Cardiac MRI after Sudden Cardiac Arrest: A Systematic Review.

Purpose To perform a systematic review to assess the diagnostic and prognostic value of cardiac MRI after sudden cardiac arrest (SCA). Materials and Methods PubMed and Cochrane Library databases were systematically searched for studies investigating cardiac MRI after SCA in adult patients (≥18 years of age). The time frame of the encompassed studies spans from January 2012 to January 2023. The study protocol was preregistered in OSF Registries (www.osf.io/nxaev), and the systematic review was performed following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. The quality of the included studies was evaluated using the Newcastle-Ottawa quality assessment scale. Results Fourteen studies involving 1367 individuals, 1257 (91.9%) of whom underwent cardiac MRI, were included. Inconsistent findings were reported on the diagnostic value of cardiac MRI-specific findings. The included studies demonstrated the following main findings: (a) cardiac MRI led to a new or alternative diagnosis in patients with SCA; (b) cardiac MRI identified pathologic or arrhythmogenic substrates; (c) cardiac MRI helped detect myocardial edema (potentially reversible); (d) cardiac MRI provided evidence for the occurrence of adverse events; and (e) functional markers or ventricular dimensions were considered prognostically relevant in a few studies. Relevant challenges in this systematic review were the lack of comparators and reference standards relative to cardiac MRI as the index test and patient selection bias. Conclusion Cardiac MRI following SCA can contribute to the diagnostic process and offer supplementary information essential for treatment planning. Limitations of the review include studies with insufficient comparators and potential bias in patient selection. Systematic review registration link: osf.io/nxaev Keywords: Cardiac MRI, Cardiovascular Disease, Cardiomyopathy, Ischemia, Myocardial Edema, Sudden Cardiac Arrest © RSNA, 2024.

Impact of cavotricuspid isthmus ablation for typical atrial flutter and heart failure in the elderly-results of a retrospective multi-center study.

Introduction: While in the CASTLE-AF trial, in patients with atrial fibrillation and heart failure with reduced ejection fraction, interventional therapy using pulmonary vein isolation was associated with outcome improvement, data on cavotricuspid isthmus ablation (CTIA) in atrial flutter (AFL) in the elderly is rare. Methods: We included 96 patients between 60 and 85 years with typical AFL and heart failure with reduced or mildly reduced ejection fraction (HFrEF/HFmrEF) treated in two medical centers. 48 patients underwent an electrophysiological study with CTIA, whereas 48 patients received rate or rhythm control and guideline-compliant heart failure therapy. Patients were followed up for 2 years, with emphasis on left ventricular ejection fraction (LVEF) over time. Primary endpoints were cardiovascular mortality and hospitalization for cardiac causes. Results: Patients with CTIA showed a significant increase in LVEF after 1 (p < 0.001) and 2 years (p < 0.001) in contrast to baseline LVEF. Improvement of LVEF in the CTIA group was associated with significantly lower 2-year mortality (p = 0.003). In the multivariate regression analysis, CTIA remained the relevant factor associated with LVEF improvement (HR: 2.845 CI:95% 1.044-7.755; p = 0.041). Elderly patients (≥ 70 years) further benefited from CTIA, since they showed a significantly reduced rehospitalization (p = 0.042) and mortality rate after 2 years (p = 0.013). Conclusions: CTIA in patients with typical AFL and HFrEF/HFmrEF was associated with significant improvement of LVEF and reduced mortality rates after 2 years. Patient age should not be a primary exclusion criterion for CTIA, since patients ≥70 years also seem to benefit from intervention in terms of mortality and hospitalization.

Case report: Short-long-short mechanism triggering sustained ventricular tachycardia in a patient with a single-chamber ICD but inhibiting antitachycardia therapy.

