Integrated multi-omic characterization of congenital heart disease.

The heart, the first organ to develop in the embryo, undergoes complex morphogenesis that when defective results in congenital heart disease (CHD). With current therapies, more than 90% of patients with CHD survive into adulthood, but many suffer premature death from heart failure and non-cardiac causes1. Here, to gain insight into this disease progression, we performed single-nucleus RNA sequencing on 157,273 nuclei from control hearts and hearts from patients with CHD, including those with hypoplastic left heart syndrome (HLHS) and tetralogy of Fallot, two common forms of cyanotic CHD lesions, as well as dilated and hypertrophic cardiomyopathies. We observed CHD-specific cell states in cardiomyocytes, which showed evidence of insulin resistance and increased expression of genes associated with FOXO signalling and CRIM1. Cardiac fibroblasts in HLHS were enriched in a low-Hippo and high-YAP cell state characteristic of activated cardiac fibroblasts. Imaging mass cytometry uncovered a spatially resolved perivascular microenvironment consistent with an immunodeficient state in CHD. Peripheral immune cell profiling suggested deficient monocytic immunity in CHD, in agreement with the predilection in CHD to infection and cancer2. Our comprehensive phenotyping of CHD provides a roadmap towards future personalized treatments for CHD.

Retrospective review of secondary prevention strategies for gastrointestinal bleeding and associated clinical outcomes in left ventricular assist device patients.

BACKGROUND: Gastrointestinal bleeding (GIB) is one of the most common bleeding complications associated with left ventricular assist devices (LVAD). Currently, there is no strong evidence or clear guidance for which secondary GIB prophylaxis strategy should be implemented after the discontinuation of aspirin. METHODS: Our single-center study describes the outcomes of 26 LVAD patients who experienced a total of 49 GIB events: these individuals were either in Group-1 (lower INR target range) or Group-2 (lower INR target plus a hemostatic agent) as the secondary prophylaxis strategy. Each GIB event was considered an independent event. Outcomes assessed were bleeding reoccurrence rates, time to next GIB, acute GIB strategies, GIB-free days, thromboembolic events, survival, coagulation, and hematologic parameters. RESULTS: GIB reoccurrence rates were not statistically different: Group-1, 9 (40.9%), versus Group-2, 15 (55.6%); p = 0.308. Danazol was utilized 81.5% of the time as the designated hemostatic agent. Additionally, no significant differences were observed with all of our secondary outcome measures for bleeding, ischemic events, or survival. CONCLUSION: While our study was not powered to assess the clinical outcomes related to survival and thromboembolic events, no discernable increased risk for ischemic events including pump thrombosis were observed. Our data suggest that a lower INR target range plus danazol does not confer any additional benefit over a lower INR target range only approach. The results of this report are hypothesis-generating and additional studies are warranted to elucidate the optimal antithrombotic strategy and role of hemostatic agents in reducing the risk of recurrent GIB events.

Prospective Multicenter Study of Myocardial Recovery Using Left Ventricular Assist Devices (RESTAGE-HF [Remission from Stage D Heart Failure]): Medium-Term and Primary End Point Results.

