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BACKGROUND Previous studies have raised serious concerns on cardiovascular safety of widely prescribed nonsteroidal anti-inflammatory drugs (NSAIDs). Therefore, the aim of this study was to characterize the electrophysiological effects of certain NSAIDs in an established whole heart model of proarrhythmia. METHODS AND RESULTS Thirty-eight hearts of New Zealand White rabbits were harvested and retrogradely perfused employing a Langendorff setup, and electrophysiology studies were performed to investigate action potential duration at 90% of repolarization (APD90 ), QT intervals, and effective refractory period (ERP). After generating baseline data, hearts were perfused with ibuprofen (Group 1, n = 12; 10 and 30 μM), indomethacin (Group 2, n = 13; 10 and 20 μM) and diclofenac (Group 3, n = 13; 10 and 20 μM), respectively, and the pacing protocols were repeated for each concentration. In all groups, perfusion with the NSAIDs resulted in a significant and reproducible shortening of APD90 and QT interval. In all groups, the arrhythmia susceptibility was significantly raised as occurrence of monomorphic ventricular tachycardia under programmed ventricular stimulation was significantly increased under perfusion with ibuprofen, indomethacin and diclofenac in all concentrations. CONCLUSION The perfusion with ibuprofen, indomethacin and diclofenac in commonly used doses raised the arrhythmia susceptibility in an established rabbit whole-heart model while APD shortening and shortened ERP seem to be crucial for arrhythmogenesis.

1. Introduction: Pulmonary vein isolation (PVI) is an established procedure used to achieve rhythm control in atrial fibrillation (AF). In obese patients (pts), in whom AF occurs more frequently, a reduced effectiveness of PVI has been observed. Therefore, this study’s aim was to compare the long-term efficacy of PVI between obese and non-obese patients. 2. Methods: We enrolled 111 consecutive pts with a body mass index (BMI) of >30 kg/m2 undergoing PVI from our large registry. Procedural data and outcomes were compared with a matched group of 115 non-obese PVI pts and the long-term outcomes were analyzed. 3. Results: Overall follow-up duration was 314 patient-years in the obese and 378 patient-years in the non-obese group. The follow-up rate was 71% in the obese and 76% in the non-obese group. In both groups, their AF-characteristics did not differ significantly, while known risk factors were significantly more prevalent in the obese group. Procedural characteristics were similar in both groups. During follow-up, the obese pts demonstrated significant weight loss compared to the non-obese pts, while at the same time, the overall recurrence rate during follow-up did not differ significantly between both groups (obese: 39.2% and non-obese: 43.7%). PVI related and long-term complications were comparable between both groups. In the univariate analysis, obesity was not found to be associated with an increased AF recurrence risk. 4. Conclusion: These real-life data demonstrate that obese pts may not show higher AF recurrence rates after PVI compared to pts with normal body weight. Furthermore, PVI was found to be safe and effective in obese patients; thus, a BMI alone may not be a criterion for refusal of PVI.

The long-QT syndrome (LQTS) is the most common ion channelopathy, typically presenting with a prolonged QT interval and clinical symptoms such as syncope or sudden cardiac death. Patients may present with a concealed phenotype making the diagnosis challenging. Correctly diagnosing at-risk patients is pivotal to starting early preventive treatment.Identification of congenital and often concealed LQTS by utilizing novel deep learning network architectures, which are specifically designed for multichannel time series and therefore particularly suitable for ECG data.A retrospective artificial intelligence (AI)-based analysis was performed using a 12-lead ECG of genetically confirmed LQTS (In this study, the XceptionTime model outperformed the FCN model for LQTS patients with even better results than in prior studies. Even when a patient cohort with cardiovascular comorbidities is used. AI-based ECG analysis is a promising step for correct LQTS patient identification, especially if common diagnostic measures might be misleading.

Atrioventricular nodal reentry tachycardia (AVNRT) is the most common regular supraventricular tachycardia (SVT). Slow pathway modification (SPM) is the accepted first line treatment with reported success rates around 95%. Information regarding possible predictors of AVNRT recurrence is scarce.Out of 4170 consecutive patients with SPM in our department from 1993-2018, we identified 78 patients (1.9%) receiving > 1 SPM (69% female, median age 50 years) with a recurrence of AVNRT after a successful SPM. We matched these patients for age, gender and number of radiofrequency applications during first SPM with 78 patients who received one successful SPM in our center without AVNRT recurrence. Both groups were analyzed for possible predictors of a recurrence of AVNRT during long-term follow-up. The recurrence group contained a significantly lower proportion of patients with an occurrence of junctional beats during SPM (69% versus 89%, P = 0.006). Moreover, significantly more cases of previously diagnosed atrial fibrillation/tachycardia (AF/AT; 21% versus 5%, P = 0.007) and inducible AF/AT during electrophysiology study (23% versus 6%, P = 0.006) were present in the recurrence group. While more than half of patients had a recurrence within the first year, in 20% symptoms reappeared ≥ 4 years after ablation.In a small percentage of patients, AVNRT recurs after an initially successful ablation. Interestingly, these patients had significantly fewer junctional beats during ablation and a higher rate of other (inducible) arrhythmias. AVNRT recurrence spanned a considerable timeframe and should remain a differential diagnosis, even years after ablation.

Several case reports suggest QT prolongation leading to ventricular arrhythmias with fatal outcome after intoxication with the μ-opioid receptor agonist and anti-diarrheal agent loperamide. The number of cases of loperamide misuse are growing due to its potential stimulating effects. Loperamide intoxications can be treated by naloxone. However, previous reports described a further QT prolongation associated with naloxone administration. Therefore, the aim of this study was to investigate the effects of loperamide and naloxone on the cardiac electrophysiology in a sensitive whole-heart model. Twenty-six hearts of New Zealand White rabbits were retrogradely perfused in a modified Langendorff apparatus. Monophasic action potentials were recorded by endo- and epicardially positioned catheters. Hearts were stimulated at different cycle lengths, thereby obtaining action potential duration at 90% of repolarization (APD90) and QT intervals. Programmed ventricular stimulation was used to assess ventricular vulnerability. Fourteen hearts were perfused with ascending concentrations of loperamide (0.2 μM, 0.35 μM, and 0.5 μM) after obtaining baseline data. Another 12 hearts were treated with naloxone (0.1 μM, 0.5 μM, 2 μM). Loperamide led to a significant increase in QT interval, APD90, and ventricular tachycardia (VT) episodes. In contrast, naloxone led to a decrease in QT interval and APD90. Accordingly, the number of VT episodes was unaltered. To the best of our knowledge, this is the first experimental study that investigated the effects of loperamide and naloxone in a whole-heart model. Loperamide led to a significant increase in action potential duration and QT interval. Simultaneously, the number of ventricular tachycardias was significantly increased. In contrast, naloxone led to a shortening of the action potential duration without altering arrhythmia susceptibility.

