Which of the following is wrong about the cardiac cycle? A: the diastolic period is longer than the systolic period B: The atria and ventricles contract at the same time C: The atria and ventricles can relax at the same time D: The length of cardiac cycle is related to heart rate

Which area allows the atria to completely empty as the ventricles fill with blood? A: A-V node B: A-V bundle C: S-A node D: Purkinje fibers

suppression of arrhythmias resulting from a reentry focus is most likely to occur if the drug A: has vagomimetic effects o the AV node B: is a beta-blocker C: converts a unidirectional block to a bidrectional block D: slows conduction through the atria E: has atropine-like effects on the AV node

房颤时，电脉冲在心房内和心房周围的许多其他部位（异位），通常接近肺静脉根部，随机产生。 A: In atrial fibrillation, electrical stimuli are relayed randomly from many other sites called ectopic sites in and around the auricle, commonly near the roofs of pulmonary veins. B: In atrial fibrillation, electrical impulses are initiated randomly from many other sites called ectopic sites in and around the atria, commonly near the roots of pulmonary veins.