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Journal of the Anatomical Society of India

Anatomy of Human Coronary Arterial Pulsation

Author(s): Kumar, Keshaw

Vol. 52, No. 1 (2003-01 - 2003-12)

Department of Anatomy, Institute of Medical Sciences, Banaras Hindu University, Varanasi. INDIA

Abstract

During autopsy, lumen circumference and wall thickness of both the coronary arteries were measured 1cm distal to their commencements in 300 human adults who had no history of suffering from any cardiovascular disease. Pulsatory power, pulse pressure and volume of blood entering the lumen of coronary arteries during each heart beat were calculated according to laws of arterial pulsation (Kumar, 1993).

Mean thickness of wall (Tunica media) in case of left coronary atery was 0.3mm while in case of right coronary artery it was 0.1mm showing the same ratio which was present not only between their pulsatory powers i.e. 600 Joule per heart beat in left coronary artery and 200 Joule per heart beat in right coronary artery but also between their pulse pressures of blood i.e. 60mm of Hg in left coronary artery and 20mm of Hg in right coronary artery. Mean circumference of lumen of left coronary artery was equal to that of right coronary artery i.e. 10mm which equals with the 10ml volume of blood entering the lumen of left coronary artery as well as right coronary artery during each heart beat.

Key words: Coronary artery, pulsatory power, blood volume, pulse pressure.

Introduction:

Diameter of coronary arteries was recorded by Baroldi and Scomazzoni (1967). Vogelberg (1957) considered that coronary diameters increase up to the age of thirtieth year. Wehn (1957) reported pulsatory activity of peripheral arteries. Kumar (1993) calculated pulsatory power of human arteries and put forth three laws to arterial pulsation. Kumar (1994) compared ventricular work of heart with the pulsatory power of great arterial trunks. Kumar (2002) observed the effect of tangential pressure of pulsation on tunica media of human arteries. Wright (1969) performed dissection study and mensuration of the human aortic arch. Greenfield and Patel (1962) noticed the relation between pressure and diameter in the ascending aorta in man. Remington (1963) studied the physiology of aorta and major arteries. Present study is conducted to describe anatomy of human coronary arterial pulsation which is not available in the literature as yet.

Material and Method:

During autopsy arterial segments of right coronary artery and left coronary artery were taken 1cm distal to their commencements to be preserved in 10% formalin in 300 human adults who had no history of suffering from any cardiovascular disease. Lumen circumference was measured in all the arterial segments by cutting their wall longitudinally. Paraffin sections of 10 micron thickness of all the arterial segments were stained with orcein to obtain 100 times magnified photomicrographs of all the stained sections. In all the photomicrographs thickness of tunica media was measured between external elastic lamina and internal elastic lamina. Mean of the lumen circumference and mean of the thickness of tunica media were calculated separately for left coronary artery and right coronary artery. Later on actual mean thickness of tunica media was obtained after dividing the mean thickness of tunica media of photomicrographs by 100 because photomicrographs were taken at 100 times magnification.

Pulsatory power, pulse pressure and volume of blood entering the lumen of coronary arteries during each heart beat were calculated according to following laws of arterial pulsation (Kumar 1993).

  1. Pulsatory power of an artery is equal to pulse pressure multiplied by volume of blood entering the lumen of that artery during each heart beat.
  2. Wall (Tunica media) thickness of an artery is directly proportional to pulsatory power of that artery having 1mm wall thickness and is reported as 2000 Joule per heart beat.
  3. Lumen circumference of an artery in millimetres equals with the volume of blood in millilitres entering the lumen of that artery during each heart beat.

Observations:

Mean thickness of tunica media in 100 times magnified photomicrograph of left coronary artery was 30mm (Fig-1) while the mean thickness of tunica media in 100 times magnified photomicrograph of right roronary artery was 10mm (Fig-2) Therefore after dividing above mentioned mean thickness by 100 the actual mean thickness of tunica media in case of left coronary artery was obtained 0.3mm while in case of right coronary artery it was obtained 0.1mm (Table-1) showing the same ratio of 3 : 1 which was present not only between their pulsatory powers i.e. 600 Joule per heart beat in left coronary artery and 200 Joule per heart beat in right coronary artery (Table-1 & 2) but also between their pulse pressures of blood i.e. 60mm of Hg in left coronary artery and 20mm of Hg in right coronary artery (Table-2)

Table-1: Proportion between pulsatory power and tunica media thickness of coronary arteries.

