Cardiac surgery during the COVID-19 pandemic

The COVID-19 pandemic had several specific as well as general implications on cardiac surgery. Acute respiratory distress made extracorporeal oxygenation necessary in a significant number of patients and accordingly many patients were treated in anesthesiological and even more in cardiac surgical intensive care units, which left only a limited number of beds in the intensive care units available for elective surgery cases. Moreover, the necessary availability of intensive care beds for severely diseased COVID-19 patients in general posed a further limit, as did the relevant number of diseased personnel. Specific emergency plans were developed for many heart surgery units, limiting the number of elective cases. Increasing waiting lists were of course stressful for numerous elective-surgery patients and the decreased number of heart operations also meant a financial burden for many units.

ECMO During COVID-19: A Society of Thoracic Surgeons/Extracorporeal Life Support Organization Survey

BACKGROUND

The Society of Thoracic Surgeons Workforce on Critical Care and the Extracorporeal Life Support Organization sought to identify how the coronavirus disease 2019 (COVID-19) pandemic has changed the practice of venoarterial (VA) and venovenous (VV) extracorporeal membrane oxygenation (ECMO) programs across North America.

METHODS

A 26-question survey covering 6 categories (ECMO initiation, cannulation, management, anticoagulation, triage/protocols, and credentialing) was emailed to 276 North American Extracorporeal Life Support Organization centers. ECMO practices before and during the COVID-19 pandemic were compared.

RESULTS

Responses were received from 93 (34%) programs. The percentage of high-volume (>20 cases per year) VV ECMO programs increased during the pandemic from 29% to 41% (P < .001), as did institutions requiring multiple clinicians for determining initiation of ECMO (VV ECMO, 25% to 43% [P = .001]; VA ECMO, 20% to 32% [P = .012]). During the pandemic, more institutions developed their own protocols for resource allocation (23% before to 51%; P < .001), and more programs created sharing arrangements to triage patients and equipment with other centers (31% to 57%; P < .001). Direct thrombin inhibitor use increased for both VA ECMO (13% to 18%; P = .025) and VV ECMO (12% to 24%; P = .005). Although cardiothoracic surgeons remained the primary cannulating proceduralists, VV ECMO cannulations performed by pulmonary and critical care physicians increased (13% to 17%; P = .046).

CONCLUSIONS

The Society of Thoracic Surgeons/Extracorporeal Life Support Organization collaborative survey indicated that the pandemic has affected ECMO practice. Further research on these ECMO strategies and lessons learned during the COVID-19 pandemic may be useful in future global situations.

Pre-surgery optimization of patients' expectations to improve outcome in heart surgery: Study protocol of the randomized controlled multi-center PSY-HEART-II trial

The PSY-HEART-I trial indicated that a brief expectation-focused intervention prior to heart surgery improves disability and quality of life 6 months after coronary artery bypass graft surgery (CABG). However, to investigate the clinical utility of such an intervention, a large multi-center trial is needed to generalize the results and their implications for the health care system. The PSY-HEART-II study aims to examine whether a preoperative psychological intervention targeting patients' expectations (EXPECT) can improve outcomes 6 months after CABG (with or without heart valve replacement). EXPECT will be compared to Standard of Care (SOC) and an intervention providing emotional support without targeting expectations (SUPPORT). In a 3-arm multi-center randomized, controlled, prospective trial (RCT), N = 567 patients scheduled for CABG surgery will be randomized to either SOC alone or SOC and EXPECT or SOC and SUPPORT. Patients will be randomized with a fixed unbalanced ratio of 3:3:1 (EXPECT: SUPPORT: SOC) to compare EXPECT to SOC and EXPECT to SUPPORT. Both psychological interventions consist of 2 in-person sessions (à 50 minute), 2 phone consultations (à 20 minute) during the week prior to surgery, and 1 booster phone consultation post-surgery 6 weeks later. Assessment will occur at baseline approx. 3-10 days before surgery, preoperatively the day before surgery, 4-6 days later, and 6 months after surgery. The study's primary end point will be patients' illness-related disability 6 months after surgery. Secondary outcomes will be patients' expectations, subjective illness beliefs, quality of life, length of hospital stay and blood sample parameters (eg, inflammatory parameters such as IL-6, IL-8, CRP). This large multi-center trial has the potential to corroborate and generalize the promising results of the PSY-HEART-I trial for routine care of cardiac surgery patients, and to stimulate revisions of treatment guidelines in heart surgery.

