The differential diagnostic value of selected cardiovascular biomarkers in Takotsubo syndrome.

INTRODUCTION: Takotsubo syndrome (TTS) is clinically indistinguishable from an acute coronary syndrome (ACS). In the absence of valid markers for differential diagnosis, coronary angiography has been indispensable. METHODS: In our study, we evaluated the serum levels of sST-2, GDF-15, suPAR and H-FABP in 92 patients with the suspicion of TTS (51 TTS and 41 ACS patients) and 40 gender matched controls (no coronary artery disease or signs of heart failure) at baseline. RESULTS: H-FABP was significantly higher in ACS patients compared to TTS patients. Even in in propensity score matching for left ventricular ejection fraction, sex and cardiovascular risk factors, differences in the plasma levels of H-FABP in the matched cohort of TTS vs ACS remained statistically significant. Whereas, sST-2 was significantly elevated in TTS patients. H-FABP was superior for prediction of an ACS with even higher accuracy than hs troponin in differential diagnosis (AUC 0.797, p ≤ 0.0001); the optimal cut off for discrimination towards a TTS was calculated as 2.93 ng/ml (sensitivity 70.0%, specificity 82.4%, PPV 75.7%, NPV 77.4%). sST-2 seemed most appropriate for identification of a TTS (AUC 0.653, p = 0.012). The optimal cut off for differential diagnosis was 11018.06 pg/ml (sensitivity 82.0%, specificity 51.2%, PPV 69.4%, NPV 71.9 %). CONCLUSION: H-FABP and sST-2 are the most promising markers with better accuracy than preexisting biomarkers in differential diagnosis in our study and therefore, could be crucial for the guidance of treatment in patients with high bleeding risk, advanced renal failure or multimorbidity.

Management of Implantable Cardioverter-Defibrillators during Pregnancy-A Systematic Review.

BACKGROUND: With the advent of implantable cardioverter-defibrillator (ICD) technology in recent decades, patients with inherited or congenital cardiomyopathy have a greater chance of survival into adulthood. Women with ICDs in this group are now more likely to reach reproductive age. However, pregnancy represents a challenge for clinicians, as no guidelines for the treatment of pregnant women with an ICD are currently available. METHODS: To analyze this issue, we performed a systematic screening of the literature using the keywords: pregnancy with ICD, lead fracture in pregnancy, lead thrombi in pregnancy, ventricular tachycardia in pregnancy, inappropriate shocks in pregnancy, ICD discharge in pregnancy and ICD shock in pregnancy. Of 1101 publications found, 27 publications were eligible for further analysis (four retrospective trials and 23 case reports). RESULTS: According to physiological changes in pregnancy, resulting in an increase in heart rate and cardiac output, a vulnerability for malignant arrhythmias and device-related complications in ICD carriers might be suspected. While the literature is limited on this issue, maternal complications including arrhythmia burden with following ICD therapies, thromboembolic events and lead complications as well as inappropriate shock therapy have been reported. According to the limited available studies, associated risk seems not to be more frequent than in the general population and depends on the underlying cardiac pathology. Furthermore, worsening of heart failure and related cardiovascular disease have been reported with associated risk of preterm delivery. These observations are exaggerated by restricted applications of diagnostics and treatment due to the risk of fetal harm in this population. CONCLUSIONS: Due to limited data on management of ICDs during pregnancy, further scientific investigations are required. Consequently, careful risk assessment with individual risk evaluation and close follow ups with interdisciplinary treatment are recommended in pregnant ICD carriers.

Cardiac Arrhythmias in Survivors of Sudden Cardiac Death Requiring Impella Assist Device Therapy.

In this retrospective single-center trial, we analyze 109 consecutive patients (female: 27.5%, median age: 69 years, median left ventricular ejection fraction: 20%) who survived sudden cardiac death (SCD) and needed hemodynamic support from an Impella assist device between 2008 and 2018. Rhythm monitoring is investigated in this population and associations with hospital survival are analyzed. Hospital mortality is high, at 83.5%. Diverse cardiac arrhythmias are frequently registered during Impella treatment. These include atrial fibrillation (AF, 21.1%) and ventricular tachycardia (VT, 18.3%), as well as AV block II°/III° (AVB, 7.3%), while intermittent asystole (ASY) is the most frequently observed arrhythmia (42.2%). Nevertheless, neither ventricular nor supraventricular tachycardias are associated with patients' survival. In patients who experience intermittent asystole, a trend towards a fatal outcome is noted (p = 0.06). Conclusions: Mortality is high in these severely sick patients. While cardiac arrhythmias were frequent, they did not predict hospital mortality in this population. The hemodynamic support of the pump seems to counterbalance the adverse effects of these 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.

