Cardiac Compression Research Articles

Hiatal hernia as a rare cause of cardiac complications - case based review of the literature.

Hiatal hernia (HH) is a condition which refers to the protrusion of an intraabdominal organ in the thorax cavity throughan oesophageal hiatus of the diaphragm. Sliding HH is usually associated with non-specific symptoms, including heartburn, regurgitation or epigastric pain. Importantly, true paraesophageal hernia may lead to cardiac compression. Knowledge of cardiac manifestations of HH is limited. The main aim of the study is to present the rare case of a patient with gastrothorax due to hiatal hernia which caused cardiac arrest, and to provide a literature-based review of the cardiac aspects of hiatal hernia. Patients with paraesophageal hernia may experience arrhythmia, including sinus tachycardia, atrial flutter, atrial fibrillation, supraventricular extrasystole and ventricular tachycardia, as well as left bundle branch block, atrioventricular conduction block and electrocardiographic changes in the ST-segment and T-wave. In echocardiograph, HH may appear as an extracardiac posterior mass encroaching on the left atrial cavity, mimicking the left atrial mass. Rarel, HH may be manifested as tension gastrothorax leading cardiac arrest. In such a case, timely diagnosis and instant adequate treatment of the underlying condition are crucial. Hiatal hernia should be considered as a possible cause of arrhythmia and changes in ST-T pattern, particularly if symptoms occurred after a meal. Differential diagnosis of the posterior mediastinal mass or intracardiac mass should include hiatal hernia. Gastrothorax is a rare condition associated with hiatal hernia which may lead to cardiac arrest. However, even timely recognition and therapy of gastrothorax does not ensure a positive clinical outcome.

Postoperative Diaphragmatic Liver Herniation Diagnosed by Point-of-Care Ultrasound.

Point-of-care ultrasound (PoCUS) is a sensitive and specific tool in early identification of malignant pathologies in unstable patients leading to improved outcomes. Postoperative diaphragmatic rupture is rare, can be life-threatening, and is difficult to diagnose. This report describes a 62-year-old women undergoing thoracoscopic right hemidiaphragm plication with acute postoperative hemodynamic instability. Bedside PoCUS identified hepatic herniation into the thorax causing cardiac compression and lateral displacement, which lead to expedited imaging and surgical reexploration.

Predictive effect of J waves on cardiac compression and clinical prognosis of esophageal tumors: a retrospective study.

The J wave syndromes (JWS) could be observed in patients with mediastinal tumors, though few studies have verified the statistical correlation between J waves and cardiac compression by tumors. This study aimed to investigate the relationship between J waves and cardiac compression by esophageal tumor and to compare the prediction of J waves on clinical prognosis with that of cardiac compression by esophageal tumor. We enrolled 273 patients (228 males, 45 females; mean 63.8±7.5 years) with esophageal tumors admitted to Shanghai Chest Hospital between August 2016 and November 2020. The J wave was defined as a J-point elevation of ≥0.1 mV in a 12-lead electrocardiogram (ECG) and classified into multiple types. Chest computed tomography (CT) was reviewed to clarify the anatomical relationship between the heart and the esophageal tumor. The prognosis of severe cardiac events and survival status were followed up through medical history, examination records and telephone records. J waves were present in 141 patients among all 273 cases. The sensitivity and specificity of cardiac compression by the tumor for J waves were 78.1% and 67.3%, respectively. The odds ratio (OR) of cardiac compression by the tumor to J waves was 7.33 [95% confidence interval (CI): 4.21-12.74; P<0.001]. The Kappa coefficient between J waves and cardiac compression was 0.44±0.05. The significance association between J waves and cardiac compression was independent from other clinical variables (P<0.001). Decreased J wave amplitude was correlated with the disappearance of cardiac compression during follow-up (P=0.03). Patients with J waves had a higher risk of severe cardiac events than those without J waves (OR =2.84, 95% CI: 1.22-6.63; P=0.01). During the follow-up period, we found that the presence of J waves [hazard ratio (HR) =2.28; 95% CI: 1.35-3.84; P=0.002] and cardiac compression by the tumor (HR =2.51; 95% CI: 1.51-4.17; P<0.001) were both negatively correlated with the survival time of patients. The presence of J waves could be used as an effective mean to predict the mechanical impact of esophageal tumor on the heart, and played an important role in predicting the survival of patients.