Baseline depressive symptoms, personal control, and concern moderate the effects of preoperative psychological interventions: the randomized controlled PSY-HEART trial

This study examined whether baseline (3–14 days pre-surgery) levels of (i) depressive or (ii) anxiety symptoms and (iii) illness beliefs moderate the effects of additional preoperative interventions before coronary artery bypass graft surgery on (i) depressive or (ii) anxiety symptoms and (iii) illness beliefs 1 day before surgery, 1 week and 6 months after surgery. In the PSY-HEART trial, 115 patients were assessed. They were randomized into one of three groups: 1. receiving standard medical care only (SMC), additional psychological interventions: 2. aiming to optimize patients’ expectations (EXPECT), or 3. focusing on emotional support. Patients with a higher baseline level of depressive symptoms receiving a preoperative psychological intervention indicated lower depressive symptoms 6 months after surgery compared to SMC. EXPECT increased personal control and concern levels in patients with low baseline personal control/concern 1 day before surgery. Brief preoperative psychological interventions can improve psychological outcomes in heart surgery patients. Baseline status may moderate these effects. The study has been approved by the medical ethics committee of the Philipps University of Marburg and has been pre-registered at www.clinicaltrials.gov (NCT01407055) on August 1, 2011.

Perioperative Coronavirus Vaccination - Timing and Implications: A Guidance Document

Cardiothoracic surgical patients are at risk of increased coronavirus disease severity. Several important factors influence the administration of the coronavirus disease vaccine in the perioperative period. This guidance statement outlines current information regarding vaccine types, summarizes recommendations regarding appropriate timing of administration, and provides information regarding side effects in the perioperative period for cardiac and thoracic surgical patients.

IL-8 and CRP moderate the effects of preoperative psychological interventions on postoperative long-term outcomes 6 months after CABG surgery - The randomized controlled PSY-HEART trial

INTRODUCTION

Inflammation has been related to several somatic and psychological disorders and may moderate effects of psychological interventions. In the PSY-HEART trial patients benefitted from preoperative psychological interventions before undergoing coronary artery bypass graft surgery (CABG) and, if necessary, concomitant valvular surgery, compared to standard medical care. In this study we examined whether patients' baseline inflammatory status moderated the intervention effects.

MATERIAL AND METHODS

In a prospective three-arm randomized clinical trial with 6-months follow-up, 124 patients scheduled for CABG surgery alone or concomitant with valvular surgery were randomized to (i) standard medical care only (SMC) or two preoperative psychological interventions: (ii) CBT-based optimizing expectations (EXPECT) and an (iii) an active control group focusing on emotional support (SUPPORT). Available baseline CRP- (n = 79), IL-6- (n = 78), IL-8- (n = 78) and TNF-alpha-(n = 80) parameters were considered as potential moderators (CRP as a categorical and continuous moderator). Linear mixed model analyses were calculated to test whether baseline inflammatory levels moderated intervention effects on disability, mental and physical quality of life at 6 months after surgery.

RESULTS

IL-8 moderated intervention effects on patients' disability and categorical CRP moderated intervention effects on mental quality of life. Follow-up tests indicated that EXPECT (and in part SUPPORT) led to lower postoperative disability and higher mental quality of life compared to SMC in patients with low baseline inflammatory markers. EXPECT indicated higher mental quality of life compared to SUPPORT in the high CRP subgroup. Patients in the SMC group had higher mental quality of life in the high CRP subgroup compared to the low CRP subgroup.

CONCLUSION

Especially for patients with a lower inflammatory baseline status preoperative psychological interventions might be helpful to optimize long-term CABG surgery outcomes.

Optimizing preoperative expectations leads to a shorter length of hospital stay in CABG patients: Further results of the randomized controlled PSY-HEART trial

OBJECTIVE

To examine the effect of a preoperative expectation-optimizing psychological intervention on length of stay in the hospital and time spent in the Intensive Care Unit (ICU) in patients undergoing elective cardiac surgery.

