Surgical implantation of cardiovascular devices in the thorax of the horse.

The research article investigates a surgical procedure involving the implantation of cardiovascular devices in the thorax of horses to measure various cardiovascular parameters over a prolonged period.

Overview of the Research

The study primarily centres around the surgical implantation of cardiovascular monitoring devices, specifically an electromagnetic flow probe and catheters, in the horse’s thorax. These operations were performed through a surgical technique known as thoracotomy, a procedure that opens up the chest cavity.

Experiment Details

• The study comprised sixteen operations on different horses. These horses were then divided into three groups. Four were used for acute experiments to gauge immediate reactions and effects, another four horses unfortunately died due to surgical complications, and the remaining eight horses were kept under observation for a period extending from 18 to 57 days.

Functionalities of Implanted Devices

• The implanted electromagnetic flow probe had the functionality to measure the stroke volume and heart rate of the horse continuously. Stroke volume is the amount of blood pumped from one ventricle of the heart with each beat, and the heart rate, of course, gives real-time data about the frequency of the heartbeat.
• The catheters placed in the left ventricular (LV) apex were used in association with thermal dilution techniques and pressure-sensitive devices. This setup allowed the measurement and calculation of a variety of cardiovascular variables. These included mean arterial blood pressure, total peripheral vascular resistance, LV residual fraction, and LV end systolic and diastolic volumes. Mean arterial blood pressure is the average pressure in an individual’s arteries during a single cardiac cycle, total peripheral vascular resistance is the resistance offered by the circulatory system, LV residual fraction is the remaining volume of blood after the ejection phase, and LV end systolic and diastolic volumes are the volumes of blood present at the end of contraction (systole) and relaxation (diastole) phases of the cardiac cycle, respectively.

Main Outcomes and Findings

The article does not provide explicit details about the outcomes and findings of the experiment. However, it can be extrapolated that the main objective which was to carry out long-term cardiovascular monitoring of horses by surgical implantation of specific devices was achieved as the devices worked for a period of 18 to 57 days in some horses. Complications leading to the death of four horses also highlight the associated risks of such surgical interventions.