The chest tubes can become clogged at any time after their placement. The status of urgency, reoperations and use of blood products can be contributing factors increasing the incidence of chest tube clogging. Clinicians likely underestimate the prevalence of this failure to drain, as most clogging occurs in the internal portion of the tube.

Research on the therapeutic modulation of cardiac autonomic tone by electrical stimulation has yielded encouraging early clinical results. Vagus nerve stimulation has reduced the rates of morbidity and sudden death from heart failure, but therapeutic vagus nerve stimulation is limited by side effects of hypotension and bradycardia. Sympathetic nerve stimulation that has been implemented in the experiment may exacerbate the sympathetic-dominated autonomic imbalance. In contrast, concurrent stimulation of both sympathetic and parasympathetic cardiac nerves increases myocardial contractility without increasing heart rate. This review assesses the current state of electrical stimulation of the cardiac autonomic nervous system to treat heart failure.

No abstract

From early experience in cardiac surgery on the mitral valve, access was gained in different ways: through left and right antero-lateral extended thoracotomy for closed and correspondingly for open mitral commissurotomy, from right parasternal access with rib resection, and via median sternotomy. Median sternotomy remains the most common approach for mitral valve procedures, such as replacement or repair, allowing good visualisation, exposure and working field. Applying the largely spread access as median sternotomy, surgeons always wanted to overcome the necessity of large incisions, get a better surgical view, to dissect with better respect to structural integrity and have better aesthetic results. Enhanced understanding of surgical bases and technological development sourced a breakthrough in minimally-invasive approach for mitral valve surgery, offering several advantages such as less postoperative pain, lower morbidity and mortality, faster recovery and shorter hospital stay. In an effort to share the institutional experience in less invasive surgery, this article demonstrates our approach in mitral valve repair through a right minithoracotomy in the 3rd or 4th intercostal space.

Heart valve disease can be extensive and may include double (mitral-aortic, mitral-tricuspid), or triple (mitral, aortic, and tricuspid) valvular regurgitation. The surgical correction of significant valvular regurgitation usually consists of the repair or replacement of all valves affected by a pathologic process. The median full-length sternotomy still serves as a classic approach for single, double, and triple valve operations in most patients. Here, we present a minimally invasive approach for the surgery of double and triple heart valve disease through a limited single-access right minithoracotomy in the 3rd intercostal space, with central aortic and percutaneous venous cannulation. A total of 48 double valve procedures were performed in our department using this technique. The minimally invasive approach through a right single-access thoracotomy has become our choice for all isolated mitral valve, and for most isolated aortic valve, replacement procedures. Triple valve surgery was performed in six cases and was feasible in all selected patients.

The net pump flow generated by the HeartMate II device at 6000 rpm depends on the degree of residual left ventricular function. In the setting of improved left ventricular function, at 6000 rpm, we noted a large regurgitant flow that reloaded the left ventricle. Although this "marker" can serve as a useful indicator for left ventricular recovery, assessing left ventricular recovery at this speed is flawed unless measures are taken to prevent regurgitant flow.

The Virtual Mock Loop, a versatile virtual mock circulation loop, was developed using a lumpedparameter model of the mechanically assisted human circulatory system. Inputs allow specification of a variety of continuous-flow pumps (left, right, or biventricular assist devices) and a total artificial heart that can selfregulate between left and right pump outputs. Hemodynamic inputs were simplified using a diseasebased input panel, allowing selection of a combination of cardiovascular disease states, including systolic and diastolic heart failure, stenosis, and/or regurgitation in each of the four valves, and high to low systemic and pulmonary vascular resistance values. The menu-driven output includes a summary of hemodynamic parameters and graphical output of selected flows, pressures, and volumes in the heart's four chambers as well as in the pulmonary artery and aorta.New tools to augment experimental research on implantable heart-assist devices and to increase our understanding of patient-specific pump interactions are in high demand. The purpose of this ongoing study is to demonstrate the use of a system analysis computer simulation to explore and better comprehend the interactions of mechanical circulatory support (MCS) pumps with a more extensive combination of patientspecific or simulation conditions than can be established by practical experimentation. Usability is an important factor in constructing computer models for research purposes, and among our primary objectives in creating this simulation model were to make it as portable and useful as possible outside the lab environment, by people not involved in the creation of its operational software.

No abstract