GPD1L-A306del modifies sodium current in a family carrying the dysfunctional SCN5A-G1661R mutation associated with Brugada syndrome.

Loss-of-function variants of SCN5A, encoding the sodium channel alpha subunit Nav1.5 are associated with high phenotypic variability and multiple cardiac presentations, while underlying mechanisms are incompletely understood. Here we investigated a family with individuals affected by Brugada Syndrome (BrS) of different severity and aimed to unravel the underlying genetic and electrophysiological basis.Next-generation sequencing was used to identify the genetic variants carried by family members. The index patient, who was severely affected by arrhythmogenic BrS, carried previously uncharacterized variants of Nav1.5 (SCN5A-G1661R) and glycerol-3-phosphate dehydrogenase-1-like protein (GPD1L-A306del) in a double heterozygous conformation. Family members exclusively carrying SCN5A-G1661R showed asymptomatic Brugada ECG patterns, while another patient solely carrying GPD1L-A306del lacked any clinical phenotype.To assess functional mechanisms, Nav1.5 channels were transiently expressed in HEK-293 cells in the presence and absence of GPD1L. Whole-cell patch-clamp recordings revealed loss of sodium currents after homozygous expression of SCN5A-G1661R, and reduction of current amplitude to ~ 50% in cells transfected with equal amounts of wildtype and mutant Nav1.5. Co-expression of wildtype Nav1.5 and GPD1L showed a trend towards increased sodium current amplitudes and a hyperpolarizing shift in steady-state activation and -inactivation compared to sole SCN5A expression. Application of the GPD1L-A306del variant shifted steady-state activation to more hyperpolarized and inactivation to more depolarized potentials.In conclusion, SCN5A-G1661R produces dysfunctional channels and associates with BrS. SCN5A mediated currents are modulated by co-expression of GDP1L and this interaction is altered by mutations in both proteins. Thus, additive genetic burden may aggravate disease severity, explaining higher arrhythmogenicity in double mutation carriers.

Oral Anticoagulants after Heart Transplantation-Comparison between Vitamin K Antagonists and Direct Oral Anticoagulants.

AIMS: Patients after heart transplantation (HTX) often require oral anticoagulants (OACs) due to atrial arrhythmias or thromboembolic events but little is known about the post-transplant use of direct oral anticoagulants (DOACs). We investigated the frequency, indications, and complications of DOACs and vitamin K antagonists (VKAs) after HTX. METHODS: We screened all adult patients for the use of post-transplant OACs who underwent HTX at Heidelberg Heart Center between 2000 and 2021. Patients were stratified by type of OAC (DOAC or VKA) and by DOAC agents (apixaban, dabigatran, edoxaban, or rivaroxaban). Indications for OACs comprised atrial fibrillation, atrial flutter, pulmonary embolism, upper and lower extremity deep vein thrombosis, as well as intracardiac thrombus. RESULTS: A total of 115 of 459 HTX recipients (25.1%) required OACs, including 60 patients with DOACs (52.2%) and 55 patients with VKAs (47.8%). Concerning DOACs, 28 patients were treated with rivaroxaban (46.7%), 27 patients with apixaban (45.0%), and 5 patients with edoxaban (8.3%). We found no significant differences between both groups concerning demographics, immunosuppressive drugs, concomitant medications, indications for OACs, ischemic stroke, thromboembolic events, or OAC-related death. Patients with DOACs after HTX had a significantly lower one-year rate of overall bleeding complications (p = 0.002) and a significantly lower one-year rate of gastrointestinal hemorrhage (p = 0.011) compared to patients with VKAs after HTX in the Kaplan-Meier estimator. CONCLUSIONS: DOACs were comparable to VKAs concerning the risk of ischemic stroke, thromboembolic events, or OAC-related death but were associated with significantly fewer bleeding complications in HTX recipients.

Frequency, Risk Factors, and Clinical Outcomes of Late-Onset Atrial Flutter in Patients after Heart Transplantation.

