A patient in the cardiac unit suddenly develops a wide-complex tachycardia on the ECG monitor.
Which of the following actions should the nurse take first?

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.

Choice A rationale:

Survivors of sudden cardiac death due to ventricular fibrillation or pulseless ventricular tachycardia are prime candidates for ICDs. These devices detect and terminate life-threatening arrhythmias via defibrillation or antitachycardia pacing. ICDs reduce mortality by preventing recurrence of fatal arrhythmias. Guidelines recommend ICDs for secondary prevention in patients with structurally abnormal hearts and documented ventricular arrhythmias.

Choice B rationale

Spontaneous sustained ventricular tachycardia, especially if symptomatic or hemodynamically unstable, warrants ICD placement. Sustained VT is defined as lasting more than 30 seconds or requiring intervention. ICDs monitor rhythm and deliver therapy when VT is detected, preventing progression to ventricular fibrillation. This is a Class I indication for ICDs in patients with structural heart disease.

Choice C rationale

Unstable angina is caused by transient myocardial ischemia due to plaque rupture or vasospasm. It is managed with anti-ischemic therapy and revascularization. ICDs are not indicated unless the patient develops sustained ventricular arrhythmias or survives cardiac arrest. ICDs do not treat ischemia directly and are not used for primary prevention in unstable angina.

Choice D rationale

Heart failure patients with reduced ejection fraction (≤35%) and NYHA class II–III symptoms despite optimal medical therapy are candidates for ICDs for primary prevention. These patients are at increased risk for sudden cardiac death due to ventricular arrhythmias. ICDs improve survival by terminating malignant rhythms. This is supported by trials like MADIT-II and SCD-HeFT.