EKG Interpretation: Hypertrophy and Enlargement of the Heart

1. 0 EKG Interpretation: Hypertrophy and Enlargement of the Heart Mustafa Salehmohamed, DO Assistant Clinical Instructor, Department of Medicine N.Y. College of Osteopathic Medicine of NYIT October 21, 2005

2. Lecture Goals and Objectives • Understand how to recognize and analyze, using criteria or typical findings, enlargement of the heart on an EKG • Be able to recognize the EKG patterns associated with atrial and ventricular hypertrophy • Be aware of important pearls in the EKG analysis of hypertrophy • Relax, proceed slowly and methodically

3. Introduction • Myocardial hypertrophy means an increase in the thickness (muscle mass) of the walls of the atria or ventricles • Dilatation, or enlargement,is an increase in the internal diameter of the atria or ventricles • EKG manifestations of hypertrophy and dilatation may be similar • R Ventricle lies anterior to L Ventricle • L Ventricle is 3-4X mass of R Ventricle and depolarization of LV produces the majority of the QRS deflection

4. Introduction • Hypertrophy is caused by a pressure overload, in which the heart is forced to pump blood against an increased resistance • Dilatation/Enlargement is typically caused by a volume overload, as in certain valvular diseases • Nomenclature • Atrial Enlargement (aka Atrial Abnormalities) • Ventricular Hypertrophy

5. Left Atrial Enlargement • EKG Findings • Broad, notched, P wave (greater than 0.10 sec in duration) in Leads I, II, aVL • Large terminal negative P wave deflection (greater than 0.04 sec) in V1, representing depolarization forces traveling posteriorly in larger L atrium • Also known as “P mitrale” because of the mitral valve diseases (mitral stenosis, mitral regurgitation) associated with it

6. Right Atrial Enlargement • EKG Findings • Tall, peaked P wave (greater than 2.5 mm in height in Leads II, III, aVF • Large initial positive P wave deflection in Lead V1 • Duration of P wave usually normal (less than 0.10 sec) • Also known in literature as “P pulmonale” or “P congenitale” because of the pulmonary or congenital heart conditions, respectively, that are associated with this entity

7. Left Ventricular Hypertrophy (LVH) • EKG Criteria (Know This!) • Increased voltage of QRS complexes (most important criteria) • R in V5 or V6 plus S in V1 > 35 mm • R in V5 or V6 > 26 mm (Memorize**) • R in aVL > 11 mm • R in I plus S in III > 25 mm • Depressed ST segment and inverted T in Leads V5, V6 (and I, aVL) • Increased duration of QRS complex. Why? • Left Axis Deviation (LAD) • Estes/Estes-Romhilt Criteria

8. Right Ventricular Hypertrophy (RVH) • EKG Criteria (diagnosis can be difficult,) • Right Axis Deviation (RAD) – Memorize** • Increased QRS complex voltage • R/S ratio in V1 > 1, or • R in V1 plus S in V5 orV6 = or > 10.5 mm, or • R in V1 > 7 mm, or • R in aVR > 5 mm, or • S in V1 < 2 mm, or • Prominent S in V5, V6 • Repolarization changes (ST-T) in V1, V2 • Mild increase in QRS duration • Small Q in V1

9. Hypertrophy EKG Pearls • For the advanced student: • Q waves in V1, V2, and V3 may be seen in LVH and may be mistaken for an old anterior myocardial infarction • RVH may be masked by complete RBBB • In RVH, chest leads show a reversal of usual QRS chest pattern with tall R in V1, V2 and deep S in V5, V6

10. Questions?