METHODS

In a randomized controlled trial, 124 patients prior to undergoing coronary artery bypass grafting (CABG) or CABG combined with heart valve surgery were randomized to either a) standard medical care alone (SMC) or an additional preoperative intervention, b) an additional expectation manipulation intervention (EXPECT) to optimize patients' expectations, or c) an additional supportive therapy (SUPPORT), containing the same amount of therapeutic attention but without a specific focus. Participants were followed-up post-operatively to assess their length of hospital stay and the time spent in the ICU.

RESULTS

Patients in both psychological intervention groups spent significantly less days in the hospital then patients in the SMC group (M(EXPECT)=12.62, M(SUPPORT)=14.13, M(SMC)=17.27, p=0.028). There was a significant linear trend (F(1112)=7.68, p=0.009) showing that the more specific the intervention patients received the shorter they stayed in the hospital. The effect of the intervention on time spent in the ICU was only marginally significant (M(EXPECT)=103.76, M(SUPPORT)=103.10, M(SMC)=158.45, p=0.066).

CONCLUSION

Changing patients' preoperative expectations via a psychological intervention leads to less days spent in the hospital. The psychological interventions are associated with positive cost-benefit ratios. Specific psychological mechanisms underlying the effect of our intervention remain unclear and need to be investigated further.

TRIAL REGISTRATION

www.clinicaltrials.gov (NCT01407055).

Epicardial left atrial appendage closure-comparison of surgical techniques in an ex vivo model

BACKGROUND

Formation of clots in the left atrial appendage (LAA) may lead to embolism and consecutive cerebral stroke. This risk is reduced by closure and resection. To address the efficacy of surgical LAA closure, resilience to pneumatic pressure was studied. Different surgical techniques were compared in an experimental model.

METHODS

From freshly slaughtered pigs cardiopulmonary preparations were taken. The left atrium was clamped airtight and the LAA was cannulated. Via a manually operated pump pressure was applied and a digital pressure gauge was connected. Four groups (each n=12) with different epicardial closures were studied: (I) purse string; (II) single layered continuous suture; (III) double layered suture; (IV) surgical stapler. A nonparametric test was used for group comparisons of mean burst pressures (mmHg). Statistical significance was defined at P<0.05.

RESULTS

Mean burst pressures in group 1 amounted to 97.1±13.0 mmHg, in group 2 to 105.5±13.3 mmHg, in group 3 to 124.6±14.2 mmHg and in group 4 to 136.6±12.5 mmHg. Excepting differences between groups 1 and 2 comparisons between groups were significantly different.

CONCLUSIONS

In an ex vivo model surgical staplers and double layered hand crafted sutures proved well suitable for closure of the LAA. They were significantly superior to single layered sutures in terms of resilience to pneumatic pressure. This may be relevant to durability and should be discussed with regard to clinical choice.

Pneumatic Burst Pressures After Inverted Closure of the Left Atrial Appendage: An Ex Vivo Model

BACKGROUND

The left atrial (LA) appendage (LAA) is the main source of thromboembolism in atrial fibrillation. This study addressed initial pressure resistance of surgical LAA closures.

METHODS

In an experimental model, pneumatic pressure resistances of different surgical closure techniques were examined, and variations in technique and access were studied. In preparations of the LA from freshly slaughtered pigs, pneumatic pressure was applied to the LAA. Burst pressures (mbar) of various closure techniques (n = 12 specimens per group) were measured: (1) epicardial double-layer suture, (2) epicardial stapler closure (staple height 2 mm), (3) epicardial stapler closure (staple height 4, 4.5, and 5 mm), (4) endocardial inverse double-layer suture, (5) endocardial inverse stapler seam (staple height 2 mm), and (6) endocardial inverse stapler seam (staple height 4, 4.5, and 5 mm).

