Abstract Right heart failure may be caused by several etiologic factors such as pulmonary embolism, post coronary bypass, chronic obstructive pulmonary disease (COPD) and right heart infarction. Traditionally, treatment has consisted of fluid loading (volume expansion) and the use of inotropic agents. In the present series of studies, an experimental model of acute right heart failure was developed using right heart infarct. Treatment with drugs chosen to specifically improve right heart performance was then evaluated. The drugs used in this series were aminophlline, adenosine, nitric oxide (NO) and losartan. Aminophylline transiently improved cardiac index and pulmonary vascular resistance, but simultaneously caused an increase in heart rate and a decrease in stroke volume. Although it may reduce right heart afterload, aminophylline did not improve overall cardiac function in this experimental model of right heart infarction. Adenosine affected an increase in cardiac index during the adenosine infusion and in stroke index, while pulmonary vascular resistance and mean pulmonary pressure were decreased. There was a marked decrease in systemic vascular resistance as a result of the drug. Heart rate remained unchanged by the infusion. Discontinuation of the drug resulted in a rapid reversal of the hemodynamic changes. The continuous infusion of adenosine therefore appears to cause an effective arterial vasodilation, with a consequent unloading of right heart afterload. NO treatment significantly reduced right heart afterload. A significant deterioration was observed in cardiac output as well as in left and right ventricle stroke work indices. The use of NO in this model of right heart infarct affected a decrease in both right heart afterload and left heart preload, with an overall deterioration in global hemodynamics. Losartan was shown to decrease central venous pressure and wedge pressure, while cardiac output, left ventricle stroke work and stroke volume all showed improvement. Compared to the control animals, pulmonary vascular resistance, systemic vascular resistance and systemic pressures were unaffected by the drug, as was heart rate. An inhibition of angiotensin II action may therefore be of benefit in the treatment of right heart failure symptoms during the first hours after right heart infarct.

Objectives: Phase 1) Establish echocardiographic reference intervals for measurements of the normal canine right heart. Phase 2) Describe the repeatability of normal right heart echocardiographic measurements. Phase 3) Describe the repeatability of right heart echocardiographic measurements which predict pulmonary artery pressure. Materials and Methods: Phase 1) 45 healthy adult dogs. Dogs underwent one echocardiographic examination by the same operator. Phase 2) 6 randomly selected dogs from the pool of Phase 1 dogs. Dogs underwent repeated echocardiograms by two operators. Phase 3) 4 client-owned dogs. Dogs underwent repeated echocardiographic examination by two operators. Results: Phase 1) The linear relationship between dimension and transformed body weight was highly variable. For linear dimensions, most of the scaling exponents were close to the theoretical value of 1/3. For area measurements, most of the scaling exponents were close to 2/3. Phase 2) Of the 168 within-day, between-day and between-operator coefficients of variation (CV) generated, 154 (91.7%) were below 15% and 135 (80.4%) were less than 10%. Phase 3) Of the 100 within-day, between-day and between-operator CVs generated, 72 (72%) were below 20% and 46 (46%) were below 10%. Conclusions: The right heart can be measured with relatively low repeatability. Measurement of the tricuspid regurgitation velocity should be the first priority when attempting to predict pulmonary artery pressure. If tricuspid regurgitation is not present, the use of transpulmonic acceleration time (AT) and the ratio of transpulmonic acceleration-to-ejection time (AT:ET) to indirectly assess pulmonary artery pressure is recommended. / Master of Science

Implantation of a left ventricular assist device (LVAD) is a potential treatment in terminal heart failure. Right ventricular (RV) failure is a severe complication in these patients and sometimes requires additional placement of a right ventricular assist device (RVAD). RVAD implantation, however, is an invasive treatment associated with both increased mortality and morbidity. The aim of this thesis was to study whether partial volume exclusion of the RV through a modified Glenn shunt or cavoaortic shunt could treat severe RV failure. The ultimate goal would be to use it as an alternative to a RVAD in RV failure during LVAD therapy. Swine were used as the model animal in all studies. In Study I, experimental RV failure was induced by ischemia, and verified by hemodynamic measurements and genetic expression. Treatment with a modified Glenn shunt reduced venous stasis and improved hemodynamics in general. In Study II, experimental RV failure was induced by the same method as in Study I. Treatment with a cavoaortic shunt in addition to LVAD therapy proved to reduce venous stasis and improved hemodynamics in general, which was feasible with preserved oxygen delivery despite cyanotic shunting. In Study III, experimental RV failure was induced by pulmonary banding, and verified by hemodynamic measurements and genetic expression. Treatment with a modified Glenn shunt reduced venous stasis but did not improve hemodynamics in general compared with a control group. In Study IV, the effects of LVAD therapy and subsequent treatment with a modified Glenn shunt on the normal RV function were studied. It demonstrated that LVAD therapy can put strain on the RV by increasing stroke work and end-diastolic volume, and that these effects can be reversed by treatment with a modified Glenn shunt during LVAD therapy. In conclusion, partial volume exclusion through a modified Glenn shunt or cavoaortic shunt is a feasible treatment of experimental RV failure. Thus, it could potentially be used as an alternative treatment to a RVAD in severe RV failure during LVAD therapy.

