CIRCOLAZIONE CORONARICA
Struttura dei vasi coronarici: arterie, capillari e
vene.
Regolazione prevalentemente metabolica del
flusso.
Fattori fisici: pressione arteriosa e compressione extravasale: forma caratteristica del flusso
coronarico (a sinistra): effetto delle variazioni
di frequenza. Principale meccanismo: liberazione
di adenosina.
Effetto della stimolazione simpatica. Riserva
coronarica. Stenosi e spasmi.
Pressione aortica
Flusso aortico
Pressione ventricolare
Flusso circonflessa
120
90
10
30
0
5
l/ min
60
0
100
0
ml/ min
50
Figure 17. Coronary blood flow and hemodynamic responses to treadmill exercise
in dogs. Modified from Khouri et al. (672). L. Circ. = left circumflex coronary artery;
Cor. = coronary; Syst. = systolic; Diast. = diastolic. See text for further explanation.
Modified from (295) with permission of the American Physiological Society.
Figure 19. Graph showing a schematic drawing of the intramyocardial microvasculature
(upper panel) and the extravascular forces acting on the coronary microvasculature
during diastole (left lower panel) and systole (lower right panel). Abbreviations: PIM =
intramyocardial pressure; PLUMEN = pressure in left ventricular lumen; PPERI = pressure in
pericardial space; PPERI = pressure in pericardial space; Left ventricular lumen pressure.
See text for further explanation. Modified from (295) with permission of the American
Physiological Society.
Figure 22. Relation beween
myocardial oxygen consumption
(MVO2) and coronary venous
oxygen tension (CVPO2) in the
right ventricle (RV) and the left
ventricle (LV) in dogs during
treadmill exercise. Note the
lower levels of MVO2 and higher
levels of CVPO2 in the RV
compared to the LV. Data are
from Hart et al. (496) for RV data
and from Gorman et al. (431) for
LV data. Data have been
presented as mean ± SE. See
text for further explanation.
Modified from (295) with
permission of the American
Physiological Society.
Figure 26. Graph summarizing the structural and functional
coronary microcirculatory adaptations to chronic exercise
training. ACh = acetylcholine; M = muscarinic receptor; NE =
norepinephrine; α1 = α1‐adrenergic receptor. β2 =
β2‐adrenergic receptor. Modified from (295) with permission
of the American Physiological Society.
CONSUMO
DI
O2
E
LAVORO
CARDIACO: diverso effetto del lavoro di
pressione e di volume. Maggiore rendimento per lavoro di volume. Non è possibile
aumentare l'estrazione dell'O2 ne' contrarre debito di O2 per cui aumentate esigenze metaboliche sono possibili solo in
funzione dell'aumento del flusso coronarico.
Il cuore produce lavoro:
gettata sistolica*pressione media in sistole=
lavoro/sistole
gettata cardiaca*pressione aortica media=
lavoro minuto cardiaco=
potenza
Rendimento (efficienza)=
lavoro prodotto/energia consumata
gettata cardiaca*pressione aortica media /consumo O2
Esempio (pressione in mmHg, gettata in l/min,
cons. O2 in unità arbitrarie):
pressione=100, gettata=5
potenza=500, cons. O2=10
pressione=100,
pressione=200,gettata=10
gettata=5
potenza=1000,
potenza=1000, cons.
cons. O
O22== 15
25
Generare pressione è energeticamente costoso:
l’aumento di pressione diminuisce il rendimento
http://www.youtube.com/watch?v=tBQa8IBzP6I
From: Coronary Flow Reserve and Pharmacologic Stress Perfusion Imaging: Beginnings and Evolution
J Am Coll Cardiol Img. 2009;2(5):664-669. doi:10.1016/j.jcmg.2008.12.024
Figure Legend:
Coronary Flow at Resting Baseline and at Maximum After Pharmacologic Stress With Timing of Radionuclides for Perfusion Imaging
Adapted with permission from Gould et al. (1).
Date of download:
3/5/2014
Copyright © The American College of Cardiology.
All rights reserved.
From: Coronary Flow Reserve and Pharmacologic Stress Perfusion Imaging: Beginnings and Evolution
J Am Coll Cardiol Img. 2009;2(5):664-669. doi:10.1016/j.jcmg.2008.12.024
Figure Legend:
Coronary Arteriogram and Arterial Diameter at Resting Baseline Conditions and at Maximum Flow in a Chronically Instrumented Animal Model
The radiopaque sphere is a steel ball bearing 3.18 mm in diameter implanted next to the coronary artery at surgery as a size reference. Flowmeter
wires and an external additional reference bar are also seen. Black arrows indicate resting baseline conditions; white arrows indicate maximum flow.
Adapted with permission from Gould et al. (15).
Date of download:
3/5/2014
Copyright © The American College of Cardiology.
All rights reserved.
Normal LV angiogram (top middle and right panels) in a patient with proximal left anterior
descending coronary artery occlusion (LAD; black arrow; top left panel).
Traupe T et al. Circulation. 2010;122:1210-1220
Copyright © American Heart Association, Inc. All rights reserved.
Figure 1. Left anterior oblique view of the right coronary arteriogram.
Koerselman J et al. Circulation. 2003;107:2507-2511
Copyright © American Heart Association, Inc. All rights reserved.