ECG Interpretation & Analysis Flashcards

Which ECG pattern represents a right ventricular MI and requires specialized lead placement to detect?

Answer: ST elevation in right-sided leads V3R-V4R

Right ventricular MI is detected using right-sided precordial leads (V3R, V4R), where ST elevation ≥1 mm is diagnostic.

The J point on an ECG is defined as:

Answer: The junction between the end of the QRS and the beginning of the ST segment

The J point marks the exact junction where the QRS complex ends and the ST segment begins, used as the reference for measuring ST changes.

A patient with syncope has ECG showing a QTc of 520 ms. Which inherited channelopathy is most likely?

Answer: Congenital long QT syndrome

A QTc ≥500 ms is markedly prolonged and strongly suggests congenital long QT syndrome (LQTS), which predisposes to torsades de pointes and syncope.

In a patient with left bundle branch block (LBBB), which of the following complicates STEMI diagnosis?

Answer: LBBB produces ST changes that mimic or obscure STEMI

LBBB alters ST segments and T waves as a secondary repolarization abnormality, which can mask or mimic ischemic ST changes, complicating STEMI diagnosis.

Which arrhythmia is characterized by three or more consecutive PVCs at a rate >100 bpm?

Answer: Ventricular tachycardia

Ventricular tachycardia (VT) is defined as three or more consecutive ventricular beats at a rate exceeding 100 bpm with wide QRS complexes.

What does the PR segment (not the PR interval) represent on an ECG?

Answer: AV nodal and His-Purkinje conduction delay

The PR segment (from end of P wave to start of QRS) represents the conduction delay through the AV node and His-Purkinje system, appearing as an isoelectric line.

Ashman's phenomenon refers to aberrant conduction that occurs when:

Answer: A PVC follows a long RR interval followed by a short RR interval

Ashman's phenomenon occurs when a short RR cycle follows a long RR cycle, causing aberrant conduction because the bundle branches have unequal refractory periods.