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External defibrillation is a common treatment for the cardiac arrhythmia atrial fibrillation. Electrode placement has been shown to affect defibrillation efficacy and required energy levels. We suggest investigating the relationship between esophageal electric fields (EEFs) and atrial defibrillation thresholds to determine the feasibility of creating patient-specific electrode placements using EEFs. This study presents the design and implementation of an esophageal probe (EP) that accurately measures three-dimensional electric fields. The root-mean-square error of the EP was 1.69% as determined by measurements performed in an electrolytic tank. The EP also performed well during in vivo testing in a pig. There was a strong positive relationship between EEF2s and applied energy during defibrillation strength shocks. The EEF measurements were also repeatable, with less than 4.24% difference between repeated shocks. This is the first description of a probe designed specifically for measuring electric fields in the esophagus. [ABSTRACT FROM AUTHOR]

The aim of this study was to compare the efficacy of internal atrial defibrillation by conventional truncated exponential biphasic waveforms with and without waveform rounding (1-2 phases) and to determine optimal duration for this novel double rounded waveform. Atrial fibrillation, induced by rapid electrical stimulation, was converted by internal shocks through defibrillation catheters (lateral right atrium and coronary sinus) in anesthetised sheep. Rounding the leading edges of the conventional biphasic waveform (Ventritex HVS-02; settings 100/-50 V, 150/-70 V. and 200/-100 V; n = 8} reduced delivered peak and trough voltages, currents, and energy (by ≥ 21%, P < 0.001; for double (both phases) rounded) without decreasing cardioversion success. At 100/-50 V the efficacy of single (first phase) rounded (53 ± 13%; mean ± SEM) and double rounded (59±11%) shocks was similar to the conventional waveform (56 ± 14%). Double rounded waveform (phase durations 1-20 ms) efficacy was optimum at 6-10 ms phase duration (100% success at 10-ms phase duration; 1.52 ± 0.04 J delivered energy; n = 6). Successful cardioversion by conventional, single rounded, and double rounded biphasic waveforms (duration 6 ms each phase), conventional monophasic, rounded monophasic (duration 12 ms), and a damped sine waveform correlated strongly with peak-to-trough voltage swing within the waveform (r = 0.832; P < 0.01; n = 8). For internal atrial defibrillation, rounding both phases of the conventional biphasic waveforms, the double rounded waveform, permits similar efficacy to the conventional truncated exponential biphasic waveform at reduced peak voltage, current, and delivered energy. Optimum phase duration is 6-10 ms (tested range 1-20 ms). [ABSTRACT FROM AUTHOR]

Aim Low-energy internal cardioversion is a new electrical treatment for patients with persistent atrial fibrillation. This paper evaluates the efficacy and safety of low-energy internal cardioversion in patients with long-lasting atrial fibrillation refractory to external electrical cardioversion, and the clinical outcome of such patients. Method and Results The study population consisted of 55 patients [32 male, mean age 65±10 years, 48 (87%) with underlying heart disease] with long-lasting (mean 18±34 months) atrial fibrillation in whom external cardioversion had failed to restore sinus rhythm. Two custom-made catheters were used: one positioned in the right atrium and one in the coronary sinus or the left pulmonary artery. A standard catheter was inserted into the right ventricular apex to provide R wave synchronization. Sinus rhythm was restored in 52 patients (95%) with a mean defibrillating energy of 6.9±2.6 J (320±60 V). No complications were observed. During follow-up (mean 18±9 months), 16 patients (31%) suffered early recurrence (≤1 week) of atrial fibrillation and 20 patients (38%) had late recurrence (>1 week, mean 3.5±3.6 months) of atrial fibrillation. Six patients with a late recurrence again underwent cardioversion and five of these maintained sinus rhythm. Therefore, a total of 21/52 patients (40%) were in sinus rhythm at the end of follow-up. No clinical difference was found between patients with and without recurrences. Conclusions Low-energy internal cardioversion is a useful means of restoring sinus rhythm in patients with long-lasting atrial fibrillation refractory to external electrical cardioversion. More than one-third of patients maintained sinus rhythm during long-term follow-up. [ABSTRACT FROM PUBLISHER]

