The nurse obtains a 6 second EKG strip on a patient. The nurse interprets this strip as what rhythm?

Choice A rationale

Ectopic beats originating from an irritable focus in the ventricles characterize this rhythm. The EKG strip shows a premature, wide, and distorted QRS complex occurring earlier than expected. This occurs because the electrical impulse skips the normal conduction pathway, leading to slower myocardial cell-to-cell depolarization. Since the ventricles do not fill adequately before contracting, the stroke volume is reduced. Frequent occurrences can signify myocardial irritability or electrolyte imbalances like hypokalemia or hypomagnesemia.

Choice B rationale

This rhythm is identified by three or more consecutive premature ventricular contractions occurring at a rate exceeding 100 beats per minute. The QRS complexes are wide and uniform, typically masking the P waves entirely. It is a life-threatening arrhythmia because the rapid rate significantly reduces diastolic filling time, leading to a precipitous drop in cardiac output and blood pressure. It may lead to cardiac arrest if not treated promptly with amiodarone, lidocaine, or cardioversion.

Choice C rationale

Characterized by a chaotic, disorganized electrical activity without any identifiable P waves, QRS complexes, or T waves, this rhythm represents a pulseless state. The ventricles merely quiver rather than contracting, resulting in zero cardiac output. This is a medical emergency requiring immediate defibrillation and high-quality CPR. The lack of coordinated depolarization means the heart cannot pump blood to the brain or vital organs, leading to biological death within minutes if left untreated.

Choice D rationale

This rhythm involves an early electrical impulse originating from an ectopic focus in the atria rather than the SA node. On an EKG, the P wave of the premature beat may have a different shape or be hidden in the preceding T wave. The QRS complex usually remains narrow because the impulse travels through the normal ventricular conduction system. While often benign, frequent occurrences can be a precursor to atrial fibrillation or supraventricular tachycardia.

Choice A rationale

This rhythm originates above the ventricles, typically from the atrioventricular node or atria, characterized by narrow QRS complexes and a regular rhythm. In the provided strip, the absence of discernible P waves and a grossly irregular ventricular response contradicts this diagnosis. Additionally, the rate calculation based on a six second strip requires counting R waves and multiplying by ten, which leads to a specific frequency not matching this option's tachycardia profile.

Choice B rationale

This rhythm involves a regular discharge from the sinoatrial node exceeding 100 beats per minute, usually displaying identifiable P waves before every narrow QRS complex. Normal sinus rhythm features regular R-R intervals, whereas the strip demonstrates significant irregularity. Tachycardia at 150 bpm is common in stress or fever, but the chaotic nature of the atrial activity and the irregular ventricular rate on the monitor strip point toward a more disorganized supraventricular arrhythmia rather than sinus.

Choice C rationale

This life threatening rhythm is defined by a wide QRS complex (>0.12 seconds) originating from ventricular ectopic foci, typically presenting as a regular, rapid rhythm. The strip shows narrow QRS complexes, which indicates that the electrical impulse is traveling through the normal conduction system rather than originating in the ventricles. A rate of 210 bpm is possible, but the narrow morphology and irregular spacing definitively rule out a primary ventricular origin for this rhythm.

Choice D rationale

This condition is characterized by disorganized atrial electrical activity resulting in no distinct P waves and an irregularly irregular ventricular rhythm. Rapid ventricular response occurs when the atrioventricular node allows numerous impulses to pass, exceeding 100 bpm. By counting the R waves in a six second strip and multiplying by ten, a rate of 210 bpm is confirmed. The baseline shows fibrillatory waves, and the R-R intervals are inconsistent, making this the most accurate clinical diagnosis.