EKG certification Certification EKG Certification Interpretation 1

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?

Accepted Answer

Mobitz Type I (Wenckebach) second-degree AV block

Answer

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?

Accepted Answer

Ventricular tachycardia

Answer

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?

Accepted Answer

Right coronary artery

Answer

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?

Accepted Answer

Wolff-Parkinson-White (WPW) syndrome

Answer

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)?

Accepted Answer

RSR' ('rabbit ears') pattern in V1 and a wide S wave in leads I and V6

Answer

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.

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EKG certification Certification EKG Certification Interpretation 1