Introduction: Short-long-short (SLS) sequences are an important cause of ICD pro-arrhythmia and can initiate both polymorphic and monomorphic ventricular tachycardias (VT). Depending on the programming of a single-chamber ICD, the interplay between SLS sequences and combined VT detection criteria can be responsible for withholding adequate anti-tachycardia pacing (ATP) or shock therapy. Methods: A 78-year-old patient with ICD was admitted to our emergency department after external cardioversion of a long-lasting VT with hemodynamic compromise. The interrogation of the ICD revealed an SLS sequence initiating a monomorphic VT at a rate of 171 bpm (350 ms). The VT discrimination of the implanted single-chamber ICD was based on the onset and stability criteria as the patient had a history of paroxysmal atrial fibrillation. The ICD was programmed that both criteria had to be met for VT detection and initiation of anti-tachycardia therapy. Results: Due to the SLS sequence in combination with the programmed VT detection interval, the onset threshold was not fulfilled and inhibited adequate therapy. Some relatively slow VT beats following the SLS sequence resulted finally in a considerable delay in the declaration of the episode onset. As a first step, the threshold for VT detection was programmed to 150 instead of 160 bpm. To avoid SLS sequences and pause-dependent ventricular tachyarrhythmias, VVI backup stimulation was increased from 35 to 55 ppm. Besides, a device-specific algorithm called rate smoothing was activated as a potential preventive feature. On the 3-month follow-up, all sustained VT episodes were detected adequately by the reprogrammed device, resulting in appropriate anti-tachycardia pacing. After further refinement and less aggressive programming of rate smoothing, the patient remained free of symptoms and arrhythmias over a follow-up of more than 2.5 years, particularly since progression to permanent atrial fibrillation and pacing at a lower rate of 60 ppm. Conclusions: SLS sequences may initiate or trigger VT episodes. Misclassification of the true onset may occur in some ICD devices due to specific programming of VT detection criteria. If both criteria "Onset and Stability" have to be fulfilled, ICD therapy is not delivered despite ongoing VT. Anti-bradycardia backup pacing at a very low stimulation rate may facilitate SLS sequences in patients with ICD resembling a potential pro-arrhythmic mechanism. In case of gradual VT onset with some intervals slower than the programmed VT threshold, the detection rate has to be adjusted down to guarantee appropriate identification of the onset.

Higher Incidence of Stroke in Severe COVID-19 Is Not Associated With a Higher Burden of Arrhythmias: Comparison With Other Types of Severe Pneumonia.

Aims: Thromboembolic events, including stroke, are typical complications of COVID-19. Whether arrhythmias, frequently described in severe COVID-19, are disease-specific and thus promote strokes is unclear. We investigated the occurrence of arrhythmias and stroke during rhythm monitoring in critically ill patients with COVID-19, compared with severe pneumonia of other origins. Methods and Results: This retrospective study included 120 critically ill patients requiring mechanical ventilation in three European tertiary hospitals, including n =60 COVID-19, matched according to risk factors for the occurrence of arrhythmias in n = 60 patients from a retrospective consecutive cohort of severe pneumonia of other origins. Arrhythmias, mainly atrial fibrillation (AF), were frequent in COVID-19. However, when compared with non-COVID-19, no difference was observed with respect to ventricular tachycardias (VT) and relevant bradyarrhythmias (VT 10.0 vs. 8.4 %, p = ns and asystole 5.0 vs. 3.3%, p = ns) with consequent similar rates of cardiopulmonary resuscitation (6.7 vs. 10.0%, p = ns). AF was even more common in non-COVID-19 (AF 18.3 vs. 43.3%, p = 0.003; newly onset AF 10.0 vs. 30.0%, p = 0.006), which resulted in a higher need for electrical cardioversion (6.7 vs. 20.0%, p = 0.029). Despite these findings and comparable rates of therapeutic anticoagulation (TAC), the incidence of stroke was higher in COVID-19 (6.7.% vs. 0.0, p = 0.042). These events also happened in the absence of AF (50%) and with TAC (50%). Conclusions: Arrhythmias were common in severe COVID-19, consisting mainly of AF, yet less frequent than in matched pneumonia of other origins. A contrasting higher incidence of stroke independent of arrhythmias also observed with TAC, seems to be an arrhythmia-unrelated disease-specific feature of COVID-19.

Thinking fast and slow: lactate and MELD-XI (model for end-stage liver disease excluding INR) are useful for estimating mortality after cardiopulmonary resuscitation.