[Austrian Consensus on High Blood Pressure 2019]. / Österreichischer Blutdruckkonsens 2019.

Elevated blood pressure remains a major cause of cardiovascular disease, disability, and premature death in Austria, with suboptimal rates of detection, treatment and control also in recent years. Management of hypertension is a common challenge for physicians with different spezializations. In an attempt to standardize diagnostic and therapeutic strategies and, ultimately, to increase the rate of patients with controlled blood pressure and to decrease the burden of cardiovascular disease, 13 Austrian medical societies reviewed the evidence regarding prevention, detection, workup, treatment and consequences of high blood pressure in general and in various clinical scenarios. The result is presented as the first national consensus on blood pressure. The authors and societies involved are convinced that a joint national effort is needed to decrease hypertension-related morbidity and mortality in our country.

Pathophysiology of Calcium Mediated Ventricular Arrhythmias and Novel Therapeutic Options with Focus on Gene Therapy.

Cardiac arrhythmias constitute a major health problem with a huge impact on mortality rates and health care costs. Despite ongoing research efforts, the understanding of the molecular mechanisms and processes responsible for arrhythmogenesis remains incomplete. Given the crucial role of Ca2+-handling in action potential generation and cardiac contraction, Ca2+ channels and Ca2+ handling proteins represent promising targets for suppression of ventricular arrhythmias. Accordingly, we report the different roles of Ca2+-handling in the development of congenital as well as acquired ventricular arrhythmia syndromes. We highlight the therapeutic potential of gene therapy as a novel and innovative approach for future arrhythmia therapy. Furthermore, we discuss various promising cellular and mitochondrial targets for therapeutic gene transfer currently under investigation.

Sympathetic Response and Outcomes Following Renal Denervation in Patients With Chronic Heart Failure: 12-Month Outcomes From the Symplicity HF Feasibility Study.

BACKGROUND: Heart failure (HF) is associated with chronic sympathetic activation. Renal denervation (RDN) aims to reduce sympathetic activity by ablating the renal sympathetic nerves. We investigated the effect of RDN in patients with chronic HF and concurrent renal dysfunction in a prospective, multicenter, single-arm feasibility study. METHODS AND RESULTS: Thirty-nine patients with chronic systolic HF (left ventricular ejection fraction [LVEF] <40%, New York Heart Association class II-III,) and renal impairment (estimated glomerular filtration rate [eGFR; assessed with the use of the Modification of Diet in Renal Disease equation] < 75 mL • min-1 • 1.73 m-2) on stable medical therapy were enrolled. Mean age was 65 ± 11 years; 62% had ischemic HF. The average number of ablations per patient was 13 ± 3. No protocol-defined safety events were associated with the procedure. One subject experienced a renal artery occlusion that was possibly related to the denervation procedure. Statistically significant reductions in N-terminal pro-B-type natriuretic peptide (NT-proBNP; 1530 ± 1228 vs 1428 ± 1844 ng/mL; P = .006) and 120-minute glucose tolerance test (11.2 ± 5.1 vs 9.9 ± 3.6; P = .026) were seen at 12 months, but there was no significant change in LVEF (28 ± 9% vs 29 ± 11%; P= .536), 6-minute walk test (384 ± 96 vs 391 ± 97 m; P= .584), or eGFR (52.6 ± 15.3 vs 52.3 ± 18.5 mL • min-1 • 1.73 m-2; P= .700). CONCLUSIONS: RDN was associated with reductions in NT-proBNP and 120-minute glucose tolerance test in HF patients 12 months after RDN treatment. There was no deterioration in other indices of cardiac and renal function in this small feasibility study.

Acute on/off effects and chronic blood pressure reduction after long-term baroreflex activation therapy in resistant hypertension.