Peritoneopericardial diaphragmatic hernia in a healthy adult feline (Felis catus domesticus): diagnosis to surgical treatment - Case repor

Peritoneopericardial diaphragmatic hernia (PPDH) is a communication between the abdomen and the pericardial sac generated by congenital anomalies triggered during diaphragmatic and pericardial development. This report aimed to present the case of an adult, mixed-breed cat, affected by PPDH, focusing on the period from diagnosis to successful surgical correction. The patient had a capricious appetite and weight loss for about four months and started, at the end of this period, a state of apathy. On abdominal ultrasound, the gallbladder (GB) was close to the heart, suggesting diaphragmatic discontinuity. On thoracic radiography, there were changes suggestive of PPDH, pericardial efusion or cardiomegaly with probable dilated cardiomyopathy. Based on these findings, an echocardiogram was performed, highlighting the hepatic lobe and GB internally to the pericardium, causing cardiac compression, although without severe cardiac changes. During surgery, a diaphragmatic defect of 4 cm in diameter was observed with the congested right medial hepatic lobe and hyperemic GB in the pericardial sac. The defect was sutured using the sultan pattern in separate stitches and polyamide threads. The feline returned to feeding with greater interest soon after the surgery, and after 15 days it was fed with dry food and had normal behavior. PPDH can be diagnosed in healthy adult cats, even if there are no apparent respiratory, gastrointestinal, or cardiac signs. The echocardiogram is relevant in the definitive diagnosis, in addition to excluding differential diagnoses, and simple surgical treatment with polyamide thread and sultan suture is successful.

Imaging of pericardial compressive syndromes – cardiac tamponade in oncologic patients

Cardiac tamponade is a state of hemodynamic compromise that results from heart compression by a variety of fac­tors and conditions, including tumoral pericarditis or tumor cardiac compression. The aim of this article is to evaluate and discuss the added value of CT imaging find­ings of impending cardiac tamponade in patients with tho­ra­cic and hematologic malignancies. We reviewed our data­base for a period of six years, between January 2015 and April 2021, and we selected five patients with cli­ni­cal, he­mo­dynamic state and CT imaging features of car­diac tam­po­nade in oncologic pathology, four of them diag­nosed with he­ma­to­logic malignancies. We included post­ra­dio­­­the­rapy pericardial complications in the case of one patient. Although echocardiography represents the modality of choice to diag­nose patients with suspected cardiac tam­po­na­de, com­pu­ted tomography can provide valuable and sup­ple­men­tary information regarding the extension of the tu­mo­ral peri­car­dial involvement or the type of pericardial effusion. Con­si­de­ring that the early diagnosis of an impending car­diac tam­po­nade and the treatment are crucial in preventing mor­ta­lity and poor outcomes, radiologists have an impor­tant role in recognizing this entity.