We report the long-term follow-up of a right side only catheter ablation approach for paroxysmal AF. Eighteen patients with AE refractory to drugs entered the study. Ablation was attempted in the right atrium only by creating linear lesions based on a specific design including from two to four linear lesions. Induction of AF was attempted before ablation and after placement of the lesions. A septal lesion was performed in nine patients. In ten patients atrial defibrillation thresholds (ADETs) before ablation and following creation of the linear lesions were compared. After a mean follow-up of 22 ±11 months, seven patients had recurrence of AE, and another nine patients experienced atrial flutter or atrial tachycardia. Eive patients remained in sinus rhythm without medications and four required the use of drugs. Three patients had sporadic AF and six were in chronic AE. The recurrence rate was similar in patients with and without the septal lesion. However, a cure with right side ablation appeared to be predicted by the presence of disorganized and earlier activity in the high right atrium and crista terminalis. Linear lesions in the right atrium were associated with a lower ADET (pre 2.6 ± 04 J vs post 1.7 ± 0.6 J). In conclusion, in a small number of patients, control of AE can be obtained with a right side only approach. Gertain activation patterns may identify patients suitable to this approach. No specific lesion pattern appeared more effective. Right atrial linear lesions resulted in lower ADET. [ABSTRACT FROM AUTHOR]

Aims Conventional external cardioversion remains the technique of choice for restoration of sinus rhythm in patients with chronic atrial fibrillation (AF). Recent reports have suggested that internal low-energy cardioversion is efficient and safe in terminating AF in patients with failed external cardioversion. Methods and Results In 20 of 118 consecutive patients with spontaneous chronic AF (>7/days), who underwent low-energy cardioversion, one or more attempts at restoring sinus rhythm with external cardioversion had failed. Low-energy internal cardioversion was performed under light sedation. Shocks were delivered (using an external custom defibrillator) between two nonapolar catheters positioned in the right atrium (cathode) and in the coronary sinus (anode). Heart disease was present in 12 and absent in eight patients (‘lone’ atrial fibrillation). Atrial fibrillation was established for a period ranging from 12 days to 53 months. Low-energy internal cardioversion restored sinus rhythm in 15 of the 20 patients (75%) with a mean energy of 4·5 ± 1·2 J, a mean conversion voltage of 355 ± 53 V and a mean impedance of 63 ± 8 ohms. No complications were observed. With a mean follow-up of 6 ± 7 months, 11 patients (73%) were in stable sinus rhythm. Conclusions This study provides evidence in support of low-energy internal cardioversion as a valuable therapeutic option in patients in whom conventional external cardioversion failed. This technique is safe and does not require general anaesthesia. [ABSTRACT FROM PUBLISHER]

Introduction: High atrial defibrillation energy requirements (ADER) in patients with chronic atrial fibrillation (AF) may limit the acceptance of transvenous atrial defibrillation. We evaluated an optimized defibrillation electrode configuration that could help to reduce the ADER in patients with AF. Methods and Results: We tested ten different configurations in nine dogs with AF (3.33 ± 2.92 days) induced by rapid atrial pacing. The configurations were: right atrial (RA) appendage as anode and coronary sinus (CS) as cathode; RA and innominate vein (I) as anode to CS (cathode); RA-CS (anode) to I (cathode); I-CS (anode) to RA (cathode); RA and left lateral subcutaneous patch (P) as anode to CS (cathode); RA-CS (anode) to P (cathode); P-CS (anode) to RA (cathode); superior vena cava (SVC) and CS (anode) to RA (cathode); RA-CS (anode) to SVC (cathode); and RA-SVC (anode) to CS (cathode). ADER was defined as the voltage needed to defibrillate the atria in 10% to 90% of 20 consecutive shocks. Three lead systems had ADER lower than the RA (anode) to CS (cathode) configuration, which required a mean of 143 ± 58 volts. These three were: RA-SVC (anode) to CS (cathode) 103 ± 29 V; I-CS (anode) to RA (cathode) 129 ± 39 V; and P-CS (anode) to RA (cathode) 130 ± 38 V. The remaining configurations had ADER higher than the RA (anode) to CS (cathode) configuration. Conclusion: Adding an additional shocking electrode may reduce ADER when compared with the RA (anode) to CS (cathode) configuration. This concept could be incorporated into future implantable atrial defibrillators or used for refractory patients undergoing temporary transvenous cardioversion. [ABSTRACT FROM AUTHOR]