Several case reports have suggested an increased risk of sudden cardiac death due to energy drinks. Therefore, the purpose of this study was to assess acute electrophysiologic effects of caffeine and taurine, two of the main ingredients of energy drinks, in an experimental whole-heart model.Twenty-five rabbit hearts were excised, retrogradely perfused, and assigned to two groups. Hearts were perfused with caffeine (2, 10, and 50 µM) or taurine (2, 10, and 50 µM) after generating baseline data. Eight monophasic action potentials and electrocardiography recordings showed a significant abbreviation of action potential duration (APDIn this experimental whole-heart study, treatment with caffeine and taurine provoked ventricular arrhythmias. The underlying mechanism was an abbreviation of cardiac repolarizations and effective refractory periods that may facilitate re-entry and thereby provokes arrhythmias. These findings help to understand the potentially hazardous and fatal outcomes after intoxication with energy drinks.

Atrial fibrillation and other atrial tachyarrhythmias are increasing with age and concomitant morbidity. First options in symptomatic patients are drug treatment and catheter ablation. Nevertheless, a considerable number of patients suffer from refractory atrial tachyarrhythmias despite treatment. Atrioventricular node ablation (AVNA) may be helpful in many of these patients. Therefore, we investigated AVNA patients with a long-term follow-up. We enrolled 82 patients with a follow-up longer than 1 year receiving AVNA for drug- and ablation-resistant atrial tachyarrhythmias (AA) in a retrospective manner. Mean follow-up duration was 48 ± 24 months. 50% of the patients initially received AVNA to optimize biventricular pacing in cardiac resynchronization therapy, the other 50% because of refractory symptomatic tachyarrhythmias. Persistent AV block was achieved in every patient. Symptom relief and patient satisfaction were high during follow-up. Due to system upgrades there were 63% of patients with a biventricular system during follow-up. In these patients, left-ventricular ejection fraction (LV-EF) increased by 7% (42-49%) after ablation. AVNA is effective in increasing biventricular pacing as well as for symptom relief in patients with refractory atrial tachyarrhythmias. AVNA should be considered as a valuable option in patients with refractory atrial tachyarrhythmias lacking other treatment options.

Vorhofflimmern (VHF) ist die mit Abstand haufigste mit Infektionen bzw. Sepsis assoziierte Herzrhythmusstorung. Neu aufgetretenes VHF im Rahmen einer Infektion ist mit einer Verschlechterung der Prognose sowohl fur das Akutereignis als auch fur die langfristige Prognose der Patienten assoziiert. Das Risiko, VHF im Rahmen einer Infektion zu entwickeln, hangt sowohl von allgemeinen (z. B. Alter, strukturelle Herzerkrankung) als auch von infektionsspezifischen Faktoren (z. B. Schwere der Sepsis, Katecholamintherapie) ab. Fur die Therapie von infektassoziiertem VHF gibt es bisher keine Leitlinienempfehlungen bzw. kaum prospektive Daten. Die Verwendung von β‑Blockern scheint sowohl zur Prophylaxe als auch zur Frequenzkontrolle selbst bei katecholaminpflichtigen Patienten vertretbar zu sein. Zur spezifischen antiarrhythmischen Therapie ist neben dem bisher uberwiegend verwendeten Amiodaron auch der Einsatz von Klasse-I-Antiarrhythmika denkbar. Neu aufgetretenes VHF im Rahmen von Infektionen wurde lange als spezifische Entitat mit niedrigem Rezidivrisiko betrachtet, sodass nur ein geringer Teil der Patienten im Verlauf eine effektive Antikoagulation erhalten hat. Daten aus groseren, retrospektiven Studien legen allerdings deutlich hohere Rezidivraten nahe, sodass die Frage, inwieweit dieses Patientenkollektiv von einer langfristigen effektiven Antikoagulation bzw. einem erweiterten Arrhythmie-Monitoring profitiert, Gegenstand zukunftiger Untersuchungen sein sollte.

The subcutaneous ICD (S-ICD™) is an important advance in device therapy for the prevention of sudden cardiac death (SCD). Although current guidelines recommend S-ICD™ use, long-term data are still limited, especially in subgroups. Among several cardiac diseases that prone to SCD, coronary artery disease (CAD) carries several peculiarities that may hamper S-ICD™ therapy in this cohort. CAD can lead to an ischemic cardiomyopathy (ICM) with a reduced left-ventricular ejection fraction (LVEF) and bundle branch blocks, which can be difficult for ICD sensing and discrimination of arrhythmia. CAD is mainly driven by risk factors such as diabetes mellitus, which put these patients at an elevated risk for infectious complications of cardiac devices. Furthermore, in ICM myocardial scars are frequent and are a potential substrate for ventricular tachycardia, which may be accessible for antitachycardia pacing. At the moment, it remains unclear if there is a value of S-ICD™ therapy in this subgroup. Therefore, this study analysed patients with CAD. All S-ICD™ patients with CAD as the main indication for ICD implantation (n = 45 patients) in our large-scaled single-center S-ICD™ registry (n = 249 patients) were included in this study. Baseline characteristics, appropriate and inappropriate shocks, and complications were documented in a mean follow-up of 22.5 ± 8.3 months. Primary prevention of SCD was the indication for implantation of an S-ICD™ in 28 patients (62%). Of all 45 patients with an overall mean age of 58.1 ± 11.4 years, 40 were male (88%). The mean LVEF was 37.7 ± 12.6%. Three episodes of ventricular arrhythmia (one monomorphic, one polymorphic, one ventricular fibrillation) were adequately terminated in three patients (7%). In only one patient, oversensing resulting in an inappropriate shock was observed, which could be managed by changing the sensing vector. 15 of the examined 45 patients previously had a transvenous ICD, which was explanted due to system-related infections. In only two patients, S-ICD™ was changed to transvenous ICD because of the need of antibradycardia stimulation. There were no S-ICD™ system-related infections. The S-ICD™ seems to be a valuable option for the prevention of SCD in CAD patients. Patients with systemic infections of a transvenous ICD and, therefore, a need for an alternative might benefit from the absence of intracardiac leads as the S-ICD™ is safe and works flawlessly in these patients. Inadequate shock delivery was very rare, while every episode of ventricular arrhythmia was terminated by the first shock.

