Pacemaker lead-associated tricuspid regurgitation in patients with or without pre-existing right ventricular dilatation.

BACKGROUND: Transcatheter tricuspid valve intervention became an option for pacemaker lead-associated tricuspid regurgitation. This study investigated the progression of tricuspid regurgitation (TR) in patients with or without pre-existing right ventricular dilatation (RVD) undergoing pacemaker implantation. METHODS: Patients were included if they had implantation of transtricuspid pacemaker lead and completed echocardiography before and after implantation. The cohort was divided in patients with and without RVD (cut-off basal RV diameter ≥ 42 mm). TR was graded in none/mild, moderate, and severe. Worsening of one grade was defined as progression. Survival analyses were plotted for 10 years. RESULTS: In total, 990 patients were analyzed (24.5% with RVD). Progression of TR occurred in 46.1% of patients with RVD and in 25.6% of patients without RVD (P < 0.001). Predictors for TR progression were RV dilatation (OR 2.04; 95% CI 1.27-3.29; P = 0.003), pre-existing TR (OR 4.30; 95% CI 2.51-7.38; P < 0.001), female sex (OR 1.68; 95% CI 1.16-2.43; P = 0.006), single RV lead (OR 1.67; 95% CI 1.09-2.56; P = 0.018), mitral regurgitation (OR 2.08; 95% CI 1.42-3.05; P < 0.001), and enlarged left atrium (OR 1.98; 95% CI 1.07-3.67; P = 0.03). Survival-predictors were pacemaker lead-associated TR (HR 1.38; 95% CI 1.04-1.84; P = 0.028), mitral regurgitation (HR 1.34; 95% CI 1.02-1.77; P = 0.034), heart failure (HR 1.75; 95% CI 1.31-2.33; P < 0.001), kidney disease (HR 1.62; 95% CI 1.25-2.11; P < 0.001), and age ≥ 80 years (HR 2.84; 95% CI 2.17-3.71; P < 0.001). CONCLUSIONS: Patients with RVD receiving pacemaker suffered from increased TR progression, leading to decreased survival.

Sex Differences and Long-Term Outcome in Patients With Pacemakers.

Introduction: Evidence of sex-related differences in patients with pacemakers regarding comorbidities is insufficiently investigated. The aim of this study was to determine the relationship of cardiovascular comorbidities and sex category with properties of pacemaker implantation, pacemaker follow-up, and long-term survival. Methods: This retrospective, single-center cohort study consisted of 6,362 pacemaker-patients (39.7% female) enrolled between May 2000 and April 2015. Functional pacemaker parameters were registered at regular pacemaker controls. Survival status and cause of death were analyzed in relation to comorbidities, implanted pacing devices, and echocardiography. Survival analyses were plotted for a 10-year follow-up. Results: Patients with hypertension or hyperlipidemia had higher rates of implantations due to sick sinus syndrome (28.6 vs. 25.5% without hypertension, P < 0.001; 30.7 vs. 25.7% without hyperlipidemia, P < 0.001), while endocarditis was associated with higher rates of implantations due to AV block (46.7 vs. 33.4%, P < 0.001). Patients with valvular heart disease had higher rates of pacemaker implantation due to bradycardic atrial fibrillation (24.9 vs. 21.0% without valvular heart disease, P < 0.001). Ventricular pacing threshold increased in both sexes during the follow-up and was higher in women in the final follow-up (0.94 vs. 0.91 V in men, P = 0.002). During the 10-years follow-up, 6.1% of women and 8.6% of men underwent lead replacement (P = 0.054). Device and lead replacement rates were increased if the comorbidities coronary artery disease, heart failure, hypertension, hyperlipidemia, valvular heart disease, previous stroke/TIA, atrial arrhythmias, chronic kidney disease, or endocarditis were present. Diabetes and previous CABG increase the rates of device replacement, but not the rate of lead replacement. Severe tricuspid regurgitation after implantation of pacemaker was present in more men than women (14.4 vs. 6.1%, P < 0.001). In a multivariate COX regression, the following variables were associated with independent decrease of 10-year survival: hypertension (HR 1.34, 95% CI 1.09-1.64), chronic kidney disease (HR 1.83, 95% CI 1.53-2.19), tricuspid regurgitation after pacemaker implantation (HR 1.48, 95% CI 1.26-1.74). Survival was independently increased in female sex (HR 0.83, 95% CI 0.70-0.99) and hyperlipidemia (HR 0.81, 95% CI 0.67-0.97). Conclusions: Cardiovascular comorbidities influenced significantly pacemaker implantations and long-term outcome. Trial Registration: ClinicalTrials.gov Unique identifier: NCT03388281.