RESULTS

The mean burst pressure in group 1 was 175.5 ± 19.35 mbar. There was no significant difference compared with group 2 (174.5 ± 28.45 mbar) or group 3 (176 ± 27.69 mbar). Group 4 scored significantly higher than all other groups (198.9 ± 18.35 mbar). Burst pressures in group 5 (136.2 ± 16.68 mbar) were significantly lower than in group 4 and in group 6 (165.1 ± 21.94 mbar), but the differences between groups 5 and 6 were also significant.

CONCLUSIONS

In an ex vivo model, double-layer suturing of the inverted LAA from an internal LA access led to higher burst pressures compared with epicardial suturing and with both endocardial and epicardial stapled closures.

Preoperative optimization of patient expectations improves long-term outcome in heart surgery patients: results of the randomized controlled PSY-HEART trial

BACKGROUND

Placebo effects contribute substantially to outcome in most fields of medicine. While clinical trials typically try to control or minimize these effects, the potential of placebo mechanisms to improve outcome is rarely used. Patient expectations about treatment efficacy and outcome are major mechanisms that contribute to these placebo effects. We aimed to optimize these expectations to improve outcome in patients undergoing coronary artery bypass graft (CABG) surgery.

METHODS

In a prospective three-arm randomized clinical trial with a 6 month follow-up, 124 patients scheduled for CABG surgery were randomized to either a brief psychological pre-surgery intervention to optimize outcome expectations (EXPECT); or a psychological control intervention focusing on emotional support and general advice, but not on expectations (SUPPORT); or to standard medical care (SMC). Interventions were kept brief to be feasible with a heart surgery environment; "dose" of therapy was identical for both pre-surgery interventions. Primary outcome was disability 6 months after surgery. Secondary outcomes comprised further clinical and immunological variables.

RESULTS

Patients in the EXPECT group showed significantly larger improvements in disability (-12.6; -17.6 to -7.5) than the SMC group (-1.9; -6.6 to +2.7); patients in the SUPPORT group (-6.7; -11.8 to 1.7) did not differ from the SMC group. Comparing follow-up scores and controlling for baseline scores of EXPECT versus SUPPORT on the variable disability only revealed a trend in favor of the EXPECT group (P = 0.09). Specific advantages for EXPECT compared to SUPPORT were found for mental quality of life and fitness for work (hours per week). Both psychological pre-surgery interventions induced less pronounced increases in pro-inflammatory cytokine concentrations reflected by decreased interleukin-8 levels post-surgery compared to changes in SMC patients and lower interleukin-6 levels in patients of the EXPECT group at follow-up. Both pre-surgery interventions were characterized by great patient acceptability and no adverse effects were attributed to them. Considering the innovative nature of this approach, replication in larger, multicenter trials is needed.

CONCLUSIONS

Optimizing patients' expectations pre-surgery helps to improve outcome 6 months after treatment. This implies that making use of placebo mechanisms has the potential to improve long-term outcome of highly invasive medical interventions. Further studies are warranted to generalize this approach to other fields of medicine.

TRIAL REGISTRATION

Ethical approval for the study was obtained from the IRB of the Medical School, University of Marburg, and the trial was registered at ( NCT01407055 ) on July 25, 2011.

Decreasing the Risk of Aortic Arch Replacement

Eight patients underwent surgical therapy because of acute dissection of the aortic arch. In all cases surgery was performed using hypothermic circulatory arrest. Seven patients survived without neurologic defi ciency. Postoperative angiography confirmed the complete resection of the diseased part of the aorta. This method of operative treatment allows inspection of the operative field with out disturbance by blood flow and es tablishes adequate cerebral protec tion. By using presealed prostheses, application of fibrin glue, and auto- transfusion, the authors were able to limit the risk of bleeding, which is the leading cause of death in surgery of acute aortic dissection.

Welche Erwartungen sagen postoperative Depressivität und Ängstlichkeit bei herzchirurgischen Patienten am stärksten vorher?

