Jan D. Schmitto

Altered Na+Currents in Atrial Fibrillation: Effects of Ranolazine on Arrhythmias and Contractility in Human Atrial Myocardium

OBJECTIVES We investigated changes in Na(+) currents (I(Na)) in permanent (or chronic) atrial fibrillation (AF) and the effects of I(Na) inhibition using ranolazine (Ran) on arrhythmias and contractility in human atrial myocardium. BACKGROUND Electrical remodeling during AF is typically associated with alterations in Ca(2+) and K(+) currents. It remains unclear whether I(Na) is also altered. METHODS Right atrial appendages from patients with AF (n = 23) and in sinus rhythm (SR) (n = 79) were studied. RESULTS Patch-clamp experiments in isolated atrial myocytes showed significantly reduced peak I(Na) density ( approximately 16%) in AF compared with SR, which was accompanied by a 26% lower expression of Nav1.5 (p < 0.05). In contrast, late I(Na) was significantly increased in myocytes from AF atria by approximately 26%. Ran (10 mumol/l) decreased late I(Na) by approximately 60% (p < 0.05) in myocytes from patients with AF but only by approximately 18% (p < 0.05) in myocytes from SR atria. Proarrhythmic activity was elicited in atrial trabeculae exposed to high [Ca(2+)](o) or isoprenaline, which was significantly reversed by Ran (by 83% and 100%, respectively). Increasing pacing rates from 0.5 to 3.0 Hz led to an increase in diastolic tension that could be significantly decreased by Ran in atria from SR and AF patients. CONCLUSIONS Na(+) channels may contribute to arrhythmias and contractile remodeling in AF. Inhibition of I(Na) with Ran had antiarrhythmic effects and improved diastolic function. Thus, inhibition of late I(Na) may be a promising new treatment option for patients with atrial rhythm disturbances and diastolic dysfunction.

Minimally-invasive valve surgery.

Minimally-invasive approaches have become increasingly important in cardiac valve surgery. Smaller incisions have become commonplace in many major centers. We reviewed the existing literature and present the current state-of-the-art of minimally-invasive valve operations in this paper.

Inhibition of Elevated Ca2+/Calmodulin-Dependent Protein Kinase II Improves Contractility in Human Failing Myocardium

Rationale: Heart failure (HF) is known to be associated with increased Ca2+/calmodulin-dependent protein kinase (CaMK)II expression and activity. There is still controversial discussion about the functional role of CaMKII in HF. Moreover, CaMKII inhibition has never been investigated in human myocardium. Objective: We sought to investigate detailed CaMKII&dgr; expression in end-stage failing human hearts (dilated and ischemic cardiomyopathy) and the functional effects of CaMKII inhibition on contractility. Methods and Results: Expression analysis revealed that CaMKII&dgr;, both cytosolic &dgr;C and nuclear &dgr;B splice variants, were significantly increased in both right and left ventricles from patients with dilated or ischemic cardiomyopathy versus nonfailing. Experiments with isometrically twitching trabeculae revealed significantly improved force frequency relationships in the presence of CaMKII inhibitors (KN-93 and AIP). Increased postrest twitches after CaMKII inhibition indicated an improved sarcoplasmic reticulum (SR) Ca2+ loading. This was confirmed in isolated myocytes by a reduced SR Ca2+ spark frequency and hence SR Ca2+ leak, resulting in increased SR Ca2+ load when inhibiting CaMKII. Ryanodine receptor type 2 phosphorylation at Ser2815, which is known to be phosphorylated by CaMKII thereby contributing to SR Ca2+ leak, was found to be markedly reduced in KN-93–treated trabeculae. Interestingly, CaMKII inhibition did not influence contractility in nonfailing sheep trabeculae. Conclusions: The present study shows for the first time that CaMKII inhibition acutely improves contractility in human HF where CaMKII&dgr; expression is increased. The mechanism proposed consists of a reduced SR Ca2+ leak and consequently increased SR Ca2+ load. Thus, CaMKII inhibition appears to be a possible therapeutic option for patients with HF and merits further investigation.