BACKGROUND: Intensivists keep getting challenged with prognostication after cardiopulmonary resuscitation (CPR). The model for end-stage liver disease, excluding INR (MELD-XI) Score has proven valuable for assessing illness severity. Serum lactate is a readily available and established indicator of general stress and tissue hypoxia. We aimed to evaluate the prognostic value of MELD-XI combined with serum lactate in patients after CPR. METHODS: A retrospective analysis on 106 patients after CPR was performed. Multivariable Cox regression was performed to evaluate associations with 30-day mortality and neurological outcome by means of cerebral performance category (CPC). An optimal cut-off was calculated by means of the Youden Index. Patients were then divided into subgroups based on the optimal cut-offs for MELD-XI and serum lactate. RESULTS: MELD-XI and lactate were independently associated with mortality. The respective cut-offs were MELD-XI>12 and lactate ≥2.5 mmol/L. Patients were split into three groups: lactate <2.5 mmol/L and MELD-XI≤12 (low-risk; N.=32), lactate ≥2.5 mmol/L or MELD-XI>12 (medium-risk; N.=39), and lactate ≥2.5 mmol/L and MELD-XI >12 (high-risk; N.=33). The mortality rates were 6%, 26% and 61% in the low, medium and high-risk group. This combined model yielded in the highest predictive abilities (AUC=0.78 95%CI: 0.68-0.85; P=0.03 vs. AUC=0.66 for SOFA Score). Worse neurological outcome (CPC 3 or 4) was more common in the medium and high-risk group (6.25%, 10.3% and 9.1%). CONCLUSIONS: The combination of MELD-XI and lactate concentration at ICU admission was superior to the more complex SOFA Score for prediction of mortality after CPR.

Left Atrial Ejection Fraction Assessed by Prior Cardiac CT Predicts Recurrence of Atrial Fibrillation after Pulmonary Vein Isolation.

Assuming that atrial fibrillation (AF) is associated with left atrial remodeling and dysfunction, we hypothesize that left atrial and left atrial appendage ejection fractions (LAEF and LAAEF) are useful and may be more sensitive outcome predictors of pulmonary vein isolation (PVI). Fifty patients who underwent PVI at our institution with available pre-interventional cardiac computed tomography (CT) for procedure planning were included in this retrospective study. The patients were separated into two groups by recurrence and non-recurrence of AF and subgroups of paroxysmal and persistent AF. Semiautomatic volumetric analysis of the left atrium was used to calculate morphological and functional parameters and optimal cut-offs were calculated using the Youden index. LAEF (accuracy 94%, sensitivity 67%) and LAAEF (accuracy 90%, sensitivity 67%) were significantly reduced in patients with AF recurrence (16% vs. 36%, p = 0.00002; 16% vs. 42%, p = 0.000002), and in the subgroup analysis, the functional parameters were independent from AF type (paroxysmal and persistent). With a cut-off of <23% for both LAEF and LAAEF (area under the curve (AUC) 0.94, 95%CI 0.84-0.99 and AUC 0.96, 95%CI 0.86-0.99, respectively), AF recurrence occurred in 77.8%, within a mean follow-up period of 229 days. In conclusion, left atrial function on prior cardiac CT offers useful parameters for predicting AF recurrence after PVI.

Infective endocarditis - A review of current therapy and future challenges.

Etiological, microbiological and epidemiological factors changed over time, but mortality rates remain high in infective endocarditis (IE). Healthcare-associated IE is nowadays responsible for a significant proportion of cases due to increasing numbers of cardiac devices. Cardiac implantable electronic devices, transcatheter aortic valve replacement, and percutaneous valve repair are meanwhile used, especially in old and sick patients. In suspected IE modified Duke criteria, integrating clinical results, imaging, and biomarkers are traditionally applied. Newer imaging technologies such as multi-slice computed tomography, photon-emission computed tomography, and magnetic resonance imaging might add value to conventional echocardiography in diagnosis and management of IE. Treatment consists of long-term antibiotic therapy, infectiological source control and/or cardiac surgery. Recently, antibiotic parenteral outpatient regimens and partial oral treatment strategies were shown to shorten hospital stays in patients suffering from IE. However, it remains unclear how to best select patients for partial oral therapy. This review describes new trends in diagnosing, imaging, and treating IE in a changing patient collective with particular focus on patients with implantable cardiac devices.

