The document provides information on the embryology, anatomy, physiology and pathology of the heart. Some key points include: 1. The heart develops from mesodermal tissue and the pericardial cavity develops from intraembryonic membranes. 2. Anatomically, the heart is located in the mediastinum, has four chambers, and is supplied by the coronary arteries. 3. Physiologically, the cardiac cycle involves rhythmic contractions and relaxations of the atria and ventricles. The heartbeat is regulated by the conduction system. 4. Abnormal heart sounds called murmurs can occur due to various cardiac defects or diseases. Cardiac output is determined by factors like pre

1. EMBROYOLOGY:-
1. heart is mesodermal in origin.
2. it is originated from splanchnopleuric mesoderm.
3.pericardial cavity is originated from intra embryonic
membtane.
4. Foramen ovale closes: LA pressure > RA pressure.

3. ANATOMY OF HEART
1. Heart is a hollow muscular organ.
2. It is middle mediastinal in thorax.
3. Its weight in male is 350gm and in female it is 250gm.
4. Its center is located about 1.5 cm to the left of the midsagittal plane.
5. It is between the 2nd and 6th ribs and posteriorly between 5th and 8th thoracic
vertebrae.
6. Its has 4 chambers right atrium , left atrium, right ventricle and left
ventricle.
7. Right part of heart receive deoxygenated blood and left part receive
oxygenated blood.
8. Each wall consist of 3 layer inner endocardium ,middle myocardium and
outer pericardium.
9. Heart has base( formed mainly by left atrium) and apex(formed by left
ventricle).

4. Contd.....
10. BORDERS :- right border RA, left border LV, inferior border RV , superior
border LA
11. SURFACES :- ant surfaces RV , infer surfaces LV , post surfaces LA , left
surfaces LV, right surface RA, SVC, and IVC.
12 VALVES :- I mitral valves a/k/a tricuspid valve or left AV valve
* normal area is 4-6 cm square.
* two cusps ant. And post.
ii tricuspid valve a/k/a rt. AV valve.
* normal area is 7-9 cm square ( largest ).
* three cusps Ant. ,Post. And septal cusps
iii aortic valve.
* normal area is 2.6-3.5 cm square.
* three cusps Rt. Cusps, Lt cusps, and post. Cusps.
iv pulmonic valve.
* normal area is 2 cm square/ m square BSA ( smallest ).
* three cusps Rt. Cusps, lt cusps and ant. Cusps.

5. Contd…..
13. Right ventricle is a triangular chamber and Left atrium is a
quadrangular chamber.
14. INTERNAL STRUCTURE :-
I SEPTAE :- Interatrial septum and Interventricle septum.
ii chordae tendinae :- connect cusps of AV valves to the apics of
papillary muscles. And prevent eversion of free margins.
iii palillary muscles :- total 5 in number 2 in LV and 3 in RV It keep AV
valves competent by active contraction thus prevent regurgitation of
blood back in to the atria.
15. Fibrous ring is present in AV valves while absent in semilunar valves.
16. Heart is conical in shape.
17. Groove and sulci :- I AV sulcus ( coronary sulcus )
ii Ant. I.V. sulcus
iii Post. I.V. sulcus
iv I.A. sulcus.

6. Contd…..
18. Pressurs changes during cardiac cycle
19. Heart is surrounded by pericardium.
20. Pericardium is divided into two layer a) serous layer b) fibrous layer.
21. The fibrous pericardium is the most superficial layer of the
pericardium.
22. Fibrous pericardium acts to protect the heart, anchoring it to the
surrounding walls, and preventing it from overfilling with blood.
AREA MAX MIN
1. Left atrium 7-8 mm hg 0-2 mm hg
2. Right atrium 5-6 mm hg 0-2 mm hg
3. Left ventricle 120 mm hg 5 mm hg
4. Right
ventricle
25 mm hg 2-3 mm hg
5. Aorta 120 mm hg 80 mm hg
6.Pulmonic 25 mm hg 7-8 mm hg