A post hoc analysis of the PALLAS trial suggested life-threatening interactions of digitalis and dronedarone. Thus, there is concern about an interplay between digitalis and other drugs that influence cardiac electrophysiology. We therefore investigated the interaction between digitalis and flecainide or ranolazine. Twenty-five rabbit hearts were Langendorff-perfused and treated with flecainide (2 µM, 12 hearts) or ranolazine (10 µM, 13 hearts). Infusion of flecainide prolonged mean action potential duration [APD90, from 153 ms (interquartile range (IQR): 29.7 ms) to 159 ms (IQR: 24.9 ms, p = 0.04)] and effective refractory period [ERP, 170 ms (IQR: 40 ms) vs. 200 ms (IQR: 32.5 ms, p

Atrioventricular nodal reentry tachycardia (AVNRT) is the most common regular supraventricular tachycardia (SVT). Slow pathway modification (SPM) is the accepted first line treatment with reported success rates around 95%. Information regarding possible predictors of AVNRT recurrence is scarce.Out of 4170 consecutive patients with SPM in our department from 1993-2018, we identified 78 patients (1.9%) receiving1 SPM (69% female, median age 50 years) with a recurrence of AVNRT after a successful SPM. We matched these patients for age, gender and number of radiofrequency applications during first SPM with 78 patients who received one successful SPM in our center without AVNRT recurrence. Both groups were analyzed for possible predictors of a recurrence of AVNRT during long-term follow-up. The recurrence group contained a significantly lower proportion of patients with an occurrence of junctional beats during SPM (69% versus 89%, P = 0.006). Moreover, significantly more cases of previously diagnosed atrial fibrillation/tachycardia (AF/AT; 21% versus 5%, P = 0.007) and inducible AF/AT during electrophysiology study (23% versus 6%, P = 0.006) were present in the recurrence group. While more than half of patients had a recurrence within the first year, in 20% symptoms reappeared ≥ 4 years after ablation.In a small percentage of patients, AVNRT recurs after an initially successful ablation. Interestingly, these patients had significantly fewer junctional beats during ablation and a higher rate of other (inducible) arrhythmias. AVNRT recurrence spanned a considerable timeframe and should remain a differential diagnosis, even years after ablation.

The aim of this study was to investigate the effects of a combination of ranolazine with different selective inhibitors of the Na+/Ca2+-exchanger (NCX) in an established experimental model of atrial fibrillation (AF). Eighteen hearts of New Zealand white rabbits were retrogradely perfused. Atrial catheters were used to record monophasic action potentials (aPRR). Hearts were paced at three different cycle lengths. Thereby, atrial action potential durations (aAPD90), atrial effective refractory periods (aERP) and atrial post-repolarization refractoriness were obtained. Isoproterenol and acetylcholine were employed to increase the occurrence of AF. Thereafter, the hearts were assigned to two groups (n = 9 each group) and additionally perfused with a combination of 10 &micro, M ranolazine and 1 &micro, M of the selective NCX-inhibitor ORM-10103 (group A: Rano-ORM) or 10 &micro, M of another NCX-inhibitor, SEA0400 (group B: Rano-SEA). The infusion of Iso/ACh led to a shortening of aAPD90, aERP, aPRR and the occurrence of AF episodes was significantly increased. Additional perfusion with ranolazine and ORM-10103 (group A) significantly prolonged the refractory periods and aPRR and AF episodes were effectively reduced. In group B, Rano-SEA led to a slight decrease in aAPD90 while aERP and aPRR were prolonged. The occurrence of AF episodes was consecutively reduced. To our knowledge, this is the first study investigating the effect of ranolazine combined with different selective NCX-inhibitors in an isolated whole-heart model of AF. Both combinations prolonged aERP and aPRR and thereby suppressed the induction of AF.

Previous studies report conflicting data regarding anti- or proarrhythmic effects of sacubitril. Aim of this study was to assess the impact of acute sacubitril treatment in different arrhythmia models.Sacubitril was administered (3, 5, 10 μM) in 12 isolated rabbit hearts. Further 12 hearts were treated with erythromycin to simulate long-QT-syndrome-2 (LQT2). Other 12 hearts were perfused with veratridine to mimic long-QT-syndrome-3 (LQT3). Both LQT-groups were treated with sacubitril (5 μM) additionally. Ventricular vulnerability was assessed by a pacing protocol. AV-blocked bradycardic hearts were perfused with a hypokalemic solution to trigger torsade de pointes (TdP). In further 13 hearts, AF was induced by a combination of acetylcholine and isoproterenol and sacubitril (5 μM) was added afterwards.With sacubitril, action potential duration (APD) was abbreviated whereas spatial dispersion of repolarisation (SDR) remained stable. In both LQT groups, APD and SDR were increased. Infusion of sacubitril reduced APD (- 21 ms, p 0.01) and SDR (- 8 ms) in the LQT2-group and did not alter APD (+2 ms) but reduced SDR (-19 ms, p 0.01) in the LQT3-group. Ventricular vulnerability was not altered by sacubitril. No TdP were observed with sacubitril or under baseline conditions in any group. Sacubitril significantly suppressed TdP in the LQT2-group (3 vs. 43 episodes, p 0.05) but not in the LQT3-group (10 vs. 16 episodes, p = ns). Sacubitril reduced inducibility of AF (9 vs. 31 episodes).Sacubitril abbreviated APD. In addition, sacubitril exhibits potential antiarrhythmic effects in LQT2 and may be beneficial in LQT3 and AF.

Background In patients with repaired Tetralogy of Fallot (ToF), implantable cardioverter defibrillators (ICD) are considered reasonable in selected adults with multiple risk factors for sudden cardiac death. Patients and methods We performed a retrospective cohort study of all 174 patients with repaired ToF who are followed at the University Hospital of Muenster. We analyzed data according to the risk score previously proposed by Khairy and coworkers and patient outcome. We analyzed data separately for patients without previous sustained ventricular tachycardia (VT) (risk stratification group, n = 157) and patients with VT/secondary prevention ICD (n = 17). Results In the risk stratification group, a mean of 4 ± 1 risk score parameters were available. All six risk parameters were known in 10%, five in 14%. Risk score increased with availability of parameters. 15 patients with secondary prevention ICD had a mean risk score of 6.3 ± 2.2 (range 2–10). 11 patients of the risk stratification group with primary prevention ICD had a mean risk score 5.8 ± 2.4 (range 3–8). During follow-up of up to 14 years, five patients died (3%): at age 58, two at 69 and two at 76 years. Conclusion In the majority of patients risk score variables were incomplete, severely limiting its applicability because the true score cannot be calculated. Risk scores were not different between patients with secondary prevention ICD and patients with ICD for primary prevention based on current guidelines. Standardization of follow-up and prospective evaluation of these standards in large prospective patient cohorts is desirable to improve risk stratification in patients with ToF.

Ivabradine has recently been demonstrated to have antiarrhythmic properties in atrial fibrillation. The aim of the present study was to assess the electrophysiologic profile of ivabradine in an experimental whole-heart model of long-QT-syndrome. In 12 isolated rabbit hearts long-QT-2-syndrome (LQT2) was simulated by infusion of d,l-sotalol (100 µM). 12 rabbit hearts were treated with veratridine (0.5 µM) to mimic long-QT-3-syndrome (LQT3). Sotalol induced a significant prolongation of QT-interval (+ 40 ms, p

A limited number of case reports of coronary sinus (CS) diverticula complicating catheter ablation have been published. We retrospectively analysed 2245 patients who underwent ablation of an accessory pathway (AP) at our institution between 1/11/1993 and 31/10/2016. Eight patients (0.36%) were found to have a CS diverticulum in venography. APs showed a mean antegrade conduction time of 276 ± 23 ms (range 220–310 ms) and a mean retrograde conduction of 301 ± 45 ms (230–350 ms). Four patients had 1 (n = 2), 2 (n = 1), or 3 (n = 1) previously failed ablation attempts. Pathways could not be ablated with a conventional 4 mm tip catheter in 7 of 8 cases. In seven patients, ablation was successful, in two using an 8-mm ablation catheter, in two using cryoablation, and in the remaining three with an irrigated tip ablation catheter. After failed femoral approach, one 9-year-old female was successfully ablated via the right jugular vein. In one 75-year-old female, ablation was not successful. During a mean follow-up of 8.9 ± 6.4 years, all patients remained free of recurrences. In inferoseptal pathways, especially with previous failed ablation attempts, venographies of the CS should be performed. After successful ablation long-term prognosis is excellent.

