1. Vasodilation
2. Vasoconstriction
3. Equal at steady state
4. Frank-Starling Mechanism
   1. The stroke volume of the heart increases in response to an increase in the volume of blood filling the heart (the EDV)
5. Inotropy
   1. Positive Inotropy
   2. Negative Inotropy
6. Cardiac Cycle
   1. Atrial Contraction
      1. Atrium contracts and tops off volume in the ventricle with a small amount of blood
      2. P wave due to atrial contraction
      3. PR segment is electrically quiet as depolarization proceeds to AV node
      4. A fourth heart sound (S4) is abnormal and is associated with the end of atrial emptying after atrial contraction.
      5. It occurs with hypertrophic congestive heart failure, massive pulmonary embolism, tricuspid incompetence, or cor pulmonale.
      6. The "a" wave occurs when the atrium contracts, increasing atrial pressure (yellow).
   2. Isovolumetric Contraction
      1. Interval between closing of AV valves and opening of semilunar valves
      2. The QRS complex is due to ventricular depolarization, and it marks the beginning of ventricular systole.
      3. It is so large that it masks the underlying atrial repolarization signal.
      4. The first heart sound (S1, "lub") is due to the closing AV valves and associated blood turbulence.
      5. The AV valves close when the pressure in the ventricles (red) exceeds the pressure in the atria (yellow).
      6. As the ventricles contract isovolumetrically -- their volume does not change (white).
      7. The pressure inside increases, approaching the pressure in the aorta and pulmonary arteries (green).
   3. Ventricular Ejection (Rapid)
      1. Semilunar valaves open causing blood to flow rapidly out ventricles
      2. The ST segment represents the period when the ventricles are depolarized. It is isoelectric.
      3. The pressure in the ventricles (red) exceeds the pressure in the aorta and pulmonary arteries (green).
      4. The semilunar valves open, blood exits the ventricles, and the volume in the ventricles decreases rapidly (white).
      5. As more blood enters the arteries, pressure there builds until the flow of blood reaches a peak.
      6. The "c" wave of atrial pressure is not normally discernible in the jugular venous pulse.
   4. Ventricular Ejection (Reduced)
      1. Blood continues to leave the ventricle, but at slower rate
      2. The T wave is due to ventricular repolarization.
      3. The end of the T wave marks the end of ventricular systole electrically.
      4. Blood flow out of the ventricles decreases and ventricular volume decreases more slowly (white).
   5. Isovolumetric Relaxation
      1. Semilunar valves close and AV valves remain closed. Atria hove been filling with blood
      2. The second heart sound (S2, "dup") occurs when the semilunar (aortic and pulmonary) valves close.
      3. S2 is normally split because the aortic valve closes slightly earlier than the pulmonary valve.
      4. The atrium in diastole has been filling with blood on top of the closed AV valve, causing atrial pressure to rise gradually (yellow).
      5. The "v" wave is due to the back flow of blood after it hits the closed AV valve.
      6. The pressure in the ventricles (red) continues to drop.
      7. Ventricular volume (white) is at a minimum and is ready to be filled again with blood.
   6. Ventricular Filling (Rapid)
      1. Accumulated blood in atria flows rapidly into ventricles through open AV valves
      2. A third heart sound (S3) is usually abnormal and is due to rapid passive ventricular filling.
      3. It occurs in dilated congestive heart failure, severe hypertension, myocardial infarction, or mitral incompetence.
      4. Ventricular volume (white) increases rapidly as blood flows from the atria into the ventricles.
   7. Ventricular FIlling (Reduced)
      1. Blood flows from atria into the ventricle at a slower rate
      2. Ventricular volume (white) increases more slowly now.
      3. The ventricles continue to fill with blood until they are nearly full.
7. Hemodynamic Parameters
   1. Cardiac Output (CO)
      1. The amount of blood pumped by the ventricle in unit time (mL/min)
      2. CO = SV x HR
         1. Heart Rate (HR)
            1. The speed of the heartbeat measured by the number of contractions of the heart per unit of time (beats/min)
         2. Stroke Volume (SV)
            1. The volume of blood ejected by the right/left ventricle in a single contraction (mL/beat)
            2. SV = EDV – ESV
            3. End Diastolic Volume (EDV)
            4. The amount of blood in the ventricles just before systole.
            5. End Systolic Volume (ESV)
            6. The volume of blood in a ventricle at the end of contraction
      3. Preload
         1. The stretching of a single cardiac myocyte immediately prior to contraction.
         2. Preload = (LVEDP×LVEDR)/2h
         3. Venous Return
            1. Musculovenous Pump
            2. Respiratory Pump
            3. Decreased venous capacitance
            4. Vena cava compression
            5. Gravity
            6. Pumping action of the heart
      4. Afterload
         1. The pressure in the wall of the left ventricle during ejection.
      5. Contractility
         1. The intrinsic ability of the heart/myocardium to contract.
   2. Stroke Work (SW)
      1. The work performed by the left or right ventricle to eject the stroke volume into the aorta or pulmonary artery
   3. Ejection Fraction (EF)
      1. The fraction of end-diastolic volume that is ejected out of the ventricle during each contraction
      2. EF = SV/EDV
8. Anatomy