Cardiac Tamponade and Pericardiocentesis: Recognition, Standard Techniques, and Modern Advancements.

Pericardiocentesis is an important diagnostic and therapeutic procedure. In the setting of cardiac tamponade, pericardiocentesis can rapidly improve hemodynamics, and in cases of diagnostic uncertainty, pericardiocentesis allows for fluid analysis to aid in diagnosis. In contemporary practice, the widespread availability of ultrasonography has made echocardiographic guidance the standard of care. Additional tools such as micropuncture technique, live ultrasonographic guidance, and adjunctive tools including fluoroscopy continue to advance and enhance procedural efficiency and safety. When performed by experienced operators, pericardiocentesis is a safe, effective, and potentially life-saving procedure.

Case report: Systemic lupus erythematosus combined with myocardial hypertrophy.

OBJECTIVE: Systemic lupus erythematosus (SLE) is a multisystem-involved, highly heterogeneous autoimmune disease with diverse clinical manifestations. We report an extremely rare case of SLE with severe diffuse myocardial hypertrophy. METHODS: The patient's echocardiography and cardiac magnetic resonance imaging (CMR) results indicated diffuse myocardial hypertrophy. After excluding coronary atherosclerosis, hypertensive cardiomyopathy, drug toxicity, and other causes, the patient was diagnosed with SLE-specific cardiomyopathy. Medications such as hormones, antimalarials, immunosuppressants, and biologics were administered. RESULTS: Ancillary test results were as follows: hs-cTnI: 0.054 ng/mL (0-0.016); NTproBNP: 1594.0 pg/mL (<150); A contrast-enhanced CMR revealed the diffuse thickening of the left ventricular wall with multiple abnormal enhancements, reduced left ventricular systolic and diastolic function, and moderate amount of pericardial effusion. Endomyocardial myocardial biopsy was performed, showing cardiomyocyte hypertrophy and degeneration, and no changes in myocarditis or amyloidosis. The pathology viewed by electron microscopy showed increased intracellular glycogen in the myocardium, and no hydroxychloroquine-associated damage in the myocardium. The 24-h ambulatory blood pressure and contrast-enhanced computed tomography of coronary arteries were normal. The diagnosis of SLE-specific cardiomyopathy was clear. The myocardial hypertrophy showed reversible alleviation following treatment with high-dose corticosteroids. CMR results before and after treatment were as follows: interventricular septum, pretreatment (28) versus post-treatment (22) mm; left ventricular inferior wall, pretreatment (18-21) versus post-treatment (12-14) mm; left ventricular lateral wall, pretreatment (17-18) versus post-treatment (10-12) mm; pericardial effusion (left ventricular lateral wall), pretreatment (25) versus post-treatment (12) mm; left ventricular ejection fraction, pretreatment (38.9%) versus post-treatment (66%). CONCLUSION: Myocardial hypertrophy may be an important sign of active and prognostic assessment in SLE diagnosis and management. Similarly, when encountering cases of myocardial hypertrophy, the possibility of autoimmune disease should be considered in addition to common causes.

Should left atrial appendage closure be considered in resistant left atrial appendage thrombus cases? 'Former Foe, New Ally'.

BACKGROUND: The study explores left atrial appendage closure (LAAC) as a safe and effective alternative to anticoagulation for atrial fibrillation (AF) patients at high bleeding risk. Complications, such as cardioembolic events due to left atrial appendage thrombus (LAAT), highlight the need for alternative stroke prevention strategies. AIMS: This research assesses LAAC's safety and efficacy in patients with LAAT, aiming to offer valuable insights into its potential as a viable option for stroke prevention in such cases. METHODS: The study included 205 patients who underwent LAAC using specific devices between September 2015 and February 2023. Among them, 32 patients had persistent LAAT. Baseline characteristics, antithrombotic medications, risk scores, and LAAC indications were documented. Patients were followed to monitor significant clinical events like stroke, cardiovascular mortality, and all-cause mortality. RESULTS: The mean age was 71.9 and mostly female. Indications for LAAC were ischemic cerebrovascular events (CVE) despite anticoagulation (25%), bleeding complications (major/minor, 37.5% each), or both. Successful LAA closure was achieved in all cases, with minimal pericardial effusion in one. One-month follow-up showed no major events or device-related issues. Median follow-up of 16.5 months saw 21.9% non-cardiac deaths. The study underscores LAAC's efficacy for stroke prevention in patients with persistent LAAT. CONCLUSIONS: The LAAC in cases of LAAT, whether pursued initially or as a deferred approach, demonstrates feasibility and safety, exhibiting notable procedural success and minimal incidence of periprocedural complications.

