration 11 ± 10 months, range 2–61 months) submitted to successful internal low energy atrial cardioversion in fully conscious state and 11 control patients without history of supraventricular arrhythmias.Methods: An electrophysiological evaluation was performed to measure atrial refractoriness and AF inducibility, by delivering single atrial extrastimuli in high right atrium, at decremental coupling, during spontaneous sinus rhythm and after 8 beats at 600, 500, 400 and 330 ms cycle length. If sustained AF was induced the protocol was terminated.Results: During programmed atrial stimulation sustained AF was induced in 8 out 19 (42%) of the AF patients but in none of the control group. Atrial effective refractory period was significantly shorter in AF patients compared to controls both at basic cycle length, at 600 ms, 500 ms and 400 ms cycle length, meanwhile no statistically significant differences were found at 330 ms cycle length. An altered relationship between atrial effective refractory period and cycle length was found in AF patients compared to controls: the slope of linear correlation slope was significantly lower in AF group than in controls (0.04 ± 0.07 vs 0.17 ± 0.10, p < 0.002).Conclusions: Marked abnormalities of atrial refractoriness and of its heart rate relationship are observed after internal cardioversion of chronic persistent AF in humans and these abnormalities are associated with an high vulnerability to AF. These observations may explain the high risk of AF recurrences in the early phases following successful cardioversion. In this scenario antiarrhythmic drug therapy seems to be mandatory for reducing arrhythmia relapses.     

Biphasic versus monophasic cardioversion in shock-resistant atrial fibrillation:

Biphasic versus Monophasic Cardioversion. INTRODUCTION: Cardioversion of atrial fibrillation using monophasic transthoracic shocks occasionally is ineffective. Biphasic cardioversion requires less energy than monophasic cardioversion, but its efficacy in shock-resistant atrial fibrillation is unknown. Thus, we compared the efficacy of cardioversion using biphasic versus monophasic waveform shocks in patients with atrial fibrillation previously refractory to monophasic cardioversion. METHODS AND RESULTS: Fifty-six patients with prior failed monophasic cardioversion were randomized to either a 360-J monophasic damped sinusoidal shock or biphasic truncated exponential shocks at 150 J, followed by 200 J and then 360 J, if necessary. If either waveform failed, patients were crossed over to the other waveform. The primary endpoint was defined as the proportion of patients achieving sinus rhythm following initial randomized therapy. Stepwise multivariate logistic regression examined independent predictors of shock success, including patient age, sex, left atrial diameter, body mass index, drug therapy, and waveform. Twenty-eight patients were randomized to the biphasic shocks and 28 to the monophasic shocks. Sinus rhythm was restored in 61% of patients with biphasic versus 18% with monophasic shocks (P = 0.001). Seventy-eight percent success was achieved in patients who crossed over to the biphasic shock after failing monophasic cardioversion, whereas only 33% were successfully cardioverted with a monophasic shock after crossover from biphasic shock (P = 0.02). Overall, 69% of patients who received a biphasic shock at any point in the protocol were cardioverted successfully, compared to 21% with the monophasic shock (P < 0.0001). The type of shock was the strongest predictor of shock success (P = 0.0001) in multivariate logistic regression. CONCLUSION: An ascending sequence of 150-, 200-, and 360-J transthoracic biphasic cardioversion shocks are successful more often than a single 360-J monophasic shock. Thus, biphasic shocks should be the recommended configuration of choice for all cardioversions.     

Inducibility of Atrial Fibrillation with a Synchronized External Low Energy Shock Post-Pulmonary Vein Isolation Predicts Recurrent Atrial Fibrillation

Background: Inducibility of atrial fibrillation (AF) with burst pacing after pulmonary vein (PV) isolation is associated with recurrent AF.
Objective: This study evaluated whether an external 30 Joule (J) shock synchronized to the R wave, during the vulnerable period of atrial repolarization, is able to risk-stratify patients further for AF recurrence after PV isolation.
Methods: One hundred and sixteen consecutive patients underwent PV isolation for AF. Atrial burst pacing was performed after PV isolation. In patients without AF induced by burst pacing, a biphasic external 30 J shock synchronized to the R wave was delivered as a further test for inducible AF. Patients were followed for a mean of 16 months, and recurrent AF was defined as more than 10 sec of AF on ambulatory monitoring.
Results: AF was induced in 19 (16%) of patients with burst pacing. Eighty-one patients who were noninducible with burst pacing had a 30 J shock administered, which induced AF in 16 (20%). In follow-up, 21% of patients who were noninducible with burst pacing or low-energy shock vs 54% who were inducible with either test developed recurrent AF at one year (HR 3.18, P = 0.0004 on multivariate analysis). Among patients who were noninducible with burst pacing, 18% who were noninducible with a low-energy shock vs 60% who were inducible with shock developed recurrent AF at one year (HR = 4.63, P = 0.0006 on multivariate analysis).
Conclusion: Inducibility of AF by a 30 J shock delivered during atrial repolarization after PV isolation may predict AF recurrence. Evaluation of inducibility of AF with burst pacing and a biphasic external synchronized shock after PV isolation may help guide postprocedure management.     