7. Contd….
23. The serous pericardium, in turn, is divided into two layers, the parietal
pericardium and the visceral pericardium.
24. Both of these layers function in lubricating the heart to prevent friction
during heart activity.
25. In between the parietal and visceral pericardial layers there is a potential
space called the pericardial cavity, which contains a supply of
lubricating serous fluid known as the pericardial fluid.
26. Function of pericardium
 Sets heart in mediastinum and limits its motion
 Protects it from infections coming from other organs (such as lungs)
 Prevents excessive dilation of the heart in cases of acute volume overload
 Lubricates the heart.
27. In a healthy adult pericardial fluid is up to 50 ml of clear, straw-coloured
fluid.
28. If > 50 ml then leads to cardiac temponade And if blood then called
haemopericardium.

8. BLOOD SUPPLY OF HEART
Blood supply of heart
ARTERIAL SUPPLY VENOUS SUPPLY
RIGHT CORONARY ARTERY LEFT CORONARY ARTERY
a) Right marginal branches a) ant interventricular branches/ AIVA/
LADA
b) Post. Interventricular artery b) circumflex artery
c) Nodal branches c) branches to diaphragmatics surface
d) Right atrial d) left atrial
e) Infundibular e) pulmonary
f) Terminal branches f) terminal

9. Contd....

10. Cont….
Imp points:-
1. RCA is smaller than LCA.
2. Mostly PIVA Is Originated From RCA But Sometimes Originated From LCA.
3. If PIVA Originated From RCA Then Called Right Cardiac Domiance (MOSTLY) And
If It Originated From LCA Then Called Left Cardiac Dominance.
4. Area of distribution of RCA :-
 Right Atrium.
 Great Part Of Right Ventricle Except Near Ant I.V. Groove.
 Small Part Of Left Ventricle Near Post I.V. Groove.
 Post Part Of I.V Septum.
 Whole Of Conducting System Except LBB.
5. Area of distribution of LCA :-
 Left Atruim.
 Great Part Of Left Ventricle Except Near Post I.V Septum.
 Small Part Of Right Ventricle At Area Near Ant I.V Septum.
 Ant Part Of I.V Septum.
 A Part Of LBB.
6. RCA originated from RIGHT AORTIC SINUS and LCA originated from LEFT
AORTIC SINUS

11. venous supply

12. Nerve supply of heart

13. Conducting system of heart
CONDUCTING SYSTEM OF HEART
SA NODE ( NATURAL PACE MAKER AND SITUATED AT RA)
ATRIAL CONTRACTION
AV NODE( INTERATRIAL SEPTUM)
BUNDLE OF HIS
RBB LBB
PURKINJE FIBER PURKINJE FIBER

14. Cont….
Rhythmicity :-
Action :-
1. Chronotropic :- frequency of heart rate.
2. Inotropic :- force of contraction.
3. Dromotropic :- conduction of impulse.
4. Bathmotropic :- excitability of cardiac muscle.
Imp points :-
 Cardiac Muscles Are Invountary , Striated Supplied By ANS.
 Its Muscles Fibers Are Separated By Modification Of Cell Membrane Called
Intercalated Disc In Which Nucleus Is Centrally Located.
TISSUE RATE IN /MT RATE IN M/SEC
1. SAnode 70 - 80 /mt
(max)
0.05
2. AV node 40 – 60 /mt 0.02 – 0.05 (least)
3. BOH 40 /mt 1
4. Purkinje
fibers
24 /mt (min ) 4( highest)

15. Physiology of heart
Cardiac cycle :- series of electrical and mechanical events that occur cyclically from
the beginning of one heart beat to the beginning of next.
a) Duration of one cardiac cycle is 0.8 sec.
b) Duration Of Systole Is 0.27 Sec.
c) Duration Of Diastole Is 0.53 Sec.
d) Duration Of Atrial Systole Is 0.1 Sec.
e) Duration Of Atrial Diastole Is 0.7 Sec.
f) Duration Of Ventricular Systole Is 0.3 Sec.
g) Duration Of Ventricular Diastole Is 0.5 Sec.
Phases of cardiac cycle :-
i) Atrial systole :- (0.1 sec )
 In this phase atrial start to contract.
 Atrial give remaining 20% of blood to the ventricle. Reaches the EDV 120 ml.
 AV valve open and semilunar valve closed.
 Ventricle relax.
 S4 sound produces