Tricuspid regurgitation (TR), back flow of blood from the right ventricle to the right atrium, has been reported in approximately 85% of the population, with 16% having mild or severe TR. Patients with untreated moderate to severe TR are likely to experience decreased exercise capacity and have increased morbidity and mortality, thus affecting the patient's quality of life. Current methods of repair offer limited rates of success, and many patients require further operations to correct returning levels of TR. Incomplete repair may be due to incomplete understanding of the functional anatomy and mechanics of the TV and the underlying causes of TR. It was hypothesized that alterations in the geometry of tricuspid valve annular and subvalvular apparatus induced by ventricular dilatation determine the severity of TR. In vivo measurements of papillary muscle (PM) position in patients with single or biventricular dilatation revealed PM displacement away from the center of the annulus as compared to control patients. Additionally, pulmonary arterial pressure, annulus area, ventricular size and apical displacement of the anterior PM were highly correlated with the severity of TR. An in vitro right-heart simulator was developed to investigate isolated mechanics of TR. Through these in vitro studies it was demonstrated that the tricuspid valve begins to leak at only 40% dilation, much lower than the mitral valve. Additionally, it was shown that isolated PM displacement resulted in significant TR. The highest levels of TR were achieved with a combination of annular dilatation and PM displacement. Alterations in leaflet coaptation, as quantified by measuring the amount of leaflet available for coaptation and leaflet mobility were observed with annular dilatation and PM displacement, both isolated and combined. The changes in leaflet coaptation resulted in redistribution of the forces on the chords originating from the anterior PM and inserting into the anterior and posterior leaflets. The findings herein provide the clinical and scientific community with a mechanistic understanding of the tricuspid valve to further improve intervention and repair of TV disease.

Right ventricular function (RV) is one of the most important predictors of prognosis in many cardiovascular disease states. Despite the significance of RV function to survival, there are no therapies that directly nor selectively improve RV function. As well, the basis for RV failure is poorly understood. This is particularly relevant for patients with pulmonary arterial hypertension (PAH), where RV failure in the setting of pressure overload is the leading cause of death. PAH will be introduced in the 2nd chapter of this thesis by comparing and refining contemporary mortality risk assessment strategies. I will then explore 1) RV neurohormonal function and, 2) RV energetics, two molecular pathways thought to be involved in the pathogenesis and progression of maladaptive RV failure. I employed small animal molecular imaging using positron emission tomography (PET) to non-invasively investigate these pathways. The PET imaging techniques employed in this thesis have the unique potential for translation to human studies, to further explore disease mechanisms.

OBJECTIVES: Clot in transit represents a life-threatening manifestation of venous thromboembolism of which we have limited understanding. This study was designed to describe the risk factors, clinical characteristics and outcomes associated with the development of a clot in transit as well as death within clot in transit patients. METHODS: We enrolled 1,093 consecutive patients into our single-center Pulmonary Embolism Response Team Registry. We compared 76 patients who had a clot in transit to 589 pulmonary embolism patients who did not have a clot in transit. RESULTS: Clot in transit was present in 11.4% of patients who received an echocardiogram to look for it. Multivariate analysis showed congestive heart failure (OR 2.954, 95% CI 1.349 – 6.467, P = 0.0068), a pre-existing inferior vena cava filter (OR 2.777, 95% CI 1.204 – 6.407, P = 0.0167), and hemodynamic collapse (OR 3.495, 95% CI 1.129 – 10.823, P = 0.0300) to be independent predictors of clot in transit. All-cause mortality by 30 days was higher in clot in transit patients (24.3% vs 9.7%, P < 0.001). All-cause mortality by 7 days within clot in transit patients was associated with hemodynamic collapse (45.5% vs 12.3%, P = 0.018) and mental status change (63.6% vs 21.5%, P = 0.008). CONCLUSIONS: The presence of congestive heart failure, a pre-existing inferior vena cava filter, and hemodynamic collapse are independent predictors of clot in transit and should alert physicians to patients who may require an echocardiogram. The mortality for clot in transit is high even when compared to a more severe pulmonary embolism population. Clot in transit represents a high-risk finding that may require more aggressive interventions. / 2020-06-14T00:00:00Z

