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What percent of EDV does atrial systole account for?
20%-30%
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What are the three factors that affect contractility?
- ANS
- Hormones (catecholamines)
- Calcium
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what are two methods of increaseing RV pressure and SV?
- negative intrathoracic pressure
- increase Central Venous Pressure
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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
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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
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What are the three reasons for S2 widening split?
- pulmonary stenosis
- RV failure
- Right branch block/failure
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What is the reason for S2 narrowing or disappearing?
Left branch block/failure
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What causes a paradoxical split and what does paradoxical split mean?
- Aortic stenosis
- ***Pulmonary valve closes before Aortic valve
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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
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In the cardiac cycle, how does mitral valve stenosis affect the graph?
- LAP greater than LVP during filling times
- diastolic murmur
- ***Pulmonary congestion
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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
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In the cardiac cycle, how does mitral regurgitation affect the graph?
- holosystolic murmur
- LAP increases upon Ventricular systole
- **venous congestion
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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
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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
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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
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How does the SNS affect contractility?
Release of NE causes positive inotropic effect = increased SV at given EDV
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What happens to SV as contraction increases?
- The SV increases so there is less ESV
- Ejection fraction increases as well
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What is Treppe modulation?
As HR increases, calcium is trapped and used for higher contractility
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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
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What increases during exercise, pressure or volume?
Volume b/c pressure is too costly
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What are the exogenous fuels for the heart?
- Glucose
- lactate
- fatty acids
- ketone bodies
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What are the endogenous fuels for the heart?
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What is the percentage of fuel provided by carbs and fatty acids?
- Carbs= 30%
- Fatty Acids = 70%
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What are the four sources of glucose metabolism?
- Glycolysis
- glucose oxidation
- lactate oxidation
- glycogen stores
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What are the four sources of FA metabolism?
- Triglyceride lipolysis
- Beta-oxidation of FA
- chylomicrons oxidation
- ketone body oxidation
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During fasting, what are the three things caused by low insulin?
- lipolysis
- FFA circulation
- FFA uptake
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During fed state, what are the three things caused by high insulin?
- lipolysis inhibition
- glucose uptake
- glucose use
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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
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What is the result of inhibiting glucose oxidation?
LV failure
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Why is diabetes dangerous for the heart?
No insulin or IR = all FA use for heart and no glucose use = LV failure
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What happens to FFA circulation during and after surgery?
Increased and used in heart
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What is the function of Ranolazine and trimetazidine?
inhibit B-oxidation
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What is the function of etomoxir and oxfenicine?
inhibit CPT shuttle into mito
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What is the function of extra carnitine derivatives?
buffer Acetyl-CoA
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What is the function of dichloroacetate?
stimulate PDH
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What wave determines Snus Rhythm?
- P-wave
- **Depressed in V1, V2
- **Positive in all others
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