Fully Magnetically Levitated Left Ventricular Assist System for Treating Advanced HF: A Multicenter Study

BACKGROUND The HeartMate 3 left ventricular assist system (LVAS) is intended to provide long-term support to patients with advanced heart failure. The centrifugal flow pump is designed for enhanced hemocompatibility by incorporating a magnetically levitated rotor with wide blood-flow paths and an artificial pulse. OBJECTIVES The aim of this single-arm, prospective, multicenter study was to evaluate the performance and safety of this LVAS. METHODS The primary endpoint was 6-month survival compared with INTERMACS (Interagency Registry for Mechanically Assisted Circulatory Support)-derived performance goal. Patients were adults with ejection fraction ≤ 25%, cardiac index ≤ 2.2 l/min/m(2) without inotropes or were inotrope-dependent on optimal medical management, or listed for transplant. RESULTS Fifty patients were enrolled at 10 centers. The indications for LVAS support were bridge to transplantation (54%) or destination therapy (46%). At 6 months, 88% of patients continued on support, 4% received transplants, and 8% died. Thirty-day mortality was 2% and 6-month survival 92%, which exceeded the 88% performance goal. Support with the fully magnetically levitated LVAS significantly reduced mortality risk by 66% compared with the Seattle Heart Failure Model-predicted survival of 78% (p = 0.0093). Key adverse events included reoperation for bleeding (14%), driveline infection (10%), gastrointestinal bleeding (8%), and debilitating stroke (modified Rankin Score > 3) (8%). There were no pump exchanges, pump malfunctions, pump thrombosis, or hemolysis events. New York Heart Association classification, 6-min walk test, and quality-of-life scores showed progressive and sustained improvement. CONCLUSIONS The results show that the fully magnetically levitated centrifugal-flow chronic LVAS is safe, with high 30-day and 6-month survival rates, a favorable adverse event profile, and improved quality of life and functional status. (HeartMate 3™ CE Mark Clinical Investigation Plan [HM3 CE Mark]; NCT02170363).

Flush perfusion with low potassium dextran solution improves early graft function in clinical lung transplantation

OBJECTIVES We have previously demonstrated experimentally an amelioration of reperfusion injury of the lung after preservation using low potassium dextran (LPD) solution compared to Euro-Collins (EC) solution. Now we report on early graft function in 106 lung transplant recipients of LPD or EC preserved grafts. METHODS Initial graft function was assessed by measurement of lung compliance and oxygenation index 2 h after transplantation. Length of stay on the intensive care unit and hours of mechanical ventilation were compared. Correlation of donor oxygenation, ischemic time, type of transplant, recipient age and sex as well as initial lung compliance and oxygenation with early postoperative course were calculated. RESULTS Dynamic lung compliance was significantly (P<0.05) improved in the LPD group. PO(2)/fiO(2) was comparable in both groups (303+/-122 mmHg LPD, 282+/-118 mmHg EC). Mechanical ventilation was used for 321+/-500 h in the EC group and 189+/-365 h in the LPD group (P=0.006). Intensive care therapy was required for 17.2+/-23.7 days in the EC group and 10.4+/-16 days in the LPD group (P=0.012). Significantly higher lung function parameters were obtained in extubated recipients of LPD preserved grafts 2 weeks after TX. Thirty day graft survival was improved in the LPD group (P=0.045). In the EC group, 30 day mortality was 14.2 and 8% in the LPD group. CONCLUSIONS A reduction of perioperative mortality and morbidity suggests that LPD solution has superior early graft function compared to lung preservation using EC solution.