Zusammenfassung. Theoretischer Hintergrund: Depressivität und Ängstlichkeit beeinträchtigen den Behandlungserfolg von herzchirurgischen Patienten. Fragestellung: Untersucht wurde, ob und wie präoperative Patientenerwartungen mit postoperativer Depressivität und Ängstlichkeit zusammenhängen und welche präoperativen Erwartungen hierbei den höchsten prädiktiven Wert haben. Methoden: 124 aortocoronare Bypass-Patienten bearbeiteten eine Woche vor der Operation einen Fragebogen, der verschiedene Aspekte von Erwartungen mischt (Positive Health Expectation Questionnaire; PHES) und einen Fragebogen, der einzelne Erwartungsaspekte getrennt erfasst (Expected Illness Perception Questionnaire, IPQ-E) und eine Woche vor sowie eine Woche nach der Operation Fragen zu ihrer Depressivität und Ängstlichkeit (Hospital Anxiety and Depression Scale (HADS)). Ergebnisse: Postoperative Depressivität wird durch präoperative Erwartungen vorhergesagt (R2 = 0.32, F = 3.13, p = .02). Der einzig signifikante Prädiktor hierbei sind positive Gesundheitserwartungen gemessen mit dem PHES. Auch postoperative Ängstlichkeit wird durch präoperative Erwartungen vorhergesagt (R2 = 0.27, F = 2.55, p < .05). Bei der Vorhersage postoperativer Ängstlichkeit haben erwartete Konsequenzen gemessen mit dem IPQ-E den stärksten prädiktiven Wert. Schlussfolgerungen: Die Studie belegt die Relevanz von präoperativen Erwartungen bei herzchirurgischen Patienten. Interventionen, die auf die Verringerung von Depressivität herzchirurgischer Patienten abzielen, sollten den Fokus auf verschiedene Aspekte von Erwartungen legen. Bei der Verringerung postoperativer Ängstlichkeit könnten hingegen einzeln erfasste Erwartungsaspekte von Bedeutung sein.

Cyclic three-dimensional wall motion of the human ascending and abdominal aorta characterized by time-resolved three-dimensional ultrasound speckle tracking

The aim of this study was to measure, characterize, and compare the time-resolved three-dimensional wall kinematics of the ascending and the abdominal aorta. Comprehensive description of aortic wall kinematics is an important issue for understanding its physiological functioning and early detection of adverse changes. Data on the three-dimensional, dynamic cyclic deformation of the aorta in vivo are scarce. Either most imaging techniques available are too slow to capture aortic wall motion (CT, MRI) or they do not provide three-dimensional geometry data. Three-dimensional volume data sets of ascending and abdominal aortae of male healthy subjects (25.5 [24.5, 27.5] years) were acquired by use of a commercial echocardiography system with a temporal resolution of 11-25 Hz. Longitudinal and circumferential strain, twist, and relative volume change were determined by use of a commercial speckle tracking algorithm and in-house software. The kinematics of the abdominal aorta is characterized by diameter change, almost constant length and unidirectional, either clockwise or counter clockwise twist. In contrast, the ascending aorta undergoes a complex deformation with alternating clockwise and counterclockwise twist. Length and diameter changes were in the same order of magnitude with a phase shift between both. Longitudinal strain and its phase shift to circumferential strain contribute to the proximal aorta's Windkessel function. Complex cyclic deformations are known to be highly fatiguing. This may account for increased degradation of components of the aortic wall and therefore promote aortic dissection or aneurysm formation.

[Multiple inappropriate defibrillator shocks due to insulation failure of a Biotronik Linox defibrillator lead with externalized conductor]

In this article the case of a patient who received a total of 35 inappropriate defibrillator shocks due to insulation failure with externalized conductor of a Biotronik Linox® lead is described. The implanted defibrillator was immediately inactivated and the failed lead was extracted using a laser sheath system.

Factors associated with disability expectations in patients undergoing heart surgery

BACKGROUND

Heart surgery patients' expectations have been shown to be related to surgery outcome, independent of medical status. However, it is unclear which factors determine patients' expectations about disability following heart surgery.

PURPOSE

Investigating the associations of patients' disability expectations with demographic, medical, and psychosocial factors as well as other aspects of patients' expectations might help to tailor psychological interventions more specifically to optimize patient's expectations.