The subcutaneous ICD is a promising treatment option in patients at risk for sudden cardiac death. Approved in 2009, the first S-ICD® in Germany was implanted in June 2010. Although large prospective registry studies have shown safety and efficacy of the system, there is a lack of long-term data with regard to battery longevity of the S-ICD®. Therefore, we report follow-up of our first initial S-ICD® cases from implantation till battery depletion. All S-ICD® patients with device replacement for battery depletion in our large single-center S-ICD® registry were included in this study. Baseline characteristics, appropriate and inappropriate shocks, and complications were documented in a median follow-up of 75.9 ± 6.8 months. Twenty-eight patients with S-ICD® systems were included in this study. Of these patients, 21 were male and 7 were female, with an overall mean age of 41.9 ± 12.6 years. Primary prevention of sudden cardiac death was the indication in 19 patients (67.9%). Ventricular tachycardia was adequately terminated in two patients (7.1%). In 7 patients, non-sustained ventricular arrhythmias were not treated. A total of three inappropriate shocks occurred in three patients (10.7%). Mean time from implantation till battery depletion was 65.8 ± 8.1 months. Only one patient presented premature elective replacement criteria because of rapid battery depletion. No lead-related complication occurred during follow-up and no complications were seen regarding device replacement. In one patient (3.6%), the system was explanted without replacement due to patient’s preference. The estimated battery longevity of S-ICD® of about 5 years was reached in all but one patient. Compared to larger S-ICD® registry studies, frequency of inappropriate shocks was relatively high in the initial S-ICD® cases. Both technological improvement as well as programming and operators’ experience have led to a reduction of complications. Replacement of the S-ICD® seems to be a safe and effective procedure.

Background: Pulmonary vein isolation (PVI) and antiarrhythmic drug therapy are established treatment strategies to preserve sinus rhythm in atrial fibrillation (AF). However, the efficacy of both interventional and pharmaceutical therapy is still limited. Solid evidence suggests an important role of the cardiac sympathetic nervous system in AF. In this blinded, prospective observational study, we studied left ventricular cardiac sympathetic activity in patients treated with PVI and with antiarrhythmic drugs. Prospectively, Iodine-123-benzyl-guanidine single photon emission computer tomography (123I-mIBG-SPECT) was performed in a total of 23 patients with paroxysmal AF, who underwent PVI (n = 20) or received antiarrhythmic drug therapy only (n = 3), respectively. 123I-mIBG planar and SPECT/CT scans were performed before and 4 to 8 weeks after PVI (or initiation of drug therapy, respectively). For semiquantitative SPECT image analysis, attenuation-corrected early/late images were analyzed. Quantitative SPECT analysis was performed using the AHA 17-segment model of the left ventricle. Results: PVI with point-by-point radiofrequency ablation led to a significantly (p &lt, 0.05) higher visual sympathetic innervation defect score when comparing pre-and post PVI. Newly emerging innervation deficits post PVI were localized predominantly in the inferior lateral wall. These findings were corroborated by semiquantitative SPECT analysis identifying inferolateral segments with a reduced tracer uptake in comparison to SPECT before PVI. Following PVI, patients with an AF relapse showed a different sympathetic innervation pattern compared to patients with sufficient rhythm control. Conclusions: PVI results in novel defects of cardiac sympathetic innervation. Differences in cardiac sympathetic innervation remodelling following PVI suggest an important role of the cardiac autonomous nervous system in the maintenance of sinus rhythm following PVI.

Recent experimental studies suggested direct effects of the anti-influenza drug oseltamivir on cardiac electrophysiology. We therefore aimed at analyzing potential antiarrhythmic effects of oseltamivir on atrial fibrillation (AF) in an experimental whole-heart model. Twelve rabbit hearts were isolated and Langendorff perfused. Thereafter, hearts were paced at cycle lengths of 350, 250, and 200 ms in the atrium. A standardized protocol employing atrial burst pacing induced AF in 4 of 12 hearts under baseline conditions (33%, 11 episodes). Subsequently, a combination of acetylcholine (1 μM) and isoproterenol (1 μM) was administered to increase AF occurrence. Two monophasic action potential recordings on the left and two on the right atrial epicardium displayed a decrease of atrial action potential duration (aAPD, −38 ms, p

Background There is a lack of procedural and follow-up data on pulmonary vein isolation (PVI) with the second-generation pulmonary vein ablation catheter® (PVAC Gold) in patients with atrial fibrillation (AF). This study provides data on PVI procedures and 1-year follow-up results with PVAC Gold in patients with AF treated in clinical practice. Methods and results Three hundred and eighty four patients with documented symptomatic paroxysmal (n=198) or persistent (n=186) AF were included in a non-randomized prospectively designed database. Patients were enrolled consecutively at 2 high-volume centers. Procedural as well as 1year follow-up data were systematically analyzed. Average procedure times±standard deviations were 94±23min and 97±23min, respectively, in patients with paroxysmal and persistent AF. Average fluoroscopy times were 14.7±5.4min and 15.2±5.6min and total application times 18.1±5.0min and 18.8±5.2min, respectively, in the 2 patient cohorts. At 12months, 70.7% (70/99) and 61.9% (70/113) of patients with paroxysmal and persistent AF, respectively, were free from AF. Four early complications occurred. In the group with persistent AF, 1 posterior cerebral infarction occurred 2days after the procedure during initiation of anticoagulation. There was no phrenic nerve palsy or esophageal injury associated with the procedures. No thromboembolic events were recorded during follow-up. Conclusions In patients with paroxysmal or persistent AF, second generation multi-electrode-phased radiofrequency ablation delivers favorable mid-term PVI success rates with few procedure-related or follow-up complications.

The performance of the subcutaneous ICD (S-ICD™) has been described in different kinds of heart disease and has been proven to be an important advance in prevention of sudden cardiac death (SCD). While positive experiences with the S-ICD™ initially came from collectives of patients without structural heart diseases, positive results have also been collected from cohorts with structural heart disease. All S-ICD™ patients with either ischemic cardiomyopathy (ICM), dilated cardiomyopathy (DCM) or hypertrophic cardiomyopathy (HCM) as the main indication for ICD implantation (n = 144 patients) or electrical heart disease/idiopathic ventricular fibrillation (n = 83 patients) in our large-scaled single-center S-ICD™ registry were included in this study. Baseline characteristics, appropriate and inappropriate shocks, and complications were documented in a mean follow-up of 18 ± 15 months. Baseline characteristics were significantly different between the two groups in most categories. In contrast, there was no difference concerning neither appropriate nor inappropriate shock delivery between the two groups. Also other outcome parameters such as need for surgical revisions and all-cause mortality did not differ. There was a significant difference between the first- and second-generation S-ICDs™ in inadequate shocks mainly driven by patients with HCM. In our study, S-ICD™ performance was similar in patients with and without structural heart disease. Decision pro- or contra-S-ICD™ should be made rather on the basis of expected shock rate and probability of the need for future anti-tachycardia or anti-bradycardia pacing than in dependence of the underlying heart disease.