Safe application of extensive radiotherapy to a cardiac resynchronization device.

Patients with cardiac implantable electronic devices undergoing radiotherapy (RT) are prone to the risk of device failure. Guidelines and manufacturer's instructions are lacking practical recommendations for cumulative radiation doses to pacemakers or implantable cardioverter defibrillators. The present case demonstrates the effect of RT of a Merkel cell carcinoma near the location of a cardiac resynchronization therapy pacemaker. Despite guideline recommendations, surgical relocation or de novo implantation of the device on the contralateral side was avoided to prevent the dissemination of tumour cells, inflammation, and wound healing complications. A total dose of 47.25 Gy applied in very close proximity to the cardiac resynchronization therapy pacemaker was carried out safely without jeopardizing the patient and any device malfunction during and after treatment within >1.5 years of follow-up period. The present case demonstrates that high-dose RT near to a cardiac resynchronization therapy device can be carried out safely. Special precautions during RT as well as close device follow-up interrogations are mandatory. Large-scale studies are needed for the true frequency of adverse events.

Classic and Novel Biomarkers as Potential Predictors of Ventricular Arrhythmias and Sudden Cardiac Death.

Sudden cardiac death (SCD), most often induced by ventricular arrhythmias, is one of the main reasons for cardiovascular-related mortality. While coronary artery disease remains the leading cause of SCD, other pathologies like cardiomyopathies and, especially in the younger population, genetic disorders, are linked to arrhythmia-related mortality. Despite many efforts to enhance the efficiency of risk-stratification strategies, effective tools for risk assessment are still missing. Biomarkers have a major impact on clinical practice in various cardiac pathologies. While classic biomarkers like brain natriuretic peptide (BNP) and troponins are integrated into daily clinical practice, inflammatory biomarkers may also be helpful for risk assessment. Indeed, several trials investigated their application for the prediction of arrhythmic events indicating promising results. Furthermore, in recent years, active research efforts have brought forward an increasingly large number of "novel and alternative" candidate markers of various pathophysiological origins. Investigations of these promising biological compounds have revealed encouraging results when evaluating the prediction of arrhythmic events. To elucidate this issue, we review current literature dealing with this topic. We highlight the potential of "classic" but also "novel" biomarkers as promising tools for arrhythmia prediction, which in the future might be integrated into clinical practice.

Exercise-related T-wave oversensing: an underestimated cause of reduced exercise capacity in a pacemaker-dependent patient-a case report and review of the literature.

A 62-year-old pacemaker-dependent patient presented to our department with a sudden onset of reduced physical capacity. While initial physical and pacemaker evaluations remained without specific findings, Holter-ECG monitoring revealed an abnormal rate response with unusual pauses during physical exercise. Consequently, closer evaluation of the pacemaker system revealed intermittent, exercise-related T-wave oversensing (TWOS). While TWOS remains a significant burden in ICD-patients, it might be an underestimated but clinically significant event in pacemaker patients. Further studies should evaluate the impact of TWOS in this patient population.

Polymorphisms in the GNAS Gene as Predictors of Ventricular Tachyarrhythmias and Sudden Cardiac Death: Results From the DISCOVERY Trial and Oregon Sudden Unexpected Death Study.

