Mechano-electrical interactions and heterogeneities in wild-type and drug-induced long QT syndrome rabbits.

Electromechanical reciprocity - comprising electro-mechanical (EMC) and mechano-electric coupling (MEC) - provides cardiac adaptation to changing physiological demands. Understanding electromechanical reciprocity and its impact on function and heterogeneity in pathological conditions - such as (drug-induced) acquired long QT syndrome (aLQTS) - might lead to novel insights in arrhythmogenesis. Our aim is to investigate how electrical changes impact on mechanical function (EMC) and vice versa (MEC) under physiological conditions and in aLQTS. To measure regional differences in EMC and MEC in vivo, we used tissue phase mapping cardiac MRI and a 24-lead ECG vest in healthy (control) and IKr -blocker E-4031-induced aLQTS rabbit hearts. MEC was studied in vivo by acutely increasing cardiac preload, and ex vivo by using voltage optical mapping (OM) in beating hearts at different preloads. In aLQTS, electrical repolarization (heart rate corrected RT-interval, RTn370) was prolonged compared to control (P < 0.0001) with increased spatial and temporal RT heterogeneity (P < 0.01). Changing electrical function (in aLQTS) resulted in significantly reduced diastolic mechanical function and prolonged contraction duration (EMC), causing increased apico-basal mechanical heterogeneity. Increased preload acutely prolonged RTn370 in both control and aLQTS hearts (MEC). This effect was more pronounced in aLQTS (P < 0.0001). Additionally, regional RT-dispersion increased in aLQTS. Motion-correction allowed us to determine APD-prolongation in beating aLQTS hearts, but limited motion correction accuracy upon preload-changes prevented a clear analysis of MEC ex vivo. Mechano-induced RT-prolongation and increased heterogeneity were more pronounced in aLQTS than in healthy hearts. Acute MEC effects may play an additional role in LQT-related arrhythmogenesis, warranting further mechanistic investigations. KEY POINTS: Electromechanical reciprocity comprising excitation-contraction coupling (EMC) and mechano-electric feedback loops (MEC) is essential for physiological cardiac function. Alterations in electrical and/or mechanical heterogeneity are known to have potentially pro-arrhythmic effects. In this study, we aimed to investigate how electrical changes impact on the mechanical function (EMC) and vice versa (MEC) both under physiological conditions (control) and in acquired long QT syndrome (aLQTS). We show that changing the electrical function (in aLQTS) results in significantly altered mechanical heterogeneity via EMC and, vice versa, that increasing the preload acutely prolongs repolarization duration and increases electrical heterogeneity, particularly in aLQTS as compared to control. Our results substantiate the hypothesis that LQTS is an ?electro-mechanical', rather than a 'purely electrical', disease and suggest that acute MEC effects may play an additional role in LQT-related arrhythmogenesis.

Center Volumes Correlate with Likelihood of Stent Implantation in German Coronary Angiography.

Aims: Literature on percutaneous coronary intervention (PCI) stated an inverse relationship between hospital volume and mortality, but the effects on other characteristics are unclear. Methods: Using German national records, all coronary angiographies with coronary artery disease in 2017 were identified. We applied risk-adjustment to account for differences in population characteristics. Results: Of overall 528,188 patients, 55.22% received at least one stent, with on average 1.01 stents implanted in all patients. Based on those patients who received at least one stent, this corresponds to an average number of 1.82 stents. In-hospital mortality across all patients was 2.93%, length of hospital stay was 6.46 days, and mean reimbursement was €5,531. There were comparatively more emergency admissions in low volume centers and more complex cases (3-vessel disease, left main stenosis, and in-stent stenosis) in high volume centers. In multivariable regression analysis, volume and likelihood of stent implantation (p=0.003) as well as number of stents (p=0.020) were positively correlated. No relationship was seen for in-hospital mortality (p=0.105), length of stay (p=0.201), and reimbursement (p=0.108). Nonlinear influence of volume suggests a ceiling effect: In hospitals with ≤100 interventions, likelihood and number of implanted stents are lowest (∼34% and 0.6). After that, both rise steadily until a volume of 500 interventions. Finally, both remain stable in the categories of over 500 interventions (∼60% and 1.1). Conclusion: In PCI, lower volume centers contribute to emergency care. Higher volume centers treat more complex cases and show a higher likelihood of stent implantations, with a stable safety.

Gene- and variant-specific efficacy of serum/glucocorticoid-regulated kinase 1 inhibition in long QT syndrome types 1 and 2.