Background Sarcoidosis is a multisystem granulomatous disease of not sufficiently understood origin. Some patients develop cardiac involvement in course of the disease which is mostly responsible for adverse outcome. In addition to complications like high degree atrioventricular (AV) block or ventricular tachyarrhythmias, there is a certain percentage of patients developing atrial tachyarrhythmias. Data is limited and the role of catheter ablation uncertain. Therefore, we studied sarcoid patients who presented with supraventricular tachyarrhythmias. Hypothesis Treatment and ablation of supraventricular tachycardia could be hampered by inflammation in patients with cardiac sarcoidosis. Methods We enrolled 37 consecutive patients with cardiac sarcoidosis who presented with atrial tachyarrhythmias and underwent an electrophysiologic study over a period of 6 years (03/2013‐04/2019). In total, 16 catheter ablations for atrial tachyarrhythmias were performed. Mean follow‐up duration was 2.5 years. Results Most common ablation performed was cavo‐tricuspid isthmus ablation for typical atrial flutter in seven patients (54%). Pulmonary vein isolation for treatment of atrial fibrillation (AF) was performed in five patients (38%). Two patients received slow‐pathway modulation for treatment of recurrent atrioventricular nodal reentry tachycardia (AVNRT). All but two patients with AF had no clinical recurrence during follow‐up. Two patients had recurrence of AF but still reported markedly improved european heart rhythm association (EHRA) class. Periprocedural safety was very high. There were no adverse events related to the ablation procedure. One patient died during follow‐up in the presence of electrical storm. Conclusion Catheter ablations of supraventricular tachycardias seem to be safe and effective in patients with cardiac sarcoidosis. Outcome is comparable to patients without inflammatory heart disease, although data from larger patient collectives are mandatory to make recommendations in this special entity.

Several studies suggest QT prolongation and torsade de pointes with acetylcholine-esterase inhibitors. We therefore examined the electrophysiologic profile of donepezil, rivastigmine, and galantamine in a sensitive whole-heart model of proarrhythmia. 34 rabbit hearts were isolated and retrogradely perfused employing the Langendorff setup. Hearts were treated either with donepezil, rivastigmine, or galantamine in rising concentrations and electrophysiologic studies were performed. In the presence of donepezil and galantamine, spatial dispersion of repolarization was amplified. Cardiac repolarization (QT interval and action potential duration) was prolonged with donepezil but not with galantamine. Remarkably, both drugs induced triggered activity (early afterdepolarizations and torsade de pointes tachycardia). Despite a pronounced prolongation of repolarization with rivastigmine, no increase in spatial dispersion of repolarization and thus no triggered activity was observed. In the present study, donepezil and galantamine provoked triggered activity, whereas rivastigmine did not have proarrhythmic effects. Spatial dispersion of repolarization but not duration of cardiac repolarization was associated with increased risk of drug-induced proarrhythmia with acetylcholine-esterase inhibitors. Consequently, QT interval duration might be insufficient to estimate the risk of proarrhythmia with acetylcholine-esterase inhibitors. Our findings emphasize the need for further electrocardiographic risk predictors.

Introduction The AliveCor Kardia ECG monitor (ACK) offers a smartphone-based one-lead ECG recording for the detection of atrial fibrillation. We compared ACK lead I recordings with the 12-lead ECG and introduce a novel parasternal lead (NPL). Methods Consecutive cardiac inpatients were recruited. In all patients a 12-lead ECG, ACK lead I and NPL were obtained. Two experienced electrophysiologists were blinded and separately evaluated all ECG. We calculated sensitivity, specificity, and predictive values of the ACK ECG compared to the 12-lead ECG. Results 296 ECG from 99 patients (38 female, age 64 ± 15 years, BMI 27.8 ± 5.1 kg/m2) were analyzed. 20% of ACK lead I recordings contained a critical amount of artifact. The electrophysiologists’ interpretation of the ACK recordings yielded a sensitivity of 100% and specificity of 94% for atrial fibrillation or flutter in lead I (κ = 0.90) and a sensitivity of 96% and specificity of 97% in the NPL (κ = 0.92). The ACK diagnostic algorithm displayed a significantly lower sensitivity (55–70%), specificity (60–69%), and accuracy (κ = 0.4–0.53) but a high negative predictive value (100%). Patients with atrial flutter (n = 5) and with ventricular stimulation (n = 12) had a high likelihood of being misclassified by the algorithm. Conclusion The AliveCor Kardia ECG monitor allows a highly accurate detection of atrial fibrillation by an interpreting electrophysiologist both in the standard lead I and a novel parasternal lead. The diagnostic algorithm offered by the system may be useful in screening recordings for further review. Diagnostic challenges present in atrial flutter and ventricular pacemaker stimulation.

Recent experimental studies showed a protective effect of the renin inhibitor aliskiren regarding atrial structural remodeling. Purpose of this study was to assess acute electrophysiologic effects of aliskiren in a whole-heart model of atrial fibrillation (AF) and to investigate its impact on the ventricle. Twelve rabbit hearts were excised, retrogradely perfused, and paced at different cycle lengths. To enhance atrial vulnerability, a combination of acetylcholine (ACh) and isoproterenol (Iso) was infused and significantly reduced atrial action potential duration (aAPD90) and atrial effective refractory period (aERP). Additional infusion of aliskiren prolonged aAPD90 but did not alter aERP. A triangulation of action potential with ACh/Iso and a further triangulation after treatment with aliskiren were noted. Vulnerability to AF was tested by employing trains of burst pacing. Administration of ACh/Iso provoked more episodes of AF (baseline: 26 episodes, Iso/Ach: 48 episodes). Additional treatment with aliskiren induced AF significantly more often (108 episodes). Another nine hearts were perfused with aliskiren to examine its ventricular effects. Infusion with aliskiren abbreviated ventricular APD90 and ERP. Utilizing programmed ventricular stimulation, a trend towards more ventricular arrhythmias in aliskiren-treated hearts was observed. Though aliskiren did not reduce aAPD90 or aERP, acute treatment with aliskiren promoted AF. Triangulation of atrial action potentials, which is an established risk factor for ventricular proarrhythmia, may contribute to the increased atrial vulnerability. This effect may interfere with its recently demonstrated beneficial properties in atrial remodeling. Of note, aliskiren might have a proarrhythmic effect on the ventricular level.