Implantation of a centrifugal pump as a left ventricular assist device through a novel, minimized approach: Upper hemisternotomy combined with anterolateral thoracotomy

From the Department of Cardiac, Thoracic, Transplantation and Vascular Surgery and the Department of Anaesthesiology and Intensive Care, Hannover Medical School, Hannover, Germany. Disclosures: Authors have nothing to disclose with regard to commercial support. Received for publication June 7, 2011; revisions received July 12, 2011; accepted for publication July 22, 2011; available ahead of print Sept 8, 2011. Address for reprints: Jan D. Schmitto, MD, PhD, Department of Cardiac, Transplantation, Thoracic and Vascular Surgery, Hannover Medical School, Carl-NeubergStrasse 1, 30625 Hannover, Germany (E-mail: schmitto.jan@mh-hannover.de). J Thorac Cardiovasc Surg 2012;143:511-3 0022-5223/

Ca2+/Calmodulin-Dependent Protein Kinase II and Protein Kinase A Differentially Regulate Sarcoplasmic Reticulum Ca2+ Leak in Human Cardiac Pathology

36.00 Copyright 2012 by The American Association for Thoracic Surgery doi:10.1016/j.jtcvs.2011.07.046

First implantation in man of a new magnetically levitated left ventricular assist device (HeartMate III).

Background —Sarcoplasmatic reticulum (SR) Ca2+-leak through ryanodine receptor type 2 (RyR2) dysfunction is of major pathophysiological relevance in human heart failure (HF). However, mechanisms underlying progressive RyR2 dysregulation from cardiac hypertrophy (Hy) to HF are still controversial. Methods and Results —We investigated healthy control myocardium (NF, n=5) as well as myocardium from patients with compensated Hy (n=25) and HF (n=32). In Hy, Ca2+/calmodulin-dependent protein kinase II (CaMKII) and protein kinase A (PKA) both phosphorylate RyR2 at levels which are not different from NF. Accordingly, inhibitors of these kinases reduce the SR Ca2+-leak. In HF, however, the SR Ca2+-leak is nearly doubled compared to Hy leading to reduced systolic Ca2+-transients, a depletion of SR Ca2+-storage and elevated diastolic Ca2+-levels. This is accompanied by a significantly increased CaMKII-dependent phosphorylation of RyR2. In contrast, PKA-dependent RyR2 phosphorylation is not increased in HF and is independent of previous β-blocker treatment. In HF CaMKII inhibition but not inhibition of PKA yields a reduction of the SR Ca2+-leak. Moreover, PKA inhibition further reduces SR Ca2+-load and systolic Ca2+-transients. Conclusions —In human Hy CaMKII as well as PKA functionally regulate RyR2 and may induce SR Ca2+-leak. In the transition from Hy to HF the diastolic Ca2+-leak increases and disturbed Ca2+-cycling occurs. This is associated with an increase in CaMKII- but not PKA-dependent RyR2-phosphorylation. CaMKII inhibition may thus reflect a promising therapeutic target for the treatment of arrhythmias and contractile dysfunction.Background— Sarcoplasmic reticulum (SR) Ca2+ leak through ryanodine receptor type 2 (RyR2) dysfunction is of major pathophysiological relevance in human heart failure (HF); however, mechanisms underlying progressive RyR2 dysregulation from cardiac hypertrophy to HF are still controversial. Methods and Results— We investigated healthy control myocardium (n=5) and myocardium from patients with compensated hypertrophy (n=25) and HF (n=32). In hypertrophy, Ca2+/calmodulin-dependent protein kinase II (CaMKII) and protein kinase A (PKA) both phosphorylated RyR2 at levels that were not different from healthy myocardium. Accordingly, inhibitors of these kinases reduced the SR Ca2+ leak. In HF, however, the SR Ca2+ leak was nearly doubled compared with hypertrophy, which led to reduced systolic Ca2+ transients, a depletion of SR Ca2+ storage and elevated diastolic Ca2+ levels. This was accompanied by a significantly increased CaMKII-dependent phosphorylation of RyR2. In contrast, PKA-dependent RyR2 phosphorylation was not increased in HF and was independent of previous &bgr;-blocker treatment. In HF, CaMKII inhibition but not inhibition of PKA yielded a reduction of the SR Ca2+ leak. Moreover, PKA inhibition further reduced SR Ca2+ load and systolic Ca2+ transients. Conclusions— In human hypertrophy, both CaMKII and PKA functionally regulate RyR2 and may induce SR Ca2+ leak. In the transition from hypertrophy to HF, the diastolic Ca2+ leak increases and disturbed Ca2+ cycling occurs. This is associated with an increase in CaMKII- but not PKA-dependent RyR2 phosphorylation. CaMKII inhibition may thus reflect a promising therapeutic target for the treatment of arrhythmias and contractile dysfunction.