Aims To characterize the prevalence and clinical relevance of malnutrition in patients undergoing transcatheter tricuspid valve edge-to-edge repair (TTVR). Methods and results Overall, 86 consecutive patients (mean age 78 ± 7 years) with moderate-to-severe tricuspid regurgitation (TR) at prohibitive surgical risk were analysed. Mini Nutritional Assessment (MNA), quality of life assessment, 6-min walk test distance and laboratory analyses were performed before and 1 month after TTVR. A total of 43 patients (50%) underwent concomitant transcatheter mitral valve repair. According to MNA, 81 patients (94%) were malnourished or at risk of malnutrition before TTVR. Following TTVR, MNA improved in 64 patients (74%). As compared to patients without MNA improvement, patients with increased MNA score had greater reductions in TR [regurgitation volume −17.0 (interquartile range, IQR −25.0; −7.0) mL vs. −26.4 (IQR −40.3; −14.5) mL, P < 0.001] and inferior vena cava diameter. Only patients with increased MNA score displayed a decrease in N-terminal pro-brain natriuretic peptide levels [−320 (IQR −1294; 105) pg/mL vs. +708 (IQR −342; 2708) pg/mL, P = 0.009], improvements in cholinesterase levels (0.0 ± 11.9 μmoL/L vs. +10.9 ± 16.7 μmoL/L, P < 0.001) and renal function during follow-up. Beneficial effects on quality of life scores and 6-min walk test distance following TTVR were observed exclusively in patients with improvement in MNA. During a median follow-up of 6 months, patients with worsened MNA had an increased risk of death and rehospitalization for heart failure. Conclusion Nutritional impairment is common and of prognostic importance in patients undergoing TTVR. Hepatorenal function modestly improves after successful TTVR. Further study of extracardiac implications of TR-associated right heart failure is warranted to improve care in this vulnerable patient population.

Background: Pulmonary hypertension (PH) is a rare condition characterized by endothelial dysfunction and vascular remodelling, leading to increased pulmonary vascular resistance (PVR) and right ventricular heart failure. Endothelial dysfunction is associated with an imbalance between vasoconstrictor compounds, such as endothelin and thromboxane A2, and vasodilator compounds, such as prostacyclin and nitric oxide (NO). Asymmetric dimethylarginine (ADMA), a methyl derivate of L-arginine, inhibits synthesis of NO. Vardenafil, a phosphodiesterase type 5 inhibitor (PDE5-inhibitors), causes vasodilation through the NO/cGMP pathway. Aim: This thesis investigates the pharmacological effects and diagnostic utility of vardenafil in PH patients. In addition, to evaluate the change of L-arginine and dimethylarginines before and during PAHspecific therapy in PAH patients compared to patients with left ventricular heart failure (LVHF) and healthy subjects. Methods: The pharmacokinetics and hemodynamic effects of vardenafil were examined during right heart catheterization (RHC) in 16 PH patients and plasma concentrations were measured for up to nine hours after oral administration. In 20 PH patients, acute vasoreactivity test with vardenafil was performed during RHC. Hemodynamic responses were recorded, responders were defined and followed for up to seven years. Additionally, plasma ADMA, symmetric dimethylarginine (SDMA), L-arginine, L-citrulline and L-ornithine levels before and after PAH drug treatment were monitored in 21 PAH patients and compared to values measured in 14 LVHF patients and 27 healthy subjects. Results: Vardenafil concentrations increased rapidly to maximum plasma concentration (tmax 1h) and elimination half-life was 3.4 h. Patients co-medicated with bosentan had reduced vardenafil concentration. Significant acute hemodynamic responses were observed for mean pulmonary artery pressure (mPAP) (p&lt;0.001), pulmonary vascular resistance (PVR) (p&lt;0.001), cardiac output (CO) (p=0.015), cardiac index (CI) (p=0.010), systemic vascular resistance (SVR) (p&lt;0.001) and PVR/SVR (p=0.002) and were related to plasma vardenafil concentrations. PAH patients had significantly higher ADMA and SDMA levels and significantly lower L-arginine levels and L-arginine/ADMA ratio compared with healthy subjects (p&lt;0.001). L-arginine was also lower in PAH patients compared to patients with LVHF (p&lt;0.05). WHO functional class and six minutes walking distance (6MWD) correlated to Larginine and L-arginine/ADMA ratio in PAH at baseline (p&lt;0.05). At follow-up, patients on mono- or combinationtherapy with endothelin receptor antagonists (ERA) had lower ADMA levels than patients without ERA (p&lt;0.05). In contrast, patients on PDE5-inhibitors had higher ADMA levels compared to patients without PDE5-inhibitors (p&lt;0.05). Conclusion: Vardenafil is safe in acute vasoreactivity test in PH patients. Cardiopulmonary hemodynamic response was related to plasma drug concentrations. There was a high inter-individual variability of vardenafil pharmacokinetics and co-medication with bosentan caused a pharmacokinetic drug interaction. Baseline L-arginine and dimethylarginines levels were different in PAH patients compared to LVHF patients and healthy controls. PAH-specific treatment influenced L-arginine and dimethylarginines. Our data suggest that L-arginine might be useful for differentiating PAH from LVHF, and L-arginine/ADMA ratios were related to the severity of PAH and might be useful for follow-up evaluations of PAH patients.

