Please click here to obtain permission to reproduce this image.
Click on image to view larger version.
Figure 3 Pharmacologic effects on pre-excitation in mutant transgenic mice. (A) The left panel shows a six-lead electrocardiogram (ECG) at baseline, with a short PR interval and wide, initially slurred QRS complex. The right panel shows the same six-lead ECG 2 min after procainamide infusion, which lengthens the PR interval and narrows the QRS complex. The initial positive deflection of the QRS complex in leads I, II, III (LI, LII, and LIII), and aVF in the left panel suggests an anteroseptal accessory AV pathway. (B) In the left panel, surface ECG leads I, II, and aVF, as well as the HBE, from a wild-type mouse are displayed. Atrial pacing at 130 ms initially conducts 1:1 to the ventricles; however, adenosine infusion (arrow) produces AV block with 2:1 conduction to the ventricles. In the right panel, the same ECG leads, along with the HBE, are displayed from a TGN488I mouse. Atrial pacing at 100 ms conducts 1:1 to the ventricles, despite the presence of adenosine. A = atrial electrogram; AVB = atrioventricular block; His = His potential; V = ventricular electrogram.
|