Hyperhidrosis: Evolving concepts and a comprehensive review

Outcomes of heart failure patients supported by a continuous-flow left ventricular assist device (LVAD) have steadily improved during the past decade, largely due to better patient selection and management. Nevertheless, adverse events, such as bleeding, infection, stroke, and thrombus, persist and limit the overall effectiveness of this therapy. Bleeding is the most common serious adverse event that results from the extensive surgery required for implantation and blood component damage due to shear forces in the small blood flow paths of current design axialflow and centrifugal-flow pumps. Excessive bleeding results in reoperations, intensive care time, and total hospital stay, which greatly increases a patient’s exposure for infection. The current clinically used pumps create levels of shear force that can activate platelets and damage von Willebrand factor, causing a disruption in the coagulation system that can manifest as thrombosis or gastrointestinal bleeding. The HeartMate III LVAD (Thoratec Corp, Pleasanton, CA) is a new compact intrapericardial centrifugal-flow pump with a full magnetically levitated rotor (Figure 1). The design differs from currently used devices due to actively controlled rotation and levitation of the rotor allowing gaps in the blood flow that are 10 to 20 times wider, which may minimize blood component trauma and result in more stable coagulation. The HeartMate III is now under clinical investigation, and we present here a case report of the first implantation of the device to support a patient with severe heart failure. The patient is a 55-year-old man with the diagnosis of dilated cardiomyopathy and a recent history of multiple hospital admissions due to worsening heart failure symptoms. With multiple medications, the mean arterial blood pressure was 70 mm Hg, cardiac index was 2.1 liters/min/m, and the left ventricular ejection fraction was 10% to 15%. He was classified as Interagency Registry for Mechanically Assisted Circulatory Support Profile 3. After meeting the HeartMate III Conformite Europeene Mark Study inclusion criteria, the patient gave informed consent, and the implantation was performed by Dr. Schmitto and his team at Hannover Medical School, Hanover, Germany on June 25, 2014. After a median sternotomy, the pericardium was only partially opened to help protect right heart function yet allowing access to the vena cava and aorta for cardiopulmonary bypass cannulation. Once full cardiopulmonary bypass was started, the pericardium was fully opened, the heart was elevated, and the myocardium was cored with the HeartMate coring knife approximately 1 cm medial to the left ventricular apex. The sewing cuff was attached around the apical opening with 2-0 Ethibond pledgeted sutures. The inflow conduit was inserted into the left ventricle, and the device was quickly secured to the heart with a locking mechanism. The outflow graft was trimmed for length and anastomosed to the ascending aorta. The percutaneous lead (driveline) was externalized with a doubletunnel technique and exited through the right upper quadrant of the abdominal wall. Cardiopulmonary bypass lasted 59 minutes, and the total operative time was 149 minutes.

Outpatient management of intra-corporeal left ventricular assist device system in children: a multi-center experience.

Hyperhidrosis (primary or secondary) describes a disorder of excessive sweating. It has a significant negative impact on quality of life and affects nearly 1% of the population living in the United Kingdom (UK). Axillary involvement is the most common affecting 80% of cases. A common link to these disorders is an extreme non-thermoregulatory sympathetic stimulus of exocrine sweat glands, mostly due to emotional stimuli. Non-surgical treatment involves topical medication, iontophoresis and systemic anti-cholinergics. More recently the use of intradermal botulinum toxin has gained popularity. Surgical treatment reserved for severe cases, not responding to conservative management involves local excision, curettage and thoracoscopic sympathectomy. Evolving concepts for treatment, risks and benefits are discussed in the paper herein.