An irregular R-R interval with P waves present and a normal PR interval describes which rhythm?

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Multiple Choice

An irregular R-R interval with P waves present and a normal PR interval describes which rhythm?

Recognizing a benign breathing-related variation in heart rate. Sinus arrhythmia happens when the sinus node’s firing rate fluctuates with the respiratory cycle, so the intervals between beats are irregular even though the atrial rhythm stays organized. You can see P waves before each QRS complex, the PR interval remains within normal limits, and the QRS is narrow. This combination—irregular R-R intervals with present P waves and a normal PR interval—points to sinus arrhythmia, a normal variant usually more pronounced in younger people and during inspiration (rate speeds up) and slows with expiration. This differs from other rhythms: atrial fibrillation would have no discrete P waves and an irregularly irregular rhythm; atrial flutter shows characteristic flutter waves with a regular or variable ventricular response; multifocal atrial tachycardia has multiple different P-wave morphologies with a faster rate.

Recognizing a benign breathing-related variation in heart rate. Sinus arrhythmia happens when the sinus node’s firing rate fluctuates with the respiratory cycle, so the intervals between beats are irregular even though the atrial rhythm stays organized. You can see P waves before each QRS complex, the PR interval remains within normal limits, and the QRS is narrow. This combination—irregular R-R intervals with present P waves and a normal PR interval—points to sinus arrhythmia, a normal variant usually more pronounced in younger people and during inspiration (rate speeds up) and slows with expiration.

This differs from other rhythms: atrial fibrillation would have no discrete P waves and an irregularly irregular rhythm; atrial flutter shows characteristic flutter waves with a regular or variable ventricular response; multifocal atrial tachycardia has multiple different P-wave morphologies with a faster rate.

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