Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Assisted Circulation”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 685 records · Page 38Linked to original sources
PubMed1990

Mechanical myocardial actuation during ventricular fibrillation improves tolerance to ischemia compared with cardiopulmonary bypass.

Direct mechanical ventricular actuation (DMVA) is a unique non-blood-contacting biventricular assist device that provides circulatory support during ventricular fibrillation without demonstrating adverse effects on the myocardium. The purpose of this study was to assess the preservation of myocardial energy stores and myocardial responses to ischemia after circulatory support during ventricular fibrillation with direct mechanical ventricular actuation versus cardiopulmonary bypass. Twenty adult mongrel dogs were randomized to receive circulatory support with either cardiopulmonary bypass or direct mechanical ventricular actuation. After 4 hours of ventricular fibrillation, hearts were defibrillated and left ventricular transmural biopsies were obtained. Hearts were then excised and subjected to 90 minutes of normothermic total ischemia. Serial biopsies were obtained at 15-minute intervals to determine regional depletion of high energy phosphates. The time-to-peak ischemic contracture was recorded by using needle-tipped Millar catheters placed in the left ventricular endocardium, epicardium, septum, and right ventricle. Time-to-peak ischemic contracture of the endocardium (62.6 +/- 1.4 vs. 58.8 +/- 1.0 minutes, p less than 0.05) and septum (61.1 +/- 6.9 vs. 46.9 +/- 6.2 minutes, p less than 0.004) were significantly prolonged after direct mechanical ventricular actuation versus cardiopulmonary bypass, respectively. Similar trends were noted in the epicardium and right ventricular regions; however, these differences were not statistically significant. Left ventricular adenosine triphosphate (ATP) levels were better preserved after direct mechanical ventricular actuation (22 +/- 1.5 mumols/g dry wt) compared with cardiopulmonary bypass (17 +/- 1.9 mumols/g dry wt). The depletion of left ventricular endocardium ATP during normothermic ischemia was significantly delayed after direct mechanical ventricular actuation compared with cardiopulmonary bypass.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenosine Triphosphate↗
PubMedDate not supplied

Performance of skeletal muscle ventricles: effects of ventricular chamber size.

Skeletal muscle ventricles were constructed in 12 dogs. In one group of dogs (n = 7) the skeletal muscle ventricles were constructed around a 17 ml Teflon mandrel, and in the other group (n = 5) a 45 ml mandrel was used. Use of the larger mandrel resulted in an increase in compliance and greater stroke work over the physiologic range of preloads and afterloads. With the larger mandrel, stroke work consistently exceeded normal canine stroke work at physiologic filling pressures.

Animals↗
PubMed1989

[Right ventricular assistance by intrapulmonary counterpulsation].

Right ventricular failure is relatively frequent and constitutes one of the causes of post-operative heart failure. Few drugs are available to treat right ventricular failure. We present a simple and effective means of mechanical support available in all cardiovascular units: counterpulsation in the pulmonary artery. Our experience and a review of the literature have enabled us to determine the indications for this method to support a failing heart.

Assisted Circulation↗
PubMed1989

Management: by circulatory assist devices.

The current status of mechanical circulatory support in patients with cardiogenic shock is presented in terms of patient and device selection. Advantages of the complications associated with this type of therapy is discussed.

Assisted Circulation↗
PubMed1987

State of the art and future trends in heart transplantation and ventricular assist devices.

The authors present a short review of the milestones in clinical heart transplantation and the prerequisites they regarded as indispensable to be able to start a clinical programme in their own centre. Next, they describe various types of ventricular assist devices (VAD) and the indications for their use. In conclusion, the authors discuss the prospects of, and future trends in, heart transplantation and VAD that have become, despite their short history, a clinical reality and whose practical importance is to grow further.

Assisted Circulation↗
PubMedDate not supplied

Counterpulsation in atrio-aortic bypass: theoretical and experimental aspects.

Mechanical support of the heart is becoming an established method for emergency situations or bridge to transplant applications. Nevertheless the discussion concerning the importance of co- or counterpulsation isn't yet finished. Using a theoretical model of the cardiovascular system, the influence of a LVAD triggered to co- and counterpulsation will be discussed. The theoretically obtained results are compared to a series of six experiments in calves, where the influence of LVAD-pumping in co- and counterpulsation pumping mode was investigated. Additional benefits were seen compared to the copulsation pump method: there was more reduction of the cardiac stroke work, afterload and an increase of the diastolic pressure, which is important for the coronary blood flow. In order to verify the benefits of the additional reduction of pressure work a small series of animal experiments was performed.

Animals↗
PubMed1986

Left heart and biventricular bypass.

Various forms of circulatory assist devices are currently under investigation. Clinical use of ventricular bypass devices ranging from roller-pump-driven units to pneumatically powered VADs have been in use for several years. These devices are indicated for patients in cardiogenic shock following cardiac surgery or myocardial infarction when all other forms of conventional therapy have failed. Success, though modest, is encouraging in these patients with a dismal prognosis. An increasing role for the VAD may be found in supporting patients whose condition deteriorates while awaiting cardiac transplantation.

Assisted Circulation↗
PubMedDate not supplied

Roller screw electric motor ventricular assist device.

The roller screw electric VAD is easier to manufacture and 25% lighter than the previously described drum cam model. This device requires 12 to 15 W to pump 6 to 8 l/min with minimal hemolysis. The motor drive has functioned for periods up to 93 days in vivo with no measurable wear. The compliance chamber volume varies by 100 cc during VAD function but does so while maintaining pressure variations below 15 mmHg. Compliance chamber volume loss of 2 to 5 cc/day is explained by gas transport through SPU. The subcutaneous sampling port provides ready access to the sealed system.

Animals↗