Purulent pericarditis caused by methicillin-sensitive Staphylococcus aureus bacteriuria.

BACKGROUND: Purulent pericarditis (PP)- a purulent infection involving the pericardial space-requires a high index of suspicion for diagnosis as it often lacks characteristic signs of pericarditis and carries a mortality rate as high as 40% even with treatment. Common risk factors include immunosuppression, diabetes mellitus, thoracic surgery, malignancy, and uremia. Most reported cases of PP occur in individuals with predisposing risk factors, such as immunosuppression, and result from more commonly observed preceding infections, such as pneumonia, osteomyelitis, and meningitis. We report a case of PP due to asymptomatic bacteriuria in a previously immunocompetent individual on a short course of high-dose steroids. CASE PRESENTATION: An 81-year-old male presented for severe epigastric pain that worsened with inspiration. He had been on high-dose prednisone for presumed inflammatory hip pain. History was notable for urinary retention requiring intermittent self-catheterization and asymptomatic bacteriuria and urinary tract infections due to methicillin-sensitive Staphylococcus aureus (MSSA). During the index admission he was found to have a moderate pericardial effusion. Pericardial fluid cultures grew MSSA that had an identical antibiogram to that of the urine cultures. A diagnosis of purulent pericarditis was made. CONCLUSION: PP requires a high index of suspicion, especially in hosts with atypical risk factors. This is the second case of PP occurring as a result of asymptomatic MSSA bacteriuria. Through reporting this case we hope to highlight the importance of early recognition of PP and the clinical implications of asymptomatic MSSA bacteriuria in the setting of urinary instrumentation and steroid use.

Multisystem inflammatory syndrome in children (MIS-C) post-COVID-19 in Iran: clinical profile, cardiac features, and outcomes.

BACKGROUND: In April 2020, an association between multisystem inflammatory syndromes (MIS-C) was observed in children with severe acute respiratory syndrome coronavirus infection (SARS-CoV-2). Most patients had heart involvement alone, and most patients had pericardial effusion. This study aimed to express and emphasize cardiac involvement in pediatric patients with respiratory symptoms who were diagnosed with COVID-19. METHODS: This study was conducted in July 2021 in Kerman province, Southeastern Iran, during a notable surge in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections. The study included 904 pediatric patients diagnosed with COVID-19. Data collection involved a comprehensive assessment of clinical symptoms and manifestations. Patients with fever lasting more than five days were admitted to the hospital. Echocardiography was utilized for cardiac involvement diagnosis, with 47 patients undergoing this diagnostic procedure. RESULTS: Of the 904 patients, most of them had high fevers (74%). Fifty-five patients had a fever for more than five days and were hospitalized. Of the 47 patients who underwent echocardiography, 45 (81%) had heart involvement. In 75% of patients, pericardial effusion was the only cardiac involvement. Patients with pericardial effusion were treated with dexamethasone up to 3 mg every 8 h for 72 h. CONCLUSIONS: MIS-C has a wide range of clinical symptoms. In cases where the fever is prolonged and there are gastrointestinal symptoms, physicians have clinical suspicion to diagnose this syndrome. Most cases of pericardial effusion are alone and improve with treatment with glucocorticosteroids.

Acute type a aortic intramural hematoma complicated with preoperative hemopericardium: early and late surgical outcome analyses.