Automatic Atrial Defibrillator. Atrial fibrillation is a common arrhythmia, accounting for more consumption of medical resources than any other arrhythmia. The impact of the disease results from the combination of a loss of atrial contraction, and atrial control over cardiac rate. Studies in animals demonstrated the basic feasibility of atrial defibrillation using electrodes passed intravenously. Subsequent studies in patients confirmed that low-energy shocks were effective in converting atrial fibrillation and were safe if delivered synchronous to the R wave in the absence of a short preceding RR interval. Preliminary experience suggests that a small implanted device might provide beneficial therapy for patients with recurring episodes of persistent, drug-refractory, atrial fibrillation. [ABSTRACT FROM AUTHOR]

Introduction: The feasibility of entrainment of macroreentrant atrial arrhythmias such as atrial flutter is well documented. Recently, it has been shown that regional entrainment of atrial fibrillation is feasible in dogs. Methods and Results: Three patients with chronic atrial fibrillation underwent electrophysiologic evaluation with attempted entrainment of atrial fibrillation prior to successful endocardial atrial defibrillation. A 16-pole catheter was positioned in the trabeculated right atrium, and in two patients a multipolar catheter was positioned along the septum. In addition, two large surface area defibrillation catheters were placed, one in the lateral right atrium and one in the coronary sinus. Regional entrainment was attempted in the right atrium and from the catheter in the coronary sinus. Entrainment was achieved in the right atrium in all three patients over a cycle length range of 28, 17, and 13 msec, respectively, and over a radius of atrial tissue of at least 2.8 cm. Regional entrainment was demonstrated from the coronary sinus in one patient during simultaneous right atrial entrainment. Termination of atrial fibrillation during entrainment was not observed. Conclusion: Regional entrainment of chronic atrial fibrillation is feasible in humans. [ABSTRACT FROM AUTHOR]

Due to the limited efficacy of antiarrhythmic drugs for atrial fibrillation, several nonpharmacologic therapeutic options have evolved. One of these is an implantable atrial defibrillator. Recent studies have shown that internal atrial defibrillation is feasible with relatively low energies. To date, the optimal electrode configuration involves large surface area catheters in the right atrium and coronary sinus. In humans, atrial defibrillation can generally be achieved with < 2 J using this electrode configuration and a biphasic shock waveform. For shocks lt; 5 J, there is no significant pathological damage to the atria or coronary sinus. Further investigation is needed to guarantee that atrial defibrillation shocks do not provoke ventricular arrhythmias. Preliminary data suggest that atrial defibrillation shocks synchronized to R waves that are not closely coupled are safe. In addition, the shocks are well tolerated if the shock energy is < 1.5 J. With additional studies to confirm the safety of implantable atrial defibrillators, further reduce shock energy, and improve patient tolerance, an implantable atrial defibrillator can become an acceptable therapy for patients with symptomatic, paroxysmal atrial fibrillation. [ABSTRACT FROM AUTHOR]

Spontaneous reinitiation of atrial fibrillation (AF) has not been systematically looked at in patients undergoing transvenous AF. This study involved 11 patients, the mean age 60 ± 8 years, 3 male and 8 female, in whom transvenous a trial defibrillation successfully converted AF to sinus rhythm. Eight patients had paroxysmal AF and three patients had chronic persistent AF for 4 weeks or more. Four patients were taking antiarrhythmic medications at the time of testing. Multipolar transvenous catheters were positioned inside the coronary sinus, right atrium, and the right ventricle. A trial defibrillation testing was performed using the METRIX atrial defibrillation system in nine patients and the Ventritex HVSO2 in the remaining two patients. A total of 64 therapeutic shocks (range 3-11) were delivered in the ii patients, and 31 of these successfully converted AF to sinus rhythm. In four patients spontaneous AF was reinitiated following 12 successful transvenous atrial defibrillation episodes. The mean time to reinitiation of AF following shock delivery and restoration of sinus rhythm was 8.26 ± 5.25 seconds, range 1.8-19.9 seconds. All 12 episodes of spontaneous AF were preceded by a spontaneous premature atrial complex. The coupling interval of the premature atrial complexes was 443 ± 43 ms, range 390-510 ms. None of the patients taking antiarrhythmic medications or those demonstrating no premature atrial complexes had spontaneous reinitiation of AF. In conclusion, spontaneous reinitiation of AF can occur in a significant proportion of patients with AF undergoing transvenous atrial defibrillation. This phenomenon is preceded by the occurrence of a trial premature complex. Findings of this study may have significant clinical implications. [ABSTRACT FROM AUTHOR]