BACKGROUND: Left ventricular assist device (LVAD) unloading and hemodynamic support in patients with advanced chronic heart failure can result in significant improvement in cardiac function allowing LVAD removal; however, the rate of this is generally considered to be low. This prospective multicenter nonrandomized study (RESTAGE-HF [Remission from Stage D Heart Failure]) investigated whether a protocol of optimized LVAD mechanical unloading, combined with standardized specific pharmacological therapy to induce reverse remodeling and regular testing of underlying myocardial function, could produce a higher incidence of LVAD explantation. METHODS: Forty patients with chronic advanced heart failure from nonischemic cardiomyopathy receiving the Heartmate II LVAD were enrolled from 6 centers. LVAD speed was optimized with an aggressive pharmacological regimen, and regular echocardiograms were performed at reduced LVAD speed (6000 rpm, no net flow) to test underlying myocardial function. The primary end point was the proportion of patients with sufficient improvement of myocardial function to reach criteria for explantation within 18 months with sustained remission from heart failure (freedom from transplant/ventricular assist device/death) at 12 months. RESULTS: Before LVAD, age was 35.1±10.8 years, 67.5% were men, heart failure mean duration was 20.8±20.6 months, 95% required inotropic and 20% temporary mechanical support, left ventricular ejection fraction was 14.5±5.3%, end-diastolic diameter was 7.33±0.89 cm, end-systolic diameter was 6.74±0.88 cm, pulmonary artery saturations were 46.7±9.2%, and pulmonary capillary wedge pressure was 26.2±7.6 mm Hg. Four enrolled patients did not undergo the protocol because of medical complications unrelated to the study procedures. Overall, 40% of all enrolled (16/40) patients achieved the primary end point, P<0.0001, with 50% (18/36) of patients receiving the protocol being explanted within 18 months (pre-explant left ventricular ejection fraction, 57±8%; end-diastolic diameter, 4.81±0.58 cm; end-systolic diameter, 3.53±0.51 cm; pulmonary capillary wedge pressure, 8.1±3.1 mm Hg; pulmonary artery saturations 63.6±6.8% at 6000 rpm). Overall, 19 patients were explanted (19/36, 52.3% of those receiving the protocol). The 15 ongoing explanted patients are now 2.26±0.97 years after explant. After explantation survival free from LVAD or transplantation was 90% at 1-year and 77% at 2 and 3 years. CONCLUSIONS: In this multicenter prospective study, this strategy of LVAD support combined with a standardized pharmacological and cardiac function monitoring protocol resulted in a high rate of LVAD explantation and was feasible and reproducible with explants occurring in all 6 participating sites. Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT01774656.

Mechanical circulatory support in pre and postheart transplant period.

PURPOSE OF REVIEW: Progression of heart failure (HF) and its unpredictable and volatile nature, often requires advanced therapies including heart transplant. Mechanical circulatory support plays an integral part in the advanced treatment options. This technology can be deployed in several ways, particularly in the preparation and patient optimization for heart transplants. This article discusses the use of temporary and durable devices and their deployment strategies in the pre and posttransplant period. RECENT FINDINGS: Recently temporary mechanical support devices have allowed us to improve survival to transplant as well as posttransplant. Early implementation of temporary devices both for stabilization of advanced HF patients being considered for transplant as well as those with posttransplant primary graft dysfunction (although utilization of extracorporeal membrane oxygenation has repeatedly shown to be associated with worse outcomes compared to the other devices discussed), is reflective of the degree of disease progression in these patients. The outcomes of patients supported with durable devices have significantly improved with advancing technology. HeartMate 3 device has not only been shown to improve survival as well as the quality of life but in comparison to its predecessor, has been shown to decrease the morbidity associated with this technology. SUMMARY: Both temporary and durable devices are now associated with improved survival and allow us to transplant patients in a more stable and safer manner with fewer adverse events. Based on the new United Network of Organ Sharing allocation system, it allows us to upgrade those who do not have the luxury of time to wait for a transplant. Primary graft dysfunction now also can be assisted with those devices, which is reflected in improved survival of posttransplant patients.

Intrapericardial Left Ventricular Assist Device for Advanced Heart Failure.

BACKGROUND: Mechanical circulatory support with a left ventricular assist device (LVAD) is an established treatment for patients with advanced heart failure. We compared a newer LVAD design (a small intrapericardial centrifugal-flow device) against existing technology (a commercially available axial-flow device) in patients with advanced heart failure who were ineligible for heart transplantation. METHODS: We conducted a multicenter randomized trial involving 446 patients who were assigned, in a 2:1 ratio, to the study (centrifugal-flow) device or the control (axial-flow) device. Adults who met contemporary criteria for LVAD implantation for permanent use were eligible to participate in the trial. The primary end point was survival at 2 years free from disabling stroke or device removal for malfunction or failure. The trial was powered to show noninferiority with a margin of 15 percentage points. RESULTS: The intention-to treat-population included 297 participants assigned to the study device and 148 participants assigned to the control device. The primary end point was achieved in 164 patients in the study group and 85 patients in the control group. The analysis of the primary end point showed noninferiority of the study device relative to the control device (estimated success rates, 55.4% and 59.1%, respectively, calculated by the Weibull model; absolute difference, 3.7 percentage points; 95% upper confidence limit, 12.56 percentage points; P=0.01 for noninferiority). More patients in the control group than in the study group had device malfunction or device failure requiring replacement (16.2% vs. 8.8%), and more patients in the study group had strokes (29.7% vs. 12.1%). Quality of life and functional capacity improved to a similar degree in the two groups. CONCLUSIONS: In this trial involving patients with advanced heart failure who were ineligible for heart transplantation, a small, intrapericardial, centrifugal-flow LVAD was found to be noninferior to an axial-flow LVAD with respect to survival free from disabling stroke or device removal for malfunction or failure. (Funded by HeartWare; ENDURANCE ClinicalTrials.gov number, NCT01166347 .).

