Question

Based on the provided ECG description (Sinus Bradycardia with First Degree Heart Block), which of the following statements is correct?

A) The P wave is present, and there is a QRS complex after each P wave.

B) The QRS complex is absent, leading to an irregular rhythm.

C) The PR interval is shorter than usual, indicating a potential issue with atrial depolarization.

D) The heart rate is elevated, causing a narrow complex QRS pattern.

Answer 1

The P wave is present, and there is a QRS complex after each P wave. Thus the correct option is A.

Explanation:

Sinus bradycardia with first-degree heart block implies a slow heart rate (bradycardia) with a delay in the electrical signal between the atria and ventricles (first-degree heart block). In this scenario, the P wave signifies atrial depolarization, and despite the delay (reflected in the prolonged PR interval), there is a subsequent QRS complex after each P wave, indicating ventricular depolarization following atrial activation.

Sinus bradycardia involves a heart rate less than 60 beats per minute, and first-degree heart block is characterized by a prolonged PR interval (>0.20 seconds) but without a missed QRS complex. Therefore, option A is correct, as it specifies the presence of both P waves and subsequent QRS complexes.

The PR interval is measured from the beginning of the P wave to the beginning of the QRS complex. In this case, while the PR interval is extended due to the first-degree heart block, it does not result in a missing QRS complex. This condition typically doesn't significantly affect the QRS complex unless it progresses to more severe heart block types.

Understanding electrocardiogram (ECG) readings involves deciphering the sequence of electrical events in the heart. Sinus bradycardia suggests a slower-than-normal heart rate, while the first-degree heart block points to a delay in electrical conduction. Despite this delay, the QRS complex follows each P wave, indicating that while there's a delay, the electrical impulse eventually reaches the ventricles, resulting in a correctly timed QRS complex after each atrial depolarization.Thus the correct option is A.

Answer 2

Based on the provided ECG description (Sinus Bradycardia with First Degree Heart Block), the correct statement for Sinus Bradycardia with First Degree Heart Block is that there is a P wave followed by a QRS complex for each P wave, indicating a regular rhythm despite the prolonged PR interval. Option A.

Step-by-step explanation:

The correct statement for Sinus Bradycardia with First Degree Heart Block is the P wave is present, and there is a QRS complex after each P wave.

In First Degree Heart Block, there is a delay in the conduction between the atria and the ventricles, which can be recognized on the ECG as an abnormally long PR interval.

However, this does not typically affect the regularity of the rhythm, and therefore, every P wave is still usually followed by a QRS complex, just at a delayed interval.

In a First Degree Heart Block, the P waves are followed by the QRS complex, but the PR interval is longer than 200 ms.

Despite this, sinus rhythm is maintained where atrial activity (the P wave) is coordinated with ventricular activity (the QRS complex), unlike third-degree heart block where there is no correlation between the P wave and the QRS complex.

Option B is incorrect because it describes a situation you might find in atrial fibrillation or a higher degree of heart block.

Option C is incorrect because, in a first-degree heart block, the PR interval is longer than usual, not shorter.

Option D is irrelevant and incorrect as Sinus Bradycardia indicates a slow heart rate, not an elevated one.

Hence, the right answer is option A.