Which rhythm represents a junctional escape rhythm, where the junctional pacemaker overtakes the normal pacemaker, often associated with AMI, open‑heart surgery, myocarditis, or digoxin toxicity, and is usually asymptomatic?

Which rhythm represents a junctional escape rhythm, where the junctional pacemaker overtakes the normal pacemaker, often associated with AMI, open‑heart surgery, myocarditis, or digoxin toxicity, and is usually asymptomatic?

• A. Accelerated Junctional Rhythm
• B. Junctional Escape Rhythm
• C. Premature Junctional Complex
• D. First Degree Heart Block

Answer: (B)

When the SA node slows or fails, the AV junction can take over as the heart’s pacemaker. This junctional escape rhythm typically runs at about 40–60 beats per minute and produces a narrow QRS because ventricular depolarization still follows the normal conduction pathway. P waves aren’t reliably seen before each QRS; they may be absent or inverted and sometimes appear after the QRS, reflecting the origin of the impulse at the AV junction rather than the atria. This pattern fits a junctional escape rhythm, and its associations—AMI, open‑heart surgery, myocarditis, and digoxin toxicity—help explain why the higher pacemaker has been subdued. Clinically, it’s often asymptomatic because the rate is enough to maintain perfusion without causing symptoms. By contrast, an accelerated junctional rhythm would have a faster rate (60–100 bpm) and isn’t characterized as an escape rhythm; a premature junctional complex is a single early beat; first-degree heart block shows a prolonged PR interval with otherwise regular conduction.

When the SA node slows or fails, the AV junction can take over as the heart’s pacemaker. This junctional escape rhythm typically runs at about 40–60 beats per minute and produces a narrow QRS because ventricular depolarization still follows the normal conduction pathway. P waves aren’t reliably seen before each QRS; they may be absent or inverted and sometimes appear after the QRS, reflecting the origin of the impulse at the AV junction rather than the atria. This pattern fits a junctional escape rhythm, and its associations—AMI, open‑heart surgery, myocarditis, and digoxin toxicity—help explain why the higher pacemaker has been subdued. Clinically, it’s often asymptomatic because the rate is enough to maintain perfusion without causing symptoms. By contrast, an accelerated junctional rhythm would have a faster rate (60–100 bpm) and isn’t characterized as an escape rhythm; a premature junctional complex is a single early beat; first-degree heart block shows a prolonged PR interval with otherwise regular conduction.