Legends of figures
Figure 1. Effects of astemizole (1 mg/kg, iv), dofetilide (0.1 mg/kg, po) and dofetilide (1 mg/kg, po) alone or in combination with atenolol (1 mg/kg, iv) on QTc, stroke volume (SV), S1, S2 and/or HFQT oscillations in beagle dogs. Vehicle: red filled circles, drug alone: blue filled circles, drug combined with atenolol: blue empty circles. Data are presented as mean values ± SEM, n=6.
Figure 2. (A) Example of S2 oscillations superimposed with BP signal showing large HF heart rate (HR) and stroke volume (SV) oscillations in a control dog. (B, C, D) Mean SV/HFHR, DAP/HFHR and SAP/HFHR relationships were built from mean values and from values recorded at maximum (HRhigh) and minimum (HRlow) of HR oscillations during all 10-seconds sequences recorded over the whole circadian cycle in control dogs. Data are presented as mean values ± SEM, n=6.
Figure 3. Effects of thioridazine (1.5 mg/kg, po), prazosin (1 mg/kg, iv) and milrinone (3 mg/kg, iv) on stroke volume (SV), S2 and HFQT oscillations in beagle dogs. Vehicle: red filled circles, drug alone: blue filled circles, drug combined with atenolol: blue empty circles. Data are presented as mean values ± SEM, n=6.
Figure 4. Effects of cisapride (6 mg/kg, po) and pimozide (1 mg/kg, iv) on and cardiac output (CO), S2 and HFQT oscillations in beagle dogs. Vehicle: red filled circles, drug alone: blue filled circles. Data are presented as mean values ± SEM, n=6.
Figure 5. Examples of blunted QTc or concealed QTc prolongation revealed under β adrenoceptors blockade by atenolol (1 mg/kg, iv) in dogs. Vehicle: red filled circles, drug alone: blue filled circles, drug combined with atenolol: blue empty circles. Data are presented as mean values ± SEM, n=6.
Figure 6. Comparison of LQT1 and LQT2 patients with QTc prolongation (n=75 LQT1, n=26 LQT2) to patients with concealed QTc prolongation (n=29 LQT1, n=9 LQT2) on QT interval, S3 and HFQT oscillations. Patients with concealed QTc prolongation: red filled circles, patients with QTc prolongation: blue filled circles. Data are presented as mean values ± SEM.
Figure 7. Comparison of LQT1 and LQT2 patients with concealed QTc prolongation (n=29 LQT1, n=9 LQT2) to healthy subjects (n=200) on QT interval, S1 and HFQT oscillations. Healthy subjects: red filled circles, patients with concealed QTc prolongation: blue filled circles. Data are presented as mean values ± SEM.
Figure 8. Update of Coumel’s triangle concept applied to torsadogenic drug and LQT (type 1 and 2) syndromes. Detailed explanations are provided in the last part of the discussion.