Outcomes of Severely Obese Patients Supported by a Centrifugal-Flow Left Ventricular Assist Device.

BACKGROUND: Ventricular assist devices provide improved outcomes for patients with advanced heart failure, but their benefit in the severely obese is not well documented. METHODS: Patients enrolled in the HeartWare ADVANCE trial (n=382) were divided into 2 body mass index (BMI) groups. Patients with severe obesity (>35 kg/m2) were compared with a control group with BMI ≤35 kg/m2. The association of BMI with survival was tested using Kaplan-Meier analysis and major adverse events were compared. RESULTS: At implantation, 48 (13%) of patients were severely obese. There was no difference in survival through 2 years of support between severely obese patients and the control group. Severely obese patients were at higher risk of driveline infection (P = .01) and acute renal dysfunction (P = .002). Both groups experienced similar improvements in quality of life. Functional capacity improved in both severely obese and control patients, although severely obese patients had smaller improvements than controls in their 6-minute walk scores. CONCLUSIONS: Despite an increased risk of adverse events, severe obesity was not associated with reduced survival or quality of life. A better understanding of the risks and benefits of left ventricular assist device therapy in obese patients will help in the shared decision-making of the patient selection process.

Impact of QRS Duration and Ventricular Pacing on Clinical and Arrhythmic Outcomes in Continuous Flow Left Ventricular Assist Device Recipients: A Multicenter Study.

OBJECTIVES: Wide QRS duration and ventricular pacing are common in recipients of continuous-flow left ventricular assist devices (CF-LVADs) but their impact on outcomes remains unclear. We assessed the clinical and arrhythmic outcomes of CF-LVAD patients with wide QRS or right ventricular (RV) pacing at baseline, compared with those with narrow QRS and those with continued cardiac resynchronization therapy (CRT). METHODS AND RESULTS: A total of 520 patients (57 ± 13 years) with an implantable cardioverter-defibrillator (ICD) (n = 240) or CRT-defibrillator (n = 280) who underwent CF-LVAD implantation at 5 centers in 2007-2015 were studied. Patients were divided into 3 groups: ICD-N (QRS ≤120 ms; n = 134), ICD-W (QRS >120 ms; n = 106), and CRT (n = 280). Mortality, hospitalization, and ventricular arrhythmia (VA) incidence were compared among the groups. Baseline QRS duration was different among the groups (100 ± 13 [ICD-N] vs 155 ± 26 [ICD-W] vs 159 ± 29 ms [CRT]; P < .0001). In the ICD-W group, 37 (35%) had >80% RV pacing at baseline. Median biventricular pacing in the CRT group was 96%. Over 523 days of CF-LVAD support, Kaplan-Meier analysis showed no difference in survival among groups (log rank P = .9). According to multivariate Cox regression, wide QRS duration and RV pacing were not associated with survival. QRS narrowed during CF-LVAD support in the ICD-W and CRT groups but was not associated with improved survival (P = .9). No differences were noted among the groups in hospitalizations (P = .9), VA (P = .2), or ICD shocks (P = .06). CONCLUSIONS: In this large CF-LVAD cohort, a wide QRS duration, high percentage of RV pacing at baseline, and changes in QRS duration after LVAD implantation were not associated with survival. Continued CRT after CF-LVAD implantation also was not associated with improved survival or HF hospitalizations.

Impact of cardiac resynchronization therapy on clinical outcomes in patients with continuous-flow left ventricular assist devices.