AIMS: Current long QT syndrome (LQTS) therapy, largely based on beta-blockade, does not prevent arrhythmias in all patients; therefore, novel therapies are warranted. Pharmacological inhibition of the serum/glucocorticoid-regulated kinase 1 (SGK1-Inh) has been shown to shorten action potential duration (APD) in LQTS type 3. We aimed to investigate whether SGK1-Inh could similarly shorten APD in LQTS types 1 and 2. METHODS AND RESULTS: Human-induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) and hiPSC-cardiac cell sheets (CCS) were obtained from LQT1 and LQT2 patients; CMs were isolated from transgenic LQT1, LQT2, and wild-type (WT) rabbits. Serum/glucocorticoid-regulated kinase 1 inhibition effects (300 nM-10 µM) on field potential durations (FPD) were investigated in hiPSC-CMs with multielectrode arrays; optical mapping was performed in LQT2 CCS. Whole-cell and perforated patch clamp recordings were performed in isolated LQT1, LQT2, and WT rabbit CMs to investigate SGK1-Inh (3 µM) effects on APD. In all LQT2 models across different species (hiPSC-CMs, hiPSC-CCS, and rabbit CMs) and independent of the disease-causing variant (KCNH2-p.A561V/p.A614V/p.G628S/IVS9-28A/G), SGK1-Inh dose-dependently shortened FPD/APD at 0.3-10 µM (by 20-32%/25-30%/44-45%). Importantly, in LQT2 rabbit CMs, 3 µM SGK1-Inh normalized APD to its WT value. A significant FPD shortening was observed in KCNQ1-p.R594Q hiPSC-CMs at 1/3/10 µM (by 19/26/35%) and in KCNQ1-p.A341V hiPSC-CMs at 10 µM (by 29%). No SGK1-Inh-induced FPD/APD shortening effect was observed in LQT1 KCNQ1-p.A341V hiPSC-CMs or KCNQ1-p.Y315S rabbit CMs at 0.3-3 µM. CONCLUSION: A robust SGK1-Inh-induced APD shortening was observed across different LQT2 models, species, and genetic variants but less consistently in LQT1 models. This suggests a genotype- and variant-specific beneficial effect of this novel therapeutic approach in LQTS.

Impact of the COVID-19 pandemic on aortic valve replacement procedures in Germany.

BACKGROUND: COVID-19 has caused the deferral of millions of elective procedures, likely resulting in a backlog of cases. We estimate the number of postponed surgical aortic valve replacement (sAVR) and transcatheter aortic valve replacement (TAVR) procedures during the first two waves of the COVID-19 pandemic in Germany. METHODS: Using German national records, all isolated TAVR and sAVR procedures between 2007 and 2020 were identified. Using weekly TAVR and sAVR procedures between 2017 and 2019, we created a forecast for 2020 and compared it with the observed number of procedures in 2020. RESULTS: In Germany, a total of 225,398 isolated sAVR and 159,638 isolated TAVR procedures were conducted between 2007 and 2020 that were included in our analysis. The reduction in all AVR procedures (sAVR and TAVR) for the entire year 2020 was 19.07% (95%CI: 15.19-22.95%). During the first wave of the pandemic (week 12-21), the mean weekly reduction was 32.06% (23.44-40.68%) and during the second wave of the pandemic (week 41-52), the mean weekly reduction was 25.58% (14.19-36.97%). The number of sAVR procedures decreased more than the number of TAVR procedures (24.63% vs. 16.42% for the entire year 2020). CONCLUSION: The first year of the COVID-19 pandemic saw a substantial postponing of AVR procedures in Germany. Postponing was higher for sAVR than for TAVR procedures and less pronounced during the second wave of the COVID-19 pandemic.

Docosahexaenoic acid normalizes QT interval in long QT type 2 transgenic rabbit models in a genotype-specific fashion.