METHODS

Eighty-three patients were invited to a psycho-educational intervention to optimize expectations prior to elective coronary artery bypass graft (CABG). Before the psychological intervention and before surgery, disability expectations, demographical, medical, psychosocial variables as well as patient and treatment related expectations were collected via questionnaires and patients' files. Associations with disability expectations were assessed using hierarchical linear multiple regression analysis.

RESULTS

Patients self-rated disability (β = 0.50; p < 0.001) and beliefs about treatment efficacy (β = -0.42; p < 0.001) was independently associated with disability expectations. Expectations about the efficacy of patients' own health behavior as well as demographical variables, psychological distress, perceived social support, and measures of medical morbidity did not explain any additional variance in patients' disability expectations.

CONCLUSION

CABG patients seem to form their disability expectations upon their perceptions about their current disability and their expectations about the efficacy of treatment. Patients' disability expectations appear to be independent from scientifically established risk factors and other psychosocial patient characteristics in heart surgery. Future research is necessary to further determine what factors psychological interventions should focus on to modify patients' disability expectations.

Optimizing preoperative expectations in cardiac surgery patients is moderated by level of disability: the successful development of a brief psychological intervention

Patients' expectations have shown to be a major psychological predictor of health outcome in cardiac surgery patients. However, it is unclear whether patients' expectations can be optimized prior to surgery. This study evaluates the development of a brief psychological intervention focusing on the optimization of expectations and its effect on change in patients' expectations prior to cardiac surgery. Ninety patients scheduled for coronary artery bypass graft were randomly assigned to (1) standard medical care, (2) additional expectation manipulation intervention (EMI), and (3) additional attention control group. Therapists' fidelity to intervention manuals and patients satisfaction with the intervention were assessed for both active intervention conditions. Patients' expectations about post-surgical disability, treatment control, personal control, and disease duration were assessed before and after the psychological intervention. Demographical, medical, and psychosocial characteristics and disability were assessed at baseline. Treatment fidelity and patient satisfaction was very high in both intervention conditions. Only patients receiving EMI developed higher personal control expectations and longer (more realistic) expectations of disease duration. The effect of intervention group on patients' disability expectations and patients' personal control expectations was moderated by patient's level of disability. EMI patients with low to moderate disability developed positive expectations whereas patients with high disability did not. This study shows the successful development of a short psychological intervention that was able to modify patients' expectations, especially in those with low to moderate disability. Given the robust association of expectations and surgery outcome, such an intervention might offer the opportunity to enhance patients' health following cardiac surgery.

[Laser sheath extraction of an infected pacemaker lead]

A case of pacemaker electrode infection with Staphylococcus aureus is presented. In order to avoid sternotomy, the right ventricular pacemaker lead, which had been implanted for 15 years, was successfully extracted using a laser sheath despite large endocarditic vegetations on the pacemaker lead. After completion of a 6-week course of antibiotics, the patient was discharged without any further evidence of infection.

In vivo determination of elastic properties of the human aorta based on 4D ultrasound data

Computational analysis of the biomechanics of the vascular system aims at a better understanding of its physiology and pathophysiology. To be of clinical use, however, these models and thus their predictions, have to be patient specific regarding geometry, boundary conditions and material. In this paper we present an approach to determine individual material properties of human aortae based on a new type of in vivo full field displacement data acquired by dimensional time resolved three dimensional ultrasound (4D-US) imaging. We developed a nested iterative Finite Element Updating method to solve two coupled inverse problems: The prestrains that are present in the imaged diastolic configuration of the aortic wall are determined. The solution of this problem is integrated in an iterative method to identify the nonlinear hyperelastic anisotropic material response of the aorta to physiologic deformation states. The method was applied to 4D-US data sets of the abdominal aorta of five healthy volunteers and verified by a numerical experiment. This non-invasive in vivo technique can be regarded as a first step to determine patient individual material properties of the human aorta.