BACKGROUND: Implantable cardioverter-defibrillators (ICDs) can improve survival in left ventricular assist device (LVAD) recipients. However, the impact of cardiac resynchronization therapy (CRT-D) on outcomes in continuous-flow left ventricular assist device (CF-LVAD) patients is not known. We sought to determine if CRT-D improved clinical outcomes in CF-LVAD patients compared with ICDs alone. METHODS AND RESULTS: Sixty-one consecutive CF-LVAD patients with an ICD or CRT-D were evaluated. Impacts of CRT-D on mortality, all-cause hospitalization, and incidence of atrial (AA) and ventricular (VA) arrhythmias after LVAD implantation was compared with patients with ICD alone. Of the 61 LVAD patients, 31 (age 59.8 ± 16 years, 84% male) had CRT-D and 30 (age 57.2 ± 13 years, 74% male) had ICD. Before LVAD implantation, no significant differences were noted between the groups in demographic and clinical characteristics, LVAD indications, and incidence of AA and VA. Over 682 ± 45 days of LVAD support, 8 patients (25.8%) died in the CRT-D arm versus 5 (16.7%) in the ICD arm (P = .35). No differences were noted between the CRT-D and ICD groups in all-cause (96.8 vs 93.3%; P = .63) and HF (19.4 vs 26.7%; P = .78) hospitalizations, left ventricular (LV) end-diastolic diameter (6.4 ± 1.5 vs 6.2 ± 1.1 cm, P = .47), and incidence of AA (35.4% vs 33.3%; P = .80), VA (29% vs 26.6%; P = .86), and ICD shocks (22.6% vs 16.7%; P = .93). Beta-blocker and antiarrhythmic drug use after LVAD implantation was similar in both groups. CONCLUSIONS: In patients with refractory HF who received CF-LVADs, CRT-D, compared with ICD, did not significantly improve mortality, all-cause hospitalization, LV dimensions, and incidence of AA and VA.

Molecular changes after left ventricular assist device support for heart failure.

Heart failure is associated with remodeling that consists of adverse cellular, structural, and functional changes in the myocardium. Until recently, this was thought to be unidirectional, progressive, and irreversible. However, irreversibility has been shown to be incorrect because complete or partial reversal can occur that can be marked after myocardial unloading with a left ventricular assist device (LVAD). Patients with chronic advanced heart failure can show near-normalization of nearly all structural abnormalities of the myocardium or reverse remodeling after LVAD support. However, reverse remodeling does not always equate with clinical recovery. The molecular changes occurring after LVAD support are reviewed, both those demonstrated with LVAD unloading alone in patients bridged to transplantation and those occurring in the myocardium of patients who have recovered enough myocardial function to have the device removed. Reverse remodeling may be attributable to a reversal of the pathological mechanisms that occur in remodeling or the generation of new pathways. A reduction in cell size occurs after LVAD unloading, which does not necessarily correlate with improved cardiac function. However, some of the changes in both the cardiac myocyte and the matrix after LVAD support are specific to myocardial recovery. In the myocyte, increases in the cytoskeletal proteins and improvements in the Ca²âº handling pathway seem to be specifically associated with myocardial recovery. Changes in the matrix are complex, but excessive scarring appears to limit the ability for recovery, and the degree of fibrosis in the myocardium at the time of implantation may predict the ability to recover.

Safety and Feasibility of Induction Immunosuppression When Driveline Infection Is an Indication for Cardiac Transplantation.

BACKGROUND: There is a paucity of data on the use of induction immunosuppression in patients with active infections undergoing orthotopic heart transplantation (OHT). We hypothesized that induction immunosuppression in patients with ventricular assist device (VAD) undergoing OHT with localized active driveline infection (DLI) does not lead to worse outcomes. MATERIALS AND METHODS: We retrospectively analyzed our database for bridge-to-transplant VAD patients who underwent OHT and received induction therapy. Patients were stratified into those with and without active DLI at the time of OHT and followed up till death or at least 30 months after OHT. Posttransplant length of stay (LOS), frequency of infections, and mortality were compared between the two groups. RESULTS: Thirty-eight patients (30 males) with mean age of 57.5 ± 13 years with VAD underwent OHT during the study period. Twelve had active DLI. Mean follow-up was 46.4 ± 23.1 months. In the DLI versus non-DLI group, there was no difference in mortality (17 vs. 23%, p = NS), LOS (16.3 ± 5.4 vs. 17.2 ± 13.7, p = NS), postoperative renal function, incidence of hyperacute or late rejection or infection either in the first month (25 vs. 23%, p = NS) or during entire follow-up (92 vs. 88%, p = NS). No patient in the DLI group had infections attributable to the same organism responsible for pretransplant DLI. CONCLUSION: In patients with active DLI, induction immunosuppression after OHT did not increase LOS, infections, or mortality after at least 30 months of follow-up and therefore it appears to be a safe and feasible therapeutic option.

