EKG certification Certification EKG Certification Interpretation 1 — Questions and Answers
Question 1: A rhythm strip shows a PR interval that progressively lengthens with each beat until a QRS complex is dropped, after which the cycle repeats. Which type of heart block does this represent?
- First-degree AV block
- Mobitz Type I (Wenckebach) second-degree AV block (Correct answer)
- Mobitz Type II second-degree AV block
- Complete (third-degree) AV block
Correct answer: Mobitz Type I (Wenckebach) second-degree AV block
Progressive PR prolongation followed by a non-conducted P wave (dropped QRS) that then resets is the hallmark of Mobitz Type I (Wenckebach) block. Mobitz Type II has a constant PR interval before sudden dropped beats, and third-degree block shows AV dissociation.
Question 2: An EKG shows a wide QRS complex tachycardia at 180 bpm with AV dissociation and fusion beats. What is the most likely diagnosis?
- Supraventricular tachycardia with aberrant conduction
- Atrial flutter with 2:1 block
- Ventricular tachycardia (Correct answer)
- Wolff-Parkinson-White syndrome
Correct answer: Ventricular tachycardia
AV dissociation (P waves unrelated to QRS complexes) and fusion beats (a blend of sinus and ventricular beats) are strong indicators of ventricular tachycardia. These findings help differentiate VT from SVT with aberrancy.
Question 3: A patient's EKG reveals ST elevation in leads II, III, and aVF with reciprocal ST depression in leads I and aVL. Which coronary artery is most likely involved?
- Left anterior descending artery
- Left circumflex artery
- Right coronary artery (Correct answer)
- Left main coronary artery
Correct answer: Right coronary artery
ST elevation in the inferior leads (II, III, aVF) with reciprocal changes in I and aVL indicates an inferior STEMI, which is most commonly caused by occlusion of the right coronary artery (RCA), as it supplies the inferior wall in most patients.
Question 4: An EKG shows a short PR interval of 0.10 seconds and a slurred upstroke at the beginning of the QRS complex (delta wave). Which condition does this pattern indicate?
- Brugada syndrome
- Long QT syndrome
- Wolff-Parkinson-White (WPW) syndrome (Correct answer)
- Left bundle branch block
Correct answer: Wolff-Parkinson-White (WPW) syndrome
A short PR interval combined with a delta wave (slurred initial QRS deflection) indicates pre-excitation via an accessory pathway, which is the defining EKG pattern of Wolff-Parkinson-White syndrome. This pathway bypasses the AV node, causing early ventricular activation.
Question 5: Which EKG finding is most consistent with a right bundle branch block (RBBB)?
- Broad, notched R wave in leads V5 and V6 with lateral ST depression
- RSR' ('rabbit ears') pattern in V1 and a wide S wave in leads I and V6 (Correct answer)
- Tall R wave in V1 with ST depression and T-wave inversion
- Diffuse ST elevation in a saddle-shaped pattern across multiple leads
Correct answer: RSR' ('rabbit ears') pattern in V1 and a wide S wave in leads I and V6
RBBB is characterized by an RSR' (M-shaped or 'rabbit ears') pattern in the right precordial lead V1, along with a wide, slurred S wave in the lateral leads (I, V5, V6). This reflects delayed right ventricular depolarization due to blocked conduction through the right bundle.
Question 6: A patient on digoxin therapy has an EKG showing a downsloping ST depression described as 'scooped' or 'Salvador Dali moustache' morphology. What does this finding represent?
- Acute anterolateral STEMI
- Digoxin effect (digitalis effect) (Correct answer)
- Hypokalemia-induced T-wave changes
- Third-degree AV block
Correct answer: Digoxin effect (digitalis effect)
The characteristic downsloping, scooped ST-segment depression — often compared to a Salvador Dali moustache — is a classic EKG manifestation of digoxin effect (not toxicity). It reflects altered ventricular repolarization caused by the drug's action and does not necessarily indicate toxicity or ischemia.
EKG certification Certification EKG Certification Interpretation 1
A rhythm strip shows a PR interval that progressively lengthens with each beat until a QRS complex is dropped, after which the cycle repeats.
Which type of heart block does this represent?