ACLS ACLS Cardiac Rhythms and ECG Interpretation 2

Question 1

A patient has third-degree (complete) heart block. Which ECG finding is characteristic?

Accepted Answer

P waves and QRS complexes with no relationship to each other (AV dissociation)

Answer

Complete heart block shows complete AV dissociation — P waves and QRS complexes fire independently at different rates with no consistent PR relationship.

Question 2

What ECG finding is associated with hyperkalemia that warrants immediate ACLS intervention?

Accepted Answer

Peaked (tall, narrow, tent-shaped) T waves

Answer

Hyperkalemia classically produces tall, peaked, tent-shaped T waves as an early ECG sign, which can progress to wide QRS, sine wave pattern, and cardiac arrest.

Question 3

In ACLS, which ECG finding is a classic sign of right ventricular strain in massive pulmonary embolism?

Accepted Answer

S1Q3T3 pattern (S wave in I, Q wave and T inversion in III)

Answer

The S1Q3T3 pattern (large S in lead I, Q wave and inverted T in lead III) is a classic ECG sign of acute right heart strain seen in massive pulmonary embolism.

Question 4

Asystole on ECG appears as what pattern?

Accepted Answer

A flat (isoelectric) line with no electrical activity

Answer

Asystole appears as a flat isoelectric line on ECG, confirming the absence of any organized cardiac electrical activity.

Question 5

Which ECG finding indicates Wolff-Parkinson-White (WPW) syndrome that is important in ACLS?

Accepted Answer

Short PR interval with a delta wave (slurred QRS upstroke)

Answer

WPW is identified by a short PR interval (<0.12 s) and a delta wave (slurred initial QRS deflection) caused by ventricular pre-excitation via an accessory pathway.

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ACLS ACLS Cardiac Rhythms and ECG Interpretation 2