BACKGROUND: Acute type A aortic intramural hematoma (ATAIMH) is a variant of acute type A aortic dissection (ATAAD), exhibiting an increased risk of hemopericardium and cardiac tamponade. It can be life-threatening without emergency treatment. However, comprehensive studies of the clinical features and surgical outcomes of preoperative hemopericardium in patients with ATAIMH remain scarce. This retrospective study aims to investigate the clinical features and early and late outcomes of patients who underwent aortic repair surgery for ATAIMH complicated with preoperative hemopericardium. METHODS: We investigated 132 consecutive patients who underwent emergency ATAIMH repair at this institution between February 2007 and August 2020. These patients were dichotomized into the hemopericardium (n = 58; 43.9%) and non-hemopericardium groups (n = 74; 56.1%). We compared the clinical demographics, surgical information, postoperative complications, 5-year cumulative survival rates, and freedom from reoperation rates. Furthermore, multivariable logistic regression analysis was utilized to identify independent risk factors for patients who underwent re-exploration for bleeding. RESULTS: In the hemopericardium group, 36.2% of patients presented with cardiac tamponade before surgery. Moreover, the hemopericardium group showed higher rates of preoperative shock and endotracheal intubation and was associated with an elevated incidence of intractable perioperative bleeding, necessitating delayed sternal closure for hemostasis. The hemopericardium group exhibited higher blood transfusion volumes and rates of re-exploration for bleeding following surgery. However, the 5-year survival (59.5% vs. 75.0%; P = 0.077) and freedom from reoperation rates (93.3% vs. 85.5%; P = 0.416) were comparable between both groups. Multivariable analysis revealed that hemopericardium, cardiopulmonary bypass time, and delayed sternal closure were the risk factors for bleeding re-exploration. CONCLUSIONS: The presence of hemopericardium in patients with ATAIMH is associated with an elevated incidence of cardiac tamponade and unstable preoperative hemodynamics, which could lead to perioperative bleeding tendencies and high complication rates. However, patients of ATAIMH complicated with hemopericardium undergoing aggressive surgical intervention exhibited long-term surgical outcomes comparable to those without hemopericardium.

Pericardial Effusion in Association With Periodontitis: Case Report and Review of 8 Patients in Literature.

Periodontal diseases are well-known background for infective endocarditis. Here, we show that pericardial effusion or pericarditis might have origin also in periodontal diseases. An 86-year-old man with well-controlled hypertension and diabetes mellitus developed asymptomatic increase in pericardial effusion. Two weeks previously, he took oral new quinolone antibiotics for a week because he had painful periodontitis along a dental bridge in the mandibular teeth on the right side and presented cheek swelling. The sputum was positive for Streptococcus species. He was healthy and had a small volume of pericardial effusion for the previous 5 years after drug-eluting coronary stents were inserted at the left anterior descending branch 10 years previously. The differential diagnoses listed for pericardial effusion were infection including tuberculosis, autoimmune diseases, and metastatic malignancy. Thoracic to pelvic computed tomographic scan demonstrated no mass lesions, except for pericardial effusion and a small volume of pleural effusion on the left side. Fluorodeoxyglucose positron emission tomography disclosed many spotty uptakes in the pericardial effusion. The patient denied pericardiocentesis, based on his evaluation of the risk of the procedure. He was thus discharged in several days and followed at outpatient clinic. He underwent dental treatment and pericardial effusion resolved completely in a month. He was healthy in 6 years until the last follow-up at the age of 92 years. We also reviewed 8 patients with pericarditis in association with periodontal diseases in the literature to reveal that periodontal diseases would be the background for developing infective pericarditis and also mediastinitis on some occasions.

Acute pericarditis as the presenting symptom of a case of oesophageal carcinoma.

Oesophageal carcinoma is a globally prevalent form of cancer. Patients with advanced disease often experience progressive dysphagia and weight loss as initial symptoms, but pericarditis is an uncommon presentation. This study describes a young man who presented with pericarditis and was diagnosed with oesophageal squamous cell carcinoma. The patient's diagnosis came after presenting with intermittent chest pain. His diagnostic tests included an ECG showing ST elevation, echocardiography showing pericardial effusion and elevated inflammatory markers. His imaging tests revealed a neoplastic lesion in the lower oesophagus with metastases. He was initially treated as a case of pericarditis, followed by palliative chemotherapy for his cancer. Pericarditis, as the initial presentation of oesophageal carcinoma, is rare. There have only been 19 cases reported and published in the literature. Treatment depends on the stage of the disease. This case emphasises the importance of considering malignancy in unusual presentations of pericarditis, especially in young patients.

Cardiac Magnetic Resonance to Predict Cardiac Mass Malignancy: The CMR Mass Score.