Aims: Atrial flutter (AFL) is a common late-onset complication after heart transplantation (HTX) and is associated with worse clinical outcomes. Methods: This study investigated the frequency, risk factors, and outcomes of late-onset post-transplant AFL. We analyzed 639 adult patients undergoing HTX at the Heidelberg Heart Center between 1989 and 2019. Patients were stratified by diagnosis and type of late-onset post-transplant AFL (>90 days after HTX). Results: A total of 55 patients (8.6%) were diagnosed with late-onset post-transplant AFL, 30 had typical AFL (54.5%) and 25 had atypical AFL (45.5%). Patients with AFL were younger at HTX (p = 0.028), received more biatrial anastomosis (p = 0.001), and presented with moderate or severe tricuspid regurgitation (56.4%). Typical AFL was associated with graft rejection (p = 0.016), whereas atypical AFL was associated with coronary artery disease (p = 0.028) and stent implantation (p = 0.042). Patients with atypical AFL showed a higher all-cause 1-year mortality (p = 0.010) along with a higher rate of graft failure after diagnosis of AFL (p = 0.023). Recurrence of AFL was high (83.6%). Patients with catheter ablation after AFL recurrence had a higher 1-year freedom from AFL (p = 0.003). Conclusions: Patients with late-onset post-transplant AFL were younger at HTX, received more biatrial anastomosis, and showed a higher rate of moderate or severe tricuspid regurgitation. Typical AFL was associated with graft rejection, whereas atypical AFL was associated with myocardial ischemia, graft failure, and mortality. Catheter ablation represents a viable option to avoid further episodes of late-onset AFL after HTX.

Improved Generation of Human Induced Pluripotent Stem Cell-Derived Cardiac Pacemaker Cells Using Novel Differentiation Protocols.

Current protocols for the differentiation of human-induced pluripotent stem cells (hiPSC) into cardiomyocytes only generate a small amount of cardiac pacemaker cells. In previous work, we reported the generation of high amounts of cardiac pacemaker cells by co-culturing hiPSC with mouse visceral endoderm-like (END2) cells. However, potential medical applications of cardiac pacemaker cells generated according to this protocol, comprise an incalculable xenogeneic risk. We thus aimed to establish novel protocols maintaining the differentiation efficiency of the END2 cell-based protocol, yet eliminating the use of END2 cells. Three protocols were based on the activation and inhibition of the Wingless/Integrated (Wnt) signaling pathway, supplemented either with retinoic acid and the Wnt activator CHIR99021 (protocol B) or with the NODAL inhibitor SB431542 (protocol C) or with a combination of all three components (protocol D). An additional fourth protocol (protocol E) was used, which was originally developed by the manufacturer STEMCELL Technologies for the differentiation of hiPSC or hESC into atrial cardiomyocytes. All protocols (B, C, D, E) were compared to the END2 cell-based protocol A, serving as reference, in terms of their ability to differentiate hiPSC into cardiac pacemaker cells. Our analysis revealed that protocol E induced upregulation of 12 out of 15 cardiac pacemaker-specific genes. For comparison, reference protocol A upregulated 11, while protocols B, C and D upregulated 9, 10 and 8 cardiac pacemaker-specific genes, respectively. Cells differentiated according to protocol E displayed intense fluorescence signals of cardiac pacemaker-specific markers and showed excellent rate responsiveness to adrenergic and cholinergic stimulation. In conclusion, we characterized four novel and END2 cell-independent protocols for the differentiation of hiPSC into cardiac pacemaker cells, of which protocol E was the most efficient.

Pre-transplant Type 2 Diabetes Mellitus Is Associated With Higher Graft Failure and Increased 5-Year Mortality After Heart Transplantation.

Aims: Cardiac transplant recipients often suffer from type 2 diabetes mellitus (T2DM) but its influence on graft failure and post-transplant mortality remains unknown. The aim of this study was to investigate the long-term effects of pre-transplant T2DM in patients after heart transplantation (HTX). Methods: This study included a total of 376 adult patients who received HTX at Heidelberg Heart Center between 01/01/2000 and 01/10/2016. HTX recipients were stratified by diagnosis of T2DM at the time of HTX. Patients with T2DM were further subdivided by hemoglobin A1c (HbA1c ≥ 7.0%). Analysis included donor and recipient data, immunosuppressive drugs, concomitant medications, post-transplant mortality, and causes of death. Five-year post-transplant mortality was further assessed by multivariate analysis (Cox regression) and Kaplan-Meier estimator. Results: About one-third of all HTX recipients had T2DM (121 of 376 [32.2%]). Patients with T2DM showed an increased 5-year post-transplant mortality (41.3% versus 29.8%; P = 0.027) and had a higher percentage of death due to graft failure (14.9% versus 7.8%; P = 0.035). Multivariate analysis showed T2DM (HR: 1.563; 95% CI: 1.053-2.319; P = 0.027) as an independent risk factor for 5-year mortality after HTX. Kaplan-Meier analysis showed a significantly better 5-year post-transplant survival of patients with T2DM and a HbA1c < 7.0% than patients with T2DM and a HbA1c ≥ 7.0% (68.7% versus 46.3%; P = 0.008) emphasizing the clinical relevance of a well-controlled T2DM in HTX recipients. Conclusion: Pre-transplant T2DM is associated with higher graft failure and increased 5-year mortality after HTX.