BACKGROUND: Baroreflex activation therapy (BAT) by electrical stimulation of baroreceptors at the carotid sinus is a promising therapeutic approach to reduce elevated blood pressure (BP). To assess the efficacy of long-term BAT, we investigated acute BP alterations after device deactivation and reactivation (on/off effects) in patients on chronic BAT, as well as chronic BP reductions. METHOD: Resistant hypertension patients (n = 17) were enrolled in an open-label, single-arm evaluation of unilateral BAT after exclusion of secondary hypertension. Initial eligibility criteria were SBP≥  140 mmHg, despite stable medical therapy with at least three antihypertensive drugs including at least one diuretic. For on/off testing, several office cuff BP measurements were performed: at rest with activated device, 4-6 min after deactivation, and 4-6 min after reactivation. RESULTS: Before BAT, mean office cuff BP was 179 ±â€Š25 over 98 ±â€Š18 mmHg. At the time of on/off testing (15.1 ±â€Š8.7 months after initial activation and before deactivation), BP was reduced to 147 ±â€Š29 over 84 ±â€Š20 mmHg. On deactivation, SBP increased to 158 ±â€Š38 mmHg (P = 0.004) and DBP to 89 ±â€Š23 mmHg (P = 0.04). After reactivation, SBP decreased to 144 ±â€Š34 mmHg (P = 0.002 vs. deactivation) and DBP to 83 ±â€Š23 mmHg (P = 0.009). There was no correlation between duration of chronic BAT and systolic or diastolic acute on/off response. CONCLUSION: Unilateral BAT reduces BP in patients with resistant hypertension in the long term. There is a significant on/off effect on BP, supporting the efficacy of BAT. The acute on/off response to BAT does not depend on treatment duration. Thus, no evidence of tolerance over time to chronic BAT was found.

Clinical application of interventional renal sympathetic denervation: recommendations of the Austrian Society of Hypertension 2012.

Increased activity of the sympathetic nervous system plays a major role in the pathophysiology of primary arterial hypertension. Interventional renal sympathetic denervation (RSD) is a novel percutaneous treatment, decreasing sympathetic activity and consecutively blood pressure by ablating sympathetic nervous fibers located in the adventitia of the renal arteries. The procedure has been tested in several clinical trials in patients with resistant hypertension (defined as systolic office blood pressure > 160 mmHg-in diabetic patients > 150 mmHg-treated with ³ 3 antihypertensive drugs) and caused a meaningful blood pressure reduction, lasting for at least 3 years. So far, no major adverse events have been identified; however, data on the long-term consequences are lacking. The present position paper of the Austrian Society of Hypertension is aiming to assist in choosing possible indications for RSD in clinical routine, based on the available evidence in 2012.

Effects of renal sympathetic denervation on arterial stiffness and central hemodynamics in patients with resistant hypertension.

OBJECTIVES: This study investigated the effect of catheter-based renal sympathetic denervation (RD) on central hemodynamics in patients with resistant hypertension. BACKGROUND: High central blood pressure (BP) increases cardiovascular events and mortality independently of peripheral BP. The effect of RD on central BP is unclear. METHODS: A total of 110 patients underwent bilateral RD. Radial artery applanation tonometry and pulse wave analysis were used to derive central aortic pressure and hemodynamic indices at baseline and 1, 3, and 6 months after ablation. Ten patients with resistant hypertension not undergoing RD served as controls. RESULTS: RD significantly reduced mean central aortic BP from 167/92 mm Hg to 149/88 mm Hg, 147/85 mm Hg, and 141/85 mm Hg at 1, 3, and 6 months (p < 0.001), respectively. Aortic pulse pressure decreased from 76.2 ± 23.3 mm Hg to 61.5 ± 17.5 mm Hg, 62.7 ± 18.1 mm Hg, and 54.5 ± 15.7 mm Hg 1, 3, and 6 months after RD (p < 0.001), respectively. Six months after RD aortic augmentation and augmentation index were significantly reduced by -11 mm Hg (p < 0.001) and -5.3% (p < 0.001), respectively. Carotid to femoral pulse wave velocity showed a significant reduction from 11.6 ± 3.2 m/s to 9.6 ± 3.1 m/s at 6 months (p < 0.001). Consistently, ejection duration and aortic systolic pressure load were significantly diminished, indicating improvement of cardiac work load by RD. No significant changes were obtained in control patients. CONCLUSIONS: Besides the known effect of RD on brachial blood pressure, the study showed for the first time that this novel approach significantly improves arterial stiffness and central hemodynamics, which might have important prognostic implications in patients with resistant hypertension at high cardiovascular risk.

Spironolactone prevents aldosterone induced increased duration of atrial fibrillation in rat.

