Coronary Circulation Coronary Heart Disease
Assoc. Prof. MUDr. Markéta Bébarová, Ph.D.
Department of Physiology, Faculty of Medicine, Masaryk University
Coronary Circulation
• a. cor sinistra
• a. cor dextra
02 diffusion directly from the blood situated in the cardiac cavities
placing of coronary arteries and capillaries in the cardiac walls; consequences!
Epicardial coronary arteries
^-X
Cardiac muscle |
Subendocardial arterial plexus
Right coronary artery
Left coronary artery
Circumflex branch
Anterior
descending
branch
Septal branches
Marginal branch
Marginal branch
Posterior descending branch
Ganong's Review od Medical Physiology, 23rd edition
Guyton and Hall. Textbook of Medical Physiology, 11th edition
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Coronary Circulation
Coronary angiography
http://pochp.mp.pl/aktualnosci/show.html?id=55102
Coronary Circulation
TABLE 34-4 Pressure in aorta and left and right ventricles (vent) in systole and diastole.
	Pressure (mm Hg) in			Pressure Differential (mm Hg) between Aorta and	
	Aorta	Left Vent	Right Vent	Left Vent	Right Vent
Systole	120	121	25	-1	95
Diastole	80	0	0	80	80
intramural vessels
left vs. right ventricle high heart rate
120
QJ=E 100 a- £
0.4 0.6 Time (s)
1.0
Ganong's Review od Medical Physiology, 23rd edition
Coronary Circulation
02 extraction is almost maximal already at rest, capillaries are open
The only possibility how to increase 02 supply (for example during exercise) is the coronary vasodilation!
Coronary Circulation
Control of coronary blood flow
1) reduction/interruption of the blood flow or increased demands
hyperaemia (reactive or active) based on the metabolic vasodilation
Coronary Circulation
Control of coronary blood flow
2) the neural regulation of the vessel diameter-secondary impact
a) indirect effects w
Y  (mostly opposite)
b) direct effects ,x
Coronary Circulation
Control of coronary blood flow
2) the neural regulation of the vessel diameter-secondary impact
a) indirect effects
sympathetic system (NE, E)
t HR + contractility -»• rate of cardiac metabolism -»• increased 02 consumption ->■ activation of local vasodilating mechanisms
parasympathetic system (ACH)
opposite changes -> vasoconstriction
Coronary Circulation
Control of coronary blood flow
2) the neural regulation of the vessel diameter-secondary impact
a) indirect effects
b) direct effects vasospastic
sympathetic system (NE, E)   myocardial ischemia
epicardial vessels - mostly a-rec. ->• vasoconstriction intramural vessels - mostly |3-rec. ->• vasodilation
parasympathetic system (ACH)
vasodilation, but not significant (only few fibers) f\/|W
^r.
Coronary Circulation
Control of coronary blood flow
2) the neural regulation of the vessel diameter secondary impact
a) indirect effects
b) direct effects
Whenever the direct effects alter the coronary blood flow in the wrong direction the metabolic control overrides them
within seconds!
Coronary Reserve
• ability of coronary vessels to adapt blood flow to the actual cardiac work (ergometry)
• the maximal blood flow / the resting blood flow
• reduction of the coronary reserve:
- relative coronary insufficiency
- absolute coronary insufficiency (~ coronary heart disease)
Reduced coronary reserve is a limiting factor of the cardiac output, thus, also of the effort of organism!
Coronary Heart Disease
ischemic heart disease, coronary artery disease
the most often cardiac disease in Western culture about 1/3 of all deaths
vs. myocardial ischemia
Coronary Heart Disease
• pathogenesis: atherosclerotic process of one or more branches of the coronary circulation
Coronary Heart Disease
• symptoms:
- pain behind the sternum (angina pectoris)
- changes of ST segment and T wave on ECG ; character of the changes
Symptoms are usually provoked by physical exertion, cold, rapid increase of the blood pressure, etc.
Coronary Heart Disease
Myocardial infarction
= sudden closure of a coronary branch, usually by a thrombus originating on the strength of a rupture of the atherosclerotic plate, changes are irreversible
• symptoms:
- severe unremitting pain behind sternum heart failure (in the case of a bigger extent)
- on ECG: ST elevation followed by T wave without any decrease to the isoelectric line (the
Pardee's sign)
healing by a scar
(deep Q wave)
http://www.wikiskripta.eu/ index.php/Popis_EKG
Coronary Heart Disease
Myocardial infarction
Ganong's Review od Medical Physiology, 23rd edition
A. Physiological tracing in lead I
B. Myocardial infarction - acute phase - hours from infarction
C. Many hours till days from infarction.
D. Late pattern - many days till weeks from infarction.
E. Very late pattern - months till years from infarction.
Coronary Heart Disease
The degree of damage of the heart muscle is determined to a great extent by the degree of collateral circulation!
Guyton and Hall. Textbook of Medical Physiology, 11th edition
Vein
Coronary Heart Disease
• Treatment with drugs
- Vasodilator/ drugs
- Beta-blockers
Coronary Heart Disease
Surgical treatment
Coronary Angioplasty
obnovení normálního krevního pro Jdu
http://www.ikem.cz/www?docid= 1005912
Aortic-Coronary Bypass
Aorta
Bypass
(štěp z kryté ží
Closure of a coronary artery
http://www.sedmstatecnych.cz/clanek/opr avene-srdce-po-trech-letech/
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