A patient is to have synchronized cardioversion for treatment of atrial flutter.
He has received Heparin 500 units subcutaneously.
Which of the following interventions should now be performed?
Set the defibrillator in asynchronous mode and charge to 300 joules.
Steadily increase the voltage until the beats are captured.
Sedate the patient per physician orders and hospital protocol.
Assist physician in intubating patient to stabilize airway.
The Correct Answer is C
Choice A rationale
Setting the defibrillator in asynchronous mode and charging to 300 joules is contraindicated for synchronized cardioversion. Asynchronous shocks deliver energy regardless of the cardiac cycle, potentially striking during the vulnerable repolarization phase (T wave) and precipitating ventricular fibrillation. Synchronized cardioversion requires synchronized discharge on the R wave, using typically 50–100 joules for atrial flutter, ensuring depolarization of abnormal reentrant circuits without inducing malignant arrhythmias.
Choice B rationale
Gradual voltage increase until beats are captured describes pacing, not cardioversion. Electrical pacing delivers low-energy impulses to stimulate myocardial depolarization, used for bradyarrhythmias rather than atrial flutter. Cardioversion requires a single synchronized shock to terminate reentrant tachyarrhythmias by depolarizing cardiac tissue simultaneously, interrupting the abnormal conduction loop. Incremental voltage adjustment would be ineffective and potentially arrhythmogenic in tachydysrhythmic conditions.
Choice C rationale
Sedation before synchronized cardioversion prevents pain and anxiety because the electrical shock, though brief, causes skeletal muscle contraction and discomfort. Short-acting benzodiazepines or propofol are commonly administered per protocol. Cardioversion is synchronized with the R wave to restore sinus rhythm safely. Pre-procedure sedation ensures patient comfort, minimizes sympathetic stimulation, and prevents recall of the event while maintaining airway reflexes and hemodynamic stability.
Choice D rationale
Intubation is not routinely required for synchronized cardioversion in stable patients. Airway stabilization is necessary only if respiratory compromise or deep sedation occurs. Cardioversion is typically performed under short procedural sedation using non-paralyzing agents. Routine intubation would unnecessarily increase procedural risk and delay rhythm restoration in hemodynamically stable patients with atrial flutter. Continuous monitoring ensures airway protection without mandatory endotracheal intervention.
Nursing Test Bank
Naxlex Comprehensive Predictor Exams
Related Questions
Correct Answer is B
Explanation
Choice A rationale
Using the highest energy setting available is generally not the initial approach for synchronized cardioversion, especially for rhythms like atrial flutter, which often respond to lower energy levels (e.g., 50-100 J biphasic). Starting high increases the risk of myocardial damage and post-shock dysrhythmias. Energy delivery should be titrated based on the patient's response and the specific arrhythmia being treated.
Choice B rationale
Ensuring the synchronizer switch is on is the most crucial step in synchronized cardioversion. This setting detects the patient's R wave and delivers the shock precisely during ventricular depolarization, which is a period of relative refractoriness. This timing prevents the shock from falling during the vulnerable T wave (repolarization), which could induce lethal ventricular fibrillation.
Choice C rationale
Applying firm pressure to the pads is important to ensure optimal contact and minimize transthoracic impedance, allowing the maximum amount of energy to reach the myocardium. While essential for effective shock delivery, it is secondary to the synchronizer setting, which ensures the safety and correct timing of the shock.
Choice D rationale
Administering a shock during expiration is sometimes recommended for defibrillation to minimize air in the lungs, which can increase impedance. However, for synchronized cardioversion, the timing relative to the R wave is the absolute priority; the respiratory cycle is a minor consideration compared to the risk of inducing ventricular fibrillation if the synchronizer is off. —.
Correct Answer is B
Explanation
Choice A rationale
The ST segment represents the interval between ventricular depolarization and repolarization, and its deviation (elevation or depression) is a key indicator of myocardial ischemia or injury. While abnormal ventricular depolarization can sometimes influence the repolarization phases, the ST segment primarily reflects the repolarization plateau phase.
Choice B rationale
The QRS complex graphically represents the rapid depolarization of the right and left ventricles, the main event that precedes ventricular contraction. Therefore, any abnormality in the ventricular conduction system or the pathway of ventricular depolarization, such as a bundle branch block or ventricular hypertrophy, will directly manifest as an abnormal or widened QRS complex.
Choice C rationale
The P wave on the EKG strip represents the electrical activity associated with atrial depolarization, which is the contraction of the atria. It provides information about the origin of the impulse and atrial function, but it does not directly reflect the electrical process of ventricular depolarization.
Choice D rationale
The T wave represents the final phase of ventricular repolarization, during which the ventricles return to their resting, polarized state. While ventricular depolarization sets the stage for repolarization, the T wave itself reflects the return to the polarized state, not the initial abnormal electrical spread of the depolarization impulse. —.
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