Hypertrophy of Atria and Ventricles - lecture

Question 1

Atrial enlargement

Answer 1

– Chamber enlargement occurs because of either an:
• Increase in volume of blood in the chamber or
• Increase in resistance to blood flow out of chamber
• Volume overload or diastolic overload – dilation
• Pressure overload or systolic overload – causes hypertrophy
• Good leads I, II, III, V1
• RA activated first
• LA activated later

Question 2

ECG basics of atria

Answer 2

– P wave depolarization of atria

– Rounded contour (not pointed, tall, peaked) (not notched, wide, “M shaped”

– Not exceed 3 mm

– Increased amplitude – hypertrophy, hypertension, AV valve disease, cor pulmonale, congenital
• RAE – tall, pointed; taller in III than in I – P ‐ pulmonale
• LAE – wide, notched; taller in I than in III – P – mitrale
– 2nd half of P wave negative in V1 or III

Question 3

Right atrial enlargement disease associations

Answer 3

– Associated with TV disease or pul hypertension

– COPD, PE, MS or MR are causes of pul hypertension

Question 4

Right atrial enlargement EKG changes

Answer 4

– P – pulmonale peaked P wave with amplitude greater than .25 (2.5 mm) mv in leads II, III AVF and greater than .1 mv in leads V1, V2
– P wave has a slight rightward axis

Question 5

Left atrial enlargement EKG changes

Answer 5

o Wide, notched “M” shaped P waves, taller in I than in III
o P-mitrale, AV disease
o Second half of P wave negative in V1 or III
• >1 mm deep and 0.04 sec wide with slight axis of P wave
o Causes: MS, MR

Question 6

Ventricular hypertrophy

Answer 6

o Dilate – excess preload
o Hypertrophy – increased resistance during systole
o EKG unable to distinguish between enlargement or hypertrophy; need echo
• Specificity Low – 40-50%; Specificity high – 90%

Question 7

Causes and EKG pattern for left ventricular hypertrophy

Answer 7

– Most common cause is hypertension. AS, AI, hypertrophic cardiomyopathy and coarction of aorta
– Wall of the LV is thicker so impulse will take longer to traverse it and arrive at epicardial surface
– Voltage and interval of QRS complex will increase, producing deeper S waves over RV and taller R waves over LV

ECG pattern of LVH fails to distinguish between concentric hypertrophy and dilated chamber; need echo

Question 8

Sokolow lyon criteria

Answer 8

R in I + S in III > 25 mm
R in AVL > 11 mm
R in V6 >26mm

Question 9

Right ventricular hypertrophy

Answer 9

– Causes include chronic lung disease – COPD
– RVOT obstruction, VSD
– Congenital – Tetralogy of Fallot, pulmonic stenosis,
transposition of great vessels
– Mitral stenosis, tricuspid regurgitation

• R waves assume prominence in right precordial leads and deep S waves develop in left precordial leads
• R:S ratio greater than 1

Question 10

Clues to RVH

Answer 10

• RAD + 90◦ OR MORE
• R in V1 7 mm or more
• R in V1 + S in V6 10 mm or more
• R/S ratio in V1 >1 or more
• S/R ratio in V6 >1 or more
• Late intrinsicoid deflection in V1 (.03 or more)
• Incomplete RBBB
• ST‐T strain pattern in II, III, AVF
• P pulmonale
• S1 S2 S3 pattern (children)

Question 11

Causes of dominant R waves in V1

Answer 11

• RVH
• Posterior or lateral MI
• WPW
• Hypertrophic cardiomyopathy
• Muscular dystrophy
• Normal variant

Question 12

Junctional Rhythm

Answer 12

o Inverted P waves before QRS complex in I, II, III
• Low in atria
o P wave is upright in AVR

Question 13

Strain pattern with LVH

Answer 13

• Leads I, AVL, V6 – QRS blends down into T wave, almost looks like BBB
• Causes: HTN, aortic stenosis, aortic insufficiency, cardiomyopathy with outflow track obstruction