Background: Pulmonary artery sarcoma is a rare tumor with a poor prognosis. Case Report: We report the case of a 64-year-old man with an intimal pulmonary artery sarcoma presenting with severe high oxygen flow-demanding dyspnea and weight loss of 12 kg in the last 6 months. On echocardiography, right heart insufficiency, markedly elevated right ventricular pressure, a pressure gradient along the right outflow tract, and a tumor mass adherent to the wall of the truncus pulmonalis were detected. The tentative diagnosis by echocardiographic findings was pulmonary artery sarcoma. Computed tomography of the thorax and 18-fluorodeoxyglucose positron emission tomography showed an advanced local tumor manifestation. Surgical resection of the tumor to improve hemodynamics confirmed the diagnosis. Conclusions: Pulmonary artery sarcoma should be considered as a rare differential diagnosis in patients with dyspnea due to right heart failure, particular in the case of additional weight loss, and echocardiographic examination is a useful first diagnostic approach in establishing the diagnosis. / Hintergrund: Das Pulmonalarteriensarkom ist eine seltene Erkrankung mit einer schlechten Prognose. Fallbericht: Wir berichten über einen 64-jährigen Mann mit einem intimalen Pulmonalarteriensarkom, der sich mit starker Luftnot trotz hoher Sauerstoffsubstitution und einem Gewichtsverlust von 12 kg in den letzten 6 Monaten vorstellte. Echokardiographisch fielen eine Rechtsherzinsuffizienz, ein deutlich erhöhter rechtsventrikulärer Druck, ein Druckgradient über dem rechten Ausflusstrakt und eine Tumormasse im Bereich des Trunkus pulmonalis mit Kontakt zur Gefäßwand auf. Die mittels Echokardiographie erhobene Verdachtsdiagnose lautete Pulmonalarteriensarkom. Die Computertomographie des Thorax und die 18-Flur-Desoxyglukose-Positron-Emissionstomographie erbrachten den Befund eines lokal fortgeschrittenen Tumors. Die chirurgische Resektion des Tumors, die zur Verbesserung der Hämodynamik durchgeführt wurde, bestätigte die Diagnose. Schlussfolgerungen: Das Pulmonalarteriensarkom sollte differenzialdiagnostisch als eine seltene Ursache der Luftnot im Rahmen einer Rechtsherzinsuffizienz, insbesondere bei zusätzlichem Gewichtsverlust, in Erwägung gezogen werden. Die Echokardiographie stellt eine wertvolle initiale Untersuchungsmethode bei der Diagnosestellung dar. / Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG-geförderten) Allianz- bzw. Nationallizenz frei zugänglich.

Yes / We investigated the steepened dynamic action potential duration (APD) restitution of rats with pulmonary artery hypertension (PAH) and right ventricular (RV) failure and tested whether the observed APD restitution properties were responsible for negative mechanical restitution in these myocytes. PAH and RV failure were provoked in male Wistar rats by a single injection of monocrotaline (MCT) and compared with saline-injected animals (CON). Action potentials were recorded from isolated RV myocytes at stimulation frequencies between 1 and 9Hz. Action potential waveforms recorded at 1Hz were used as voltage clamp profiles (action potential clamp) at stimulation frequencies between 1 and 7Hz to evoke rate-dependent currents. Voltage clamp profiles mimicking typical CON and MCT APD restitution were applied and cell shortening simultaneously monitored. Compared with CON myocytes, MCT myocytes were hypertrophied; had less polarized diastolic membrane potentials; had action potentials that were triggered by decreased positive current density and shortened by decreased negative current density; APD was longer and APD restitution steeper. APD90 restitution was unchanged by exposure to the late Na+-channel blocker (5μM) ranolazine or the intracellular Ca2+ buffer BAPTA. Under AP clamp, stimulation frequency-dependent inward currents were smaller inMCTmyocytes and were abolished by BAPTA. In MCT myocytes, increasing stimulation frequency decreased contraction amplitude when depolarization duration was shortened, to mimic APD restitution, but not when depolarization duration was maintained. We present new evidence that the membrane potential of PAH myocytes is less stable than normal myocytes, being more easily perturbed by external currents. These observations can explain increased susceptibility to arrhythmias. We also present novel evidence that negative APD restitution is at least in part responsible for the negative mechanical restitution in PAH myocytes. Thus, our study links electrical restitution remodeling to a defining mechanical characteristic of heart failure, the reduced ability to respond to an increase in demand.