Atrial Fibrillation: The Role of Atrial Defibrillation

Dual defibrillator implantation represents an emerging option to treat patients with drug refractory atrial fibrillation. Atrial antitachycardia pacing and cardioversion have been demonstrated to be highly effective in treating spontaneous tachyarrhythmias and may reduce atrial fibrillation burden by preventing atrial remodeling. Device implantation has been associated to improved quality of life and reduced hospitalization rate. Patient selection and tailored device programming are critical as regard to clinical outcome. Individual psychological profile analysis as well as underlying heart disease and atrial fibrillation clinical patterns represent the main drivers for the right strategy. Controlled studies are needed in order to define the subset of patients who can benefit more from device implantation.     

A Novel Echocardiographic Predictor of Atrial Fibrillation Recurrence: L‐Wave

Diastolic dysfunction leads to atrial fibrillation (AF) by increasing left atrial pressure and also increases recurrence rate after cardioversion. So, L‐wave, which is associated with severe diastolic dysfunction, could predict recurrent AF after cardioversion. The aim of this study was to investigate predictive value of L‐wave for AF recurrence at first month after electrical cardioversion. A total of 127 patients with persistent AF were evaluated for this study and finally 73 patients were included according to the study criteria. Echocardiographic examinations were performed for all patients before and at 24th hour after electrical cardioversion. Heart rates and rhythms were followed with electrocardiography monitor and 12‐lead ECG at first week and first month. Seventy patients achieved sinus rhythm (SR) after cardioversion and 3 patients who did not go into SR excluded from the study. Patients were divided into 2 groups according to having (group 1) or not having (group 2) L‐wave on echocardiography. Twenty‐two patients (6 men, 16 women) had L‐wave and 48 patients (19 men, 29 women) did not have L‐wave. Duration of AF was longer in group 1 as compared to group 2 (P = 0.03). Mean heart rate was lower in group 1 than in group 2 (P < 0.001). Duration of AF and presence of L‐wave were significant parameters for AF recurrence in univariate analysis, however, presence of L‐wave was the only significant parameter for AF recurrence in multivariate analysis. Ten patients in group 1 (45.5%) and 7 patients (14.6%) in group 2 (P = 0.005) had AF recurrence at the end of first month after cardioversion. L‐wave did predict AF recurrence with 59% sensitivity, 77% specificity, 45% positive predictive value, and 85% negative predictive value at 1 month. Echocardiographic L‐wave could predict the AF recurrence.     

Transient Symptomatic Severe Mitral Regurgitation after Electric Cardioversion of Atrial Fibrillation

Introduction: After electric cardioversion (EC), several cases of cardiac stunning with cardiogenic shock have been reported. Several hypotheses have been proposed, including stunning of the left ventricle (LV) and modifications in the LV conformation that could lead to severe mitral regurgitation (MR). We report 2 cases of cardiogenic shock with severe MR after EC for atrial fibrillation (AF). Case 1: A 75‐year‐old man presented with AF. A transesophageal echocardiography before the EC showed moderate MR. Shortly after successful EC, the patient developed a cardiogenic shock. The transthoracic and a transesophageal echocardiography showed severe MR. Four days later, an echocardiography showed recovery of MR to a moderate grade. Case 2: An 85‐year‐old woman with a history of percutaneous aortic valve replacement presented with AF. After EC, she developed a cardiogenic shock. The transthoracic echocardiography showed severe MR. After recovery, the echocardiography showed moderate MR. Discussion: Cardiac stunning after EC is well known and could explain the development of severe MR due to restrictive movement of leaflets. The transient character of the MR favors a functional origin with an alteration in the geometry of the mitral apparatus. Some cases of so‐called “eclipsed MR” are described in the literature, however, independently to electric shocks. Conclusion: In some patients, flash pulmonary edema seems to be due to transient severe functional MR, although the exact underlying physiopathologic mechanism remains unclear. An ischemic origin with papillary muscle dysfunction due to transient low perfusion could also be advocated.