Resuscitation Medicine in Undergraduate Curriculum

A fresh medical graduate posted as an intern in wards has the biggest fear of any patient needing cardiopulmonary resuscitation during his duty hours. He had listened to lectures on cardiopulmonary resuscitation (CPR) in his final year medicine posting, witnessed his seniors performing chest compressions, and also participated by doing some errand jobs (making phone calls, calling nurse, loading drugs) but he is always worried to face a similar situation all by himself as a first responder. The simulation course in CPR which is available under the newer guidelines of the National Medical Council (NMC) undergraduate curriculum is a group activity and it is very much possible that few students get left out in understanding the nuances of good CPR practice. Resuscitation medicine (RM) is a rapidly evolving area that crosses the boundaries of emergency medicine, intensive care medicine, anaesthesia, and acute medicine.1 It is the process of correcting physiological disturbances (such as lack of breathing or heartbeat) in an acutely ill patient. Resuscitation entails more than just guidelines, training centres, and public training. The clinical practice of resuscitation, whether in-hospital or out-of-hospital, has taken on a seriousness that concerns the quality of practice, speed of implementation, and an increasing realization that every one of our patients deserves only the best skill we can offer. It has evolved from the practice of barbaric methods of yelling, slapping, hanging of the victim in face-down condition, etc to the discovery of external chest compressions by William Harvey in 1628.2 The most important contribution to the field of resuscitation medicine was given by an electrical engineer William Kouwenhoven (1886–1975) by rediscovering the science of external cardiac compression by accident during his research on internal and external defibrillation. No doubt that he is remembered as the founder of modern CPR.2 Many pharmacological and device technologies were developed thereafter and integrated into resuscitation protocols, such as the use of epinephrine, calcium, lidocaine, sodium bicarbonate, defibrillation waveforms, and improved electrocardiographic monitoring. More recently, therapeutic hypothermia (TH) in which the body is cooled to between 33 and 36 °C in an effort to decrease the metabolic injury due to ischemia, emergency use of extracorporeal membrane oxygenation (ECMO) in which a pulseless person is rapidly placed on a fully artificial heart and lung machine and controlled reperfusion in which the patient receives pulsatile blood flow rather than a continuous flow to better mimic normal physiology have emerged.3 These therapeutic interventions require the earliest possible recognition of cardiac arrest with the initiation of basic protocols during the initial 3-4 minutes and decision planning for indications and contraindications of advanced techniques. The science of RM is highly subjected to the time taken to address the situation which further makes it compulsory that the education and training should be blended in the curriculum during growing years as a medical student. he first-year students while studying anatomy, physiology and biochemistry should learn about the electrical and circulatory phase of cardiac arrest, the various adverse biochemical reactions associated with arrest, and the anatomy related to efficient chest compressions and basic airway support. The progress of the student’s curriculum into pharmacology, microbiology, pathology, ophthalmology and ENT should simultaneously expose him to the pharmacology of drugs used in resuscitation, pathophysiology and molecular aspects of cardiac arrest, assessment of eye signs for brain dead patients, and the advanced airway management. During the final semesters, education should include the current protocols of CPR and defibrillation. In this way, we can achieve a trained medical graduate well versed with basic tenets of knowledge in resuscitation. The period of internship should expose him to learn advanced protocols of quality management, real-life limitations occasioned by

Cardiac compression due to a large peri-prosthetic aneurysm of the descending aorta.

A 77-year-old hypertensive man was admitted in cardiology department with acute chest pain and dyspnea. In his past medical history, he underwent endovascular aortic repair with stent grafting for a DeBakey III aortic dissection at the age of 64. His physical examination as well as a 12-lead electrocardiogram were unremarkable. Laboratory tests showed normal troponin levels. Renal function tests were normal. Hemoglobin count was 8.9 g/dL. Echocardiography revealed a preserved left ventricular function, a mild pericardial effusion and most importantly a large peri-prosthetic aneurysm with partial semi-circumferential thrombosis, compressing the left ventricle and the left atrium. Computed tomography (CT) angiography of the chest showed the same huge, partially thrombosed aneurysm of the descending aorta with a mass effect on the neighboring mediastinal structures. The course was marked by the worsening of symptoms and the increase in the size of the aneurysm. Based on these findings, the patient was referred to urgent surgery. During the operation, the patient passed away due to a fatal bleeding.