BACKGROUND: Multimodality imaging is currently suggested for the noninvasive diagnosis of cardiac masses. The identification of cardiac masses' malignant nature is essential to guide proper treatment. We aimed to develop a cardiac magnetic resonance (CMR)-derived model including mass localization, morphology, and tissue characterization to predict malignancy (with histology as gold standard), to compare its accuracy versus the diagnostic echocardiographic mass score, and to evaluate its prognostic ability. METHODS: Observational cohort study of 167 consecutive patients undergoing comprehensive echocardiogram and CMR within 1-month time interval for suspected cardiac mass. A definitive diagnosis was achieved by histological examination or, in the case of cardiac thrombi, by histology or radiological resolution after adequate anticoagulation treatment. Logistic regression was performed to assess CMR-derived independent predictors of malignancy, which were included in a predictive model to derive the CMR mass score. Kaplan-Meier curves and Cox regression were used to investigate the prognostic ability of predictors. RESULTS: In CMR, mass morphological features (non-left localization, sessile, polylobate, inhomogeneity, infiltration, and pericardial effusion) and mass tissue characterization features (first-pass perfusion and heterogeneity enhancement) were independent predictors of malignancy. The CMR mass score (range, 0-8 and cutoff, ≥5), including sessile appearance, polylobate shape, infiltration, pericardial effusion, first-pass contrast perfusion, and heterogeneity enhancement, showed excellent accuracy in predicting malignancy (areas under the curve, 0.976 [95% CI, 0.96-0.99]), significantly higher than diagnostic echocardiographic mass score (areas under the curve, 0.932; P=0.040). The agreement between the diagnostic echocardiographic mass and CMR mass scores was good (κ=0.66). A CMR mass score of ≥5 predicted a higher risk of all-cause death (P<0.001; hazard ratio, 5.70) at follow-up. CONCLUSIONS: A CMR-derived model, including mass morphology and tissue characterization, showed excellent accuracy, superior to echocardiography, in predicting cardiac masses malignancy, with prognostic implications.

Hemorrhagic pericardial tamponade in a hemodialysis patient with catheter-related superior vena cava syndrome: a case report.

BACKGROUND: Iatrogenic complications of endovascular treatment for central venous stenosis have not yet been reported. Here we present a case of a patient on maintenance hemodialysis who developed catheter-related superior vena cava syndrome and subsequently suffered from hemorrhagic pericardial tamponade after undergoing percutaneous transluminal angioplasty and stenting. CASE PRESENTATION: A 72-year-old male patient presented with uremia, and had been receiving maintenance hemodialysis for the past five years. The patient initially presented with dysfunction of the dialysis catheter (a cuffed tunneled double-lumen catheter in the right internal jugular vein). Imaging examination revealed a segmental occlusion of the superior vena cava stretching from the distal end of the dialysis catheter up to right atrium entrance, apparent compensatory dilatation of the azygos vein, and abundant subcutaneous collaterals. The patient underwent percutaneous transluminal balloon dilatation and stenting (covered stent) of the superior vena cava in the Cath Lab. During the procedure, with forceful advancement of the guidewire, it was observed to progress for a distance before a "smoke" appeared, and an outward spillage of contrast agent was visible, which suggested a possible vessel puncture leading into the mediastinum. Unfortunately, postoperative hemorrhagic pericardial tamponade occurred and the patient developed cardiogenic shock. He experienced symptoms included chest tightness and breath shortness with a recorded blood pressure of 84/60mmHg. After draining 600 ml of bloody fluid through pericardiocentesis, the patient's symptoms alleviated and his condition improved. CONCLUSIONS: The case emphasizes the need for increased attention to iatrogenic endovascular injuries during catheter placement and endovascular treatment, such as causing pericardial hemorrhage leading to cardiac tamponade.

Screening Tests Predicting Cancer Metastasis in the Etiology of Pericardial Effusion: HALP Score and PNI. / Testes de Triagem Prevendo Metástase de Câncer na Etiologia do Derrame Pericárdico: HALP Score e PNI.

