Atrial and Ventricular EnlargementChapter 6

Cardiac Enlargementdilation

stretched

congestive heart failure

hypertrophy

increase size of heart muscle fibers

aortic stenosis

Cardiac Enlargement

Increase amount of cardiac tissue

How would this affect amount of depolarization?

How could that affect an ECG?

Right Atrial Abnormality

Overload of the right atria

dilation

hypertrophy

Increase voltage of the P wave

Right Atrial Abnormality

Normal P wave amplitude is less than 2.5 mm and 0.12 seconds in width.

Abnormal P waves are typically taller than 2.5 mm but not longer the 0.12 sec.

Right Atrial Abnormality

Causes:

Pulmonary disease

Congenital heart disease

Right Atrial Abnormality

• Tall P waves in any of the following leads:

• II, III, aVF or sometimes V1.

Right Atrial Abnormality

P pulmonale

artial enlargement due to severe pulmonary disease

Atrial enlargement can occur in the absence of tall P waves.

Left Atrial AbnormalityLeft atria normally depolarizes after the right atria.

Left atrial enlargement should prolong the P wave greater than 0.12 sec.

P wave height may be normal or increased

Left Atrial Abnormality

CAD may produce wide P waves without left atrial enlargement.

Left Atrial Abnormality

• Leads I and/or II may show notched P waves

• (second hump due to delayed depolarization of the left atrium)

• (P mitrale: mitral valve disease)

• V1 may show a bi-phasic P wave

• negative part is > 0.4 sec. or 1 mm in depth

• (right atria is anterior to the left atria)

Left Atrial Abnormality

Causes:

Valvular heart disease

Hypertensive heart disease

Cardiomyopathies

CAD

Right Ventricular Hypertrophy

What do you think will happen to the ECG with ventricular hypertrophy?

V1? V1?

V6?V6?

FIG. 4-6

Normal QRS

Normal QRS

V1V6

Right Ventricular Hypertrophy

Consider right ventricular hypertrophy and V1

NORMAL HYPERTROPHY

Right Ventricular Hypertrophy

1.In V1, R wave is greater than the S wave

2.In V1, T wave inversion (reason unknown)

3.Right axis deviation

Right Ventricular Hypertrophy

Causes of RVH

congenital heart disease

atrial septal defects

others

Emphysema may mask signs of RVH

Left Ventricular HypertrophyWith LVH, the electrical balance is tipped even further to the left.

Predominate S waves in the right chest leads

Tall R waves in the left chest leads

Left Ventricular Hypertrophy

• If S wave in V1 + R wave in either V5 or V6 > 35 mm (not specific indicator).

• R wave > 11-13 mm in aVL

• ST segment changes

• Left axis deviation

• Left atrial abnormality

ST strain patterns

Left Ventricular HypertrophyCauses:

Hypertension

Aortic stenosis

Risks of LVH

congestive heart failure

arrhythmias

Left Ventricular Hypertrophy

High voltage can be seen in normal people, especially athletes

Hypertrophy in both ventricles the ECG will show more evidence of LVH