Five-year results of heart rate control with ivabradine or metoprolol succinate in patients after heart transplantation.

BACKGROUND: Cardiac graft denervation causes inadequate sinus tachycardia in patients after heart transplantation (HTX) which is associated with reduced survival. This study investigated the 5-year results of heart rate control with ivabradine or metoprolol succinate in patients after HTX. METHODS: This registry study analyzed 104 patients receiving either ivabradine (n = 50) or metoprolol succinate (n = 54) within 5 years after HTX. Analysis included patient characteristics, medication, echocardiographic features, cardiac catheterization data, cardiac biomarkers, heart rates, and post-transplant survival including causes of death. RESULTS: Demographics and post-transplant medication revealed no significant differences except for ivabradine and metoprolol succinate use. At 5-year follow-up, patients with ivabradine had a significantly lower heart rate (73.3 bpm) compared to baseline (88.6 bpm; P < 0.01) and to metoprolol succinate (80.4 bpm; P < 0.01), a reduced left ventricular mass (154.8 g) compared to baseline (179.5 g; P < 0.01) and to metoprolol succinate (177.3 g; P < 0.01), a lower left ventricular end-diastolic pressure (LVEDP; 12.0 mmHg) compared to baseline (15.5 mmHg; P < 0.01) and to metoprolol succinate (17.1 mmHg; P < 0.01), and a reduced NT-proBNP level (525.4 pg/ml) compared to baseline (3826.3 pg/ml; P < 0.01) and to metoprolol succinate (1038.9 pg/ml; P < 0.01). Five-year post-transplant survival was significantly better in patients with ivabradine (90.0%) versus metoprolol succinate (68.5%; P < 0.01). CONCLUSION: Patients receiving ivabradine showed a superior heart rate reduction and a better left ventricular diastolic function along with an improved 5-year survival after HTX.

Risk Factors, Treatment and Prognosis of Patients with Lung Cancer after Heart Transplantation.

Long-term survival after heart transplantation (HTX) is impacted by adverse effects of immunosuppressive pharmacotherapy, and post-transplant lung cancer is a common occurrence. This study aimed to examine the risk factors, treatment, and prognosis of patients with post-transplant lung cancer. We included 625 adult patients who received HTX at Heidelberg Heart Center between 1989 and 2018. Patients were stratified by diagnosis and staging of lung cancer after HTX. Analysis comprised donor and recipient characteristics, medications including immunosuppressive drugs, and survival after diagnosis of lung cancer. A total of 41 patients (6.6%) were diagnosed with lung cancer after HTX, 13 patients received curative care and 28 patients had palliative care. Mean time from HTX until diagnosis of lung cancer was 8.6 ± 4.0 years and 1.8 ± 2.7 years from diagnosis of lung cancer until last follow-up. Twenty-four patients (58.5%) were switched to an mTOR-inhibitor after diagnosis of lung cancer. Multivariate analysis showed recipient age (HR: 1.05; CI: 1.01-1.10; p = 0.02), COPD (HR: 3.72; CI: 1.88-7.37; p < 0.01), and history of smoking (HR: 20.39; CI: 2.73-152.13; p < 0.01) as risk factors for post-transplant lung cancer. Patients in stages I and II had a significantly better 1-year (100.0% versus 3.6%), 2-year (69.2% versus 0.0%), and 5-year survival (53.8% versus 0.0%) than patients in stages III and IV (p < 0.01). Given the poor prognosis of late-stage post-transplant lung cancer, routine reassessment of current smoking status, providing smoking cessation support, and intensified lung cancer screening in high-risk HTX recipients are advisable.

Low-Level Elevations of Procalcitonin Are Associated with Increased Mortality in Acute Heart Failure Patients, Independent of Concomitant Infection.