AIM: Long QT syndrome (LQTS) is a cardiac channelopathy predisposing to ventricular arrhythmias and sudden cardiac death. Since current therapies often fail to prevent arrhythmic events in certain LQTS subtypes, new therapeutic strategies are needed. Docosahexaenoic acid (DHA) is a polyunsaturated fatty acid, which enhances the repolarizing IKs current. METHODS AND RESULTS: We investigated the effects of DHA in wild type (WT) and transgenic long QT Type 1 (LQT1; loss of IKs), LQT2 (loss of IKr), LQT5 (reduction of IKs), and LQT2-5 (loss of IKr and reduction of IKs) rabbits. In vivo ECGs were recorded at baseline and after 10 µM/kg DHA to assess changes in heart-rate corrected QT (QTc) and short-term variability of QT (STVQT). Ex vivo monophasic action potentials were recorded in Langendorff-perfused rabbit hearts, and action potential duration (APD75) and triangulation were assessed. Docosahexaenoic acid significantly shortened QTc in vivo only in WT and LQT2 rabbits, in which both α- and ß-subunits of IKs-conducting channels are functionally intact. In LQT2, this led to a normalization of QTc and of its short-term variability. Docosahexaenoic acid had no effect on QTc in LQT1, LQT5, and LQT2-5. Similarly, ex vivo, DHA shortened APD75 in WT and normalized it in LQT2, and additionally decreased AP triangulation in LQT2. CONCLUSIONS: Docosahexaenoic acid exerts a genotype-specific beneficial shortening/normalizing effect on QTc and APD75 and reduces pro-arrhythmia markers STVQT and AP triangulation through activation of IKs in LQT2 rabbits but has no effects if either α- or ß-subunits to IKs are functionally impaired. Docosahexaenoic acid could represent a new genotype-specific therapy in LQT2.

Annual hospital procedural volume and outcome in extracorporeal membrane oxygenation for respiratory failure.

BACKGROUND: The hospital mortality of patients suffering from pulmonary failure requiring venovenous extracorporeal membrane oxygenation (V-V ECMO) or extracorporeal carbon dioxide removal (ECCO2 R) is high. It is unclear whether outcome correlates with a hospital's annual procedural volume. METHODS: Data on all V-V ECMO and ECCO2 R cases treated from 2007 to 2019 were retrieved from the German Institute for Medical Documentation and Information. Comorbidities and outcomes were assessed by DRG, OPS, and ICD codes. The study population was divided into 5 groups depending on annual hospital V-V ECMO and ECCO2 R volumes (<10 cases; 10-19 cases; 20-29 cases; 30-49 cases; ≥50 cases). Primary outcome was hospital mortality. RESULTS: A total of 25 096 V-V ECMO and 3607 ECCO2 R cases were analyzed. V-V ECMO hospitals increased from 89 in 2007 to 214 in 2019. Hospitals handling <10 cases annually increased especially (64 in 2007 to 149 in 2019). V-V ECMO cases rose from 807 in 2007 to 2597 in 2019. Over 50% of cases were treated in hospitals handling ≥30 cases annually. Hospital mortality was independent of the annual hospital procedural volume (55.3%; 61.3%; 59.8%; 60.2%; 56.3%, respectively, p = 0.287). We detected no differences when comparing hospitals handling <30 cases to those with ≥30 annually (p = 0.659). The numbers of ECCO2 R hospitals and cases has dropped since 2011 (287 in 2007 to 48 in 2019). No correlation between annual hospital procedural volume and hospital mortality was identified (p = 0.914). CONCLUSION: The number of hospitals treating patients requiring V-V ECMO and V-V ECMO cases rose from 2007 to 2019, while ECCO2 R hospitals and their case numbers decreased. We detected no correlation between annual hospital V-V ECMO or ECCO2 R volume and hospital mortality.

Impact of Procedure Volume on the Outcomes of Surgical Aortic Valve Replacement.

BACKGROUND: Literature demonstrated that procedure volumes affect outcomes of patients undergoing transcatheter aortic valve implantation. We evaluated the outcomes of surgical aortic valve replacement. METHODS: All isolated surgical aortic valve replacement procedures in Germany in 2017 were identified. Hospitals were divided into five groups from ≤25 (very low volume) until >100 (very high volume) annual procedures. RESULTS: In 2017, 5,533 patients underwent isolated surgical aortic valve replacement. All groups were of comparable risk (logistic EuroSCORE, 5.12-4.80%) and age (66.6-68.1 years). In-hospital mortality and complication rates were lowest in the very high-volume group. Multivariable logistic regression analyses showed no significant volume-outcome relationship for in-hospital mortality, stroke, postoperative delirium, and mechanical ventilation > 48 hours. Regarding acute kidney injury, patients in the very high-volume group were at lower risk than those in the very low volume group (odds ratio [OR] = 0.53, p = 0.04). Risk factors for in-hospital mortality were previous cardiac surgery (OR = 5.75, p < 0.001), high-grade renal disease (glomerular filtration rate < 15 mL/min, OR = 5.61, p = 0.002), surgery in emergency cases (OR = 2.71, p = 0.002), and higher grade heart failure (NYHA [New York Heart Association] III/IV; OR = 1.80, p = 0.02). Risk factors for all four complication rates were atrial fibrillation and diabetes mellitus. CONCLUSION: Patients treated in very low volume centers (≤25 operations/year) had a similar risk regarding in-hospital mortality and most complications compared with very high-volume centers (>100 operations/year). Only in the case of acute kidney injury, very high-volume centers showed better outcomes than very low volume centers. Therefore, surgical aortic valve replacement can be performed safely independent of case volume.