Arteries Mean thickness of
tunica media
Pulsatory power (Joules/Heart Beat)
Left coronary artery 0.3 mm 600
Right coronary artery 0.1mm 200

Table-2: Pulse pressure, Pulsatory power and volume of blood entering the lumen of coronary arteries during each heart beat. (B.V)

Arteries Volume
of blood
entering
the lumen
during each
heart beat (B.V)
Pulse
pressure
of blood
Pulsatory
power
Left coronary artery 10ml. 60mm of Hg 10 x60 = 600 Joule per heart beat
Right Coronary artery 10ml. 20 mm of Hg 10 x 20 = 200 Joule per heart beat

The mean lumen circumference of lumen of left coronary artery was equal to that of right coronary artery i.e. 10mm which equals with the 10ml volume of blood entering the lumen of left coronary artery as well as right coronary artery during each heart beat (Table-3).

Table-3: Circumference of lumen and volume of blood entering the lumen of coronary arteries during each heart beat.

Arteries Mean
Circumference
of lumen
Volume of
blood
entering
the lumen
during
each heart
beat
Left Coronary artery 10ml 10ml
Right Cornoary artery 10ml 10ml

During systole of heart contraction of thrice more thicker left ventricular wall (myocardium) in comparison to right ventricular wall (myocardium) is responsible for thrice more pulse pressure of blood in left coronary artery in comparison to pulse pressure of blood in right coronary artery. Thrice more wall (tunica media) thickness of left coronary artery in comparison to wall (tunica media) thickness of right coronary artery is due to thrice more pulsatory power of left coronary artery in comparison of pulsatory power of right coronary artery.

Discussion:

Aorta is not a static organ, it is in fact a dynamic structure, its inherent distensibility being responsible, at least in part for the pulse wave pattern produced by left ventricular ejection (Remington, 1963). Furthermore, it has also been shown that changes in circumference and diameter may correlate quite closely with intra aortic pressure changes(Greenfield and Patel, 1962). Pulse pressure of blood varies considerably in the peripheral arteries (Wehn, 1957).

Baroldi and Scomazzoni (1967) gave means of 4mm and 3.2mm in case of coronary artery diameters at their origins, the left exceeds the right in about 60% of hearts, the right being larger in 17%, the vessels approximately equal in 23%. Vogelberg (1957) considered that coronary diameters increase up to the age of thirtieth year. In the present study the equal lumen circumference of left and right coronary arteries resembles with the findings of Baroldi and Scomazzoni (1967) where in case of 23% hearts diameters of both the coronary arteries were equal. In the present study finding of 10mm lumen circumference in case of both the coronary arteries 1cm distal to their commencements resembles with the 3.2mm diameter of coronary arteries at their orgin observed by Baroldi and Scomazzoni (1967).

Because 1mm thick tunica media has pulsatory power of 2000 Joule per heart beat (Kumar, 1993). Therefore 0.3mm thick tunica media of left coronary artery will have pulsatory power of 600 Joule per heart beat and 0.1mm thick tunica media of right coronary artery will have pulsatory power of 200 Joule per heart beat.

Because lumen circumference of an artery in millimetres equals with the volume of blood in millilitres entering the lumen of that artery during each heart beat (Kumar, 1993). Therefore 10mm lumen circumference of right as well as left coronary artery will be equal with the 10ml volume of blood entering the lumen of right as well as left coronary artery during each heart beat.

Because pulsatory power of an artery is equal to pulse pressure multiplied by volume of blood entering the lumen of that artery during each heart beat (Kumar, 1993) therefore after dividing the 600 Joule pulsatory power by 10ml volume of blood entering the lumen, the 60mm of Hg pulse pressure of blood in left coronary artery was obtained. Similarly after dividing 200 Joule pulsatory power by 10ml. volume of blood entering the lumen, the 20mm of Hg pulse pressure of blood in right coronary artery was obtained.

In the present study, ratio obtained between pulse pressures of blood in left and right coronary arteries was equal to the ratio between pulse pressures of blood in ascending aorta and pulmonary trunk i.e. 3:1 which resembles the ratio between pulse pressures of blood in left and right ventricles (Kumar 1993, 1994).