BACKGROUND: Atrial fibrillation (AF) is the most common sustained arrhythmia in clinical practice. The Renin-Angiotensin-Aldosterone-System plays a major role for the atrial structural and electrical remodelling. Recently elevated aldosterone levels have been suggested to increase the risk for the development of AF. METHODS: Rats were treated with aldosterone by means of an osmotic minipump (0.5µg/h) over a period of 4 weeks. AF was induced by transesophageal burst pacing. Action potentials (AP) were recorded from left atrial preparations with microelectrodes. Atrial collagen was quantified by histological studies. RESULTS: Aldosterone treatment resulted in hypertrophy as indicated by an increased ratio of heart weight/tibia length and doubled the time until the AF converted spontaneously into sinus rhythm (85.8±13.4 s vs. 38.3±6.9 s, p<0.01). This was associated with a significant shortening of the AP (APD90 26.2±1.1 vs. 31.2±1.9, p<0.05) and an increased protein expression of Kir2.1 and Kv1.5. Atrial collagen deposition was significantly greater in aldosterone-treated rats. The alterations could be prevented by additional application spironolactone. CONCLUSIONS: The results of the present study suggest that in addition to the structural remodelling aldosterone also promotes AF by altering repolarising potassium currents leading to action potential shortening.

Renal sympathetic denervation reduces left ventricular hypertrophy and improves cardiac function in patients with resistant hypertension.

OBJECTIVES: This study investigated the effect of catheter-based renal sympathetic denervation (RD) on left ventricular hypertrophy (LVH) and systolic and diastolic function in patients with resistant hypertension. BACKGROUND: LVH and diastolic dysfunction are associated with elevated sympathetic activity and increased morbidity and mortality. The effect of RD on LVH and LV function is unclear. METHODS: Forty-six patients underwent bilateral RD, and 18 patients served as controls. Transthoracic echocardiography was performed at baseline, and after 1 month and 6 months. RESULTS: Besides reduction of systolic and diastolic blood pressure (-22.5/-7.2 mm Hg at 1 month and -27.8/-8.8 mm Hg at 6 months, p < 0.001 at each time point), RD significantly reduced mean interventricular septum thickness from 14.1 ± 1.9 mm to 13.4 ± 2.1 mm and 12.5 ± 1.4 mm (p = 0.007), and LV mass index from 53.9 ± 15.6 g/m(2.7) (112.4 ± 33.9 g/m(2)) to 47.0 ± 14.2 g/m(2.7) (103.6 ± 30.5 g/m(2)) and 44.7 ± 14.9 g/m(2.7) (94.9 ± 29.8 g/m(2)) (p < 0.001) at 1 month and 6 months, respectively. The mitral valve lateral E/E' decreased after RD from 9.9 ± 4.0 to 7.9 ± 2.2 at 1 month and 7.4 ± 2.7 at 6 months (p < 0.001), indicating reduction of LV filling pressures. Isovolumic relaxation time shortened (baseline 109.1 ± 21.7 ms vs. 85.6 ± 24.4 ms at 6 months, p = 0.006), whereas ejection fraction significantly increased after RD (baseline: 63.1 ± 8.1% vs. 70.1 ± 11.5% at 6 months, p < 0.001). No significant changes were obtained in control patients. CONCLUSIONS: Besides the known effect on blood pressure, our study showed for the first time that RD significantly reduces LV mass and improves diastolic function, which might have important prognostic implications in patients with resistant hypertension at high cardiovascular risk.

Cardiorespiratory response to exercise after renal sympathetic denervation in patients with resistant hypertension.

OBJECTIVES: This study sought to investigate the effects of interventional renal sympathetic denervation (RD) on cardiorespiratory response to exercise. BACKGROUND: RD reduces blood pressure at rest in patients with resistant hypertension. METHODS: We enrolled 46 patients with therapy-resistant hypertension as extended investigation of the Symplicity HTN-2 (Renal Denervation With Uncontrolled Hypertension) trial. Thirty-seven patients underwent bilateral RD and 9 patients were assigned to the control group. Cardiopulmonary exercise tests were performed at baseline and 3-month follow-up. RESULTS: In the RD group, compared with baseline examination, blood pressure at rest and at maximum exercise after 3 months was significantly reduced by 31 ± 13/9 ± 13 mm Hg (p < 0.0001) and by 21 ± 20/5 ± 14 mm Hg (p < 0.0001), respectively. Achieved work rate increased by 5 ± 13 W (p = 0.029) whereas peak oxygen uptake remained unchanged. Blood pressure 2 min after exercise was significantly reduced by 29 ± 17/8 ± 15 mm Hg (p < 0.001 for systolic blood pressure; p = 0.002 for diastolic blood pressure). Heart rate at rest decreased after RD (4 ± 11 beats/min; p = 0.028), whereas maximum heart rate and heart rate increase during exercise were not different. Heart rate recovery improved significantly by 4 ± 7 beats/min after renal denervation (p = 0.009). In the control group, there were no significant changes in blood pressure, heart rate, maximum work rate, or ventilatory parameters after 3 months. CONCLUSIONS: RD reduces blood pressure during exercise without compromising chronotropic competence in patients with resistant hypertension. Heart rate at rest decreased and heart rate recovery improved after the procedure. (Renal Denervation With Uncontrolled Hypertension; [Symplicity HTN-2]; NCT00888433).