Device interaction between cardiac contractility modulation (CCM) and subcutaneous defibrillator (S-ICD).

Combined implantation of cardiac contractility modulation (CCM) with subcutaneous implantable cardioverter-defibrillator (S-ICD) appears a suitable option to reduce the amount of intracardiac leads and complications for patients. Here we report on a patient with ischemic cardiomyopathy carrying an S-ICD in which a CCM device was implanted. During crosstalk testing post-CCM implantation, the S-ICD misannotated QRS complexes and T waves. The problem was solved through reprogramming the CCM, while preserving S-ICD functionality and improving heart failure symptoms. In conclusion, S-ICD combined with CCM seems to be a good and safe option for patients when device interference is being ruled out.

Ventral calcification in the common femoral artery: A risk factor for major transcatheter aortic valve intervention access site complications.

OBJECTIVES: We aimed to identify risk factors for major transcatheter aortic valve intervention (TAVI) access site complications based on detailed analysis of the preprocedural computed tomography angiogram (CTA). BACKGROUND: Transfemoral TAVI has become the treatment of choice for severe aortic stenosis in elderly patients, especially with increased perioperative risk. Frailty, however, favors complications at the vascular access site due to the large bore vascular sheath devices necessary for valve deployment. METHODS: In this monocentric study, we retrospectively analyzed the preprocedural CTA of 417 consecutive patients that received transfemoral TAVI between 2015 and 2019 to quantify vessel diameter, calcification volume and calcified plaque location in detail within 10 cm proximal to the femoral bifurcation. RESULTS: The mean age of the study cohort was 81.4 ± 6.5 years with a STS of 8 ± 5.2 representing a population at increased periprocedural risk. 54.4% of patients were female. Major vascular access site complications occurred in 8.2% of patients. Major vascular complications correlated statistically with a sheath-to-vessel diameter (SFAR) when measured 1 cm proximal to the femoral bifurcation using a line-derived diameter and ventral calcification within the first 5 cm proximal to the bifurcation. In contrast, overall calcification volume had no influence. CONCLUSIONS: Transfemoral TAVI harbors a considerable risk for vascular access site complications especially if vessel diameter is too small to comfortably host the sheath diameter at the area of the femoral bifurcation. For preprocedural TAVI planning and risk assessment, location of calcification, especially if located ventrally, seems to be more relevant than consideration of overall calcification alone.

Two siblings with early repolarization syndrome: clinical and genetic characterization by whole-exome sequencing.

AIMS: The early repolarization syndrome (ERS) can cause ventricular fibrillation (VF) and sudden death in young, otherwise healthy individuals. There are limited data suggesting that ERS might be heritable. The aim of this study was to characterize the clinical phenotype and to identify a causal variant in an affected family using an exome-sequencing approach. METHODS AND RESULTS: Early repolarization syndrome was diagnosed according to the recently proposed Shanghai ERS Score. After sequencing of known ERS candidate genes, whole-exome sequencing (WES) was performed. The index patient (23 years, female) showed a dynamic inferolateral early repolarization (ER) pattern and electrical storm with intractable VF. Isoproterenol enabled successful termination of electrical storm with no recurrence on hydroquinidine therapy during 33 months of follow-up. The index patient's brother (25 years) had a persistent inferior ER pattern with malignant features and a history of syncope. Both parents were asymptomatic and showed no ER pattern. While there was no pathogenic variant in candidate genes, WES detected a novel missense variant affecting a highly conserved residue (p. H2245R) in the ANK3 gene encoding Ankyrin-G in the two siblings and the father. CONCLUSION: We identified two siblings with a malignant ERS phenotype sharing a novel ANK3 variant. A potentially pathogenic role of the novel ANK3 variant is suggested by the direct interaction of Ankyrin-G with the cardiac sodium channel, however, more patients with ANK3 variants and ERS would be required to establish ANK3 as novel ERS susceptibility gene. Our study provides additional evidence that ERS might be a heritable condition.

Impact of Preprocedural Aortic Valve Calcification on Conduction Disturbances after Transfemoral Aortic Valve Replacement.

