What percent of EDV does atrial systole account for?
What are the three factors that affect contractility?
- Hormones (catecholamines)
what are two methods of increaseing RV pressure and SV?
- negative intrathoracic pressure
- increase Central Venous Pressure
What are the effects on FFA and glucose with and without insulin?
- W/O: lipolysis = FFA circulation and use in heart
- W/: no lipolysis = glucose use in heart
What are the goals of the 4 pharmacological methods to increase glucose oxidation? What are the drugs associated with each?
- 1) decrease B-oxidation: Ranolazine, trimetazidine
- 2) decrease FFA uptake: etomoxir, oxfenecine
- 3) decrease/block AcetylCoA from Mitochondria: Carnitine
- 4) Activate glucose metabolism: Dichloroacetate
What are the three reasons for S2 widening split?
- pulmonary stenosis
- RV failure
- Right branch block/failure
What is the reason for S2 narrowing or disappearing?
Left branch block/failure
What causes a paradoxical split and what does paradoxical split mean?
- Aortic stenosis
- ***Pulmonary valve closes before Aortic valve
In the cardiac cycle, how does aortic stenosis affect the graph?
- Cause LVP to rise and the Aortic pressure to slightly drop
- mid-Systolic murmur
- ***cardiac hypertrophy and paradoxical split
In the cardiac cycle, how does mitral valve stenosis affect the graph?
- LAP greater than LVP during filling times
- diastolic murmur
- ***Pulmonary congestion
In the cardiac cycle, how does aortic regurgitation affect the graph?
- rate of decline in aortic pressure is greater
- Slight increase in LV pressure, but countered by SV
- ***congestion and widening pulse pressure
In the cardiac cycle, how does mitral regurgitation affect the graph?
- holosystolic murmur
- LAP increases upon Ventricular systole
- **venous congestion
What are the 5 determinants of afterload on Cardiac performance? AMP VA
- Arterial pressure
- Mass of blood in aorta
- Peripheral vascular resistance
- Viscosity of blood
- Arterial wall complaince
How does the Frank Starling law compensate for Afterload?
- Even though ESV is high, the ventricle will still fill up normally to restore SV
- LVSW increases
What factors increase contractility of the heart? (heart ACHe
What happens to fiber length as EDV increases?
Fiber length is stretched so there is higher contractility
How does the SNS affect contractility?
Release of NE causes positive inotropic effect = increased SV at given EDV
What happens to SV as contraction increases?
- The SV increases so there is less ESV
- Ejection fraction increases as well
What is Treppe modulation?
As HR increases, calcium is trapped and used for higher contractility
What is the relationship b/t HR and CO?
- - HR up to 150 = no change in CO since HR and SV are inverse
- - HR > 150 = change in CO due to SNS to maintain or increase SV
What increases during exercise, pressure or volume?
Volume b/c pressure is too costly
What are the exogenous fuels for the heart?
- fatty acids
- ketone bodies
What are the endogenous fuels for the heart?
What is the percentage of fuel provided by carbs and fatty acids?
- Carbs= 30%
- Fatty Acids = 70%
What are the four sources of glucose metabolism?
- glucose oxidation
- lactate oxidation
- glycogen stores
What are the four sources of FA metabolism?
- Triglyceride lipolysis
- Beta-oxidation of FA
- chylomicrons oxidation
- ketone body oxidation
During fasting, what are the three things caused by low insulin?
- FFA circulation
- FFA uptake
During fed state, what are the three things caused by high insulin?
- lipolysis inhibition
- glucose uptake
- glucose use
Explain the Randle cycle of the heart?
- Increased FFA
- Enter the mitochondria via CPT
- oxidized to Acetyl-Co-A = PDH inhibition
- oxidized to Citrate = PFK
- PFK inhibition = HK inhibition by G6P = glucose stored
What is the result of inhibiting glucose oxidation?
Why is diabetes dangerous for the heart?
No insulin or IR = all FA use for heart and no glucose use = LV failure
What happens to FFA circulation during and after surgery?
Increased and used in heart
What is the function of Ranolazine and trimetazidine?
What is the function of etomoxir and oxfenicine?
inhibit CPT shuttle into mito
What is the function of extra carnitine derivatives?
What is the function of dichloroacetate?
What wave determines Snus Rhythm?
- **Depressed in V1, V2
- **Positive in all others