We postulated that reducing peak leading edge shock voltage and its rate of rise (waveform rounding) would reduce energy requirements for cardioversion of AF and AFl, and may therefore reduce patient discomfort. Transvenous defibrillating catheters (In-Control Inc.) were placed in the RAA (active fixation) and the CS of six anesthetized sheep. AF or AFl was induced by electrical stimulation (100 Hz, 2 V; Grass stimulator). A standard trapezoidal biphasic (S) waveform (3-ms duration each phase) was compared with a similar waveform that had the first phase rounded (H). Cardioversion was attempted after 30 seconds of arrhythmia, using a Ventritex HVS-O2 defibrillator modified to allow waveform rounding. Each waveform was randomly tested several times at 100-, 150-. and 200-V leading edges, and percentage cardioversion success calculated. Shock energy was calculated from delivered current and voltage using Flukeview (Fluke, Inc.) software. At 100-V leading edge R (64% success) and S (59%), shocks were similarly efficacious (P = 0.37). However. R delivered less current, voltage, and energy than the comparable S shock (means 1.30 A, 65.0 V, 0.33 f B vs 1.92 A, 94.2 V, 0.47 JS;P = 0.0001). Both waveforms were equally successful at 150 V (88% vs 100%; P = NS) and 200 V (100% vs 100%), but again R delivered less current, voltage, and energy (2.05 A, 102.5 V, 0.82 J R vs 2.78 A, 142.3 V. 1.11 f S at 150 V: 2.76 A, 141.2 V, 1.56 J R vs 3.77 A, 189.4 V. 2.03 J S at 200 V; both P = 0.0001). No arrhythmic or other complications occurred in the 174 shocks delivered. Waveform rounding reduces delivered peak voltage, current, and energy without reducing defibrillation efficacy. To determine if these changes are associated with a reduction in discomfort, patients with AF are currently being cardioverted with these waveforms during electrophysiological studies. [ABSTRACT FROM AUTHOR]

Introduction: This prospective observational study aimed to investigate the incidence of symptomatic and silent cerebral thromboembolisms after balloon-based ablation of paroxysmal atrial fibrillation (PAF) in patients receiving periprocedural oral anticoagulation with direct oral anticoagulants (DOACs), and compare that between cryoballoon ablation (CBA) and HotBalloon ablation (HBA). Methods: We enrolled 106 consecutive patients (65 ± 10 years; 86 males) undergoing balloon-based pulmonary vein isolation (PVI) of PAF and brain magnetic resonance (MR) imaging on the next day after the ablation procedure (CBA, n = 54; HBA, n = 52). The DOACs were uninterrupted in 47 patients (CBA, n = 21; HBA, n = 26) throughout the periprocedural period, and interrupted in 59 patients (CBA, n = 33; HBA, n = 26) on the day of the procedure. Intravenous heparin was infused to maintain an activated clotting time (ACT) of 300 - 400 seconds during the procedure. Results: No symptomatic thromboembolisms occurred in this series. Silent cerebral ischemic lesions (SCILs) were detected on MR imaging in 20 patients (18.9%), and the incidence of SCILs did not significantly differ between the CBA and HBA groups (24.1% vs. 13.5%; P = 0.163). The CBA group included fewer patients requiring touch-up ablation than the HBA group (18.9% vs. 36.5%; P = 0.043), while the age, CHA2DS2-VASc score, left atrial size, total procedure time, intraprocedural ACT value, and percentage of periprocedural DOAC continuation did not significantly differ between the two groups. According to the multivariable logistic regression analysis, an older age was an independent positive predictor of SCILs after the balloon-based PVI (odds ratio 1.089; 95% confidence interval, 1.014 - 1.169; P = 0.019), but neither the balloon catheter type (CB or HB) nor periprocedural continuation or discontinuation of the DOACs were significant predictors. The incidence of major and minor bleeding complications was comparable between the CBA and HBA groups (1.9% vs. 0%, P = 0.509; 9.3% vs. 5.8%, P = 0.379). Conclusions: Both the CBA and HBA of PAF revealed a similar incidence of post-ablation cerebral thromboembolisms. Elderly patients may be at a risk of SCILs after a balloon-based PVI with periprocedural DOAC treatment. [ABSTRACT FROM AUTHOR]