AIM: The present study analyzes in depth the impact of different calcification patterns on disturbances of the conduction system in transcatheter aortic valve replacement (TAVR) patients. METHODS AND RESULTS: A total of 169 preprocedural TAVR multislice computed tomography scans from consecutive transfemoral (TF) TAVRs performed between 2014 and 2017 using either Edwards SAPIEN or Medtronic Evolut R valves were retrospectively evaluated. The volume, distribution, and orientation of annular and valvular aortic valve calcification were measured and their impact on postoperative conduction disturbances was determined using linear and logistic regression analyses. The total volume of calcification and distribution at the aortic annulus or valve did not influence the conduction system. Oval calcification of the left aortic cusp was independently associated with an elevated risk for an increase in atrioventricular block degree (+0.6, p = 0.03). Moreover, orthogonal calcifications at the level of the aortic annulus were associated with an increased risk for QRS prolongation (+26 ms, p = 0.004) and an increased risk for permanent pacemaker implantation (OR 4.3, p = 0.03) after TF TAVR. This was more pronounced in patients undergoing TF TAVR using a balloon-expandable Edwards SAPIEN 3 valve (QRS +38.195 ms, p < 0.001; OR permanent pacemaker 15.48, p = 0.013). CONCLUSION: Orthogonal annular calcification confers an increased risk for conduction disturbances after TAVR. This is even more pronounced after implantation of balloon-expandable valves.

Nationwide outcomes of aortic valve replacement for pure aortic regurgitation in Germany 2008-2015.

BACKGROUND: Transcatheter aortic valve replacement (TAVR) is routinely used in patients with severe aortic stenosis at increased operative risk. Due to potential technical difficulties, TAVR is not recommended for pure aortic regurgitation (AR). Smaller studies reported its use in AR, but data from big registries are lacking. The present study analyzes the nationwide use of surgical aortic valve replacement (SAVR) and TAVR in patients with AR from 2008 until 2015. METHODS: We identified 138,237 cases of aortic valve replacement in Germany based on ICD and OPS codes. RESULTS: Of 13.2% SAVR-cases and 1.3% of TAVR cases were performed in AR. AR patients undergoing SAVR were younger with lower logistic EuroSCORE (stenosis: 6.1 ± 5.6; AR: 4.5 ± 4.9). Nevertheless, stroke rates, bleedings, prolonged mechanical ventilation, and in-hospital mortality were higher (mortality: stenosis 2.6%, AR: 4.7%). In the TAVR group, patients with AR were at higher operative risk (logistic EuroSCORE: transfemoral (TF)-TAVR: stenosis: 14.3 ± 10.4; AR: 17.3 ± 13.3. Transapical (TA)-TAVR: stenosis: 16.1 ± 11.4; AR: 15.7 ± 12.2). Stroke rates were lower, but bleedings and prolonged ventilation occurred more frequently after TF-TAVR in AR compared to stenosis. The mortality varied markedly (TF-TAVR: 15.2% in 2011; 2.8% in 2015; TA-TAVR: 17.7% in 2012 and 0% in 2014). CONCLUSION: TAVR is off-label used in AR in clinical practice. TAVR seems to be a safe option for AR with regard to in-hospital outcomes. However, further research evaluating long-term outcomes is required to establish the feasibility of TAVR in pure AR.

Predictors of survival in patients with acute coronary syndrome undergoing percutaneous coronary intervention of unprotected left main coronary artery stenosis.

OBJECTIVE: Aim of this study was to investigate predictors of survival in unstable patients with high SYNTAX-1-score. BACKGROUND: In significant unprotected left main coronary artery (ULMCA) stenosis, treatment options include percutaneous coronary intervention (PCI) and coronary artery bypass graft (CABG). While CABG is recommended for stable patients with ULMCA stenosis and a SYNTAX-1-score > 32, PCI may be preferable in unstable or high operative risk patients. METHODS: Retrospective single-center all-comers registry study. RESULTS: A total of 142 patients underwent ULMCA-PCI (~72.9 years, 23.2% females, 54.2% survival in 2-year follow-up), 84 of whom had a SYNTAX-1 > 32 (37.4 ± 12.8). Patients in the high-SYNTAX-1-group (score > 32) were more often in an acute condition compared to low-SYNTAX-2-group (score ≤ 32) including acute myocardial infarction (76.2% vs. 57.4%, p = .024), cardiogenic shock (48.2% vs. 14.8%, p = .001), or need for mechanical support (36.1% vs. 11.1%, p = .001). Survival was predicted by the acute condition including cardiogenic shock (OR 0.06 and 0.05) and myocardial infarction (OR 0.03 and 0.34) in both groups. Performance of the SYNTAX-1-score was limited in our patient collective in both groups (c-index 0.65 vs. 0.63) while SYNTAX-2-PCI-score performed better (c-index 0.67 vs. 0.67). EuroScore II had the best discriminative ability (c-index 0.87 vs. 0.78). CONCLUSIONS: The majority of patients undergoing ULMCA-PCI presented in acute conditions with high SYNTAX-1-score, and is therefore underrepresented in clinical trials. Prognosis was best predicted by the acute condition and the EuroScore II. These data suggest that therapy in unstable patients should be guided by clinical condition over the anatomical SYNTAX-1-score.

