Variations in hemodynamic parameters and ECG in healthy, conscious, freely moving telemetrized beagle dogs

Interpretation of the dynamic cardiovascular parameters on safety pharmacology studies is a challenging process; sometimes, it is difficult to separate normal physiological variations from the effects of the test drug. Data from healthy control Beagle dogs (41 males and 25 females) implanted with telemetry transmitters (DSI, St. Paul, MN) from 34 studies performed from 2003 to 2005 were analyzed. Telementry data were collected for a 30-s period every 10 min for 24 h after sham dosing. One-hour averages were analyzed. Prior to dosing, heart rate (HR) was 95.6±26.6 bpm; mean systolic, and diastolic blood pressure (BP) were 105.3±12.7, 142.5±5.3, and 84.7±11.1 mmHg, respectively. PR, QRS, QT, and corrected (Van de Water) QT intervals were 121±13, 33±3, 217±23, and 245±18 ms, respectively. Seasonal and slight diurnal patterns were noticed only in HR; BP and body temperature were more stable. PR and QT intervals were inversely related to HR; in addition, the duration of PR was influenced by the light cycle. A comparison of three QT correction formulas demonstrated that Van de Water's formula provided the optimal results in Beagle dogs over a wide range of HR.