What best describes a premature atrial contraction (PAC)?

What best describes a premature atrial contraction (PAC)?

• A. Regular heart rhythm
• B. Irregular heart rhythm occurring early
• C. Normal conduction of impulses
• D. Rate over 250 bpm

Answer: (B)

A premature atrial contraction (PAC) is best described as an irregular heart rhythm that occurs when an electrical impulse starts in the atria earlier than the next expected heartbeat. This early impulse results in an irregularity, as it disrupts the normal heart rhythm and can lead to a brief pause followed by a compensatory beat. The irregularity caused by a PAC is noticeable on an electrocardiogram (ECG) as there is a premature P wave that occurs before the normal heart rhythm would dictate. The other choices do not accurately describe PACs. A regular heart rhythm would imply a consistent, predictable heartbeat without interruptions, which does not apply in this case. Normal conduction of impulses refers to the typical flow of electrical signals in the heart, which is not the case with PACs, as they arise from ectopic activity in the atria. Lastly, a heart rate over 250 bpm is indicative of other arrhythmias, such as atrial flutter or fibrillation, rather than a PAC, which usually occurs in a normal or slightly elevated heart rate context.

A premature atrial contraction (PAC) is best described as an irregular heart rhythm that occurs when an electrical impulse starts in the atria earlier than the next expected heartbeat. This early impulse results in an irregularity, as it disrupts the normal heart rhythm and can lead to a brief pause followed by a compensatory beat. The irregularity caused by a PAC is noticeable on an electrocardiogram (ECG) as there is a premature P wave that occurs before the normal heart rhythm would dictate.

The other choices do not accurately describe PACs. A regular heart rhythm would imply a consistent, predictable heartbeat without interruptions, which does not apply in this case. Normal conduction of impulses refers to the typical flow of electrical signals in the heart, which is not the case with PACs, as they arise from ectopic activity in the atria. Lastly, a heart rate over 250 bpm is indicative of other arrhythmias, such as atrial flutter or fibrillation, rather than a PAC, which usually occurs in a normal or slightly elevated heart rate context.