Prone positioning in severe ARDS requiring extracorporeal membrane oxygenation.

BACKGROUND: Prone positioning (PP) has shown to improve survival in patients with severe acute respiratory distress syndrome (ARDS). To this point, it is unclear if PP is also beneficial for ARDS patients treated with veno-venous extracorporeal membrane oxygenation (VV ECMO) support. METHODS: We report retrospective data of a single-centre registry of patients with severe ARDS requiring VV ECMO support between October 2010 and May 2018. Patients were allocated to the PP group if PP was performed during VV ECMO treatment or the supine positioning group. VV ECMO weaning success and hospital survival were analysed before and after propensity score matching. RESULTS: A total of 158 patients could be analysed, and 38 patients (24.1%) received PP. There were no significant differences in VV ECMO weaning rate (47.4% vs. 46.7%, p = 0.94) and hospital survival (36.8% vs. 36.7%, p = 0.98) between the prone and supine groups, respectively. The analysis of 38 propensity score matched pairs also showed no difference in hospital survival (36.8% vs. 36.8%, p = 1.0) or VV ECMO weaning rate (47.4% vs. 44.7%, p = 0.82). Hospital survival was superior in the subgroup of patients treated with early PP (cutoff < 17 h via Youden's Index) as compared to late or no PP (81.8% vs. 33.3%, p = 0.02). CONCLUSION: In this propensity score matched cohort of severe ARDS patients requiring VV ECMO support, prone positioning at any time was not associated with improved weaning or survival. However, early initiation of prone positioning was linked to a significant reduction of hospital mortality.

Transgenic short-QT syndrome 1 rabbits mimic the human disease phenotype with QT/action potential duration shortening in the atria and ventricles and increased ventricular tachycardia/ventricular fibrillation inducibility.

AIMS: Short-QT syndrome 1 (SQT1) is an inherited channelopathy with accelerated repolarization due to gain-of-function in HERG/IKr. Patients develop atrial fibrillation, ventricular tachycardia (VT), and sudden cardiac death with pronounced inter-individual variability in phenotype. We generated and characterized transgenic SQT1 rabbits and investigated electrical remodelling. METHODS AND RESULTS: Transgenic rabbits were generated by oocyte-microinjection of ß-myosin-heavy-chain-promoter-KCNH2/HERG-N588K constructs. Short-QT syndrome 1 and wild type (WT) littermates were subjected to in vivo ECG, electrophysiological studies, magnetic resonance imaging, and ex vivo action potential (AP) measurements. Electrical remodelling was assessed using patch clamp, real-time PCR, and western blot. We generated three SQT1 founders. QT interval was shorter and QT/RR slope was shallower in SQT1 than in WT (QT, 147.8 ± 2 ms vs. 166.4 ± 3, P < 0.0001). Atrial and ventricular refractoriness and AP duration were shortened in SQT1 (vAPD90, 118.6 ± 5 ms vs. 154.4 ± 2, P < 0.0001). Ventricular tachycardia/fibrillation (VT/VF) inducibility was increased in SQT1. Systolic function was unaltered but diastolic relaxation was enhanced in SQT1. IKr-steady was increased with impaired inactivation in SQT1, while IKr-tail was reduced. Quinidine prolonged/normalized QT and action potential duration (APD) in SQT1 rabbits by reducing IKr. Diverse electrical remodelling was observed: in SQT1, IK1 was decreased-partially reversing the phenotype-while a small increase in IKs may partly contribute to an accentuation of the phenotype. CONCLUSION: Short-QT syndrome 1 rabbits mimic the human disease phenotype on all levels with shortened QT/APD and increased VT/VF-inducibility and show similar beneficial responses to quinidine, indicating their value for elucidation of arrhythmogenic mechanisms and identification of novel anti-arrhythmic strategies.

Postpartum hormones oxytocin and prolactin cause pro-arrhythmic prolongation of cardiac repolarization in long QT syndrome type 2.