We aimed to evaluate the prognostic value of procalcitonin (PCT) in acute heart failure (AHF) patients, especially in those without underlying infection. We enrolled patients presenting with acute dyspnea to the emergency department (ED) of Heidelberg University Hospital and studied the prognostic role of PCT on all-cause death. Of 312 patients, AHF was diagnosed in 139 patients. Of these, 125 patients had AHF without signs of infection, and 14 had AHF complicated by respiratory or other infection. The optimal prognostic PCT cutoff value for mortality prediction was calculated by a receiver operating characteristics curve. In patients with AHF, the prognostic PCT cutoff value was 0.08 ng/mL. The Kaplan-Meier survival analysis showed that AHF patients with PCT values > 0.08 ng/mL had a higher all-cause mortality at 120 days than those with PCT values ≤ 0.08 ng/mL (log-rank p = 0.0123). Similar results could be obtained after subdivision into AHF patients with and without signs of overt infection. In both cases, mortality was higher in patients with PCT levels above the prognostic PCT cutoff than in those with values ranging below this threshold. Moreover, we show that the prognostic PCT cutoff values for mortality prediction ranged below the established PCT cutoff for the guidance of antibiotic therapy. In conclusion, the data of our study revealed that low-level elevations of PCT were associated with an increased mortality in patients with AHF, irrespective of concomitant respiratory or other infection. PCT should thus be further used as a marker in the risk stratification of AHF.

Atrial fibrillation before heart transplantation is a risk factor for post-transplant atrial fibrillation and mortality.

AIMS: Atrial fibrillation (AF) after heart transplantation (HTX) is associated with worse clinical outcomes. The current study aimed to analyse the association between AF before HTX and AF within 30 days after HTX. METHODS AND RESULTS: This study included 639 adults who received HTX at Heidelberg Heart Center. Patients were subdivided into four groups depending on the status of AF before and after HTX. Analyses comprised recipient and donor data, medication, echocardiographic features, permanent pacemaker implantation, stroke, and mortality after HTX. Three hundred thirty-two patients (52.0%) had neither AF before nor after HTX, 15 patients (2.3%) had no AF before HTX but showed AF after HTX, 219 patients (34.3%) showed AF before HTX but had no AF after HTX, and 73 patients (11.4%) had AF before and after HTX. Patients with AF before and after HTX had a higher 1 year post-transplant mortality (39.7%) than patients without AF before or after HTX (18.1%, P < 0.01). Secondary outcomes showed a higher percentage of enlarged atria, ventricular dysfunction, mitral regurgitation, 1-year stroke, and 1-year permanent pacemaker implantation in patients with AF before and after HTX. Multivariate analysis revealed a six-fold elevated risk for post-transplant AF in patients with AF before HTX (hazard ratio: 6.59, confidence interval: 3.72-11.65; P < 0.01). Further risk factors for post-transplant AF were higher donor age and prolonged ischaemic time, whereas total orthotopic HTX was associated with a two-fold lower risk for post-transplant AF. CONCLUSIONS: Atrial fibrillation before HTX is a risk factor for post-transplant AF, permanent pacemaker implantation, and mortality after HTX.

Newly acquired complete right bundle branch block early after heart transplantation is associated with lower survival.

AIMS: Right bundle branch block (RBBB) after heart transplantation (HTX) is a common finding, but its impact on post-transplant survival remains uncertain. This study investigated the post-transplant outcomes of patients with complete RBBB (cRBBB) ≤ 30 days after HTX. METHODS: This registry study analysed 639 patients receiving HTX at Heidelberg Heart Center between 1989 and 2019. Patients were stratified by diagnosis of cRBBB ≤ 30 days after HTX. Analysis included recipient and donor data, medication, echocardiographic features, graft rejections, atrial fibrillation, heart rates, permanent pacemaker implantation and mortality after HTX including causes of death. RESULTS: One hundred thirty-nine patients showed cRBBB ≤ 30 days after HTX (21.8%), 20 patients with pre-existing cRBBB in the donor heart (3.2%) and 119 patients with newly acquired cRBBB (18.6%). Patients with newly acquired cRBBB had a worse 1-year post-transplant survival (36.1%, P < 0.01) compared with patients with pre-existing cRBBB (85.0%) or without cRBBB (86.4%), along with a higher percentage of death due to graft failure (P < 0.01). Multivariate analysis indicated cRBBB ≤ 30 days after HTX as significant risk factor for 1-year mortality after HTX (HR: 2.20; 95% CI: 1.68-2.87; P < 0.01). Secondary outcomes showed a higher rate of an enlarged right atrium (P = 0.01), enlarged right ventricle (P < 0.01), reduced right ventricular function (P < 0.01), 30-day atrial fibrillation (P < 0.01) and 1-year permanent pacemaker implantation (P = 0.02) in patients with cRBBB after HTX. CONCLUSIONS: Newly acquired cRBBB early after HTX is associated with increased post-transplant mortality.

