Fig. 5

HR slowdown in relation to respiration. A Plot of HR over time, showing cyclical decreases of HR, and in one case a block of conduction between atria and ventricles. B left panel: ECG trace showing two consecutive P waves preceding an R wave, which indicates a momentary absence of conduction between atria and ventricles after the first P wave (Atrioventricular block of conduction). B right panel: cyclical decreases of HR but with the normal succession between P and R waves. V = voltage