BACKGROUND: Cancer screening is absolutely necessary in patients with pericardial effusion, given that cancer is one of the most serious diseases in the etiology of pericardial effusion. In previous studies, it was stated that the systemic immune-inflammation index (SII); the prognostic nutrition index (PNI); and the hemoglobin, albumin, lymphocyte, platelet (HALP) score can produce scores related to cancer. OBJECTIVES: This study began considering that these scoring systems could predict cancer in the etiology of patients with pericardial effusion. METHODS: This study produced a retrospective analysis of patients who underwent pericardiocentesis between 2006 and 2022. Pericardiocentesis was performed in a total of 283 patients with moderate-to-large pericardial effusion or pericardial tamponade within the specified period. HALP, PNI, and SII scores were calculated according to the peripheral venous blood taken before the pericardiocentesis procedure. The statistical significance level was set at p<0.05. RESULTS: The HALP score proved to be 0.173 (0.125-0.175) in cancer patients and 0.32 (0.20-0.49) in non-cancer patients (p<0.001). The PNI score proved to be 33.1±5.6 in cancer patients and 39.8±4.8 in non-cancer patients (p<0.001). CONCLUSION: The HALP score and PNI proved to be easy and fast cancer screening tests that can predict cancer metastasis in the etiology of patients with pericardial effusion.

FUNDAMENTO: A triagem do câncer é absolutamente necessária em pacientes com derrame pericárdico, pois o câncer é uma das doenças mais graves em sua etiologia. Estudos anteriores indicaram que o índice de inflamação imunológica sistêmica (IIS), o índice prognóstico nutricional (PNI) e o escore de hemoglobina, albumina, linfócitos e plaquetas (HALP) podem ser escores relacionados ao câncer. OBJETIVOS: Este estudo foi iniciado considerando que esses sistemas de pontuação poderiam prever o câncer na etiologia de pacientes com derrame pericárdico. MÉTODOS: Os pacientes submetidos à pericardiocentese entre 2006 e 2022 foram analisados retrospectivamente. A pericardiocentese foi realizada em um total de 283 pacientes com derrame pericárdico ou tamponamento cardíaco de moderado a grande no período especificado. Os índices de HALP, PNI e IIS foram calculados do sangue venoso periférico retirado antes do procedimento de pericardiocentese. O nível de significância estatística foi aceito em p<0,05. RESULTADOS: O escore HALP foi de 0,173 (0,125-0,175) em pacientes com câncer. Detectou-se que em pacientes não oncológicos o escore foi de 0,32 (0,20-0,49; p<0,001). O escore de PNI foi de 33,1±5,6 em pacientes com câncer. Detectou-se que em pacientes não oncológicos o escore foi 39,8±4,8 (p<0,001). CONCLUSÃO: Os escores HALP e PNI são testes de triagem de câncer fáceis e rápidos que podem prever metástases de câncer na etiologia de pacientes com derrame pericárdico.

Early chest tube removal on the 1st postoperative day protocol of an enhanced recovery after cardiac surgery programme is safe.

OBJECTIVES: The aim of this study was to assess the safety of early chest tube removal (CTR) protocol on the 1st postoperative day (POD1) of our Enhanced Recovery After Surgery (ERAS) programme by comparing the risk of postoperative pneumothorax, pleural and pericardial effusion requiring intervention and hospital mortality. METHODS: All consecutive patients undergoing elective coronary revascularization and/or valve surgery between 2015 and 2021 were assessed in terms of their perioperative management pathways: conventional standard of care (control group) versus standardized systematic perioperative ERAS programme including an early CTR on POD1 (ERAS group). A propensity score matching was applied. The primary end-point was a composite of postoperative pneumothorax, pleural and pericardial effusion requiring intervention and hospital mortality. RESULTS: A total of 3153 patients were included. Propensity score analysis resulted in 2 groups well-matched pairs of 1026 patients. CTR on POD1 was significantly increased from 29.5% in the control group to 70.3% in the ERAS group (P < 0.001). The incidence of the primary end-point was 6.4% in the control group and 6.9% in the ERAS group (P = 0.658). Patients in the ERAS group, as compared with control group, had significant lower incidence of bronchopneumonia (9.0% vs 13.5%; P = 0.001) and higher incidence of mechanical ventilation ≤6 h (84.6% vs 65.2%; P < 0.001), length of intensive care unit ≤1 day (61.2% vs 50.8%; P < 0.001) and hospital ≤6 days (67.3% vs.43.2%; P < 0.001). CONCLUSIONS: CTR on POD1 protocol can be safely incorporated into a standardized systematic ERAS programme, enabling early mobilization, and contributing to the improvement of postoperative outcomes. CLINICAL TRIAL REGISTRATION NUMBER: Ethics committee of the French Society of Thoracic and Cardio-Vascular Surgery (CERC-SFCTCV-2022-09-13_23140).