Cryoballoon pulmonary vein isolation-mediated rise of sinus rate in patients with paroxysmal atrial fibrillation.

BACKGROUND: Modulation of the cardiac autonomic nervous system by pulmonary vein isolation (PVI) influences the sinoatrial nodal rate. Little is known about the causes, maintenance and prognostic value of this phenomenon. We set out to explore the effects of cryoballoon PVI (cryo-PVI) on sinus rate and its significance for clinical outcome. METHODS AND RESULTS: We evaluated 110 patients with paroxysmal atrial fibrillation (AF), who underwent PVI using a second-generation 28 mm cryoballoon by pre-, peri- and postprocedural heart rate acquisition and analysis of clinical outcome. Ninety-one patients could be included in postinterventional follow-up, indicating that cryo-PVI resulted in a significant rise of sinus rate by 16.5% (+ 9.8 ± 0.9 beats/min, p < 0.001) 1 day post procedure compared to preprocedural acquisition. This effect was more pronounced in patients with initial sinus bradycardia (< 60 beats/min.) compared to patients with faster heart rate. Increase of rate was primarily driven by ablation of the right superior pulmonary vein and for a subset of patients, in whom this could be assessed, persisted ≥ 1 year after the procedure. AF recurrence was neither predicted by the magnitude of the initial rate, nor by the extent of rate change, but postprocedural sinus bradycardia was associated with higher recurrence of AF in the year post PVI. CONCLUSIONS: Cryo-PVI causes a significant rise of sinus rate that is more pronounced in subjects with previous sinus bradycardia. Patient follow-up indicates persistence of this effect and suggests an increased risk of AF recurrence in patients with postprocedural bradycardia.

In vivo cardiac pacemaker function of differentiated human mesenchymal stem cells from adipose tissue transplanted into porcine hearts.

BACKGROUND: Mesenchymal stem cells (MSC) modified by gene transfer to express cardiac pacemaker channels such as HCN2 or HCN4 were shown to elicit pacemaker function after intracardiac transplantation in experimental animal models. Human MSC derived from adipose tissue (haMSC) differentiate into cells with pacemaker properties in vitro, but little is known about their behavior after intracardiac transplantation. AIM: To investigate whether haMSC elicit biological pacemaker function in vivo after transplantation into pig hearts. METHODS: haMSC under native conditions (nhaMSC) or after pre-conditioning by medium differentiation (dhaMSC) (n = 6 pigs each, 5 × 106 cells/animal) were injected into the porcine left ventricular free wall. Animals receiving PBS injection served as controls (n = 6). Four weeks later, total atrioventricular (AV)-block was induced by radiofrequency catheter ablation, and electronic pacemaker devices were implanted for backup stimulation and heart rate monitoring. Ventricular rate and rhythm of pigs were evaluated during a follow-up of 15 d post ablation by 12-lead-ECG with heart rate assessment, 24-h continuous rate monitoring recorded by electronic pacemaker, assessment of escape recovery time, and pharmacological challenge to address catecholaminergic rate response. Finally, hearts were analyzed by histological and immunohistochemical investigations. RESULTS: In vivo transplantation of dhaMSC into the left ventricular free wall of pigs elicited spontaneous and regular rhythms that were pace-mapped to ventricular injection sites (mean heart rate 72.2 ± 3.6 bpm; n = 6) after experimental total AV block. Ventricular rhythms were stably detected over a 15-d period and were sensitive to catecholaminergic stimulation (mean maximum heart rate 131.0 ± 6.2 bpm; n = 6; P < 0.001). Pigs, which received nhaMSC or PBS presented significantly lower ventricular rates (mean heart rates 47.2 ± 2.5 bpm and 37.4 ± 3.2 bpm, respectively; n = 6 each; P < 0.001) and exhibited little sensitivity towards catecholaminergic stimulation (mean maximum heart rates 76.4 ± 3.1 bpm and 60.5 ± 3.1 bpm, respectively; n = 6 each; P < 0.05). Histological and immunohistochemical evaluation of hearts treated with dhaMSC revealed local clusters of transplanted cells at the injection sites that lacked macrophage or lymphocyte infiltrations or tumor formation. Intense fluorescence signals at these sites indicated membrane expression of HCN4 and other pacemaker-specific proteins involved in cardiac automaticity and impulse propagation. CONCLUSION: dhaMSC transplanted into pig left ventricles sustainably induced rate-responsive ventricular pacemaker activity after in vivo engraftment for four weeks. The data suggest that pre-conditioned MSC may further differentiate along a pacemaker-related lineage after myocardial integration and may establish superior pacemaker properties in vivo.