BACKGROUND: Population-based studies suggest that genetic factors contribute to sudden cardiac death (SCD). METHODS AND RESULTS: In the first part of the present study (Diagnostic Data Influence on Disease Management and Relation of Genetic Polymorphisms to Ventricular Tachy-arrhythmia in ICD Patients [DISCOVERY] trial) Cox regression was done to determine if 7 single-nucleotide polymorphisms (SNPs) in 3 genes coding G-protein subunits (GNB3, GNAQ, GNAS) were associated with ventricular tachyarrhythmia (VT) in 1145 patients receiving an implantable cardioverter-defibrillator (ICD). In the second part of the study, SNPs significantly associated with VT were further investigated in 1335 subjects from the Oregon SUDS, a community-based study analyzing causes of SCD. In the DISCOVERY trial, genotypes of 2 SNPs in the GNAS gene were nominally significant in the prospective screening and significantly associated with VT when viewed as recessive traits in post hoc analyses (TT vs CC/CT in c.393C>T: HR 1.42 [CI 1.11-1.80], P=0.005; TT vs CC/CT in c.2273C>T: HR 1.57 [CI 1.18-2.09], P=0.002). TT genotype in either SNP was associated with a HR of 1.58 (CI 1.26-1.99) (P=0.0001). In the Oregon SUDS cohort significant evidence for association with SCD was observed for GNAS c.393C>T under the additive (P=0.039, OR=1.21 [CI 1.05-1.45]) and recessive (P=0.01, OR=1.52 [CI 1.10-2.13]) genetic models. CONCLUSIONS: GNAS harbors 2 SNPs that were associated with an increased risk for VT in ICD patients, of which 1 was successfully replicated in a community-based population of SCD cases. To the best of our knowledge, this is the first example of a gene variant identified by ICD VT monitoring as a surrogate parameter for SCD and also confirmed in the general population. CLINICAL TRIAL REGISTRATION: URL: http://www.clinicaltrials.gov. Unique identifier: NCT00478933.

Short-term pacemaker dependency after transcatheter aortic valve implantation.

BACKGROUND: Transcatheter aortic valve implantation (TAVI) is a less invasive technique for the treatment of severe aortic stenosis in high-risk patients. Occurrence of conduction disturbances requiring permanent pacemaker (PPM) implantation after TAVI is frequently observed. METHODS: The retrospective analysis comprised 153 patients (96 women, aged from 65 to 97 years) who underwent TAVI due to high-grade aortic stenosis. The aim was to evaluate the incidence of high-grade atrioventricular (AV) block after TAVI and the percentage of ventricular pacing and pacemaker (PM)-dependency at the first follow-up 6-8 weeks after implantation. RESULTS: Out of the 153 patients (age 81 ± 6 years) who underwent TAVI, 144 (94 %) had a transfemoral and 9 (6 %) patients a transapical approach. A PPM was implanted in 31 (20 %) patients, 24 (16 %) were implanted with the Medtronic CoreValve® and 7 (5 %) with the Edwards Sapien® valve (p = n.s.). Complete AV block was the indication in 21 patients (68 %), second-degree AV block in 1 patient (3 %), slow atrial fibrillation in 3 patients (10 %), new left bundle branch block (LBBB) plus sustained ventricular tachycardia (VT) in 1 patient (3 %), sick sinus syndrome in 2 patients (7 %), whereas in 3 patients (10 %) a PPM was inserted for safety reasons because of new LBBB and first-grade AV block. All of the nine patients (6 %) with a preexisting bundle branch block developed total AV block after TAVI. At follow-up PM-dependency (intrinsic rhythm < 30 bpm) occurred in 11/30 patients (37 %), whereas an intrinsic rhythm > 50 bpm was seen in 17 patients (57 %). At nominal device programming the percentage of ventricular stimulation (VP) during the short-term observation period was 60 ± 44 % in dual-chamber devices (N = 18), and 70 ± 36 % in single-chamber PPM (N = 5). CONCLUSION: The PPM implantation rate of about 20 % after TAVI is comparable to previously published data. The need for permanent pacing is linked to the valve type and preexistence of a right bundle branch block. At short-term more than half of the patients implanted with a device were not strictly PM-dependent, but presented an underlying intrinsic rhythm, indicating that temporary AV conduction disturbances may recover over time. This might justify a more conservative approach in some patients under watchful waiting. From another point of view, ventricular pacing at a regular or sensor-modulated rate may provide rhythm stability and chronotropy during the short-term period post-TAVI.

Frailty scoring in transcatheter aortic valve replacement patients.