Hematologic markers better predict left ventricular assist device thrombosis than echocardiographic or pump parameters.

BACKGROUND: Left ventricular assist device (LVAD) thrombosis is a life-threatening complication that remains a major clinical problem. Consensus diagnostic criteria do not exist. We investigated whether hematologic, echocardiographic, or pump parameters reliably change during LVAD thrombosis. METHODS: A retrospective analysis of 20 consecutive cases of continuous-flow LVAD thrombosis (Thoratec HeartMate II n = 16, HeartWare HVAD n = 4) was performed. Hematologic markers (lactate dehydrogenase, plasma-free hemoglobin, hemoglobin, creatinine), echocardiographic parameters (left ventricular end-systolic and end-diastolic diameter, mitral regurgitation, aortic insufficiency, inflow-cannula velocity), and pump characteristics (speed, power, estimated flow, pulsatility index) were analyzed with one-way repeated measures ANOVA with Tukey post-test or paired Student t-tests. RESULTS: Lactate dehydrogenase and plasma-free hemoglobin were significantly (p < 0.05) elevated at admission for LVAD thrombosis. Hemoglobin and creatinine were not significantly different at admission but changed significantly after admission. Left ventricular end-systolic and end-diastolic diameter, mitral regurgitation, aortic insufficiency, inflow-cannula velocity, LVAD speed, power consumption, estimated flow, and pulsatility index were not significantly different at admission for LVAD thrombosis. CONCLUSION: Hematological markers of hemolysis, but not echocardiographic or pump parameters, reliably changed during LVAD thrombosis. Markers of hemolysis are the best early predictors of LVAD thrombosis.

Using electronic medical records to identify patients at risk for underlying cardiac amyloidosis.

BACKGROUND: Identification of transthyretin cardiac amyloidosis (ATTR-CA) patients is largely based on pattern recognition by providers, and this can be automated through electronic medical systems (EMR). METHODS: All patients in a large academic hospital with age > 60, ICD-10 code for chronic diastolic heart failure and no previous diagnosis of any amyloidosis were included. An Epic EMR scoring logic assigned risk scores to patients for ICD-10 and CPT codes associated with ATTR-CA, as follows: carpal tunnel syndrome (score 5), aortic stenosis/TAVR (5), neuropathy (4), bundle branch block (4), etc. The individual patients' scores were added, and patients were arranged in descending order of total scores- ranging from 50 to 0. Data is reported as median (interquartile range) and analyzed with non-parametric tests. RESULTS: Of the total 11,648 patients identified, 132 consecutive patients with highest risk scores (score ≥ 30) were enrolled as cases, while 132 patients with scores between 10 and 19 with available echocardiography data served as age-matched controls. Strain echocardiography is not routinely performed. Patients with high scores were more likely to have CA associated findings- African-American race, higher left ventricular (LV) mass index and left atrial volume and lower LV ejection fraction. High score patients had higher troponin and a trend towards high NT-proBNP. CONCLUSION: The modern EMR can be used to flag patients with high risk for ATTR-CA (score ≥ 30 using the proposed logic) through best practice advisory. This could encourage screening during echocardiography using strain or during unsuspected clinic visits.

Telethonin deficiency is associated with maladaptation to biomechanical stress in the mammalian heart.

RATIONALE: Telethonin (also known as titin-cap or t-cap) is a 19-kDa Z-disk protein with a unique ß-sheet structure, hypothesized to assemble in a palindromic way with the N-terminal portion of titin and to constitute a signalosome participating in the process of cardiomechanosensing. In addition, a variety of telethonin mutations are associated with the development of several different diseases; however, little is known about the underlying molecular mechanisms and telethonin's in vivo function. OBJECTIVE: Here we aim to investigate the role of telethonin in vivo and to identify molecular mechanisms underlying disease as a result of its mutation. METHODS AND RESULTS: By using a variety of different genetically altered animal models and biophysical experiments we show that contrary to previous views, telethonin is not an indispensable component of the titin-anchoring system, nor is deletion of the gene or cardiac specific overexpression associated with a spontaneous cardiac phenotype. Rather, additional titin-anchorage sites, such as actin-titin cross-links via α-actinin, are sufficient to maintain Z-disk stability despite the loss of telethonin. We demonstrate that a main novel function of telethonin is to modulate the turnover of the proapoptotic tumor suppressor p53 after biomechanical stress in the nuclear compartment, thus linking telethonin, a protein well known to be present at the Z-disk, directly to apoptosis ("mechanoptosis"). In addition, loss of telethonin mRNA and nuclear accumulation of this protein is associated with human heart failure, an effect that may contribute to enhanced rates of apoptosis found in these hearts. CONCLUSIONS: Telethonin knockout mice do not reveal defective heart development or heart function under basal conditions, but develop heart failure following biomechanical stress, owing at least in part to apoptosis of cardiomyocytes, an effect that may also play a role in human heart failure.