Indications for and outcome in patients with the wearable cardioverter-defibrillator in a nurse-based training programme: results of the Austrian WCD Registry.

BACKGROUND: The wearable cardioverter-defibrillator is a treatment option for patients at temporarily high risk of sudden cardiac death or in whom implantation of a cardioverter-defibrillator is temporarily not possible. OBJECTIVES: The aim of this study was to provide real-world data on patients receiving this therapy in a nurse-based wearable cardioverter-defibrillator training programme. METHODS: A registry including all patients prescribed with a wearable cardioverter-defibrillator in Austria between 2010 and 2016. Overall, 448 patients received a wearable cardioverter-defibrillator in 48 centres. Patients received structured nurse-based wearable cardioverter-defibrillator educational initial training followed by remote monitoring. RESULTS: Main indications were: severe non-ischaemic cardiomyopathy (21%); recent myocardial infarction and percutaneous coronary intervention (20%); and stable coronary artery disease with percutaneous coronary intervention/coronary artery bypass grafting (14%). Eleven patients (2.5%) received 22 appropriate wearable cardioverter-defibrillator shocks. Two patients (0.4%) received three inappropriate shocks. The risk of sudden cardiac death varied between different aetiologies. Eight out of 11 (73%) patients received their first wearable cardioverter-defibrillator shock within 30 days. The main reasons for termination of the wearable cardioverter-defibrillator therapy were implantable cardioverter-defibrillator implantation (55.5%) and improvement of left ventricular ejection fraction to more than 35% (33%). CONCLUSION: The wearable cardioverter-defibrillator is an effective and safe treatment option in patients at either transiently elevated risk of ventricular tachycardia/ventricular fibrillation or mandated postponed implantable cardioverter-defibrillator implantation, with a 2.5% shock rate over a median 54 days wearable cardioverter-defibrillator treatment period. However, both the wearable cardioverter-defibrillator shock rate and implantable cardioverter-defibrillator implantation rate vary widely depending on the wearable cardioverter-defibrillator indication. Nurse-based wearable cardioverter-defibrillator training is associated with high patient adherence, with a median wearing duration per day of 23.5 (1-24) hours.

Landiolol: pharmacology and its use for rate control in atrial fibrillation in an emergency setting.

This article provides new insight on landiolol, an ultra-short acting injectable betablocker, recently approved in Europe, with regard to its pharmacokinetic and pharmacodynamic profile, along with its first experience in Caucasian healthy volunteers and patients with atrial fibrillation. Landiolol as iv formulation exhibited in an emergency setting rapid rate reduction in patients with tachycardic atrial fibrillation without pronounced blood pressure drop both in caucasian and asian populations in similar manner.

Possible risks due to exposure of workers and patients with implants by TETRA transmitters.

Several studies have demonstrated that mobile telephones that use different technologies, such as Global System for Mobile Communication (GSM) or Universal Mobile Telecommunication System (UMTS), have the potential to influence the functionality of active electronic implants, including cardiac pacemakers. According to these studies, a few safety measures, such as maintaining minimum distances of 25 cm between implants and transmitters, are sufficient to avoid such effects. Terrestrial Trunked Radio (TETRA) has become a well-established communication standard in many countries, including Germany and Austria. TETRA transmitters are typically used by police forces and emergency services. Employees and volunteers working for such institutions are often in close contact with patients, causing TETRA transmitters to potentially have an impact on the functionality of the implants of patients. Therefore, the main focus of our study was to investigate the functionality of several types of implants when exposed to TETRA transmitters. Moreover, we investigated the difference in the degree of exposure of users of TETRA transmitters when they carry the devices in different locations near the body, and when they use them in different positions near the head. Our results show that a compliance distance of 30 cm between implant and transmitter is sufficient to exclude any influence on the examined implants. All examined exposure conditions demonstrated that the levels were well below recommended limits. If a user wants to minimize their exposure, use of transmitters in front of the mouth leads to somewhat lower exposure when compared to typical mobile phone like use.