Combined amiodarone and digitalis therapy before heart transplantation is associated with increased post-transplant mortality.

AIMS: Amiodarone and digitalis are frequently used drugs in patients with heart failure. Both have separately been linked to reduced post-transplant survival, but their combined impact on mortality after HTX remains uncertain. This study investigated the effects of combined amiodarone and digitalis use before HTX on post-transplant outcomes. METHODS AND RESULTS: This registry study analysed 600 patients receiving HTX at Heidelberg Heart Center between 1989 and 2016. Patients were stratified by amiodarone and digitalis use before HTX. Analysis included patient characteristics, medication, echocardiographic features, heart rates, permanent pacemaker implantation, atrial fibrillation, and post-transplant survival including causes of death. One hundred eighteen patients received amiodarone before HTX (19.7%), hereof 67 patients with digitalis (56.8%) and 51 patients without digitalis before HTX (43.2%). Patients with and without amiodarone before HTX showed a similar 1 year post-transplant survival (72.0% vs. 78.4%, P = 0.11), but patients with combined amiodarone and digitalis before HTX had a worse 1 year post-transplant survival (64.2%, P = 0.01), along with a higher percentage of death due to transplant failure (P = 0.03). Echocardiographic analysis of these patients showed a higher percentage of an enlarged right ventricle (P = 0.02), left atrium (P = 0.02), left ventricle (P = 0.03), and a higher rate of reduced left ventricular ejection fraction (P = 0.03). Multivariate analysis indicated combined amiodarone and digitalis use before HTX as a significant risk factor for 1 year mortality after HTX (hazard ratio: 1.69; 95% confidence interval: 1.02-2.77; P = 0.04). CONCLUSIONS: Combined pre-transplant amiodarone and digitalis therapy is associated with increased post-transplant mortality.

Elevated pre-transplant pulmonary vascular resistance is associated with early post-transplant atrial fibrillation and mortality.

AIMS: Severely elevated pre-transplant pulmonary vascular resistance (PVR) has been linked to adverse effects after heart transplantation (HTX). The impact of a moderately increased PVR before HTX on post-transplant outcomes remains uncertain. The aim of this study was to investigate the effects of an elevated pre-transplant PVR ≥ 300 dyn·s·cm-5 (≥3.75 Wood units) on outcomes after HTX. METHODS AND RESULTS: This observational retrospective single-centre study included 561 patients receiving HTX at Heidelberg Heart Center between 1989 and 2015. Patients were stratified by degree of pre-transplant PVR. Analyses covered demographics, post-transplant medication, mortality and causes of death after HTX, early post-transplant atrial fibrillation (AF), and length of the initial hospital stay after HTX. Ninety-four patients (16.8%) had a PVR ≥ 300 dyn·s·cm-5 (≥3.75 Wood units). These patients had a higher rate of early post-transplant AF [20.2 vs. 10.7%, difference: 9.5%, 95% confidence interval (CI): 0.9-18.1%, P = 0.01] and an increased 30 day post-transplant mortality (25.5 vs. 6.4%, hazard ratio: 4.4, 95% CI: 2.6-7.6, P < 0.01), along with a higher percentage of death due to transplant failure (21.2 vs. 4.1%, difference: 17.1%, 95% CI: 8.7-25.5%, P < 0.01). Multivariate analysis revealed a PVR ≥ 300 dyn·s·cm-5 (≥3.75 Wood units) as a significant risk factor for increased 30 day mortality after HTX (hazard ratio: 4.4, 95% CI: 2.5-7.6, P < 0.01). Kaplan-Meier estimator showed a lower 2 year survival after HTX (P < 0.01) in patients with a PVR ≥ 300 dyn·s·cm-5 (≥3.75 Wood units). CONCLUSIONS: Elevated pre-transplant PVR ≥ 300 dyn·s·cm-5 (≥3.75 Wood units) is associated with early post-transplant AF and increased mortality after HTX.

Pacemaker cell characteristics of differentiated and HCN4-transduced human mesenchymal stem cells.

