Telemetric ECG Recordings in Mice

Telemetric ECG recordings in freely-moving mice were performed as previously described^{23 (link),34 (link),35 (link)}. Briefly, mice were anesthetized using gas anesthesia with 2% isoflurane (Forene, Abbott, UK). An ETA-F10 telemetric transmitter (Data Sciences International) was placed subcutaneously along the animal’s back. Transmitter’s wire electrodes were placed in DII derivation against the heart axis. Advil (ibuprofen, 7 mL/L) was added to the drinking water for 4 days after implantation to prevent post-operative pain. Mice were left to recover for 10 days before experiments. ECG signals were recorded by employing a telemetric receiver connected to an analog-to-digital conversion acquisition system. Analysis was performed off-line using the Dataquest A.R.T. software (Data Sciences International). Heart rates (HR) were determined from RR intervals and atrial rates from PP intervals, under control conditions or following recording of 4-h baseline to evaluate drugs effects. All drugs were administered by intraperitoneal (IP) injection. Mean HR values were calculated by analyzing periods of 5 min at different time points corresponding to the peak effect of the drug. ECG parameters were measured by employing ECG Auto 1.5.7 software (EMKA Technologies).