In the present study, the ratio obtained between the tunica media thickness of left and right coronary artery was equal to the ratio between tunica media thickness of ascending aorta and pulmonary trunk i.e. 3 : 1 which resembles the ratio between myocardial thickness of left and right ventricles (Kumar 1993, 1994).

In the present study, ratio between pulsatory powers of left and right coronary arteries was equal to the ratio between pulsatory powers of ascending aorta and pulmonary trunk i.e. 3:1 which resembles with the ratio between pulsatory powers of left and right ventricles (Kumar 1993, 1994).

In the present study, ratio between volume of blood entering the lumen of left and right coronary arteries during each heart beat was equal to the ratio between the volume of blood entering the lumen of ascending aorta and pulmonary trunk during each heart beat i.e. 1:1 which resembles with the ratio between volume of blood entering the lumen of left and right ventricles during diastole of heart. During each heart beat 10ml volume of blood enters the lumen of left as well as right coronary artery from ascending aorta and 60ml volume of blood is ejected by left ventricle into ascending aorta which equals with the 60ml volume of blood ejected by right ventricle into pulmonary trunk during systole of heart (Kumar 1993, 1994).

Therefore ratio of 3:1 is existing between the structures related to systemic circulation (Left ventricle, ascending aorta, left coronary artery) and the structures related to pulmonary circulation (Right ventricle, pulmonary turnks, right coronary artery) as far as their wall thickness, pulse pressure and pulsatory power are concerned but in case of volume of blood entering the lumen during each heart beat, this ratio is 1 : 1 between the structures related to systemic and pulmonary circulations. In an individual not suffering from any cardiovascular disease these above mentioned ratios (3 : 1 and 1 : 1) remain always constant and may be known as "Keshaw Constants". Any deviation/alteration in the "Keshaw Constants" in an individual is the indication of cardiovascular disease in that individual either in the form of left/right sided cardiac failure or in the form of cardiac coronary inefficiency.

Left coronary artery supplies left ventricle which is related to systemic circulation and right coronary artery supplies right ventricle which is related to pulmonary circulation therefore left coronary artery is forming the part of systemic circulation and right coronary artery is forming the part of pulmonary circulation. Coronary arteries are actually vasavasorum of arterial heart from which ventricles are developed.

References:

  1. Baroldi, G; Scomazzoni, G. (1967) : Coronary circulation in the normal and pathologic heart. Office of the surgeon General : Washington D.C.
  2. Greenfield, J.C., Jnr, & Patel, D.J. (1962) : Relation between pressure and diameter in the ascending aorta in man. Circulation. Research 10 : 778-781.
  3. Kumar, Keshaw (1993) Pulsatory power of human arteries. Vijnana Parishad Anusandhan Patrika. Vol. 36 (2) : 115- 120
  4. Kumar, Keshaw (1994): Ventricular work of heart and pulsatory power of great arterial trunks. Vijnana Parishad Anusandhan Patrika. Vol. 37 (3) : 205-208.
  5. Kumar, Keshaw (2002); Effect of tangential pressure of pulsation on tunica media of human arteries. Journal of Anatomical Society of India, Vol. 51 (1) :35 - 38.
  6. Remington, J.W. Hand Book of physiology In : Physiology of the aorta and major arteries. Section II Circulation Volume II, American Physiological Society, Washington, D. C.: pp 799835 (1963).
  7. Vogelberg, K. (1957): Diedichtung sweite der KOronarostein an normalen and hypertrophen herzen. Z Kreislanfforch. 46 : 101-115.
  8. When, P.S. (1957) : Pulsatory activity of peripheral arteries, Scandenavian Journal of Clinical Laboratory Investigation. 9. Suppl. 30, : 1.
  9. Wright, N.L. (1969) Dissection study and mensuration of the human aortic arch. Journal of Anatomy 104 : 377-385

Missing Image

Fig. 1 - T.S. of human left coronary artery 1cm distal to its commencement. (T.A. Tunica Adventitia; TM-Tunica Media; EEL-External elastic lamina; IEL-Internal elastic lamina) (orcein x 100)

Missing Image

T.S. of human right caronary artery 1cm distal to its commencement. (T.A. Tunica Adventitia; TM-Tunica Media; EEL-External elastic lamina; IEL-Internal elastic lamina) (orcein x 100)

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