Chapter 7: Dysrhythmia Interpretation and Management | Questions with 100% Correct Answers | New Update 2023 | 26 Pages

The nurse is caring for a patient who is on a cardiac monitor. The nurse realizes that the sinus node is the pacemaker of the heart because it is: a. the fastest pacemaker cell in the heart. b. the only pacemaker cell in the heart. c. the only cell that does not affect the cardiac cycle. d. located in the left side of the heart. - a. the fastest pacemaker cell in the heart. ANS: A The cardiac cycle begins with an impulse that is generated from a small concentrated area of pacemaker cells high in the right atria called the sinoatrial node (sinus node or SA node). The SA node has the fastest rate of discharge and thus is the dominant pacemaker of the heart. The AV node has pacemaker properties and can discharge an impulse if the SA node fails. The ventricles have pacemaker capabilities if the sinus node or the AV node ceases to generate impulses. One of the functions of the atrioventricular (AV) node is to: a. pace the heart if the ventricles fail. b. slow the impulse arriving from the SA node. c. send the impulse to the SA node. d. allow for ventricular filling during systole. - b. slow the impulse arriving from the SA node.ANS: B The impulse from the SA node quickly reaches the atrioventricular (AV) node located in the area called the AV junction, between the atria and the ventricles. Here the impulse is slowed to allow time for ventricular filling during relaxation or ventricular diastole. The AV node has pacemaker properties and can discharge an impulse if the SA node (not the ventricle) fails. The electrical impulse is then rapidly conducted through the bundle of His to the ventricles (not the SA node) via the left and right bundle branches.