Traumatic left ventricular free-wall laceration by a gunshot: report of a case.

This report describes the case of a 47-year-old man who shot himself in the left side of the chest in an attempted suicide, and was transferred to the hospital. Two gunshot wounds were found in the left side of the chest and the back. CT scans revealed left hemopneumothorax, the accumulation of pericardial blood, and lacerations of the heart and the spleen. Emergency thoracotomy and laparotomy were performed. There was a contusion of the left lung and lacerations of the left ventricular free wall, the diaphragm, and the spleen. The laceration of the heart was repaired by 3 pairs of mattress sutures with felt strips, and covered with fibrin glue and a TachoComb(®) tissue sealing sheet without the use of cardiopulmonary bypass. The patient was discharged on foot on the 18th postoperative day. Such patients can only be saved with an efficient emergency medical-care system including quick transportation, and close cooperation of the hospital staff.

Left ventricular pressure gating in ovine cardiac studies: a software-based method.

Cardiac imaging using magnetic resonance requires a gating signal in order to compensate for motion. Human patients are routinely scanned using an electrocardiogram (ECG) as a gating signal during imaging. However, we found that in sheep the ECG is not a reliable method for gating. We developed a software based method that allowed us to use the left ventricular pressure (LVP) as a reliable gating signal. By taking the time derivative of the LVP (dP/dt), we were able to start imaging at both end-diastole for systolic phase images, and end-systole for diastolic phase images. We also used MR tissue tagging to calculate 3D strain information during diastole. Using the LVP in combination with our digital circuit provided a reliable and time efficient method for ovine cardiac imaging. Unlike the ECG signal the left ventricular pressure was a clean signal and allowed for accurate, nondelay based triggering during systole and diastole.

A computationally efficient formal optimization of regional myocardial contractility in a sheep with left ventricular aneurysm.

A non-invasive method for estimating regional myocardial contractility in vivo would be of great value in the design and evaluation of new surgical and medical strategies to treat and/or prevent infarction-induced heart failure. As a first step towards developing such a method, an explicit finite element (FE) model-based formal optimization of regional myocardial contractility in a sheep with left ventricular (LV) aneurysm was performed using tagged magnetic resonance (MR) images and cardiac catheterization pressures. From the tagged MR images, 3-dimensional (3D) myocardial strains, LV volumes and geometry for the animal-specific 3D FE model of the LV were calculated, while the LV pressures provided physiological loading conditions. Active material parameters (T(max_B) and T(max_R)) in the non-infarcted myocardium adjacent to the aneurysm (borderzone) and in myocardium remote from the aneurysm were estimated by minimizing the errors between FE model-predicted and measured systolic strains and LV volumes using the successive response surface method for optimization. The significant depression in optimized T(max_B) relative to T(max_R) was confirmed by direct ex vivo force measurements from skinned fiber preparations. The optimized values of T(max_B) and T(max_R) were not overly sensitive to the passive material parameters specified. The computation time of less than 5 hours associated with our proposed method for estimating regional myocardial contractility in vivo makes it a potentially very useful clinical tool.

Use of an audible ultrasonic flowmeter to locate deeply buried coronary arteries for off-pump coronary artery bypass grafting.

In patients with coronary arteries that are deeply buried in the myocardium and fat, it is difficult and sometimes risky to expose them for off-pump coronary artery bypass grafting (OPCAB), leading to unavoidable conversion to conventional coronary artery bypass grafting (C-CABG) to ensure their safety. We have developed a new search procedure for these coronary arteries using a dedicated ultrasonic flowmeter with a small tip probe for OPCAB. This technique enables the identification of intramuscular and intra-fat coronary arteries that are less diseased and thus more suited for bypass surgery instead of switching to C-CABG. We believe this procedure will not only improve the quality of OPCAB but also expand its indication.

Surgery for aortic dissection involving an aberrant right subclavian artery.