BACKGROUND: Transcatheter aortic valve replacement (TAVR) is a less invasive treatment option for patients that are deemed too high a risk for surgical aortic valve replacement (SAVR). The aim of this review is to evaluate the frailty tools currently being used in patients referred for TAVR. METHODS: Using a literature search involving database search engines from CINAHL, PubMed, SAGE publications and European Society of Cardiology conducted from 2010 to the present, a critical evaluation of studies dealing with frailty assessment in patients referred for TAVR/SAVR is discussed. RESULTS: Eight studies met the criteria using frailty assessment in TAVR/SAVR patients. In all reviewed studies the impact of frailty on clinical outcome has been proved. Different instruments for measurements of frailty were used that have not been robustly evaluated. Frailty was defined differently and results may not be comparable. All reviewed studies used different cutoffs and scales and some a composite scoring system, although validity was limited. CONCLUSION: For frailty assessment implementation of validated standardized test protocols based on well-established assessment tools, covering all domains of frailty among TAVR centers is crucial for patient selection. Secondly, validated cutoffs and scoring systems are essential.

The influence of cavotricuspid isthmus length on total radiofrequency energy to cure right atrial flutter.

BACKGROUND AND AIM: The complexity and success rate of right atrial flutter ablation is highly dependent on anatomical structures. METHODS: The study comprised 35 consecutive patients (33-77 years old; 30 men) who underwent ablation of typical atrial flutter. The linear ablation line was measured offline as a surrogate for the cavotricuspid isthmus (CTI) length with the help of a three-dimensional mapping and navigation system (Ensite™). Biophysical parameters, such as total radiofrequency (RF) energy and time of the ablation procedure, were analysed to test the hypothesis that any of these variables show a correlation with the length of the ablation line. RESULTS: Bidirectional isthmus block was achieved in all cases. The isthmus length had a mean value of 32 ± 12 mm with a range of 14-57 mm. The linear regression between the CTI length and the total RF energy was not significant. There was no significant difference in energy (32.281 ± 25.587 vs. 37.136 ± 24.250 W-s, p = NS) or in the total ablation time (759 ± 646 vs. 802 ± 533 s, p = NS) between the group with short (< 29 mm; n = 17) vs. long CTI (≥ 29 mm, n = 18). When comparing different ablation technologies, total RF energy delivered with 8-mm catheter technology (group I) was significantly lower than in patients with cross over from 8-mm to cooled ablation technology (group III) (29.615 ± 12.331 vs. 62.674 ± 28.735 W-s, p = 0.01). The same was true for the comparison between cooled ablation technology (group II) and group III (19.879 ± 13.669 vs. 62.674 ± 28.735 W-s, p = 0.002). CONCLUSIONS: The length of the CTI as measured with help of a three-dimensional mapping system may reflect only a weak indicator for the complexity of flutter ablation procedures. The thickness of musculature and specific anatomy of the CTI seem to be the main challenges in performing a linear ablation to achieve bidirectional block.

Fontan-like circulation as a criterion for heart transplantation in arrhythmogenic right ventricular dysplasia.

BACKGROUND: Arrhythmogenic right ventricular dysplasia (ARVD) is often associated with progressive right ventricular dysfunction. Although heart transplantation (HTx) is suggested in these patients, indication and optimal timing for listing can be challenging. METHODS AND RESULTS: The study comprises four patients (two male, range: 37-56 years) with advanced ARVD who were considered for HTx. Standard inclusion criteria for HTx listing such as clinical signs, New York Heart Association (NYHA) classification (II-III), and N-terminal pro-brain natriuretic peptide (NT-proBNP) (3672 ± 1407 pg/ml) were heterogeneous and did not add unequivocally to decision making. In all patients, though, right heart hemodynamics revealed Fontan-like circulation (FLC) with equilibrated pressure tracings between the right atrium (16 ± 4 mmHg) and the pulmonary artery (16 ± 5 mmHg). In this condition, the pulmonary blood flow can be regarded as nearly non-pulsatile, as it is passive and propelled by the transpulmonary gradient and intrathoracic pressure alterations produced by breathing to the left atrium. Based on these findings, all patients were listed for HTx and were finally successfully transplanted. CONCLUSIONS: In patients with ARVD, evidence of FLC may serve as an additional criterion for HTx. This applies particularly to patients who do not clearly fulfill standard transplant criteria and to patients with electrical instability.