Chylopericardium following esophagectomy: a case report and systematic review.

BACKGROUND: Chylopericardium is a rare condition characterized by the accumulation of chyle in the pericardial space. It is most commonly caused by thoracic duct injury. Chylopericardium following esophagectomy is extremely rare but can cause life-threatening complications. This report presents a case of chylopericardium post-esophagectomy, resulting in cardiac tamponade and cardiac arrest. A systematic literature review was also conducted to facilitate the understanding of this rare condition. CASE PRESENTATION: A 41-year-old male was admitted to our hospital with intermediate to highly differentiated squamous cell carcinoma of the mid-thoracic esophagus (clinical T4NxM0). He underwent thoracoscopic-laparoscopic esophagectomy with cervical anastomosis. On postoperative day 1, patient had a cardiac arrest secondary to cardiac tamponade, requiring emergency ultrasound-guided drainage. The drained fluid was initially serous but became chylous after the administration of enteral nutritional emulsion. As a result of significant daily pericardial drainage, patient subsequently underwent thoracic duct ligation. The amount of drainage was substantially reduced post-thoracic duct ligation. Over a period of 2 years and 7 months, patient recovered well and tolerated full oral diet. A comprehensive literature review was conducted and 4 reported cases were identified. Among these cases, three patients developed pericardial tamponade secondary to chylopericardium post-esophagectomy. CONCLUSION: Chylopericardium is a rare but serious complication post-esophagectomy. Prompt echocardiography and thorough pericardial fluid analysis are crucial for diagnosis. Thoracic duct ligation has been shown to be an effective management approach for this condition.

Initial diagnosis of extranodal NK/T-cell lymphoma in pericardial fluid with concomitant hemophagocytic lymphohistiocytosis (HLH).

Extranasal natural killer/T-cell lymphoma arising in the heart is rare and typically presents with non-specific clinical symptoms, necessitating a biopsy for a definitive diagnosis. We report an unusual case of a 48-year-old male who initially presented with chest pain and shortness of breath. Subsequent diagnosis via pericardial fluid analysis, including flow cytometry and immunohistochemical stains, revealed extranasal NK/T-cell lymphoma without sinonasal involvement. The analysis identified neoplastic lymphoid cells expressing CD2, cytoplasmic CD3, Epstein-Barr virus, and CD56 and exhibiting increased Ki-67 staining. Additionally, the patient developed hemophagocytosis lymphocytosis secondary to NK/T cell lymphoma. Treatment included an interleukin-1 receptor antagonist (anakinra), dexamethasone, rituximab, and etoposide. Unfortunately, the patient's condition rapidly deteriorated, leading to multiorgan failure and eventual demise. Given the rarity of this lymphoma, early diagnosis based on a high suspicion level provides the best chance for improved overall survival.

Effects of pericardiocentesis on renal function and cardiac hemodynamics.

BACKGROUND: Previous case studies have reported reversal of acute renal failure after pericardiocentesis in pericardial effusion. This study examines the effects of pericardiocentesis on preprocedural low cardiac output and acute renal dysfunction in patients with pericardial effusion. METHODS: This is a retrospective study of 95 patients undergoing pericardiocentesis between 2015 and 2020. Pre- and post-procedure transthoracic echocardiograms (TTE) were reviewed for evidence of cardiac tamponade, resolution of pericardial effusion, and for estimation of right atrial (RA) pressure and cardiac output. Laboratory values were compared at presentation and post-procedure. Patients on active renal replacement therapy were excluded. RESULTS: Ninety-five patients were included for analysis (mean age 62.2 ± 17.8 years, 58% male). There was a significant increase in glomerular filtration rate pre- and post-procedure. Fifty-six patients (58.9%) had an improvement in glomerular filtration rate after pericardiocentesis (termed "responders"), and these patients had a lower pre-procedure glomerular filtration rate than "non-responders." There was a significant improvement in estimated cardiac output and right atrial pressure for patients in both groups. Patients who had an improvement in renal function had significantly lower pre-procedural diastolic blood pressure and mean arterial pressure. CONCLUSIONS: Pericardial drainage may improve effusion-mediated acute renal dysfunction by reducing right atrial pressure and thus systemic venous congestion, and by increasing forward stroke volume and perfusion pressure.