An analysis of the U-wave and its relation to the T-wave in body surface potential maps for healthy subjects and MI patients.

BACKGROUND: The aim of this study was to analyze the U-wave morphology and its relation to the T-wave in one group of healthy subjects and in two groups of myocardial infarction (MI) patients-with and without ventricular tachycardia (VT) episodes. The context of the U-wave origin was also discussed and the U-wave as a potential marker of VT was investigated. METHODS: The study was carried out on three groups of subjects: 20 healthy subjects, 14 MI patients not at risk of VT, and 22 MI patients at risk of VT. The morphology of the repolarization phase was examined in the high-resolution body surface potential maps recorded from 64 surface ECG leads. The temporal and spatial distributions of several ECG parameters were studied. RESULTS: The U-wave was present in almost all the studied subjects. The spatial heterogeneity and smooth change in both the T- and U-wave shapes on the entire torso were observed in all the studied groups. The statistical significance of discrimination between the MI patients without VT and MI patients with VT was observed for QRS interval, QT interval, U-wave integral, and normalized U-wave integral. CONCLUSIONS: High-resolution measurement of body surface potentials and an advanced data analysis allow for a detailed description of U-wave morphology and its relation to the T-wave. This might be of value in discriminating intracardiac repolarization effects, mechano-electrical feedback, and arrhythmia risk stratification.

The effect of precordial lead displacement on ECG morphology.

Inaccurate electrode placement and differences in inter-individual human anatomies can lead to misinterpretation of ECG examination. The aim of the study was to investigate the effect of precordial electrodes displacement on morphology of the ECG signal in a group of 60 patients with diagnosed cardiac disease. Shapes of ECG signals recorded from precordial leads were compared with signals interpolated at the points located at a distance up to 5 cm from lead location. Shape differences of the QRS and ST-T-U complexes were quantified using the distribution function method, correlation coefficient, root-mean-square error (RMSE), and normalized RMSE. The relative variability (RV) index was calculated to quantify inter-individual variability. ECG morphology changes were prominent in all shape parameters beyond 2 cm distance to precordial leads. Lead V2 was the most sensitive to displacement errors, followed by leads V3, V1, and V4, for which the direction of electrodes displacement plays a key role. No visible changes in ECG morphology were observed in leads V5 and V6, only scaling effect of signal amplitude. The RV ranged from 0.639 to 0.989. Distortions in ECG tracings increase with the distance from precordial lead, which are specific to chosen electrode, direction of displacement, and for ECG segment selected for calculations.

Impact of accelerated ventricular tachyarrhythmias on mortality in patients with implantable cardioverter-defibrillator therapy.

BACKGROUND: Anti-tachycardia pacing (ATP) and shock delivery may induce or accelerate tachyarrhythmias in patients with implantable cardioverter-defibrillator (ICD). We investigated the incidence, triggers and impact on mortality of accelerated ventricular tachyarrhythmias. METHODS: Database analysis concerning ventricular tachyarrhythmias accelerated by ATP or shock in 1275 ICD patients (age at implantation 59.7 ± 14.0 years; 81% male). RESULTS: Within a mean follow-up period of 5.3 ± 4.0 years, intracardiac electrograms were available in 1170 patients (91.8%). Overall 157 episodes of accelerated ventricular tachyarrhythmias were found in 100 of 1170 patients (8.5%). Termination of tachyarrhythmias was achieved by shock delivery in 153 episodes (96.8%). Triggers of accelerated tachyarrhythmias were appropriate ATP in 139 (88.5%) and inappropriate ATP in 14 (8.9%), as well as appropriate and inappropriate shocks in 2 (1.3%) episodes, respectively. Chronic heart failure was significantly correlated with the occurrence and recurrence of acceleration (p<0.001). Patients with accelerated ventricular tachyarrhythmia and subsequent shock therapy revealed higher all-cause mortality (HR 1.760; 95% CI 1.286-2.410; p<0.001) as well as higher cardiac mortality (HR 2.555; 95% CI 1.446-4.513; p=0.001). The correlation between acceleration and all-cause mortality was independent of left ventricular function (HR 2.076; 95% CI 1.633-2.639; p<0.001). CONCLUSIONS: Ventricular ATP with arrhythmia acceleration and subsequent shock delivery is a frequent and serious complication of ICD therapy that predominantly occurs in patients with reduced left ventricular function. Finally, occurrence of accelerated ventricular tachyarrhythmias was associated with increased all-cause mortality.

