Assoc. Prof. MUDr. Markéta Bébarová, Ph.D.
Department of Physiology, Faculty of Medicine, Masaryk University
Coronary Circulation
Coronary Heart Disease
This presentation includes only the most
important terms and facts. Its content by
itself is not a sufficient source of
information required to pass the
Physiology exam.
Coronary Circulation
• a. cor. sinistra
• a. cor. dextra
Ganong´s Review od Medical
Physiology, 23rd edition
• placing of coronary arteries and
capillaries in the cardiac walls;
consequences!
• O2 diffusion directly from the blood
situated in the cardiac cavities
Guyton and Hall.
Textbook of Medical
Physiology, 11th edition
Coronary Circulation
http://pochp.mp.pl/aktualnosci/show.html?id=55102
Coronary angiography
Coronary Circulation
Ganong´s Review od Medical Physiology, 23rd edition
• intramural vessels
• left vs. right ventricle
• high heart rate
Coronary Circulation
• O2 extraction is almost maximal already at rest,
capillaries are open
• The only possibility how to increase O2 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
b) direct effects
(mostly opposite)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)
parasympathetic system (ACH)
↑ HR + contractility → rate of cardiac metabolism →
increased O2 consumption → activation of local
vasodilating mechanisms
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
sympathetic system (NE, E)
parasympathetic system (ACH)
epicardial vessels – mostly α-rec. → vasoconstriction
vasodilation, but not significant (only few fibers)
intramural vessels – mostly β-rec. → vasodilation
vasospastic
myocardial ischemia
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
• the most often cardiac disease in Western culture
• about 1/3 of all deaths
= ischemic heart disease, coronary artery disease
• vs. myocardial ischemia
• pathogenesis: atherosclerotic process of one or
more branches of the coronary circulation
Coronary Heart Disease
http://int2.lf1.cuni.cz/pruvodce-pro-pacienty-pred-katetrizacnim-vysetrenim-srdce
endothelial
cells
thrombocytes
inflammatory
cells
lipid core
smooth
muscle cells
thrombus
rupture of
thin fibrous
cover
http://www.thno.org/v03p0894.htm
Coronary Heart Disease
Symptoms are usually provoked by physical exertion,
cold, rapid increase of the blood pressure, etc.
• symptoms:
- pain behind the sternum (angina pectoris)
- changes of ST segment and T wave on ECG ;
character of the changes
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
• healing by a scar
(deep Q wave)
• 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) http://www.wikiskripta.eu/
index.php/Popis_EKG
Coronary Heart Disease
• Myocardial infarction
Ganong´s Review od Medical Physiology, 23rd edition
A B C D E
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.
Guyton and Hall.
Textbook of Medical
Physiology, 11th edition
Coronary Heart Disease
The degree of damage of the heart muscle is
determined to a great extent by the degree of
collateral circulation!
Coronary Heart Disease
• Treatment with drugs
- Vasodilatory drugs
- Beta-blockers
Coronary Heart Disease
• Surgical treatment
coronarography
Coronary Angioplasty
http://www.ikem.cz/www?docid=
1005912
Aortic-Coronary Bypass
http://www.sedmstatecnych.cz/clanek/opr
avene-srdce-po-trech-letech/
Closure of a
coronary artery