AIMS: Women with long QT syndrome 2 (LQT2) have a particularly high postpartal risk for lethal arrhythmias. We aimed at investigating whether oxytocin and prolactin contribute to this risk by affecting repolarization. METHODS AND RESULTS: In female transgenic LQT2 rabbits (HERG-G628S, loss of IKr), hormone effects on QT/action potential duration (APD) were assessed (0.2-200 ng/L). Hormone effects (200 ng/L) on ion currents and cellular APD were determined in transfected cells and LQT2 cardiomyocytes. Hormone effects on ion channels were assessed with qPCR and western blot. Experimental data were incorporated into in silico models to determine the pro-arrhythmic potential. Oxytocin prolonged QTc and steepened QT/RR-slope in vivo and prolonged ex vivo APD75 in LQT2 hearts. Prolactin prolonged APD75 at high concentrations. As underlying mechanisms, we identified an oxytocin- and prolactin-induced acute reduction of IKs-tail and IKs-steady (-25.5%, oxytocin; -13.3%, prolactin, P < 0.05) in CHO-cells and LQT2-cardiomyocytes. IKr currents were not altered. This oxytocin-/prolactin-induced IKs reduction caused APD90 prolongation (+11.9%/+13%, P < 0.05) in the context of reduced/absent IKr in LQT2 cardiomyocytes. Hormones had no effect on IK1 and ICa,L in cardiomyocytes. Protein and mRNA levels of CACNA1C/Cav1.2 and RyR2 were enhanced by oxytocin and prolactin. Incorporating these hormone effects into computational models resulted in reduced repolarization reserve and increased propensity to pro-arrhythmic permanent depolarization, lack of capture and early afterdepolarizations formation. CONCLUSIONS: Postpartum hormones oxytocin and prolactin prolong QT/APD in LQT2 by reducing IKs and by increasing Cav1.2 and RyR2 expression/transcription, thereby contributing to the increased postpartal arrhythmic risk in LQT2.

Effect of Availability of Transcatheter Aortic-Valve Replacement on Clinical Practice.

BACKGROUND: Since the adoption of transcatheter aortic-valve replacement (TAVR), questions have been raised about its effect on clinical practice in comparison with the effect of surgical aortic-valve replacement, which is considered the current standard of care. Complete nationwide data are useful in examining how the introduction of a new technique influences previous clinical standards. METHODS: We analyzed data on characteristics of patients and in-hospital outcomes for all isolated TAVR and surgical aortic-valve replacement procedures performed in Germany from 2007 to 2013. RESULTS: In total, 32,581 TAVR and 55,992 surgical aortic-valve replacement procedures were performed. The number of TAVR procedures increased from 144 in 2007 to 9147 in 2013, whereas the number of surgical aortic-valve replacement procedures decreased slightly, from 8622 to 7048. Patients undergoing TAVR were older than those undergoing surgical aortic-valve replacement (mean [±SD] age, 81.0±6.1 years vs. 70.2±10.0 years) and at higher preoperative risk (estimated logistic EuroSCORE [European System for Cardiac Operative Risk Evaluation], 22.4% vs. 6.3%, on a scale of 0 to 100%, with higher scores indicating greater risk and a score of more than 20% indicating high surgical risk). In-hospital mortality decreased in both groups between 2007 and 2013 (from 13.2% to 5.4% with TAVR and from 3.8% to 2.2% with surgical aortic-valve replacement). The incidences of stroke, bleeding, and pacemaker implantation (but not acute kidney injury) also declined. CONCLUSIONS: The use of TAVR increased markedly in Germany between 2007 and 2013; the concomitant reduction in the use of surgical aortic-valve replacement was moderate. Patients undergoing TAVR were older and at higher procedural risk than those undergoing surgical aortic-valve replacement. In-hospital mortality decreased in both groups but to a greater extent among patients undergoing TAVR. (Funded by the Heart Center, Freiburg University.).

Two-year post-discharge costs of care among patients treated with transcatheter or surgical aortic valve replacement in Germany.