Background Outcome of ischemic VT ablation may differ between patients with previous myocardial infarction (MI) in relation to infarct localization. Methods We analyzed procedural data, acute and long-term outcomes of 152 consecutive patients (139 men, mean age 67 ± 9 years) with previous anterior or inferior MI who underwent ischemic VT ablation at our institution between January 2010 and October 2015. Results More patients had a history of inferior MI (58%). Mean ejection fraction was significantly lower in anterior MI patients (28 ± 10% vs. 34 ± 10%, p p = 0.18). Procedural parameters and acute success did not differ between the groups. During a mean follow-up of 3 ± 2 years, more anterior MI patients had undergone a re-ablation (49% vs. 33%, p = 0.09, Chi-square test). There was a trend towards more ICD shocks in patients with previous anterior MI (46% vs. 34%). After adjusting for risk factors and ejection fraction, multivariable Cox regression analyses showed no significant difference in mortality (p = 0.78) and cardiovascular mortality between infarct localizations (p = 0.6). Conclusion Clinical characteristics of patients with anterior and inferior MI are similar except for ejection fraction. Patients with inferior MI appear to have better outcome regarding survival, ICD shocks and re-ablation, but this appears to be related to better ejection fraction when compared with anterior MI.

Die Pulmonalvenenisolation (PVI) stellt eine etablierte Therapieoption fur Patienten mit symptomatischem Vorhofflimmern (VHF) dar. Mehrere Studien konnten eine Uberlegenheit des interventionellen Verfahrens im Vergleich zu einer rein medikamentosen Therapie belegen. Des Weiteren konnten verschiedene retrospektive Arbeiten Hinweise auf ein niedrigeres thrombembolisches Risiko nach stattgehabter PVI zeigen und so die Diskussion erneut anfeuern, ob eine PVI symptomatischen Patienten vorbehalten bleiben sollte. Zusatzlich stellt sich oft die Frage, ob initial asymptomatische Patienten im Verlauf eine Symptomatik entwickeln konnten. Bei jedoch aktuell fehlenden prospektiven, randomisierten Daten bezuglich eines prognostischen Vorteils einer PVI und in Anbetracht der prozeduralen Risiken sollte eine PVI nur in Einzelfallen bei asymptomatischen Patienten durchgefuhrt werden.

Background Left atrial tachycardias (LAT) occur in about 5% of patients after irrigated-tip circumferential antral (CA) pulmonary vein isolation (PVI). They may cause debilitating symptoms in the patient and may be very difficult to treat. Objective To assess the incidence of LAT after PVI with the multielectrode phased-radiofrequency pulmonary vein ablation catheter (PVAC) compared to circumferential antral PVI with an irrigated-tip catheter. Methods We analyzed data from our ablation database. A total of 150 patients who underwent their first PVI with the PVAC system and 300 patients who underwent their first PVI with irrigated-tip circumferential antral (CA) radiofrequency ablation were matched by age and sex, as well as by type of atrial fibrillation. Results Of 150 PVAC patients, only 1 patient (0.7%) developed LAT during mean follow-up of 21 ± 14 months. The mechanism was macroreentry and the patient underwent successful ablation at our institution. Eleven of 300 irrigated-tip CA PVI patients (3.7%) developed LAT during mean follow-up of 22 ± 14 months and subsequently underwent ablation (P = .05). Conclusion LAT occurs more frequently after irrigated-tip CA PVI compared to single-shot-device ablation with PVAC. Apart from being less technically demanding, lower incidence of LAT may influence choice of ablation technology.

Ranolazine and Vernakalant in Short QT SyndromeBackground Ranolazine has been reported to have an antiarrhythmic potential. The aim of this study was to assess the electrophysiologic effects of ranolazine and to compare its effects to vernakalant in an experimental whole-heart model of short-QT syndrome. Methods Rabbit hearts were isolated and Langendorff-perfused. After obtaining baseline data, pinacidil, an IKATP channel opener, was administered (1 μM). Results Endo- and epicardial monophasic action potentials and a 12-lead ECG showed a significant abbreviation of QT interval (− 34 milliseconds, P

In several case reports a prolongation of the QT-interval and even proarrhythmic effects of fluconazole and voriconazole were reported. The aim of the present study was to investigate if application of fluconazole or voriconazole has the potential to provoke polymorphic ventricular tachycardia in a sensitive model of proarrhythmia. In female rabbits, fluconazole (10, 30 and 50 µM, n=6) and voriconazole (10, 30 and 50 µM, n=6) were infused after obtaining baseline data. Eight endocardial and epicardial monophasic action potentials and a simultaneously recorded 12-lead ECG showed a significant QT prolongation after application of fluconazole as compared with baseline (10 µM:+12 ms, 30 µM:+22 ms, 50 µM:+37 ms; P

Background The subcutaneous implantable cardioverter defibrillator (S-ICD) has been established as a valuable alternative to transvenous ICD for prevention of sudden cardiac death. The system automatically chooses the optimal sensing vector. However, during follow-up and especially after device replacement we observed a change of the suggested sensing vector in automatic setup. Therefore, we analyzed frequency and reasons of vector change and its impact on inappropriate shocks (IAS). Material and methods Between June 2010 and December 2017, a total of 216 patients with S-ICD® were included in this analysis. In all patients sensing vectors at the time of implantation, during follow-up, and after device replacement were investigated. Median follow-up time was 27.3 ± 25.3 months. Results A change of the initial vector was seen in 77 patients (35.7%). The most frequent reason for vector change was the postoperative setup in supine and erect position in 54 patients (70.1%). In 12 patients (15.5%), the vector was manually changed due to inappropriate sensing and/or therapies. Routine setup during follow-up led to automatic vector change in 10 cases (13.0%). In only 1 patient the vector was manually changed due to oversensing in an exercise treadmill test. In 27 patients, the device was replaced due to battery depletion and in 6 of these patients the sensing vector was changed by the automatic setup. Vector change did not have an impact for inappropriate therapies in the follow-up; only 1 patient received an IAS due to an inadvertent vector change after device replacement. Conclusion In the present study, a significant number of S-ICD® patients had a manual or automatic vector change during follow-up and after device replacement. The study underlines the importance of a thoroughly performed screening and at least two valuable sensing vectors preimplant. Further studies are needed to evaluate the necessity of a routine automatic setup during follow-up.

Background Silent cerebral lesions with the multielectrode-phased radiofrequency (RF) pulmonary vein ablation catheter (PVAC®) have recently been investigated. However, comparative data on safety in relation to irrigated RF ablation are missing. Methods and results One hundred and fifty consecutive patients (58 ± 12 years, 56 female) underwent first pulmonary vein isolation (PVI) for atrial fibrillation (61% paroxysmal) using PVAC® ( PVAC ). Procedure data as well as in-hospital complications were compared with 300 matched patients who underwent PVI using irrigated RF (iRF). Procedure duration (148 ± 63 vs. 208 ± 70 min; P < 0.001), RF duration (24 ± 10 vs. 49 ± 25 min; P < 0.001), and fluoroscopy time (21 ± 10 vs. 35 ± 13 min; P < 0.001) were significantly shorter using PVAC . Major complication rates [major bleeding, transitoric ischaemic attack (TIA), and pericardial tamponade] were not significantly different between groups ( PVAC , n = 3; 2% vs. iRF n = 17; 6%). Overall complication rate, including minor events, was similar in both groups [ n = 21 (14%) vs. n = 48 (16%)]. Most of these were bleeding complications due to vascular access [ n = 8 (5.3%) vs. n = 22 (7.3%)], which required surgical intervention in five patients [ n = 1 (0.7%) vs. n = 4 (1.3%)]. Pericardial effusion [ n = 4 (2.7%) vs. n = 19 (6.3%); pericardial tamponade requiring drainage n = 0 vs. n = 6] occurred more frequently using iRF. Two patients in each group developed a TIA (1.3% vs. 0.6%). Of note, four of five thromboembolic events in the PVAC group (two TIAs and three transient ST elevations during ablation) occurred when all 10 electrodes were used for ablation. Conclusion Pulmonary vein isolation using PVAC as a ‘one-shot-system’ has a comparable complication rate but a different risk profile. Pericardial effusion and tamponade occurred more frequently using iRF, whereas thromboembolic events were more prevalent using PVAC . Occurrence of clinically relevant thromboembolic events might be reduced by avoidance of electrode 1and 10 interaction and uninterrupted anticoagulation, whereas contact force sensing for iRF might minimize pericardial effusion.