Effect of renal sympathetic denervation on glucose metabolism in patients with resistant hypertension: a pilot study.

BACKGROUND: Hypertension is associated with impaired glucose metabolism and insulin resistance. Chronic activation of the sympathetic nervous system may contribute to either condition. We investigated the effect of catheter-based renal sympathetic denervation on glucose metabolism and blood pressure control in patients with resistant hypertension. METHODS AND RESULTS: We enrolled 50 patients with therapy-resistant hypertension. Thirty-seven patients underwent bilateral catheter-based renal denervation, and 13 patients were assigned to a control group. Systolic and diastolic blood pressures, fasting glucose, insulin, C peptide, hemoglobin A(1c), calculated insulin sensitivity (homeostasis model assessment-insulin resistance), and glucose levels during oral glucose tolerance test were measured before and 1 and 3 months after treatment. Mean office blood pressure at baseline was 178/96±3/2 mm Hg. At 1 and 3 months, office blood pressure was reduced by -28/-10 mm Hg (P<0.001) and -32/-12 mm Hg (P<0.001), respectively, in the treatment group, without changes in concurrent antihypertensive treatment. Three months after renal denervation, fasting glucose was reduced from 118±3.4 to 108±3.8 mg/dL (P=0.039). Insulin levels were decreased from 20.8±3.0 to 9.3±2.5 µIU/mL (P=0.006) and C-peptide levels from 5.3±0.6 to 3.0±0.9 ng/mL (P=0.002). After 3 months, homeostasis model assessment-insulin resistance decreased from 6.0±0.9 to 2.4±0.8 (P=0.001). Additionally, mean 2-hour glucose levels during oral glucose tolerance test were reduced significantly by 27 mg/dL (P=0.012). There were no significant changes in blood pressure or metabolic markers in the control group. CONCLUSIONS: Renal denervation improves glucose metabolism and insulin sensitivity in addition to a significantly reducing blood pressure. However, this improvement appeared to be unrelated to changes in drug treatment. This novel procedure may therefore provide protection in patients with resistant hypertension and metabolic disorders at high cardiovascular risk. CLINICAL TRIAL REGISTRATION: URL: http://www.ClinicalTrials.gov. Unique identifiers: NCT00664638 and NCT00888433.

Impact of dihydrotestosterone on L-type calcium channels in human ventricular cardiomyocytes.

OBJECTIVES: Reports of testosterone effects on cardiovascular morbidity remain contradictory. Besides modulating cardiovascular risk factors recent evidence indicates direct actions of testosterone on cardiac tissue. However, the impact on human cardiac L-type calcium channels that play a central role in electro-mechanical coupling is unknown. METHODS AND RESULTS: Human ventricular myocytes were isolated from patients undergoing heart transplantation. Patch-clamp experiments in whole-cell configuration were performed to evaluate the effect of dihydrotestosterone on cardiac L-type calcium current I(Ca,L). Treatment of cultured cardiomyocytes with dihydrotestosterone 100 nmol/L for 24-30 h increased the whole-cell I(Ca,L) current density from 2.32 +/- 0.17 pA/pF (n = 11) to 3.21 +/- 0.17 pA/pF (n = 14) at +10 mV (p = 0.01) without shifting the current-voltage relation. This effect was associated with a 1.35-fold higher expression of the pore-forming Ca(V)1.2 (alpha1c) subunit of L-type calcium channels in dihydrotestosterone-treated myocytes compared with controls (p = 0.03). CONCLUSIONS: Dihydrotestosterone treatment increased L-type calcium current density by the upregulation of Ca(V)1.2 in human ventricular myocytes. These data provide a possible explanation for dihydrotestosterone effects on the cardiovascular system in androgenic steroid abuse.

Percutaneous mitral annuloplasty for functional mitral regurgitation: results of the CARILLON Mitral Annuloplasty Device European Union Study.