Une cause rare d’infarctus du myocarde sans sus-décalage du segment ST de type 2 : compression cardiaque et obstruction intraventriculaire gauche par une volumineuse hernie hiatale

We report the case of a 89 year-old woman admitted to the emergency department for epigastric pain, nausea, vomiting. Because of a circulatory failure with electrocardiographic ST changes and a slight elevation of ultra-sensible troponin, a coronary angiography was performed and found normal coronary arteries. Thoraco-abdominal CT scan revealed a large hiatal hernia causing a cardiac compression, and a left intraventricular obstruction showed by Doppler echocardiography. All signs resolved after fasting and gastric drainage.

The chest wall gender divide: females have better cardiopulmonary function and exercise tolerance despite worse deformity in pectus excavatum

Pectus excavatum (PE) is a chest wall deformity of variable severity and symptomatology. Existing female-specific literature highlights breast asymmetry and cosmetic reconstruction. We sought to evaluate gender differences in cardiopulmonary function. Cardiac MRIs, pulmonary function tests (PFTs), and cardiopulmonary exercise tests (CPETs) were reviewed in 345 patients undergoing preoperative evaluation for PE. Regression modeling was used to evaluate associations between gender and clinical endpoints of cardiopulmonary function. Mean age was 15.2years, 19% were female, 98% were white. Pectus indices included median Haller Index (HI) of 4.8, mean depression index (DI) of 0.63, correction index (CI) of 33.6%, and Cardiac Compression Index (CCI) of 2.79. Cardiac assessment revealed decreased right and left ventricular ejection fraction (RVEF, LVEF) in 16% and 22% of patients, respectively. PFTs and CPETs were abnormal in ~ 30% of patients. While females had deeper PE deformities-represented by higher pectus indices-they had superior function with higher RVEF, LVEF Z-scores, FEV1, VO2 max, O2 pulse, work, and breathing reserve (p < 0.05). Despite worse PE deformity and symptomatology, females had a better cardiopulmonary function and exercise tolerance than males. Further research is needed to assess the precise mechanisms of this phenomenon and postoperative outcomes in this population.

Ultrasound-assisted diagnosis of intraoperative cardiac tamponade during hemihepatectomy: a case report

Cardiac tamponade is a rare complication that occurs during hemihepatectomy. This particular complication has a high degree of mortality and morbidity. A 51-year-old woman was admitted to our hospital for surgical treatment of a malignant liver tumor. During surgery, she developed sudden hemodynamic instability and signs suggesting cardiac tamponade, which was confirmed via transthoracic echocardiogram. Cardiac compression and creation of a pericardial window resulted in immediate hemodynamic improvement. At completion of surgery, a repeated transthoracic echocardiogram showed no pericardial effusion. Early ultrasound-assisted diagnosis and treatment of cardiac tamponade are crucial. Although cardiac tamponade rarely occurs during hemihepatectomy, medics should be aware of this possibility to ensure prompt diagnosis. Our findings strongly support the use of early cardiac compression in cardiac arrest during surgery with echocardiography for prompt and accurate diagnosis of cardiac tamponade. Additionally, our findings will hopefully make anesthesiologists aware of the need to maintain a high index of suspicion for cardiac tamponade with sudden hypotension and a large reduction in differential pressure, and encourage early use of echocardiography and timely cardiac compression.

Cardiac Compression and Tamponade from Gastric Volvulus Presenting as Acute Chest Pain

Gastric volvulus is an uncommon condition that classically presents with Borchardt’s triad of severe epigastric pain, retching without vomiting, and inability to pass a nasogastric tube [1]. We report a rare and fatal case of severe gastric volvulus presenting as chest pain with electrocardiographic changes in a patient with a significant cardiac history.

Cardiopulmonary resuscitation in pediatric pectus excavatum patients—Where is the heart?

