Atrial Abnormalities

• P > 2.5 mm in II, III, and/or aVF
• P may be > 1.5 mm in V1 and/or V2
• when right atrium enlarges, right atrial vector increases in voltage
• P waves tall in inferior leads
• duration of right atrial depolarization may increase
• less frequently, pos. component of P wave in V1 and/or V2 is tall

• vector: a carrier; a quantity with direction
• right atrial vector: what carries the electrical pulse from the right atrium to the next chamber of the heart

• P > 0.12 secs (or 3 mm)
• P is often notched in I, II, V5, and V6
• neg. deflection of P in V1 > 1 mm x 1 mm (-0.04 mV/sec)
• when left atrium enlarges, its activation time is prolonged
• P wave becomes wider and often notched in I, II, and left chest leads (P mitrale)
• LAE best detected by observing neg. component of P wave in V1

broad, notched P waves in several or many leads of the ECG w/ a prominent late neg. component to the P wave in lead V1, presumed to be characteristic of mitral valvular (or valve) disease

• 2 types
• mitral valve regurgitation: the flaps (leaflets) of the mitral valve weaken, causing blood to leak backward into the left atrium of heart
• mitral valve stenosis: the mitral valve opening is narrowed

a membranous fold in a canal or passage that prevents backward flow of material passing through it

a fold in b/w the left atrium and the left ventricle of the heart that directs blood that has received O2 from the lungs to the aortic valve and the aorta

valve guarding the entrance to the aorta from the left ventricle

• the main blood vessel that leads away from the heart and the body's largest artery
• carries blood from the heart through the chest and abdomen, providing major branches to all of the organs in the body

• neg. P wave component in V1 > 1 mm x 1 mm 
• P wave duration is > 0.12 secs
• P waves > 2.5 mm in II, III, and aVF
• less frequently, P in V1 > 1.5 mm
• suspected when signs of left and right atrial enlargement coexist