An ICU nurse is providing continuing health education to new nurses in the unit. Which statements made by the nurse are correct?
• The SA node is the pacemaker of the heart because it possesses the highest level of automaticity.
• The SA node is regulated by the nervous system through the vagus nerve. If it fails to fire, the AV node should take over pacemaker function.
• Dysrhythmias can severely decrease the heart's ability to pump effectively, even causing death.
• This statement is correct: Dysrhythmias can occur when there are disturbances from the three mechanisms of the heart: automaticity, conduction, and re-entry of impulses.
• Incorrect: "Normal sinus rhythm is the usual heart rhythm, beginning in the atrioventricular (AV) node." Normal sinus rhythm is the usual heart rhythm, but it does not begin the AV node. The correct statement would be: Normal sinus rhythm is the usual heart rhythm that begins in the sinoatrial (SA) node.
• Incorrect: "The most serious complication of a dysrhythmia is