In children with pectus excavatum, the posteriorly depressed sternum compresses and displaces the heart. However, the currently recommended compression site and depth for cardiopulmonary resuscitation have not been studied in this population. This retrospective study investigated the location of the center of ventricles with the largest cross-sectional area to determine the optimal site and depth for chest compressions in pediatric pectus excavatum patients. Chest computed tomography images of 94 pediatric pectus excavatum patients before and after correction surgery were compared with normal patients. The caudal displacement of the ventricles was calculated by dividing the length of sternum by the length from the suprasternal notch to the transverse level of the largest cross-sectional area of the ventricles. The proportional leftward deviation of the center of the ventricles from the midline versus transverse diameter of the thorax was calculated. The remaining internal thickness was calculated at the midline assuming the recommended compression depth of one-third of the anterior to posterior diameter. Compared with the normal population (mean=81% [SD=10.3%]), pediatric pectus excavatum patients showed caudal displacement of ventricles before (98.2% [15.1%], 95% CI of mean difference; 13.7%-20.5%, P<.001) and after correction (100.4% [13.5%], 95% CI of mean difference; 16.2%-22.5%, P<.001). Compared with the normal population (6.9% [2.7%]), pediatric pectus excavatum patients showed leftward deviation of ventricles before (16.2% [5.5%], 95% CI of mean difference; 8.2%-10.4%, P<.001) and after correction (13.3% [4.8%], 95% CI of mean difference; 5.3%-7.3%, P<.001). The remaining internal thickness assuming the recommended chest compression was <10mm in 54/94(57.4%) and 18/94 (19.1%) of pediatric pectus excavatum patients before and after correction, respectively. Pediatric pectus excavatum patients showed significant caudal displacement and leftward deviation of the ventricles compared with the normal population despite correction surgery and the currently recommended compression site and depth might injure intrathoracic structures without effective cardiac compression during cardiopulmonary resuscitation.

Comparative Study of Mechanical and Manual Compression in the Resuscitation of Patients with Out-of-hospital Cardiac Arrest

Objective: To analyze the effect of mechanical and manual compression on the resuscitation effect of out-of-hospital cardiac arrest patients. Methods: The 40 trained medical personnel who are skilled in bare hand compression and cardiopulmonary resuscitation machines were divided into two groups with 20 people in each group. The control group consists of a bare hand compression group while the observation group consists of cardiopulmonary resuscitation group. The two groups of people performed heart compression on the simulated person and observe the effect of the two compression methods on the patient during the cardiac arrest operation. Results: The resuscitation success rate in the control group was 65%, the resuscitation success rate in the observation group was 90%. The systolic blood pressure, heart rate, blood oxygen saturation, the accuracy rate of compression depth frequency, and interruption time in the observation group (cardiac resuscitation compression group) were significantly better than the control group (bare hand compression group). Conclusion: The use of mechanical compression has a small error rate, a high success rate, saves time and effort, and can effectively help patients. It is worth promoting and applying.

Prone Positioning for Acute Respiratory Distress Syndrome in Adults.

Prone Positioning for Acute Respiratory Distress Syndrome in Adults.

Forward blood flow provoked by changing intravascular pressure using an extracorporeal circulation during cardiopulmonary resuscitation

Since both “cardiac pump” and “thoracic pump” theories have been proved during cardiopulmonary resuscitation (CPR), the mechanism of forward blood flow during closed chest compression still remains open to question. The cardiac pump seems to work by the direct compression of the cardiac ventricles between the sternum and vertebral column. A pressure gradient created between the ventricle and aorta generates systemic blood flow. However, the thoracic pump mechanism presumes chest compression causes a rise in intrathoracic pressure which generates a blood flow from the thoracic cavity to the systemic circulation. Retrograde blood flow from the right heart into the systemic veins is prevented by a concomitant collapse of veins at the thoracic inlet. We hypothesize that the intrinsic decrease of vascular resistance from the aorta to peripheral arteries and the existence of competent venous valves enable blood to flow unidirectionally by the fluctuation of intravascular pressures during closed chest compression. The purpose of this study is to prove an antegrade arterial blood flow without cardiac compression and intrathoracic pressure changes in an animal cardiac arrest model. We demonstrate that arterial pulses can be developed by using an extracorporeal circuit, resulting in forward blood flow from the aorta through the systemic vasculature. It can be suggested that changes in intravascular pressure provoked by either cardiac or thoracic pump generate systemic blood flow during closed chest compression, while systemic vascular patency and valve function may be required for successful CPR.