Reversal of severe heart failure with a continuous-flow left ventricular assist device and pharmacological therapy: a prospective study.

BACKGROUND: We have previously shown that a specific combination of drug therapy and left ventricular assist device unloading results in significant myocardial recovery, sufficient to allow pump removal, in two thirds of patients with dilated cardiomyopathy receiving a Heartmate I pulsatile device. However, this protocol has not been used with nonpulsatile devices. METHODS AND RESULTS: We report the results of a prospective study of 20 patients who received a combination of angiotensin-converting enzymes, ß-blockers, angiotensin II inhibitors, and aldosterone antagonists followed by the ß2-agonist clenbuterol and were regularly tested (echocardiograms, exercise tests, catheterizations) with the pump at low speed. Before left ventricular assist device insertion, patient age was 35.2 ± 12.6 years (16 male patients), patients were on 2.0 ± 0.9 inotropes, 7 (35) had an intra-aortic balloon pump, 2 were hemofiltered, 2 were ventilated, 3 had a prior Levitronix device, and 1 had extracorporeal membrane oxygenation. Cardiac index was 1.39 ± 0.43 L · min⁻¹ · m⁻², pulmonary capillary wedge pressure was 31.5 ± 5.7 mm Hg, and heart failure history was 3.4 ± 3.5 years. One patient was lost to follow-up and died after 240 days of support. Of the remaining 19 patients, 12 (63.2) were explanted after 286 ± 97 days. Eight had symptomatic heart failure for ≤6 months and 4 for >6 months (48 to 132 months). Before explantation, at low flow for 15 minutes, ejection fraction was 70 ± 7, left ventricular end-diastolic diameter was 48.6 ± 5.7 mm, left ventricular end-systolic diameter was 32.3 ± 5.7 mm, mV(O2) was 21.6 ± 4 mL · kg⁻¹ · min⁻¹, pulmonary capillary wedge pressure was 5.9 ± 4.6 mm Hg, and cardiac index was 3.6 ± 0.6 L · min⁻¹ · m⁻². Estimated survival without heart failure recurrence was 83.3 at 1 and 3 years. After a 430.7 ± 337.1-day follow-up, surviving explants had an ejection fraction of 58.1 ± 13.8, left ventricular end-diastolic diameter of 59.0 ± 9.3 mm, left ventricular end-systolic diameter of 42.0 ± 10.7 mm, and mV(O2) of 22.6 ± 5.3 mL · kg⁻¹ · min⁻¹. CONCLUSIONS: Reversal of end-stage heart failure secondary to nonischemic cardiomyopathy can be achieved in a substantial proportion of patients with nonpulsatile flow through the use of a combination of mechanical and pharmacological therapy.

High Prevalence of Cardiac Amyloidosis in Clinically Significant Aortic Stenosis: A Meta-Analysis.

Background: There is growing evidence of coexistence of aortic stenosis (AS) and transthyretin cardiac amyloidosis (CA). Not screening AS patients at the time of hospital/clinic visit for CA represents a lost opportunity. Methods: We surveyed studies that reported the prevalence of CA among AS patients. Studies that compared patients with aortic stenosis with cardiac amyloidosis (AS-CA) and AS alone were further analyzed, and meta-regression was performed. Results: We identified nine studies with 1,321 patients of AS, of which 131 patients had concomitant CA, with a prevalence of 11%. When compared to AS-alone, the patients with AS-CA were older, more likely to be males, had higher prevalence of carpal tunnel syndrome, right bundle branch block. On echocardiogram, patients with AS-CA had thicker interventricular septum, higher left ventricular mass index (LVMI), lower myocardial contraction fraction, and lower stroke volume index. Classical low-flow low-gradient (LFLG) physiology was more common among patients with AS-CA. Patients with AS-CA had higher all-cause mortality than patients with AS alone (33% vs. 22%, P = 0.02) in a follow-up period of at least 1 year. Conclusions: CA has a high prevalence in patients with AS and is associated with worse clinical, imaging, and biochemical parameters than patients with AS alone.