BACKGROUND: This study presents data on post-discharge costs of care among patients treated with transcatheter or surgical aortic valve replacement over a two year period. METHODS: Based on a prospective clinical trial, post-discharge utilization of health services and status of assistance were collected for 151 elderly patients via 2250 monthly telephone interviews, valued using standardized unit costs and analysed using two-part regression models. RESULTS: At month 1 post-discharge, total costs of care are substantially elevated (monthly mean: €3506.7) and then remain relatively stable over the following 23 months (monthly mean: €622.3). As expected, the majority of these costs are related to in-hospital care (~98% in month 1 post-discharge and ~72% in months 2-24). Patients that died during follow-up were associated with substantially higher cost estimates of in-hospital care than those surviving the two-year study period, while patients' age and other patient characteristics were of minor relevance. Estimated costs of outpatient care are lower at month 1 than during the rest of the study period, and not affected by the event of death during follow-up. The estimated costs of nursing care are, in contrast, much higher in year 2 than in year 1 and differ substantially by gender and type of procedure as well as by patients' age. Overall, these monthly cost estimates add up to €10,352 for the first and €7467.6 for the second year post-discharge. CONCLUSIONS: Substantial cost increases at month 1 post-discharge and in case of death during follow-up are the main findings of the study, which should be taken into account in future economic evaluations on the topic. Application of standardized unit costs in combination with monthly patient interviews allows for a far more precise estimate of the variability in post-discharge health service utilization in this group of patients than the ones given in previous studies. TRIAL REGISTRATION: German Clinical Trial Register Nr. DRKS00000797 .

Aortic root volume is associated with contained rupture of the aortic annulus in balloon-expandable transcatheter aortic valve replacement.

BACKGROUND: Aortic annulus rupture is a rare, but potentially fatal complication of transcatheter aortic valve replacement (TAVR), especially when it occurs by balloon-expandable devices. In order to improve the predictability of procedures and avoid ruptures we investigated whether or not the aortic root volume measures is a useful indicator of risk, and if it could be useful for the prosthesis size selection. METHODS AND RESULTS: From a retrospective series of 172 TAVR patients, seven experienced contained aortic annulus ruptures. The receiver operating curves were used to illustrate sensitivity and specificity of the different aortic annulus size and aortic root volume measures. The annulus area oversizing of ≥20% resulted in a sensitivity of 100%, specificity of 55.76%, and positive predictive value (PPV) of 8.75%. In patients receiving 26 mm prostheses, the aortic root volume (ARV <13600 mm(3)) provided a better specificity and PPV (79.63 and 18.52%, respectively). A two-step testing procedure considering the area derived average annulus diameter (Darea <23 mm) as a first separating parameter and then the ARV (<13,600 mm(3)) as a further indicator showed the most promising results with the PPV of 31.25%. Regardless of the procedure steps no false negative results were predicted. CONCLUSIONS: Our data show that the ARV provides a better predictive value for correct prosthesis sizing than established annulus measurements, especially in 'borderline' annuli. We suggest a two-step testing procedure for prostheses size selection, considering Darea and ARV to minimize the risk of annulus rupture. Prospective studies and examination of larger datasets are warranted to confirm these findings.

Quality of life among elderly patients undergoing transcatheter or surgical aortic valve replacement- a model-based longitudinal data analysis.

BACKGROUND: Quality of life (QoL) measurements reported in observational studies are often biased, since patients who failed to improve are more likely to be unable to respond due to death or impairment. In order to observe the development of QoL in patients close to death, we analyzed a set of monthly QoL measurements for a cohort of elderly patients treated for aortic valve stenosis (AS) with special consideration of the effect of distance to death. METHODS: QoL in 169 elderly patients (age ≥ 75 years), treated either with transcatheter aortic valve replacement (TAVR; n = 92), surgical aortic-valve replacement (n = 70), or drug-based therapy (n = 7), was evaluated using the standardized EQ-5D questionnaire. Over a two-year period, patients were consulted using monthly telephone interviews or outpatient visits, leading to a total of 2463 time points at which QoL values, New York Heart Association (NYHA) Functional Classification and their status of assistance were assessed. Furthermore, post-procedural clinical events and complications were monitored. Linear and ordered logistic regression analyses with random intercept were carried out, taking into account overall trends and distance to death. RESULTS: QoL measures decreased slightly over time, were temporarily impaired at month 1 after the initial episode of hospitalization and decreased substantially at the end of life with a measurable effect starting at the sixth from last follow-up (month) before death. Many clinical complications (bleeding complications, stroke, acute kidney injury) showed an impairment of QoL measurements, but the inclusion of lagged variables demonstrated medium term (three months) QoL impairments for access site bleeding only. All other complications are associated with event-related impairments that decreased dramatically at the second and third follow-up interviews (month) after event. CONCLUSIONS: Distance to death shows clear effects on QoL and should be taken into account when analyzing QoL measures in the elderly patients treated for aortic valve stenosis. TRIAL REGISTRATION: German Clinical Trial Register Nr. DRKS00000797.