ASSESSMENT OF THE QUALITY OF PEDIATRIC CARDIOPULMONARY RESUSCITATION USING THE IN SITU MOCK CODE TOOL.

ABSTRACTObjective:To evaluate the quality of individual and team care for cardiac arrest in a pediatric hospital using clinical surprise simulation (in situ mock code).Methods:We conducted an observational study with a sample of the hospital staff. Clinical simulations of cardiorespiratory arrest were performed in several sectors and work shifts. The mock code occurred in vacant beds of the sector without previous notification to the teams on call. One researcher conducted all mock codes and another evaluated individual and team attendance through a questionnaire contemplating recommendation for adequate cardiopulmonary resuscitation, based on the Pediatric Advanced Life Support (PALS) guidelines. At the end of the simulations, the research team provided a debriefing to the team tested.Results:Fifteen in situ mock code were performed with 56 nursing professionals (including nurses, nursing residents and technicians) and 11 physicians (including two pediatric residents and four residents of pediatric subspecialties). The evaluation showed that 46.7% of the professionals identified cardiac arrest checking for responsiveness (26.7%) and pulse (46.7%); 91.6% requested cardiac monitoring and venous access. In one case (8.3%) the cardiac compression technique was correct in depth and frequency, while 50% performed cardiopulmonary resuscitation correctly regarding the proportion of compressions and ventilation. According to PALS guidelines, the teams had a good performance in the work dynamics.Conclusions:There was low adherence to the PALS guidelines during cardiac arrest simulations. The quality of cardiopulmonary resuscitation should be improved in many points. We suggest periodical clinical simulations in pediatric services to improve cardiopulmonary resuscitation performance.

P61 CARDIAC TAMPONADE - A SERIOUS COMPLICATION AFTER COLON CONDUIT INTERPOSITION: A CASE REPORT

Abstract Aim Graft redundancy and anastomotic stricture after colon interposition are well-known late complications. Cardiac compression by distended colon conduit is uncommon. There is a few reports in the literature. We present a case of 58-year-old patient with a major dilatation of colon conduit occurred 7 years after esophagectomy and gastrectomy. Case report The patient was admitted to district general hospital with 4-hour history of abdominal pain. Chest X- ray and abdominal computer tomography (CT) scan revealed distended colon conduit, pneumomediastinum, small-bowel ileus and pneumoretroperitoneum. An attempt to insert a nasogastric tube failed and an emergency laparotomy was performed. At operation, a band causing small bowel strangulation and adhesions were divided. The bowel appeared viable and a clear perforation was not found. Resection was not necessery. For next 10 hours, progressing hemodynamic instability and sepsis required intravenous vasoactive medication and orotracheal intubation. Chest CT scan showed massive distention of substernal colon conduit with compression of heart and pulmonary arteries. The patient was referred to our institution. Prompt endoscopy was performed with suction of air and liquid content from colon and nasogastric tube was inserted. The colonic mucosa was viable without necrosis and perforation. Hemodynamics improved immediately after decompression of colonic roll. An exploratory laparotomy revealed fatal extensive ischemia infarction of the bowel and the patient died within 4 hours after surgery. Concluson Extrapericardial cardiac tamponade is a rare complication after substernal esophageal reconstruction and could lead to bowel hypoperfusion or ischemia. Early recognition of symptoms and management with conduit decompression are important.

Is Supplemental Oxygen Needed in Cardiac Compression?-The Influence of Oxygen on Cerebral Perfusion in Severely Asphyxiated Neonates With Bradycardia or Cardiac Asystole.