Introduction: There is substantial evidence of impaired health related quality of life (HRQoL) in patients with paroxysmal atrial fibrillation (PAF). Few studies have evaluated self-management programs aiming to decrease symptoms and improve HRQoL, in patients with PAF. Yoga has been shown to improve HRQoL, decrease blood pressure, heart rate as well as NT-ProBNP, among patients with heart failure and hypertension. Hypothesis: Yoga improves HRQoL, decrease blood pressure, heart rate as well as NT-ProBNP in patients with PAF. Methods: In this randomized controlled study, with stratification of gender, 132 patients with symptomatic PAF were randomized to yoga-(n=44), relaxation- (n=44) or control group (n=44). The yoga group performed MediYoga once a week during 12 weeks. The relaxation group listened to relaxing music, specifically used in other stress relief programs, once a week for 12 weeks. The control group only received standard treatment. HRQoL, blood pressure, heart rate as well as NT-ProBNP were assessed at baseline and at the end of the study (12 (+2) weeks). ASTA (disease specific form) and SF-36 (general form) were used to measure HRQoL. Results: At the end of the study there was a significant improvement of HRQoL parameters SF-36 in bodily pain, general health, social function, mental health and in dimension MCS within the yoga group (p = 0.014, p = 0.037, p = 0.029, p = 0.030, p = 0.019). There were no differences between other parameters in SF-36 or among the ASTA parameters. There were no differences in heart rate and NTPro-BNP between the groups. Systolic blood pressure decreased significantly in the yoga group (134±18 to 127±13) compared to the control group (126±17 to 127±15), p = 0.041, but no difference was seen compared to the relaxation group (131±17 to 125±12). Moreover, diastolic blood pressure decreased significantly in the yoga group (79±9 to 74 ±9) compared to the control group (76±9 to 79±8), p = 0.005, but no difference was seen compared to the relaxation group (76±9 to 77±8). Conclusions: MediYoga affects HRQoL positively and decrease blood pressure in patients with PAF. MediYoga may be used as a self-management program among patients with PAF. [ABSTRACT FROM AUTHOR]

Introduction: The evolution of defibrillation waveforms has dramatically progressed over time. Monophasic waveform became the standard waveform used in most defibrillators until the 1980s, and were progressively replaced after year 2000 by newer biphasic waveforms with different patterns: initially the biphasic rectilinear waveform, then biphasic truncated exponential (BTE) waveform (with high or low energy), and pulsed energy BTE. Hypothesis: Our aim was to collect data regarding the efficacy of low, high and pulsed energy of biphasic truncated exponential waveforms, in cardioversion for atrial fibrillation through a systematic research on the literature. Methods: A systematic research on PubMed and Science Direct, with key words (cardioversion atrial fibrillation biphasic waveform) and filters (title/abstract, clinical trial, English) provided 38 articles. A further selection was made by their title and abstract leading to a final selection of 6 articles. Efficacy was defined as return to sinus rhythm. Results: The figure provides cumulative energy dose-response curves for different BTE waveforms: 4 High Energy (HE) 360J, 3 Low Energy (LE) 200J and 3 Pulsed Energy 200J. Legend of the figure indicates for each study the year of publication, the recruitment period, the sample size, the delay between cardioversion and observed rhythm, and the percentage of patients in atrial flutter when appropriate. Although the studies present major disparities, the dose-response curves concentrate within 85% and 95% efficacy and 300 and 500 Joules cumulative energy. Three curves are significantly deviating from the seven others. The low efficiency due to a defective device and the high efficiencies associated to a short outcome's reading at 5s instead of 1min. Conclusion: Dose-response curves of high, low or pulsed energy of biphasic truncated exponential are rather similar, with efficacy ranging between 85% and 95% for cumulative energy between 300 and 500 Joules. [ABSTRACT FROM AUTHOR]