We compared the contour of learning curves of two “single-shot” devices used for pulmonary vein isolation (PVI) for safety and procedural data. We performed a retrospective analysis comparing the first 60 PVI performed at our center using a pulmonary vein ablation catheter (PVAC) array (39 male, mean age 57 years, 42 paroxysmal AF) to the first 60 first PVI using the Cryoballoon (44 male, mean age 59 years, 22 paroxysmal AF). Both groups were further divided into tertiles, where T1 regroups the first 20 ablations, T2 the following 20, and T3 the last 20 ablations. The mean total procedure time was reduced by 24 min between T1 and T3 for the PVAC and 15 min for the Cryoballoon (p = 0.01). Fluoroscopy increased by 5 min, total ablation time was reduced by 7 min for PVAC (p = 0.02), and both times decreased respectively by 7 and 1 min for the Cryoballoon (p = ns). In the PVAC group, a mean rate of 0.16 (T1: n = 5; T2: n = 2; T3: n = 3) complications was observed while a rate of 0.16 (T1: n = 2; T2: n = 3; T3: n = 4) occurred in the CRYO group (p = ns). Severe complications defined as stroke, pericardial tamponade with need of pericardiocentesis and phrenic nerve palsy occurred in n = 4 in both groups (6.6%). With either of the systems, no significant differences in the effect of the learning curve on the occurrence of adverse events were observed. However, the PVAC array seemed to have a steeper learning curve for procedure, as well as fluoroscopy time.

Background Permanent AV-block is a recognized and feared complication of slow pathway modulation for AVNRT. We aimed to assess incidence of transient and permanent AV-block as well as consequences of transient AV-block in a large contemporary AVNRT ablation cohort. Methods We searched our single center prospective ablation database for occurrence of transient and permanent AV-block during slow pathway modulation between January 2004 and October 2015. We analyzed patients' and procedural characteristics as well as outcome of patients in whom transient or permanent AV-block occurred. Results Of 9170 patients who underwent a catheter ablation at our institution between January 2004 and October 2015, 2101 patients (64% women, mean age 50±18years) underwent slow pathway modulation. In three patients, permanent AV-block occurred during RF application. Additional two patients had transient AV-block that recovered (after a few minutes and 25min), but recurred within two days of the procedure. All five patients underwent dual chamber pacemaker implantation (0.2%). Transient AV-block related to RF delivery occurred in 44 patients (2%). Transient mechanical AV-block occurred in additional 17 patients (0.8%). In 12 patients, ablation was continued despite transient AV-block. One of these patients developed permanent AV-block. Conclusion Permanent AV-block following slow pathway modulation is a rare event, occurring in 0.2% of patients in a large contemporary single center cohort. Transient AV-block is more frequent (2%).

The I(f) channel inhibitor ivabradine is recommended for treatment of heart failure but also affects potassium currents and thereby prolongs ventricular repolarization. The aim of this study was to examine the electrophysiological effects of ivabradine on digitalis-induced ventricular arrhythmias. Thirteen rabbit hearts were isolated and Langendorff-perfused. After obtaining baseline data, the digitalis glycoside ouabain was infused (0.2 μM). Monophasic action potentials and ECG showed a significant abbreviation of QT interval (-34 ms, p < 0.05) and action potential duration (APD90 ; -27 ms, p < 0.05). The shortening of ventricular repolarization was accompanied by a reduction in effective refractory period (ERP; -27 ms, p < 0.05). Thereafter, hearts were additionally treated with ivabradine (5 μM). Of note, this did not exert significant effects on QT interval (-4 ms, p = ns) or APD90 (-15 ms, p = ns) but resulted in an increase in ERP (+17 ms, p < 0.05). This led to a significant increase in post-repolarization refractoriness (PRR, +32 ms, p < 0.01) as compared with sole ouabain treatment. Under baseline conditions, ventricular fibrillation (VF) was inducible by a standardized pacing protocol including programmed stimulation and burst stimulation in four of 13 hearts (31%; 15 episodes). After application of 0.2 μM ouabain, eight of 13 hearts were inducible (62%, 49 episodes). Additional infusion of 5 μM ivabradine led to a significant suppression of VF. Only four episodes could be induced in two of 13 hearts (15%). In this study, ivabradine reduced digitalis-induced ventricular arrhythmias. Ivabradine did not affect ventricular repolarization in the presence of digitalis treatment but demonstrated potent anti-arrhythmic properties based on an increase in both ERP and PRR. The study further characterizes the beneficial electrophysiological profile of ivabradine.

Background The first-line therapy for atrioventricular nodal reentry tachycardia (AVNRT) is catheter-based slow pathway modulation. If AVNRT is not inducible during an electrophysiological study, an empirical slow pathway modulation (ESPM) may be considered in patients with dual atrioventricular nodal physiology and/or a typical electrocardiogram (ECG). Methods We screened 149 symptomatic patients who underwent ESPM in our department between 1993 and 2013. All patients fulfilled the following criteria: (1) either dual atrioventricular nodal (AVN) physiology with up to 2 AVN echo beats or characteristic ECG documentation or both, (2) noninducibility of AVNRT by programmed stimulation, and (3) completion of a telephone questionnaire for long-term follow-up. Out of this population we retrospectively investigated 13 patients who were primarily noninducible but in whom an AVNRT occurred during or after radiofrequency (RF) delivery. Results When AVNRT occurred, the procedure lost its empirical character, and RF delivery was continued until the procedural endpoint of noninducibility of AVNRT. This endpoint was reached in all but one patient (92%). After a follow-up of 73 ± 15 months, this patient was the only one who reported no benefit from the procedure. Conclusions Out of 149 initially noninducible patients, a considerable number (9%) exhibited AVNRT during or after RF delivery. These patients crossed over from empirical to controlled slow pathway modulation resulting in a good clinical outcome. Our observations should encourage electrophysiologists to repeat programmed stimulation even after initial empirical RF delivery to retest for inducibility.

