Cardio

9/20/99

Review the flow of blood through the heart

• Mitral valve—Left atrium will enlarge if it is stenosed (from left atrium to left ventricle)
• Chamber enlargement due to valvular stenosis
• Aortic stenosis is common for the older—
• Tricuspid valve is right atrium to right ventricle
• Pulmonary valve is right atrium to lungs
• Aortic valve is left atrium to system
• Aortic regurgitation—affects the left ventricle by enlarging b/c it has to work twice as hard to keep the blood out, heart rate will increase to compensate
• PR line is when the signal is in the AV node—allows the atrium to empty into the ventricles—AV delay—Vagus helps accomplish this
• P is atrial depolarization
• QRS is mainly the Left ventricle depolarizing (right ventricle to a small extent)
• T is repolarization of ventricles
• AV node is supraventricular
• Right bundle branch block—see both ventricles contracting on the EKG
• Left bundle branch block is always a disease (a problem)
• SA node has one innvervation of the Vagus (it can beat 60-70 bpm w/no innervation)
• Vagus is to slow the rate down of the SA node
• SA node is b2—E sensitive—increases the heart rate
• No sympathetic nerves to the SA node (it releases NE anyway)
• E gets to the SA node from general circulation
• E comes from the adrenal glands
• Sympathetics go to the wall of the atria, ventricle and the AV node
• NE enhances/increases the strength of the contraction—increase cardiac output
• Affects both atria and ventricles
• Has no affect on the heart rate
• P wave should never be taller than ½ of a large box
• Wall may be getting bigger
• May be a damaged SA node
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