A patient has been admitted to the cardiac unit with the diagnosis of bradycardia. The patient states "I am confused about what the doctor said is wrong with me, he said my pacemaker is not working. I don't have a pacemaker
" What is the nurse's best response? a. "The sinoatrial node is the ‘pacemaker' of your heart."
b. "Myocardial contractility determines your heart rate."
c. "The atrioventricular node is the ‘pace-maker' of your heart."
d. "The ventricular Purkinje network deter-mines your heart rate."
A
The conduction system originates with the sinoatrial node, the "pacemaker" of the heart. Elec-trical impulses are then transmitted along intraatrial pathways to the atrioventricular (AV) node. The AV node mediates impulse transmission between the atria and the ventricles. Delaying the impulse at the AV node before transmitting it through the bundle of His and ventricular Purkinje network. The heart rate is regulated by the sympathetic and parasympathetic systems, not by myocardial contractility and ventricular Purkinje network. Myocardial contractility is the ability of the heart to squeeze blood from the ventricles and prepare for the next contraction. This is dif-ficult to measure because preload, afterload, and heart rate must remain constant.
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