BACKGROUND: Functional mitral regurgitation (FMR), a well-recognized component of left ventricular remodeling, is associated with increased morbidity and mortality in heart failure patients. Percutaneous mitral annuloplasty has the potential to serve as a therapeutic adjunct to standard medical care. METHODS AND RESULTS: Patients with dilated cardiomyopathy, moderate to severe FMR, an ejection fraction <40%, and a 6-minute walk distance between 150 and 450 m were enrolled in the CARILLON Mitral Annuloplasty Device European Union Study (AMADEUS). Percutaneous mitral annuloplasty was achieved through the coronary sinus with the CARILLON Mitral Contour System. Echocardiographic FMR grade, exercise tolerance, New York Heart Association class, and quality of life were assessed at baseline and 1 and 6 months. Of the 48 patients enrolled in the trial, 30 received the CARILLON device. Eighteen patients did not receive a device because of access issues, insufficient acute FMR reduction, or coronary artery compromise. The major adverse event rate was 13% at 30 days. At 6 months, the degree of FMR reduction among 5 different quantitative echocardiographic measures ranged from 22% to 32%. Six-minute walk distance improved from 307+/-87 m at baseline to 403+/-137 m at 6 months (P<0.001). Quality of life, measured by the Kansas City Cardiomyopathy Questionnaire, improved from 47+/-16 points at baseline to 69+/-15 points at 6 months (P<0.001). CONCLUSIONS: Percutaneous reduction in FMR with a novel coronary sinus-based mitral annuloplasty device is feasible in patients with heart failure, is associated with a low rate of major adverse events, and is associated with improvement in quality of life and exercise tolerance.

Percutaneous mitral annuloplasty device leaves free access to cardiac veins for resynchronization therapy.

OBJECTIVES: To assess the feasibility to place a left ventricular lead into the coronary sinus following percutaneous mitral annuloplasty. BACKGROUND: Percutaneous coronary sinus-based mitral annuloplasty may reduce functional mitral regurgitation in chronic systolic heart failure. However, concerns have been raised whether the placement of an annular remodeling device in the coronary sinus might preclude subsequent lead placement for resynchronization therapy (CRT). METHODS: Three patients with ischemic cardiomyopathy included in the AMADEUS trial underwent CRT 7 to 8 months after implantation of a mitral valve annuloplasty device. RESULTS: Fluoroscopy and control coronary angiography revealed a stable position of the annuloplasty device without any compromise of coronary blood flow. Intravascular ultrasound of the coronary sinus excluded any thrombus formation and demonstrated smooth endothelialization of the annular remodeling device. Access of the coronary sinus and placement of the left ventricular lead into a posterolateral cardiac vein was not at all compromised by the mitral valve annuloplasty device in any patient. CONCLUSIONS: Positioning a left ventricular pacing lead for CRT is feasible after permanent implantation of a coronary sinus-based mitral annuloplasty device in patients with dilated cardiomyopathy.

Effects of KCNE2 on HCN isoforms: distinct modulation of membrane expression and single channel properties.

Hyperpolarization-activated cation (HCN) channels give rise to an inward current with similar but not identical characteristics compared with the pacemaker current (I(f)), suggesting that HCN channel function is modulated by regulatory beta-subunits in native tissue. KCNE2 has been proposed to serve as a beta-subunit of HCN channels; however, available data remain contradictory. To further clarify this situation, we therefore analyzed the effect of KCNE2 on whole cell currents, single channel properties, and membrane protein expression of all cardiac HCN isoforms in the CHO cell system. On the whole cell level, current densities of all HCN isoforms were significantly increased by KCNE2 without altering voltage dependence or current reversal. While these results correlated well with the KCNE2-mediated 2.2-fold and 1.6-fold increases of membrane protein levels of HCN2 and HCN4, respectively, no effect of KCNE2 on HCN1 expression was obtained. All HCN subtypes displayed faster activation kinetics upon coexpression with KCNE2. Most importantly, for the first time, we demonstrated modulation of single channel function by KCNE2, thus supporting direct functional interaction with HCN subunits. In the presence of KCNE2, the single channel amplitudes and conductance of HCN1, HCN2, and HCN4 were significantly increased versus control recordings. Mean open time was significantly increased in cells coexpressing HCN2 + KCNE2, whereas it was unaffected in HCN1 + KCNE2 cotransfected cells and reduced in HCN4 + KCNE2 cotransfected cells compared with the respective HCN subunits alone. Thus, we demonstrate KCNE2-mediated distinct effects on HCN membrane expression and direct functional modulation of HCN isoforms, further supporting that KCNE2 surves as a regulatory beta-subunit of HCN channels.