Background: Previous studies have investigated hemodynamic recovery using 21% vs. 100% oxygen during cardiopulmonary resuscitation (CPR) with chest compression (CC) in term infants. Animal studies indicate that systemic circulatory recovery is the same whether 21 or 100% oxygen is used during neonatal CPR. One of the main goals of resuscitation is to maintain cerebral oxygen delivery and prevent cerebral hypo- and hyperoxygenation. Oxygen delivery to the brain depends on cerebral hemodynamics, concentration of inhaled oxygen and blood oxygen content. The aim of this paper was to synthesize available research about cerebral oxygen delivery during CPR using different oxygen concentrations. Our research questions included how do different oxygen concentrations during CPR with CC influence cerebral perfusion and oxygen delivery, and how do cerebral hemodynamics during CC influence outcomes.Methods: A search in Medline Ovid using the search terms hypoxia AND oxygen AND cerebrovascular circulation AND infant, newborn. Inclusion criteria included studies of hypoxia and resuscitation of term infants. Studies were excluded if no measures of cerebral blood flow (CBF), oxygenation, or perfusion were reported.Results: The search retrieved 21 papers. None of the studies directly fulfilled our inclusion criteria. The reference lists of some of the retrieved papers provided relevant animal studies with slightly conflicting results regarding blood flow and oxygen delivery to the brain using 21 or 100% oxygen. No study in term infants was identified, but we included one study in preterm infants. Studies in asphyxiated animals indicate that 100% oxygen increases CBF and oxygenation during and after CC with a potential increase in oxidative stress.Conclusion: In asphyxia, cerebral autoregulation may be impaired. Pure oxygen administration during CC may result in cerebral hyperperfusion and increased cerebral oxygen delivery, which may be associated with oxidative stress-related damage to the brain tissue. As systemic circulatory recovery is the same whether 21 or 100% oxygen is used during neonatal CPR, it is important to investigate whether brain damage could be aggravated when 100% oxygen is used.

Complete Heart Block Due to Coronary Air Embolism during Trans-catheter Closure of Atrial Septal Defect

Coronary air embolism is a dreadful complication of cardiac intervention despite careful prevention. In literature reported complications of coronary air embolism ranges from clinically non significant events to cardiogenic shock, myocardial infarction and death. We report a case of massive coronary air embolism in right coronary artery, which results in hypotension and complete heart block in a 33 -year-old female undergoing elective closure of atrial septal defect (ASD) by percutaneous transcatheter intervention. The patient stabilized after timely measures like oxygen support, dopamine infusion, cardiac compression and repeated bolus injection of heparinized saline. She then underwent successful percutaneous ASD device closure.

Left ventricular simulation of cardiac compression: Hemodynamics and regional mechanics.

Heart failure is a global epidemic. Left ventricular assist devices provide added cardiac output for severe cases but cause infection and thromboembolism. Proposed direct cardiac compression devices eliminate blood contacting surfaces, but no group has optimized the balance between hemodynamic benefit and excessive ventricular wall strains and stresses. Here, we use left ventricular simulations to apply compressions and analyze hemodynamics as well as regional wall mechanics. This axisymmetric model corresponds with current symmetric bench prototypes. At nominal pressures of 3.1 kPa applied over the epicardial compression zone, hemodynamics improved substantially. Ejection fraction changed from 17.6% at baseline to 30.3% with compression and stroke work nearly doubled. Parametric studies were conducted by increasing and decreasing applied pressures; ejection fraction, peak pressure, and stroke work increased linearly with changes in applied compression. End-systolic volume decreased substantially. Regional mechanics analysis showed principal stress increases at the endocardium, in the middle of the compression region. Principal strains remained unchanged or increased moderately with nominal compression. However, at maximum applied compression, stresses and strains increased substantially providing potential constraints on allowable compressions. These results demonstrate a framework for analysis and optimization of cardiac compression as a prelude to biventricular simulations and subsequent animal experiments.