Simultaneous pulmonary and systemic blood pressure and ECG Interval measurement in conscious, freely moving rats

Here we evaluated the ability of a new, dual blood-pressure telemetry transmitter to simultaneously measure pulmonary and systemic blood pressure and the electrocardiogram in rats. The transmitter was implanted in normotensive and monocrotaline-induced pulmonary hypertensive Wistar rats, with sensing catheters placed in the pulmonary artery (channel 1) and descending aorta (channel 2). Biopotential electrodes were positioned to record an apex-based lead II electrocardiogram. Pulmonary and systemic arterial blood pressure and electrocardiographic waveforms were recorded between 2 and 12 wk after implantation of the transmitter. During this period, pulmonary arterial pressure progressively increased in monocrotaline-treated compared with saline-treated rats. The pharmacologic response of rats to reference compounds was measured by using the transmitter to validate the technique and to evaluate the ability of the device to transmit changes in blood pressure and the electrocardiogram. Validation against 2 Millar high-fidelity blood-pressure catheters confirmed the accuracy of the blood pressure data recorded with the transmitter. In addition, local tolerance of the associated catheters was confirmed by histologic examination.