Coexistence of atrioventricular nodal reentrant tachycardia with other forms of arrhythmias.

OBJECTIVE: The aim of this retrospective study was to investigate the association of atrioventricular nodal reentrant tachycardia (AVNRT) with other forms of arrhythmia in individual patients and its consequences for treatment. SUBJECTS AND METHODS: This study comprised 493 consecutive patients aged 16-88 years (296 women and 197 men) who were diagnosed with a form of AVNRT via a standard 4-catheter electrophysiological study (EPS). Patients were clinically followed (range 0.5-12 years) at a single center. RESULTS: Coexistence of AVNRT with other types of tachycardias was observed in 197 (40%) patients. Atrial fibrillation was found most frequently in 94 (19%) patients as follows: focal atrial tachycardia, n = 40 (8%); atrial flutter, n = 32 (6%), and AV reentrant tachycardia, n = 22 (4%). Double tachycardia was present in 140 (30%) patients, and more than 2 different types of tachycardias were present in 57 (12%) patients. Transitions between AVNRT and other tachycardias occurred in 25 (5%) patients. Two or more tachycardias were ablated in 42 (9%) patients. The majority of patients were free of symptoms at the first follow-up, whereas 130 (26%) patients reported a variety of symptoms. CONCLUSION: Coexistence of AVNRT with other types of arrhythmias was a common finding among these patients. The most frequently observed double tachycardia was the combination of AVNRT with atrial tachyarrhythmias, such as atrial fibrillation, with a potential significance for further patient management.

Genetic association study of QT interval highlights role for calcium signaling pathways in myocardial repolarization.

The QT interval, an electrocardiographic measure reflecting myocardial repolarization, is a heritable trait. QT prolongation is a risk factor for ventricular arrhythmias and sudden cardiac death (SCD) and could indicate the presence of the potentially lethal mendelian long-QT syndrome (LQTS). Using a genome-wide association and replication study in up to 100,000 individuals, we identified 35 common variant loci associated with QT interval that collectively explain ∼8-10% of QT-interval variation and highlight the importance of calcium regulation in myocardial repolarization. Rare variant analysis of 6 new QT interval-associated loci in 298 unrelated probands with LQTS identified coding variants not found in controls but of uncertain causality and therefore requiring validation. Several newly identified loci encode proteins that physically interact with other recognized repolarization proteins. Our integration of common variant association, expression and orthogonal protein-protein interaction screens provides new insights into cardiac electrophysiology and identifies new candidate genes for ventricular arrhythmias, LQTS and SCD.

Clinical outcome after 1 year of cardiac resynchronisation therapy: national results from the European CRT survey.

Cardiac resynchronisation therapy (CRT) is an established treatment option for heart failure patients with electromechanical dyssynchrony. Between 2008 and 2010, the Heart Failure Association (HFA) and the European Heart Rhythm Association (EHRA) of the European Society of Cardiology (ESC) initiated the European CRT survey to describe the current practice and short-term clinical outcome associated with CRT implantations in 13 countries. One year follow-up data from 150 patients collected in 10 Austrian centres are presented in comparison to the total 1,969 patients enrolled throughout Europe. In most cases (n = 120), CRT-D devices were implanted, while CRT-P devices were used in only 23 %. After 12 ± 3 months, mortality and hospitalisation rates reached 10 and 37 %, respectively. New York Heart Association (NYHA) functional classes improved significantly: NYHA I/II/III/IV were found before implantation in 2/20/71/7 % and after 1 year follow-up in 35/51/9/5 % of the patients, respectively. Left ventricular ejection fraction improved from 27 ± 8 % to 35 ± 10 %, left ventricular end-diastolic diameters were reduced from 65 ± 10 mm to 59 ± 5 mm. Median NT-proBNP was reduced from 1,886 to 997 pg/ml, QRS duration diminished from 158 ± 34 to 147 ± 27 ms. In conclusion, the Austrian data from the CRT survey confirms the efficacy of CRT in heart failure patients, but outlines that these patients still suffer from a high mortality and cardiovascular (CV) hospitalisation rate.