On diagnosis of Stanford type A acute aortic dissection with an aberrant right subclavian artery, emergency operation was performed. Aortic arch replacement was undertaken with additional 'elephant trunk' procedure to cover the entry site and decrease the blood flow through the false lumen. We consider this technique will become one of the effective procedures for acute aortic dissection involving an aberrant right subclavian artery.

Surgical treatment or conservative therapy for stanford type a acute aortic dissection with a thrombosed false lumen.

OBJECTIVES: Optimum treatment for acute aortic dissection (AAD) with a thrombosed false lumen (thrombosed AAD) remains controversial. We evaluated the outcome of thrombosed AAD according to treatment strategy. MATERIALS AND METHODS: We examined 280 patients with AAD, of which 30 had thrombosed AAD. We compared computed tomography findings, cardiac performance, and clinical course in 28 of these patients. Patients were divided into three groups for the comparison: Group E (emergency surgery), Group C (conservative therapy), and Group S (conservative therapy switched to emergency surgery). RESULTS: In Group E (n = 13), one patient died and 12 survived. In Group C (n = 10), all patients were discharged, of which two died of cancer and two of the remaining eight survivors underwent subsequent elective surgery. In Group S (n = 5), one patient died and four survived following surgery. CONCLUSIONS: It was hard to predict re-dissection or rupture following conservative treatment for thrombosed AAD. Basically, we should perform emergency surgery following the diagnosis of thrombosed AAD, particularly in complicated cases such as those with pericardial effusion, tamponade, and large aorta. Conservative therapy has a very limited application in patients with the initial stages of thrombosed AAD.

Dor procedure for dyskinetic anteroapical myocardial infarction fails to improve contractility in the border zone.

BACKGROUND: Endoventricular patch plasty (Dor) is used to reduce left ventricular volume after myocardial infarction and subsequent left ventricular remodeling. METHODS AND RESULTS: End-diastolic and end-systolic pressure-volume and Starling relationships were measured, and magnetic resonance images with noninvasive tags were used to calculate 3-dimensional myocardial strain in 6 sheep 2 weeks before and 2 and 6 weeks after the Dor procedure. These experimental results were previously reported. The imaging data from 1 sheep were incomplete. Animal specific finite element models were created from the remaining 5 animals using magnetic resonance images and left ventricular pressure obtained at early diastolic filling. Finite element models were optimized with 3-dimensional strain and used to determine systolic material properties, T(max,skinned-fiber), and diastolic and systolic stress in remote myocardium and border zone. Six weeks after the Dor procedure, end-diastolic and end-systolic stress in the border zone were substantially reduced. However, although there was a slight increase in T(max,skinned-fiber) in the border zone near the myocardial infarction at 6 weeks, the change was not significant. CONCLUSIONS: The Dor procedure decreases end-diastolic and end-systolic stress but fails to improve contractility in the infarct border zone. Future work should focus on measures that will enhance border zone function alone or in combination with surgical remodeling.

First finite element model of the left ventricle with mitral valve: insights into ischemic mitral regurgitation.

BACKGROUND: Left ventricular remodeling after posterobasal myocardial infarction can lead to ischemic mitral regurgitation. This occurs as a consequence of leaflet tethering due to posterior papillary muscle displacement. METHODS: A finite element model of the left ventricle, mitral apparatus, and chordae tendineae was created from magnetic resonance images from a sheep that developed moderate mitral regurgitation after posterobasal myocardial infarction. Each region of the model was characterized by a specific constitutive law that captured the material response when subjected to physiologic pressure loading. RESULTS: The model simulation produced a gap between the posterior and anterior leaflets, just above the infarcted posterior papillary muscle, which is indicative of mitral regurgitation. When the stiffness of the infarct region was reduced, this caused the wall to distend and the gap area between the leaflets to increase by 33%. Additionally, the stress in the leaflets increased around the chordal connection points near the gap. CONCLUSIONS: The methodology outlined in this work will allow a finite element model of both the left ventricle and mitral valve to be generated using noninvasive techniques.