During synchronized cardioversion for atrial flutter, which of the following is most important?
Using the highest energy setting available.
Ensuring the synchronizer switch is on.
Applying firm pressure to the pads.
Administering a shock during expiration.
The Correct Answer is B
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. —.
Nursing Test Bank
Naxlex Comprehensive Predictor Exams
Related Questions
Correct Answer is A
Explanation
Choice A rationale
Junctional escape rhythms serve as a protective mechanism when the sinoatrial node fails or conduction from it is blocked. The atrioventricular junction generates impulses at 40–60 beats/min, maintaining perfusion and preventing asystole. This physiologic backup ensures continued ventricular depolarization and cardiac output during sinus arrest, enhancing survival. Electrocardiographically, inverted or absent P waves precede normal QRS complexes, confirming junctional origin of rhythm.
Choice B rationale
Denying the safety role of junctional escape rhythms is incorrect because absence of such escape pacemaking would result in cardiac standstill during SA node failure. Without junctional activity, electrical silence would occur until a lower ventricular pacemaker (20–40 beats/min) initiates impulses. Hence, junctional rhythm prevents fatal bradyasystolic episodes by substituting as a secondary pacemaker maintaining ventricular conduction and systemic circulation.
Choice C rationale
The compensatory function of junctional escape rhythms does not depend on hemodynamic status. The rhythm arises automatically due to intrinsic automaticity when higher pacemaker impulses are absent. Although hemodynamic tolerance varies among patients, the physiologic mechanism of rhythm generation remains consistent, reflecting inherent pacemaker hierarchy rather than circulatory adequacy. Therefore, its existence is independent of blood pressure or cardiac output status.
Choice D rationale
Limiting the protective role of junctional escape rhythms to complete heart block is incorrect because they also occur in sinus arrest, sick sinus syndrome, or atrial standstill. Junctional pacemakers automatically assume control when supraventricular impulse formation or conduction fails, irrespective of the underlying cause. Hence, their compensatory activity is not exclusive to complete atrioventricular dissociation but applies broadly across nodal dysfunction conditions.
Correct Answer is B
Explanation
Choice A rationale
Ventricular Fibrillation (VF) is a chaotic ventricular electrical activity resulting in no cardiac output, leading to immediate circulatory collapse and sudden cardiac death. Defibrillation is the critical intervention that delivers a massive electrical shock to reset the heart's electrical system, making it the absolute priority over airway insertion or medication administration.
Choice B rationale
Immediate defibrillation is the definitive and life-saving intervention for Ventricular Fibrillation (VF) and pulseless Ventricular Tachycardia (pVT). This electrical therapy stops the chaotic activity, allowing the natural pacemaker (SA node) to resume a normal rhythm. Time is muscle and brain; every minute of delay significantly reduces survival probability.
Choice C rationale
While a 12-lead ECG is essential for diagnostic confirmation and determining the location of myocardial injury, obtaining it delays the immediate life-saving therapy needed for VF. CPR and defibrillation protocols must be initiated immediately; rhythm confirmation is done using the quick-look paddles or monitor patches.
Choice D rationale
Amiodarone is an antiarrhythmic drug used to stabilize the heart rhythm and increase the success rate of defibrillation, often administered after initial unsuccessful shocks. However, defibrillation remains the primary, most urgent intervention to terminate VF; drug administration should not delay the immediate electrical countershock. —. ##.
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