Novel c.367_369del LMNA mutation manifesting as severe arrhythmias, dilated cardiomyopathy, and myopathy.

OBJECTIVE: The 3-bp deletion in exon 2 of the Lamin A/C (LMNA) gene has not been described in association with dilated cardiomyopathy, which is characterized by progressive heart failure, atrioventricular (AV) block, tachyarrhythmias, and variable skeletal muscle involvement. CASE REPORT: In a 43-year-old woman with a long-term history of palpitations and newly diagnosed AV blocks I and II, ventricular ectopic beats, inducible nonsustained ventricular tachycardias (VTs), cardiac arrest, and successful resuscitation, an implantable cardioverter defibrillator was successfully implanted. Her family history was positive for sudden cardiac death (her father and sister), dyspnea and heart failure (her grandmother and sister), palpitations (her brother), and elevated levels of creatine-kinase (CK) (her sister). Two cousins had died of nonspecific muscular dystrophy at ages 10 years and 11 years. Upon neurological investigations revealing sore neck muscles, reduced tendon reflexes, and detached, spot-like white matter lesions bilaterally, a neuromuscular disorder was suspected. The direct sequencing of all exons and flanking intronic regions of the LMNA gene detected the heterozygote 3-bp deletion (AAG) c.367_369del in exon 2 of the gene. This mutation resulted in the deletion of a lysine at position 123 (p.lys123del) in the lamin A/C protein. CONCLUSIONS: The novel 3-bp deletion in exon 2 of the LMNA gene may phenotypically manifest as dilated cardiomyopathy, heart failure, severe tachyarrhythmias, and muscular dystrophy. Sudden cardiac death from ventricular fibrillation may be prevented in LMNA mutation carriers if the diagnosis is established early enough to implant a cardioverter defibrillator.

Risk assessment of ventricular arrhythmia using new parameters based on high resolution body surface potential mapping.

BACKGROUND: The effective screening of myocardial infarction (MI) patients threatened by ventricular tachycardia (VT) is an important issue in clinical practice, especially in the process of implantable cardioverter-defibrillator (ICD) therapy recommendation. This study proposes new parameters describing depolarization and repolarization inhomogeneity in high resolution body surface potential maps (HR BSPM) to identify MI patients threatened by VT. MATERIAL/METHODS: High resolution ECGs were recorded from 64 surface leads. Time-averaged HR BSPMs were used. Several parameters for arrhythmia risk assessment were calculated in 2 groups of MI patients: those with and without documented VT. Additionally, a control group of healthy subjects was studied. To assess the risk of VT, the following parameters were proposed: correlation coefficient between STT and QRST integral maps (STT_QRST_CORR), departure index of absolute value of STT integral map (STT_DI), and departure index of absolute value of T-wave shape index (TSI_DI). These new parameters were compared to known parameters: QRS width, QT interval, QT dispersion, Tpeak-Tend interval, total cosines between QRS complex and T wave, and non-dipolar content of QRST integral maps. RESULTS: STT_DI, TSI_DI, STT_QRST_CORR, QRS width, and QT interval parameters were statistically significant (p ≤ 0.05) in arrhythmia risk assessment. The highest sensitivity was found for the STT_DI parameter (0.77) and the highest specificity for TSI_DI (0.79). CONCLUSIONS: Arrhythmia risk is demonstrated by both abnormal spatial distribution of the repolarization phase and changed relationship between depolarization and repolarization phases, as well as their prolongation. The proposed new parameters might be applied for risk stratification of cardiac arrhythmia.

Regional prevalence and clinical benefit of implantable cardioverter defibrillators in Brugada syndrome.

