Which client problem has priority for the client with cardiac dysrhythmia?

Choice A rationale

Pulmonary embolism is a potential complication for any hospitalized patient due to immobility and venous stasis, but it is not the most common complication specifically following a myocardial infarction. While the risk of deep vein thrombosis exists, the primary pathological concerns after a heart attack are related to the damaged myocardium and the resulting electrical instability or mechanical failure of the heart pump, rather than venous thromboembolic disease.

Choice B rationale

Stroke can occur following a myocardial infarction, particularly if the patient develops atrial fibrillation or if a mural thrombus forms in the weakened left ventricle and embolizes. However, the incidence of stroke is lower compared to the immediate hemodynamic failures of the heart. While significant and life-altering, clinicians prioritize monitoring for heart failure and shock in the acute post-infarction period because these cardiac-specific complications occur with much higher frequency.

Choice C rationale

Acute renal failure can occur after a myocardial infarction as a result of decreased renal perfusion or "cardiorenal syndrome" when the heart can no longer maintain adequate mean arterial pressure. While kidneys are sensitive to drop-offs in cardiac output, this complication is usually secondary to the primary failure of the heart. It occurs less frequently as an immediate complication than cardiogenic shock, which represents the direct, catastrophic failure of the heart muscle itself.

Choice D rationale

Cardiogenic shock occurs when more than 40 percent of the left ventricular mass is infarcted, leading to a profound inability of the heart to maintain adequate systemic perfusion. This is the leading cause of in-hospital death following a myocardial infarction. The damaged muscle cannot generate enough force to maintain a stroke volume, leading to a cascade of hypotension and pulmonary edema. It remains the most common and feared major complication in the acute phase.

Choice A rationale

Sinus bradycardia is defined by a heart rate of less than 60 beats per minute originating from the sinoatrial node. On an ECG, this rhythm must demonstrate all the hallmarks of a normal sinus rhythm, including a P wave preceding every QRS complex, a constant PR interval between 0.12 and 0.20 seconds, and a regular R to R interval. The only abnormality is the slow rate. It can be physiological in athletes or a result of vagal stimulation.

Choice B rationale

An absence of P waves combined with a slow heart rate of 40 beats per minute typically indicates a junctional escape rhythm. In this scenario, the sinoatrial node fails to fire, and the atrioventricular node takes over as the primary pacemaker. Because the atria are not depolarized from the top down, P waves are either absent, inverted, or hidden within the QRS complex. This is distinct from sinus bradycardia, where the sinoatrial node is still functioning as the pacemaker.

Choice C rationale

A prolonged PR interval greater than 0.20 seconds is the defining characteristic of a first-degree atrioventricular block. While this condition can occur alongside sinus bradycardia, the prolongation of the PR interval indicates a delay in conduction through the atrioventricular node rather than a slow discharge rate from the sinoatrial node itself. Simple sinus bradycardia maintains a normal PR interval. Lab values for cardiac output may be monitored if the rate becomes too slow to maintain tissue perfusion.

Choice D rationale

A regular rhythm with a heart rate between 60 and 100 beats per minute is the definition of normal sinus rhythm. In this range, the sinoatrial node is firing at an appropriate physiological frequency for a resting adult. All ECG components, including P waves, QRS complexes, and T waves, are present and occur at regular intervals. Sinus bradycardia specifically requires the rate to drop below the 60 beats per minute threshold while maintaining the other characteristics of sinus rhythm.