Introduction: Electrical cardioversion (CV) for atrial fibrillation (AF) has been occasionally reported to cause thromboembolic events due to the transient left atrial appendage (LAA) dysfunction, which is called as LAA-stunning. However, predictive factor for the occurrence of LAA-stunning after CV has not been well studied. We investigated the risk factors of LAA-stunning after CV in patients with AF. Hypothesis: Clinical factors can predict for LAA-stunning. Methods: One hundred thirty-four patients who underwent catheter ablation (CA) for non-paroxysmal AF were studied (103 males, 68±9 years). Internal-CV was performed in all patients, and LAA emptying fraction (LAA-EF) was assessed using LAA angiography before and just after internal-CV. LAA-stunning was defined as 10% reduction of LAA-EF after CV. Patients with LAA akinesis (defined as LAA-EF <10%) in LAA angiography before CV excluded. Results: LAA-stunning was observed in 45/134 patients (34%). Patients with LAA-stunning had larger left atrial (LA) volume (p=0.001), longer AF duration (p=0.003), elevated brain natriuretic peptide (BNP) (p=0.001), not taking calcium blocker (p=0.022), and higher E wave (p=0.007). On multivariate analysis, elevated BNP (p=0.038, OR 1.041 for each 1 pg/mL increase in BNP, 95%CI 1.001-1.009) and long AF duration (p=0.015, OR 1.033 for each 1-month prolong in AF lasting duration, 95%CI 1.006-1.073) were associated with LAA-stunning. In addition, all patients were divided into four groups based on the combination between BNP and AF lasting duration. Prevalence rate of LAA-stunning in patients with high BNP (> 58.2 pg/mL) and long-lasting AF (>14 days) was 55.6%. (Figure) Conclusion: The more powerful anticoagulation therapy might be needed post electrical cardioversion in patients with elevated BNP and long AF duration. [ABSTRACT FROM AUTHOR]

Background: Prior proteomics analyses on the risk of incident AF screened for limited numbers of proteins. We report the use of single-stranded DNA-based aptamers as affinity agents to screen for 1373 proteins and identify novel biomarkers that are associated with risk of incident AF in a prospective cohort study. Methods: We studied the Framingham Heart Study Offspring Cohort participants who attended exam 5 from 1991 to 1995. We ascertained AF or atrial flutter on ECG at routine research visits and from clinical records review. Participants with prevalent AF (n=28) were excluded. Plasma protein levels were measured by the SOMAscan proteomic profiling platform, which uses single-stranded DNA-based aptamers to capture conformational protein epitopes. We used robust inference for the Cox proportional hazards models to relate each protein level with incident AF. In addition, we examined the association between AF-related genetic loci and circulating protein levels. Results: Our study included 1,885 participants (mean age 55±10 years, 54% women) who had proteomic profiles measured. A total of 349 participants developed AF during follow-up (mean follow-up 18.3 years). We found 8 proteins that were significantly associated with incident AF after adjusting for age, sex, and technical covariates and correction for multiple testing (p <0.05/1373=3.64x10-5). After additional adjustments for clinical factors (smoking, height, weight, systolic and diastolic blood pressures, antihypertensive treatment, diabetes mellitus, prevalent myocardial infarction, prevalent heart failure) associated with AF, ADAMTS13 and NT-proBNP (HR, 0.78; 95% CI, 0.70-0.88; and 1.44; 95% CI, 1.22-1.70, respectively; p <3.64x10-5 for both) remained significantly associated with the risk of incident AF. None of the 8 proteins were associated AF-related genetic loci previously identified in recent genome-wide association studies. Conclusions: In our proteomic analysis of longitudinal community-based sample, we identified 8 proteins associated with risk of incident AF after adjustment for age and sex. Future studies are needed to identify whether they are mechanistically related to AF development and whether they are clinically useful for identification of future AF risk. [ABSTRACT FROM AUTHOR]