BACKGROUND: Brugada syndrome (BS) is associated with an increased risk of sudden cardiac death (SCD) caused by ventricular tachyarrhythmia. Thus, implantable cardioverter defibrillators (ICD) became the main therapeutic option in these patients. We aimed to investigate the prevalence of BS in the Eastern Alps as well as the benefit of ICD therapy in this collective. METHODS: During physical examination before military service, 47,606 Austrian men were screened for Brugada ECG pattern. Furthermore, we followed 4491 patients with arrhythmia during the last two decades, of which 26 patients (20 male; age at diagnosis: 43.2 ± 11.6 years) revealed BS. Diagnosis was based on characteristic ECG either at rest (11 patients) or after provocation with Ajmaline (15 patients). RESULTS: The nationwide screening revealed one individual with Brugada ECG (prevalence of 2.10/100,000 inhabitants). Prior to diagnosis of BS, syncope and SCD survival were observed in 7 and 4 patients, respectively; the remaining 15 patients were asymptomatic. ICD were implanted in 17 patients (15 male). Three asymptomatic patients received no ICD because no tachyarrhythmia was inducible on programmed stimulation. Six asymptomatic patients without family history of sudden death refused further evaluation. Mean ICD follow-up period was 57.0 ± 32.2 months. Two patients (11.7%) needed defibrillation therapy. Four patients (23.5%) received exclusively inappropriate shocks (three due to T-wave oversensing, one due to atrial fibrillation). CONCLUSIONS: Brugada syndrome has a low prevalence in the Eastern alpine region. Patients with BS benefit from ICD implantation, but less frequently than anticipated. The problem of inappropriate ICD discharges is still of major concern.

Automatic home monitoring of implantable cardioverter defibrillators.

AIMS: With the expanding indications for implantable cardioverter defibrillator (ICD) and reports of unexpected ICD failures, home monitoring (HM) was proposed to decrease follow-up workload and increase patient safety. Home monitoring implantable cardioverter defibrillators offer wireless, everyday transfer of ICD status and therapy data to a central HM Service Center, which notifies the attending physician of relevant HM events. We evaluated functionality and safety of HM ICDs. METHODS AND RESULTS: A total of 260 patients with HM ICDs were monitored for a mean of 10 +/- 5 months. Time to HM events [medical (ventricular tachycardia/ventricular fibrillation) and technical (ICD system integrity)] since ICD implantation and since the latest in-clinic follow-up was analysed. Mean number of HM events per 100 patients per day was calculated, without and with a 2-day blanking period for re-notifying the same type of event. About 41.2% of the patients had HM events (38.1% medical, 0.8% technical, and 2.3% both types). Probability of any HM event after 1.5 years was 0.50 (95% confidence interval: 0.42-0.58). More than 60% of new HM event types occurred within the first month after follow-up. A mean of 0.86 event notifications was received per 100 patients per day or 0.45 with the 2-day blanking period. CONCLUSION: Home monitoring is feasible and associated with an early detection of medical and technical events.

Atrial function after ablation procedure in patients with chronic atrial fibrillation using steady-state free precession magnetic resonance imaging.

BACKGROUND: Surgical ablation procedures are an established surgical procedure for restoration of sinus rhythm and reestablishment of atrial function in patients with chronic atrial fibrillation. The purpose of this study was to evaluate the feasibility and reproducibility of steady-state free precession magnetic resonance imaging (SSFP MRI) for examination of atrial dimensions and function after ablation procedures. METHODS: Nineteen patients (mean age, 63.1 +/- 11.7 years) being at least six months after surgical ablation procedure, with stable sinus rhythm, were selected for the study. They underwent cardiac MRI. End-diastolic and end-systolic volumes were measured using Simpson's rule. The presence of visual contraction was visually assessed. RESULTS: In MRI evaluation mean end-diastolic volume of the right atrium and left atrium after an ablation procedure was 127 +/- 45 mL and 163 +/- 50 mL, respectively. Mean stroke volume was 23 +/- 15 mL and 26 +/- 12 mL for the right and left atrium. Mean ejection fraction of the right atrium was 0.19 +/- 0.14 and 0.17 +/- 0.1 for the left atrium. An atrial kick of both atria was observed in 8 of 19 (47%) patients. An atrial kick of only the right atrium was observed in an additional 13 of 19 (68%) patients. CONCLUSIONS: The anticipated events after a surgical ablation procedure are the restoration of atrial contractility and the associated atrial kick, thereby enhancing cardiac output and decreasing the risk of thromboembolism. Evaluation of atrial function after an ablation procedure using SSFP MRI is feasible and allows a standardized documentation of postoperative atrial function, thus allowing evaluation of the surgical outcome in a reproducible way. Echocardiographic evaluation seems to underestimate the transport function of the atrium.

