EKG Interpretation: Hypertrophy and Enlargement of the Heart

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

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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

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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

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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

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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

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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

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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 gt 35 mm
• R in V5 or V6 gt 26 mm (Memorize)
• R in aVL gt 11 mm
• R in I plus S in III gt 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

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Right Ventricular Hypertrophy (RVH)

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

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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

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Questions?