4 12-Lead ECG Interpretation Free Online FlashCards

What does a 12-lead ECG record?

It records the heart’s electrical activity from different directions; it does not provide 12 separate views of the heart.

What is a practical sequence for interpreting an ECG?

Rate and rhythm → axis → intervals and QRS morphology → chamber patterns → ST-T changes and localization.

What axis quadrant is suggested by positive QRS complexes in I and aVF?

Positive QRS complexes in both lead I and aVF place the axis in the normal quadrant.

What P-wave pattern suggests right atrial abnormality?

Right atrial abnormality commonly produces tall, peaked P waves, especially in the inferior leads.

What ECG pattern can suggest right ventricular hypertrophy?

Right-axis deviation, a relatively prominent R wave in V1, and deep S waves in lateral chest leads can suggest RVH; interpret the pattern in clinical context.

What morphology commonly identifies right bundle branch block?

RBBB commonly shows an rsR′/rSR′-type pattern in V1–V2 and a broad terminal S wave in leads I and V6.

Which leads form the inferior group, and what can ST elevation there suggest?

Inferior leads are II, III, and aVF. ST elevation in these contiguous leads points to an inferior injury pattern, though it does not prove a specific culprit artery.

What familiar voltage rule can support an ECG diagnosis of LVH?

One familiar voltage rule is an S wave in V1 plus an R wave in V5 or V6 of at least $35\,\text{mm}$; it is only one of several criteria.

What QRS duration generally meets the threshold for complete bundle branch block?

A complete bundle branch block generally has a QRS duration of at least $120\,\text{ms}$, along with characteristic morphology.

Can ECG criteria alone establish structural chamber enlargement?

ECG criteria alone do not establish structural chamber enlargement; echocardiography or other imaging is used to assess chamber structure.

How can the most isoelectric limb lead help estimate the QRS axis?

Find the most isoelectric limb lead; the QRS axis lies roughly perpendicular to it.

What ECG patterns can suggest left atrial abnormality?

A broad or notched P wave in lead II, or a prominent terminal negative P-wave portion in V1, can suggest left atrial abnormality.