Permanent chronic atrial fibrillation: is pulmonary vein isolation alone enough?

BACKGROUND: The efficacy of mere pulmonary vein isolation epicardially for the treatment of permanent chronic atrial fibrillation, in comparison with the left atrial endocardial maze procedure was evaluated. METHODS: Retrospective data collection and analysis toward the outcome of 72 consecutive patients who underwent left atrial maze procedures between January 2003 and December 2005 was performed. Surgical ablation was performed concomitantly with valve and (or) coronary procedures. Group I (n = 29) received an endocardial left atrial ablation using unipolar saline irrigated radiofrequency (Medtronic Cardioblate surgical ablation pen; Medtronic Inc, Minneapolis, MN). Group II (n = 43) received epicardial isolation of the pulmonary veins using bipolar saline irrigated radiofrequency (Medtronic Cardioblate). Follow-up included 24h electrocardiogram and echocardiography 6 and 12 months postoperatively. RESULTS: Mean follow-up was 19.5 +/- 1.0 months (17.7 +/- 19.5 months group I vs 20.6 +/- 1.1 months group II). Both groups were comparable with regard to duration of preoperative atrial fibrillation, European system for cardiac operative risk evaluation, left ventricular ejection fraction, aortic cross-clamp time, bypass time, intensive care unit and hospital stay (p > 0.05). No maze procedure-related mortality was observed. In group I, three patients required postoperative pacemaker implantation due to atrioventricular (AV) bloc, bradycardia, and sick sinus syndrome, respectively. In group II, five patients required postoperative pacemaker implantation (three AV bloc and two bradycardia). Freedom from atrial fibrillation at last follow-up was 85.7% and 58.5% in groups I and II, respectively (p = 0.016). CONCLUSIONS: Pulmonary vein isolation alone seems to be insufficient in treating permanent chronic atrial fibrillation. In case of chronic permanent atrial fibrillation, left atrial endocardial maze, providing the connection lines to the mitral annulus and (or) between the pulmonary veins, seems to be mandatory.

Interference of programmed electromagnetic stimulation with pacemakers and automatic implantable cardioverter defibrillators.

A commercially available magnetic therapy system, designed for clinical application as well as for private use without medical supervision, was examined with respect to its potential for causing electromagnetic interference with implantable pacemakers (PMs) and automatic implantable cardioverter defibrillators (AICDs). A sample of 15 PMs and 5 AICDs were experimentally investigated. Each of the implants was realistically positioned in a homogeneous, electrically passive torso phantom and exposed to the magnetic fields of the system's applicators (whole body mat, cushion, and bar applicator). The detection thresholds of the implants were programmed to maximum sensitivity and both unipolar as well as bipolar electrode configurations were considered. The evaluation of possible interferences was derived from the internal event storages and pacing statistics recorded by the implants during exposure. Any "heart activity" recorded by the implants during exposure was interpreted as a potential interference, because the implant obviously misinterpreted the external interference signal as a physiological signal. Only cases without any recorded "heart activity" and with nominal pacing rates (as expected from the program parameter settings) of the implants were rated as "interference-free." Exposure to the whole body mat (peak magnetic induction up to 265 microT) did not show an influence on PMs and AICD in any case. The cushion applicator at the highest field intensity (peak magnetic induction up to 360 microT) led to atrial sensing defects in four PM models with unipolar electrode configuration. Under bipolar electrode configuration no disturbances occurred. The bar applicator led to sensing problems and consecutively reduced pacing rates in all tested PM models under unipolar electrode configuration and maximum field intensity (peak magnetic induction up to 980 microT). Bipolar electrode configuration resolved the problem. The investigated AICDs did not show malfunctions under any investigated condition. In conclusion, the examined PEMF therapy system did not interfere with the investigated implantable cardiac devices with bipolar electrode configuration. However, unipolar electrode configuration in pacemakers seems to be potentially hazardous during application of the examined PEMF therapy system.

