Is third-degree heart block regular?

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Multiple Choice

Is third-degree heart block regular?

In complete heart block, there’s AV dissociation: all conduction from the atria to the ventricles is blocked, so the atria pace themselves and the ventricles pace themselves independently. The P waves come from the sinus node, while the QRS complexes come from an escape pacemaker below the block. Because there’s no fixed relationship between the atrial activity and the ventricular activity, you don’t get a single, unified rhythm with a constant pattern. The atrial rate and the ventricular rate are each regular on their own, but the overall tracing isn’t a single regular rhythm, since the two rhythms do not couple in a fixed way. That’s why third-degree heart block is described as AV dissociation and not as a regular rhythm.

In complete heart block, there’s AV dissociation: all conduction from the atria to the ventricles is blocked, so the atria pace themselves and the ventricles pace themselves independently. The P waves come from the sinus node, while the QRS complexes come from an escape pacemaker below the block. Because there’s no fixed relationship between the atrial activity and the ventricular activity, you don’t get a single, unified rhythm with a constant pattern. The atrial rate and the ventricular rate are each regular on their own, but the overall tracing isn’t a single regular rhythm, since the two rhythms do not couple in a fixed way. That’s why third-degree heart block is described as AV dissociation and not as a regular rhythm.

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