Dr. Usman's Cardiology Notes

PVC Localization on ECG: Lets start with this ECG Case: Premature ventricular contractions (PVCs) are common arrhythmias often seen on routine ECGs or Holter monitors. While isolated PVCs are frequently benign, identifying their site of origin can be clinically important—especially in patients with symptoms, frequent ectopy, or underlying structural heart disease. ECG morphology offers valuable clues to help localize the origin of these ectopic beats within the ventricles. Basic Principles: PVCs originate from a single focus in the ventricular myocardium. Because of this, the activation spreads outside the normal conduction system, creating wide and bizarre QRS complexes. The QRS morphology and axis during a PVC provide hints about where in the ventricles the beat originates. Key Clues to Localization: 1. Outflow Tract PVCs (RVOT/LVOT) Most common type in structurally normal hearts. LBBB pattern in V1 (dominant S wave). Inferior axis (positive QRS in II, III, aVF) — indicating superior...

 Atrioventricular Septal Defect AVSD on echocardiogram stands for Atrioventricular Septal Defect, also known as atrioventricular canal defect or endocardial cushion defect. It is a congenital (present at birth) heart defect that involves abnormal development of the central part of the heart where the atrial and ventricular septa meet and where the tricuspid and mitral valves form. --- 💡 Key Echocardiographic Features of AVSD: There are three main types of AVSD seen on echocardiogram: 1. Complete AVSD Single common AV valve (instead of separate mitral and tricuspid valves). Large defect in the atrial septum (ostium primum ASD). Large defect in the ventricular septum (inlet VSD). Commonly seen in Down syndrome. 2. Partial (or Incomplete) AVSD Ostium primum ASD present. No VSD. Two separate AV valves, but the mitral valve is cleft, causing mitral regurgitation. 3. Transitional (or Intermediate) AVSD Like partial AVSD but with a small VSD beneath the common valve. --- 🫀 On Echocardio...