Microwave and radiofrequency ablation yield similar success rates for treatment of chronic atrial fibrillation.

OBJECTIVE: To evaluate the influence of two different ablation devices (microwave AFx and radiofrequency Medtronic), designed to create linear lesion lines, with respect to efficacy and restoration of sinus rhythm (SR). METHODS: Between February 2001 and December 2002, 42 patients with chronic, persistent atrial fibrillation (AF) >6 months were submitted to different combinations of valve surgery (mitral+/-tricuspid, n = 30; mitral and aortic+/-tricuspid reconstruction, n = 6 aortic+/-tricuspid, n = 8) and concomitant Maze procedure. The biatrial Maze followed the concept of the Cox III procedure, using either microwave energy (AFx Lynx) (group I: age 65.8+/-11.9 years, mean duration of AF 61.9+/-28.9 months, n = 23) or radiofrequency (Medtronic Cardioblate) (group II: age 64.1+/-11.1 years, mean duration of AF 53.5+/-49 months, n = 19). RESULTS: There was one death with group I (4%), due to liver failure. Both groups were comparable with regard to Euro Score, ejection fraction, cross clamp time, cardiopulmonary bypass time, ICU (median 1 day in both groups) and hospital stay, and type of indication. The preoperative diameter of the left atrium was 69.7+/-10.8 and 74.0+/-14.3 mm in groups I and II, respectively (P = 0.359). The Maze procedure resulted in 23+/-2 and 17+/-1 min additional cross clamp time in groups I and II, respectively (P = 0.013). At the 12-month follow up, freedom from AF was 81 and 80% in groups I and II, respectively. Twenty percent in group I and 21% in group II needed a pacemaker (PM), due to sick sinus syndrome (2 versus 2 cases), AV bloc (2 versus 1 case) and preoperative bradycardia (0 versus 1 case), respectively. CONCLUSIONS: The combination of complex valve surgery and Maze procedure was safe and reproducible. Following the Cox Maze III line concept, microwave and radiofrequency ablation gave similar results even in patients with more complex double or triple valve procedures.

Electromagnetic interference by transcutaneous neuromuscular electrical stimulation in patients with bipolar sensing implantable cardioverter defibrillators: a pilot safety study.

Neuromuscular electrical stimulation (NMES) is a frequently applied therapy for the treatment of pain and a therapeutic option to increase thigh muscle strength and endurance capacity in patients with heart failure. Electromagnetic interference (EMI) by the signals with sensing of ICDs is possible. Eight patients with subpectoral ICD systems and different transvenous bipolar sensing leads were subjected to electrical stimulation of the neck and shoulder and of the thighs using different stimulation algorithms. EMI with ventricular sensing was detectable in three of eight subjects. EMI occurred during stimulation of the neck (n = 2) and thigh (n = 2). EMI by NMES with atrial sensing was seen in two of four subjects with dual chamber ICDs. The safety of peripheral NMES has to be individually tested as EMI can also occur in ICD patients with bipolar sensing.

Survivors of ventricular tachyarrhythmias due to a transient or reversible disorder have a high recurrence rate of lethal cardiac events.

OBJECTIVES: The recurrence rate of lethal cardiac events after the survival of a primary cardiac arrest in patients not having received an implantable cardioverter defibrillator (ICD) is investigated. BACKGROUND: According to current guidelines, only a small percentage of patients after successful cardiopulmonary resuscitation due to an underlying cardiac problem are eligible for the implantation of an ICD. METHODS: For retrospective analysis, we used a data registry of patients admitted to an emergency department after cardiac arrest. Patients who had a primary cardiac cause for their cardiac arrest and who did not die within the first month after successful restoration of spontaneous circulation were selected. RESULTS: From 1246 patients, 360 met the inclusion criteria. A second lethal cardiac event occurred in 94 (26%). Of those 94 patients, 57 (61%) had good neurological function before their second cardiac arrest. Of the survivors with good neurological function, 47 (82%) did not have an ICD or a cardiac transplant. Another cardiac arrest due to a primary cardiac event occurred in 34 (72%) of these patients. CONCLUSIONS: Cardiac arrest survivors without an apparent indication for an ICD have a high risk of suffering from a re-arrest of cardiac origin.