Clinically silent lesions on cerebral magnet resonance imaging have been found in larger numbers after pulmonary vein isolation (PVI) especially with phased radio frequency (pRF) using all ten electrodes. However, the neuropsychological effects of cerebral microembolism during the procedure remain unclear and data regarding this issue so far are inconsistent. Between August 2011 and June 2012, 76 patients undergoing their first PVI were randomized to ablation with either phased (40) or irrigated (36) radio frequency (iRF). A comprehensive neuropsychological test battery was performed the day before and after PVI as well as 6 months after ablation. The occurrence of cerebral microemboli during the procedure was performed via a transcranial Doppler ultrasound device. PVI using pRF was associated with increased number of microembolic signals (MES) compared to iRF (1530.0 ± 979.8 vs. 645.7 ± 448.7; p

Aims Phased radiofrequency (RF) ablation for atrial fibrillation is associated with an increased number of silent cerebral lesions on magnetic resonance imaging and cerebral microembolic signals (MESs) on transcranial Doppler ultrasound imaging compared with irrigated RF. The increased rate of embolic events may be due to a specific electrical interference of ablation electrodes attributed to the catheter design. The purpose of this study was to elucidate the effect of deactivating the culprit electrodes on cerebral MESs. Methods and results Twenty-nine consecutive patients (60 ± 11 years, 10 female) underwent their first pulmonary vein isolation using phased RF energy. Electrode pairs 1 or 5 were deactivated to avoid electrical interference between electrodes 1 and 10 (‘modified’). Detection of MESs by transcranial Doppler ultrasound was performed throughout the procedure to assess cerebral microembolism. Results were compared with the numbers of MESs in 31 patients ablated using all available electrodes (‘conventional’) and to 30 patients undergoing irrigated RF ablation of a previous randomized study. Ablation with ‘modified’ phased RF was associated with a marked decrease in MESs when compared with ‘conventional’ phased RF (566 ± 332 vs. 1530 ± 980; P < 0.001). This difference was mainly triggered by the reduction of MES during delivery of phased RF energy, resulting in MES numbers comparable to irrigated RF ablation (646 ± 449; P = 0.7). Total procedure duration as well as time of RF delivery was comparable between phased RF groups. Both times, however, were significantly shorter compared with the irrigated RF group (123 ± 28 vs. 195 ± 38; 15 ± 4 vs. 30 ± 9; P < 0.001, respectively). Conclusion Pulmonary vein isolation with ‘modified’ phased RF is associated with a decreased number of cerebral microembolism especially during the delivery of ablation impulses, supporting the significance of electrical interference between ablation electrodes 1 and 10. Deactivation of electrode pairs 1 or 5 might increase the safety of this approach without an increase in procedure duration or RF delivery time.

The traditional gout medication colchicine has been reported to effectively prevent atrial fibrillation recurrence after atrial fibrillation ablation or cardiac surgery in a few clinical trials. Severe adverse events have not yet been reported. The aim of the present study was to assess possible direct electrophysiological effects in an experimental whole-heart model. Ten rabbit hearts were isolated and Langendorff-perfused. Thereafter, colchicine was administered in two concentrations (1 and 3 μM). Eight endo- and epicardial monophasic action potentials and a 12-lead ECG showed a stable QT interval and action potential duration during colchicine infusion. Furthermore, there was no significant increase in dispersion of repolarization. However, colchicine induced a dose-dependent significant decrease of effective refractory period (ERP; 1 μM: -19 ms, 3 μM: -22 ms; p < 0.05). In the present study, acute infusion of colchicine in isolated rabbit hearts resulted in a reduction of ERP in the presence of a stable myocardial repolarization. This led to a significantly elevated inducibility of ventricular fibrillation. In 4 of 10 hearts, incessant ventricular fibrillation occurred. These results suggest a pro-arrhythmic or toxic effect of colchicine and underline that further clinical studies on potential adverse effects should be conducted before the drug can be recommended for routine use after atrial fibrillation ablation.

Background A post hoc analysis of the PALLAS trial suggested possible interactions of dronedarone and digitalis glycosides. The aim of the present study was to compare the effects dronedarone or amiodarone in combination with digitalis glycosides. Methods and results Eleven female rabbits underwent chronic oral treatment with amiodarone (50mg/kg/d for 6weeks). Ten rabbits were treated with dronedarone (50mg/kg/d for 6weeks). Ten rabbits were used as controls. Hearts were isolated and Langendorff-perfused. Monophasic action potentials and ECG showed a moderate prolongation of QT interval and action potential duration (APD). Both drugs also increased effective refractory period. Additional application of ouabain (0.2μM) resulted in a significant decrease of QT interval, APD, and ERP in all groups. Ventricular arrhythmias were induced by programmed ventricular stimulation and aggressive burst stimulation. Reproducible occurrence was defined as occurrence of at least 3 episodes. Under baseline conditions in control hearts, ventricular fibrillation (VF) was inducible in 1 of 10 hearts (7 episodes). After the application of 0.2μM ouabain, 4 of 10 control hearts were inducible (24 episodes). One of 10 dronedarone-pretreated hearts (3 episodes) and 2 of 11 amiodarone-pretreated hearts (6 episodes) showed VF before ouabain infusion. After the application of 0.2μM ouabain, 7 of 10 dronedarone-pretreated hearts were inducible (73 episodes). By contrast, only 4 of 11 amiodarone-pretreated hearts (13 episodes) showed VF. Conclusion In the present study, additional treatment with ouabain resulted in an increased ventricular vulnerability in al study groups. Of note, chronically dronedarone-pretreated hearts were significantly more vulnerable than amiodarone-pretreated hearts.

Aims The second-generation multi-electrode-phased radiofrequency pulmonary vein ablation catheter (PVAC GOLD®) was redesigned with the intent to improve its safety and efficacy. Methods and results Using a prospectively designed single-centre database, we retrospectively analysed 128 consecutive patients (102 paroxysmal and 43 female) who underwent their first pulmonary vein isolation with the PVAC GOLD®. The analysis focused on procedural data as well as in-hospital complications. Baseline characteristics of the patient collective were as follows: mean age 57.9 years, mean CHA2DS2-VASC was 1.73 ± 1.30; structural heart disease was present in seven patients. The PVAC GOLD® exhibited procedure durations of 123.1 min ± 27.9, duration of energy delivery was 18.3 min ± 11.4, and fluoroscopy duration was 16.0 min ± 7.7. The redesigned catheter shows major complication [major bleeding, transitory ischaemic attack (TIA), and pericardial tamponade] rates of 2.3% ( n = 3). The overall rate of adverse events was 5.4% ( n = 7). Bleeding complications were observed in three patients (2.3%), in particular there were two cases (1.6%) of minor bleeding and one case (0.8%) of major bleeding. Two patients suffered pericardial effusion, but there was no need for pericardiocentesis. Besides one TIA, there was no other thrombo-embolic event. Furthermore, one case of post-procedural fever was observed. No deaths, stroke, or haemorrhagic shock occurred. Of the 510 pulmonary veins, 508 could be reached with the PVAC GOLD® device using a non-steerable long sheath. Conclusion The PVAC GOLD® seems to have an acceptable safety profile. The handling is comparable with the previous generation PVAC®.