AIMS: Cell-based biological pacemakers aim to overcome limitations and side effects of electronic pacemaker devices. We here developed and tested different approaches to achieve nodal-type differentiation using human adipose- and bone marrow-derived mesenchymal stem cells (haMSC, hbMSC). MAIN METHODS: haMSC and hbMSC were differentiated using customized protocols. Quantitative RT-PCR was applied for transcriptional pacemaker-gene profiling. Protein membrane expression was analyzed by immunocytochemistry. Pacemaker current (If) was studied in haMSC with and without lentiviral HCN4-transduction using patch clamp recordings. Functional characteristics were evaluated by co-culturing with neonatal rat ventricular myocytes (NRVM). KEY FINDINGS: Culture media-based differentiation for two weeks generated cells with abundant transcription of ion channel genes (Cav1.2, NCX1), transcription factors (TBX3, TBX18, SHOX2) and connexins (Cx31.9 and Cx45) characteristic for cardiac pacemaker tissue, but lack adequate HCN transcription. haMSC-derived cells revealed transcript levels, which were closer related to sinoatrial nodal cells than hbMSC-derived cells. To substitute for the lack of If, we performed lentiviral HCN4-transduction of haMSC resulting in stable If. Co-culturing with NRVM demonstrated that differentiated haMSC expressing HCN4 showed earlier onset of spontaneous contractions and higher beating regularity, synchrony and rate compared to co-cultures with non-HCN4-transduced haMSC or HCN4-transduced, non-differentiated haMSC. Confocal imaging indicated increased membrane expression of cardiac gap junctional proteins in differentiated haMSC. SIGNIFICANCE: By differentiation haMSC, rather than hbMSC attain properties favorable for cardiac pacemaking. In combination with lentiviral HCN4-transduction, a cellular phenotype was generated that sustainably controls and stabilizes rate in co-culture with NRVM.

Risk factors and survival of patients with permanent pacemaker implantation after heart transplantation.

BACKGROUND: Permanent pacemaker (PPM) implantation after heart transplantation (HTX) may be required due to severe bradycardia. The aim of this study was to investigate the risk factors, indications, perioperative outcomes and complications of PPM implantation after HTX as well as the underlying effect on post-transplant mortality including causes of death. METHODS: This registry study included 621 patients receiving HTX at Heidelberg Heart Center between 1989 and 2018. Patients were stratified by PPM implantation after HTX. Data analysis of risk factors for PPM implantation included donor and recipient demographics, post-transplant medication, mortality, and causes of death. RESULTS: Thirty-six patients (5.8%) received PPM implantation after HTX, 12 (33.3%) with early PPM and 24 (66.7%) with late PPM. Indications for PPM implantation after HTX included sinus node dysfunction (SND) (n=15; 41.7%) and atrioventricular block (AVB) (n=21; 58.3%). Multivariate analysis revealed recipient body mass index (BMI) [hazard ratio (HR): 1.10; confidence interval (CI): 1.01-1.21; P=0.03], donor age (HR: 1.07; CI: 1.03-1.10; P<0.01), and biatrial HTX (HR: 2.63; CI: 1.22-5.68; P=0.01) as significant risk factors for PPM implantation after HTX. Kaplan-Meier estimator displayed a statistically significant inferior 5-year post-transplant survival among patients with early PPM after HTX in comparison to patients with late PPM or no PPM after HTX (P<0.01) along with a higher percentage of death due to infection (P<0.01). CONCLUSIONS: Multivariate risk factors for PPM implantation after HTX include recipient BMI, donor age, and biatrial HTX. Early PPM implantation after HTX is associated with increased 5-year post-transplant mortality due to infection.

COPD in patients after heart transplantation is associated with a prolonged hospital stay, early posttransplant atrial fibrillation, and impaired posttransplant survival.

