Günter Stix

Implantable Loop Recorder in Unexplained Syncope: Classification, Mechanism, Transient Loss of Consciousness and Role of Major Depressive Disorder in Patients with and without Structural Heart Disease

Objective: To stratify mechanisms and predictors of unexplained syncope documented by an implantable loop recorder (ILR) in patients with and without structural heart disease (SHD). Design and setting: Prospective study in consecutive patients of a university cardiac centre. Patients and methods: An ILR was implanted in 70 patients (34 male/36 female, aged 55 (17) years) in whom syncope remained unexplained after thorough testing. SHD was present in 33 patients (ischaemic cardiomyopathy in 16, dilated cardiomyopathy in 9 and hypertrophic cardiomyopathy in 8) and absent in 37 patients (mean (SD) left ventricular ejection fraction 46 (4)% vs 61 (7)%, respectively). Results: A syncopal recurrence occurred during 16 (8) months in 30 patients (91%) with SHD and in 30 patients (81%) without SHD. Fifteen patients (45%) versus 19 patients (51%), respectively, had an ILR-documented arrhythmia at the time of recurrence which led to specific treatment. The remaining 15 patients (45%) with SHD and 11 patients (30%) without SHD had normal sinus rhythm at the time of the recurrence. On stepwise multivariate analysis only major depressive disorder was predictive for early recurrence during ILR follow-up (p = 0.01, hazard ratio  =  3.35, 95% CI 1.1 to 7.1). Fifty seven per cent of patients with major depressive disorder had sinus rhythm during recurrence compared with 31% of patients without the disorder (p = 0.01). Conversely, no patient with major depressive disorder had asystole compared with 33% without (p<0.001). Conclusions: The presence of SHD has little predictive value for the occurrence or type of arrhythmia in patients with unexplained syncope. Patients with major depressive disorder are prone to early recurrence of symptoms and have no evidence of arrhythmia in most cases. The ILR leads to specific treatment in half of all patients.

Unexplained syncope in patients with structural heart disease and no documented ventricular arrhythmias: value of electrophysiologically guided implantablecardioverter defibrillator therapy

AIMS To evaluate electrophysiologically guided implantable cardioverter defibrillator (ICD) therapy in patients with syncope, structural heart disease and no documented sustained ventricular tachycardia (sVT). METHODS AND RESULTS Programmed ventricular stimulation (PVS) was performed in 52 patients (age 62+/-10 years): 40 patients had ischaemic and 12 patients had idiopathic dilated cardiomyopathy. On PVS sVT and ventricular fibrillation were induced in seven and four patients, respectively, and two patients spontaneously experienced symptomatic sVT. These patients received an ICD (ICD group, n=13). Non-inducible patients were left on conventional therapy (non-ICD group, n=39). During 5+/-2.8 years five ICD patients received therapies, all appropriate. There were seven non-sudden deaths and overall survival analysis revealed no significant difference. Recurrent syncope occurred in five ICD and four non-ICD patients and did not correlate well with sVT. The positive and negative predictive values of PVS for tachyarrhythmias or sudden death were 36 and 98%, respectively. CONCLUSION Syncope per se does not necessarily herald a bad prognosis. PVS identifies high-risk patients. Induction of ventricular fibrillation with double or triple extrastimuli is of limited value. Patients with poor left ventricular function and bad clinical condition benefit most from an ICD. Syncope and sVT are not necessarily correlated during follow-up, which may merit consideration.

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.

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

Summary 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.

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.

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.

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

Abstract 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.

An Analysis of the U‐Wave and Its Relation to the T‐Wave in Body Surface Potential Maps for Healthy Subjects and MI Patients

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.

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.