PVC Morphology and Localization Lecture Notes

Comprehensive practice flashcards covering PVC morphology rules, axis interpretation, precordial transition, and site-specific ECG hallmarks based on lecture slides.

According to the general rules for PVC localization, what do RBBB and LBBB patterns indicate regarding the side of origin?

RBBB suggests the Left Ventricle (LV), while LBBB suggests the Right Ventricle (RV) or Interventricular Septum (IVS).

How does QRS width localize the Site of Origin (SOO)?

A narrow QRS indicates a Septal origin, while a wide QRS indicates a Free wall origin.

What does an inferior axis (positive Lead II/III) indicate about the anatomical location of the SOO?

It indicates the SOO is in the basal areas of the heart, the outflow tract, or the superior aspect of the MV/TV.

What does a superior axis (negative Lead II/III) indicate about the anatomical location of the SOO?

It indicates the SOO is in the inferior aspect of both ventricles.

In the context of inferior axis PVCs, what do positive and negative Lead I findings signify?

Positive Lead I signifies rightward structures (posterior RVOT, RCC, Parahisian, superior aspect of TV), while negative Lead I signifies leftward structures (anterior RVOT, LCC, AMC, AL-MA, LV summit).

Which structures are typically associated with a superior axis PVC showing an LBBB pattern?

Inferior TV, Moderator band, and Cardiac Crux.

Which structures are typically associated with a superior axis PVC showing an RBBB pattern?

Inferior MV, Posterior PM, and left posterior fascicle.

How is the 'precordial transition' defined?

The point in Leads V1-V6 where the QRS complex changes from predominately negative to predominately positive.

How does the precordial transition of LVOT PVCs compare to RVOT PVCs relative to the sinus transition?

LVOT PVCs typically have a transition at or earlier than the sinus transition, while RVOT PVCs typically have a transition later than the sinus transition.

What is the hallmark ECG feature of para-Hisian PVCs in Lead aVL?

An isoelectrical or 'w' pattern, along with a more positive R wave in lead I.

What is the signature ECG pattern in lead V1 for the aortomitral continuity (AMC)?

A signature $qR$ pattern.

Which specific aortic root location is associated with a notched V1 and a pseudo-delta wave?

LCC (Left Coronary Cusp).

What criteria are used to identify a Cardiac crux SOO?

LBBB, V2 transition, left superior axis, QS in inferior leads, and a pseudo-delta wave or MDI > $0.55$.

How does Lead I distinguish between different RVOT septal origins?

Lead I is negative for an anteroseptal (AS) origin and positive for a posteroseptal (PS) origin; midseptal (MS) is multiphasic.

What ECG morphology is shared by the LV summit and the Cardiac crux?

Pseudo-delta wave and/or MDI > $0.55$.

Between RVOT free wall and septal/posterior origins, which produces a later precordial transition?

The RVOT free wall, because it is more anterior.

For superior axis PVCs with an RBBB pattern, what distinguishes the Left Posterior Fascicle (LPF) from the Posterior PM (PPM)?

The LPF has an $rsR'$ pattern in V1 and a narrow QRS, whereas the PPM shows R, $Rsr'$, or $qR$ in V1.