OBJECTIVES: COPD is associated with reduced physical activity, an increased risk for pulmonary infections, and impaired survival in nontransplant patients. The aim of this study was to investigate the influence of COPD in patients after heart transplantation (HTX). METHODS: We performed an observational retrospective single-center study of 259 patients receiving HTX at Heidelberg University Hospital between 2003 and 2012. Patients were stratified by the Tiffeneau index (forced expiratory volume in 1 second/forced vital capacity [FEV1/FVC]) <0.70 before HTX. The analysis included demographics, posttransplant medication, length of the initial hospital stay after HTX, early posttransplant atrial fibrillation (AF), mortality, and causes of death. RESULTS: In total, 63 (24.3%) patients had an FEV1/FVC <0.70. These patients showed a prolonged hospital stay after HTX (52.0 days vs 43.4 days, mean difference (MD) = 8.6 days, 95% CI: 0.2, 17.0 days), a higher rate of early posttransplant AF (19.0% vs 8.2%, MD = 10.8%, 95% CI: 0.4%, 21.2%), and an increased 30-day mortality (9.5% vs 2.6%, HR = 3.79, 95% CI: 1.16, 12.40). Kaplan- Meier analysis showed a significant inferior 5-year survival in patients with an FEV1/FVC <0.70, along with a higher percentage of death due to transplant failure and infection/sepsis. In addition, a multivariate analysis for mortality within 5 years after HTX indicated an FEV1/FVC <0.70 as a significant risk factor for impaired 5-year posttransplant survival (HR =4.77, 95% CI: 2.76, 8.22). CONCLUSION: COPD in patients after HTX is associated with a prolonged hospital stay, early posttransplant AF, and impaired posttransplant survival.

Control of cardiac chronotropic function in patients after heart transplantation: effects of ivabradine and metoprolol succinate on resting heart rate in the denervated heart.

BACKGROUND: Patients after heart transplantation (HTX) present with sinus tachycardia due to graft denervation. As elevated heart rates negatively affect survival, the aim of this study was to analyze the effects of ivabradine vs metoprolol succinate on heart rate, left ventricular (LV) mass and survival following HTX. METHODS: This observational retrospective single-center study assessed 84 patients continuously receiving either ivabradine (n = 40) or metoprolol succinate (n = 44) within 2 years after HTX. Patients with dual therapy (ivabradine and metoprolol succinate), other beta blockers, amiodarone, or digitalis were excluded. Patient characteristics, post-transplant medication, heart rates, LV mass, and survival were investigated. RESULTS: Analysis of patient characteristics, immunosuppressive drug regimen, and post-transplant medication showed no significant differences between groups except for ivabradine and metoprolol succinate. Baseline heart rates differed not significantly between patients treated with ivabradine [87.0 beats per minute (bpm)] and metoprolol succinate (86.2 bpm; P = 0.6395). At 2-year follow-up, patients with ivabradine (76.7 bpm) had a significantly lower heart rate compared to baseline (P < 0.0001) and to metoprolol succinate (82.0 bpm; P = 0.0283). LV mass in patients receiving ivabradine was lower at 2-year follow-up compared to baseline (P = 0.0067) and patients receiving metoprolol succinate (P = 0.0179). Patients with ivabradine had a superior 2-year survival after HTX (P = 0.0049). CONCLUSION: Treatment with ivabradine in patients within 2 years after HTX significantly reduced post-transplant heart rate and LV mass and was associated with a superior survival in comparison with patients receiving metoprolol succinate.

Chronic digitalis therapy in patients before heart transplantation is an independent risk factor for increased posttransplant mortality.

OBJECTIVES: Digitalis therapy (digoxin or digitoxin) in patients with heart failure is subject to an ongoing debate. Recent data suggest an increased mortality in patients receiving digitalis. This study investigated the effects of chronic digitalis therapy prior to heart transplantation (HTX) on posttransplant outcomes. PATIENTS AND METHODS: This was a retrospective, observational, single-center study. It comprised 530 adult patients who were heart-transplanted at Heidelberg University Hospital between 1989 and 2012. Patients with digitalis prior to HTX (≥3 months) were compared to those without (no or <3 months of digitalis). Patients with digitalis were further subdivided into patients receiving digoxin or digitoxin. Primary outcomes were early posttransplant atrial fibrillation and mortality. RESULTS: A total of 347 patients (65.5%) had digitalis before HTX. Of these, 180 received digoxin (51.9%) and 167 received digitoxin (48.1%). Patients with digitalis before HTX had a significantly lower 30-day (P=0.0148) and 2-year (P=0.0473) survival. There was no significant difference between digoxin and digitoxin in 30-day (P=0.9466) or 2-year (P=0.0723) survival. Multivariate analysis for posttransplant 30-day mortality showed pretransplant digitalis therapy as an independent risk factor (hazard ratio =2.097, CI: 1.036-4.248, P=0.0397). Regarding atrial fibrillation in the early posttransplant period, there was neither a statistically significant difference between patients with and without digitalis (P=0.1327) nor between patients with digoxin or digitoxin (P=0.5867). CONCLUSION: Digitalis in patients before HTX is an independent risk factor for increased posttransplant mortality.