Enhancing the efficacy of heart surgery by optimizing patients' preoperative expectations: study protocol of a randomized controlled trial

In coronary heart disease (CHD) and heart surgery, there is sound evidence for the relationship between patients' expectations and treatment outcome, especially for outcome variables such as disability and quality of life. In addition, patients' expectations have been shown to be modifiable through psychological interventions. Therefore, targeting patients' expectations might offer a promising opportunity to enhance heart surgery outcome. However, few studies have tried to actively change patients' expectations before surgery. The purpose of this clinical trial is to optimize patients' outcome expectations before undergoing coronary artery bypass graft surgery (CABG) through a brief psychoeducational program. The present article describes the study protocol and reports preliminary data on feasibility. Using a randomized controlled design, 180 patients who are scheduled to undergo elective CABG are randomly assigned to either (1) standard medical care (SMC) alone, (2) to an additional expectation manipulation intervention during the 2 weeks before surgery, and (3) to an additional attention-control group ("supportive therapy"). The main goal is to test (a) whether expectation manipulation intervention can optimize patients' expectations and (b) whether optimized expectations lead to enhanced surgery efficacy. The primary outcome variable is illness-related disability 6 months after surgery, whereas secondary outcome variables will be quality of life, return to work, physical activity, and medical outcome variables. First, feasibility data of 36 patients show that the patients appreciated the additional psychological intervention before CABG. Satisfaction of those who received psychological interventions was very high.

[Artificial heart and heart transplantation]

The advances in the treatment of many different heart diseases have on the one side led to a significant prolongation of life expectancy but have also contributed to an increase of patients with heart failure. This tendency is supported even more so by the demographic development of our population. The replacement of insufficient organs has always been in the focus of medical research. In the 1960's Shumway and Lower developed the technique of cardiac transplantation and also worked intensively on the treatment and diagnosis of rejection. However, it was Barnard who, in 1967 performed the first human cardiac transplantation. Other centers followed worldwide but the mortality was high and the new therapy was controversially discussed in many journals. By the introduction of cyclosporin as a new immunosuppressive agent in 1978, results improved rapidly and cardiac transplantation became an accepted therapeutic option for patients with end stage heart failure and also for children and newborns with congenital heart defects. Today, with newer immunosuppressive regimens and improved techniques, cardiac transplantation offers excellent results with a long-term survival of nearly 50% of patients after 15 years and among the pediatric population even after 20 years. However, the donor organ shortage as well as the increasing number of elderly patients with end stage heart failure has necessitated work on other alternatives. Neither stem cell transplantation nor xenotransplantation of animal organs are yet an option and there are still some obstacles to be overcome. In contrast, the development of so-called artificial hearts has made significant progress. While the first implants of totally artificial hearts were associated with many comorbidities and patients were seriously debilitated, new devices today offer a reasonable quality of life and long-term survival. Most of these systems are no longer replacing but mainly assisting the heart, which remains in place. These ventricular assist devices have been used as a bridge to transplantation for a long time and are now also offered as a destination therapy for patients who for a variety of reasons are no longer amenable to heart transplantation. Further miniaturization and a decrease of the costs will make these devices a realistic alternative to a sole medical therapy and studies have already proven the superiority in terms of survival as well as rehospitalization rates. However, at present they are still not an alternative to heart transplantation.

TASK-1 channels may modulate action potential duration of human atrial cardiomyocytes

BACKGROUND/AIMS

Atrial fibrillation is the most common arrhythmia in the elderly, and potassium channels with atrium-specific expression have been discussed as targets to treat atrial fibrillation. Our aim was to characterize TASK-1 channels in human heart and to functionally describe the role of the atrial whole cell current I(TASK-1).

METHODS AND RESULTS

Using quantitative PCR, we show that TASK-1 is predominantly expressed in the atria, auricles and atrio-ventricular node of the human heart. Single channel recordings show the functional expression of TASK-1 in right human auricles. In addition, we describe for the first time the whole cell current carried by TASK-1 channels (I(TASK-1)) in human atrial tissue. We show that I(TASK-1) contributes to the sustained outward current I(Ksus) and that I(TASK-1) is a major component of the background conductance in human atrial cardiomyocytes. Using patch clamp recordings and mathematical modeling of action potentials, we demonstrate that modulation of I(TASK-1) can alter human atrial action potential duration.

CONCLUSION

Due to the lack of ventricular expression and the ability to alter human atrial action potential duration, TASK-1 might be a drug target for the treatment of atrial fibrillation.