Prior Freezing Has Minimal Impact on the Contractile Properties of Permeabilized Human Myocardium.

Background Experiments measuring the contractile properties of human myocardium are important for translational research but complicated by the logistical difficulties of acquiring specimens. Accordingly, many groups perform contractile assays using samples that are acquired from patients at one institution and shipped to another institution for experiments. This necessitates freezing the samples and performing subsequent assays using chemically permeabilized preparations. It is unknown how prior freezing affects the contractile function of these preparations. Methods and Results To examine the effects of freezing we measured the contractile function of never-frozen and previously frozen myocardial samples. Samples of left ventricular tissue were obtained from 7 patients who were having a ventricular assist device implanted. Half of each sample was chemically permeabilized and used immediately for contractile assays. The other half of the sample was snap frozen in liquid nitrogen and maintained at -180 °C for at least 6 months before being thawed and tested in a second series of experiments. Maximum isometric force measured in pCa 4.5 solution, passive force measured in pCa 9.0 solution, and Hill coefficients were not influenced by prior freezing (P=0.07, P=0.14, and P=0.27 respectively). pCa50 in never-frozen samples (6.11±0.04) was statistically greater (P<0.001) than that measured after prior freezing (5.99±0.04) but the magnitude of the effect was only ≈0.1 pCa units. Conclusions We conclude that prior freezing has minimal impact on the contractile properties that can be measured using chemically permeabilized human myocardium.

Biology of myocardial recovery in advanced heart failure with long-term mechanical support.

Cardiac remodeling is an adaptive, compensatory biological process following an initial insult to the myocardium that gradually becomes maladaptive and causes clinical deterioration and chronic heart failure (HF). This biological process involves several pathophysiological adaptations at the genetic, molecular, cellular, and tissue levels. A growing body of clinical and translational investigations demonstrated that cardiac remodeling and chronic HF does not invariably result in a static, end-stage phenotype but can be at least partially reversed. One of the paradigms which shed some additional light on the breadth and limits of myocardial elasticity and plasticity is long term mechanical circulatory support (MCS) in advanced HF pediatric and adult patients. MCS by providing (a) ventricular mechanical unloading and (b) effective hemodynamic support to the periphery results in functional, structural, cellular and molecular changes, known as cardiac reverse remodeling. Herein, we analyze and synthesize the advances in our understanding of the biology of MCS-mediated reverse remodeling and myocardial recovery. The MCS investigational setting offers access to human tissue, providing an unparalleled opportunity in cardiovascular medicine to perform in-depth characterizations of myocardial biology and the associated molecular, cellular, and structural recovery signatures. These human tissue findings have triggered and effectively fueled a "bedside to bench and back" approach through a variety of knockout, inhibition or overexpression mechanistic investigations in vitro and in vivo using small animal models. These follow-up translational and basic science studies leveraging human tissue findings have unveiled mechanistic myocardial recovery pathways which are currently undergoing further testing for potential therapeutic drug development. Essentially, the field is advancing by extending the lessons learned from the MCS cardiac recovery investigational setting to develop therapies applicable to the greater, not end-stage, HF population. This review article focuses on the biological aspects of the MCS-mediated myocardial recovery and together with its companion review article, focused on the clinical aspects, they aim to provide a useful framework for clinicians and investigators.

SUMOylation does not affect cardiac troponin I stability but alters indirectly the development of force in response to Ca2.

Post-translational modification of the myofilament protein troponin I by phosphorylation is known to trigger functional changes that support enhanced contraction and relaxation of the heart. We report for the first time that human troponin I can also be modified by SUMOylation at lysine 177. Functionally, TnI SUMOylation is not a factor in the development of passive and maximal force generation in response to calcium, however this modification seems to act indirectly by preventing SUMOylation of other myofilament proteins to alter calcium sensitivity and cooperativity of myofilaments. Utilising a novel, custom SUMO site-specific antibody that recognises only the SUMOylated form of troponin I, we verify that this modification occurs in human heart and that it is upregulated during disease.