16. Contd….
ii) Isovolumetric contraction :- (0.05 sec )
 Ventricle Start To Contract Increases The Pressure Of Ventricle.
 Ventricle Pressure More Then Atrial Pressure So Av Valve Get Closed Produce Sound S1
But Not More Than Aortic Or Pulmonic Pressure So Semilunar Valve Still Closed.
 Now The System Act As Closed Where Neither Input Nor Outout Hence The The
Volume Is Constant.
iii) Rapid ejection :- (0.10 sec)
 In this phase ventricular pressure more than aortic or pulmonic pressure due to further
contraction.
 This cause the opening of semilunar valve so blood eject rapidly into the aorta or
pulmonary trunk.
iv) Reduce ejection phase:- ( 0.15 sec)
 In this phase the ventricular pressure is slightly decrease than that of aorta or pulmonary
trunk, but the blood flow is continuesly due to momentum.
 After the complete ejection of blood 30 – 50 ml blood remain in the ventricle called END
SYSTOLIC VOUME.
v) Protodiastole :- (0.04 sec)
 Ventricle start relaxing leads to rapid falling of pressure in ventricle.
 Blood from aorta or pulmonary trunk try to back into the ventricle causing semilunar
valve get closed produces sound s2.

17. contd….
vi) Isovolumetric relaxation :- (0.06 sec )
 Start with the closure of aortic valve.
 In this phase semilunar valve and AV valve both are closed so ventricle act as closed chamber.
 Neither blood input nor output hence the volume is same.
vii) Rapid filling phase :- (0.10 sec)
 Ventricular pressure less than atrial pressure becoz blood continously enter into the atrium
from lungs.
 Due to the the more pressure in atrial cause opening of AV valve and blood rapidly goes into
the ventricle as much as possible produces s3.
viii) Slow filling phase :- (0.2 sec )
 In this phase blood flow gradually decreases.
 This phase is also called diastesis.
 Stroke volume :- blood pumped out by the ventricles in each cardiac cycle.
STOKE VOLUME = EDV- ESV
70 ml = 120 ml – 50 ml
 Ejection fraction :- Fraction of EDV ejected by ventricle.
EJECTION FRACTION = EDV-ESV/EDV * 100 = 60 – 70 % of EDV

18. Heart sound (normal and abnormal)
Features S 1 S 2 S 3 S 4
1. Occurs during Isometric contraction
period and part of
ejection period
Protodiastole and part
of isometric
relaxation
Rapid filling phase Atrial systole
2.Characteristics Long, soft and low
pitched
Resembles the word
‘LUBB’
Short, sharp and high
pitched
Resembles the word
‘DUBB’
Low pitched Inaudible sound
3. Cause Closure of
atrioventricular valves
Closure of semilunar
valves
Rushing of blood
into ventricle
Contraction of atrial
musculature
4. Duration
(sec)
0.10 to 0.17 0.10 to 0.14 0.07 to 0.10 0.02 to 0.04
5. Frequency
(cycles per sec)
25 to 45 50 1 to 6 1 to 4 1 to 4
6. Relation with
ECG
Coincides with peak
of
‘R’ wave
Precedes or appears
0.09 second after
peak of ‘T’ wave
wave
Between ‘T’ wave
and ‘P’ wave
Between ‘P’ wave
and ‘Q’ wave
7. Number of
vibrations in
phonocardiogram
9 to 13 4 to 6 1 to 4 1 to 2

19. Contd….
 „TRIPLE AND QUADRUPLE HEART SOUNDS :-
„
i) TRIPLE HEART SOUND OR GALLOP RHYTHM
 Triple heart sound or triple rhythm is an abnormal rhythm of heart, characterized by three clear heart sounds
during each heart beat.
 It is due to an abnormal third or fourth heart sound that is heard besides first and second heart sounds.
 It is also called gallop rhythm since it resembles the sound of a horse’s gallop.
 Usually, it is indicative of serious cardiovascular disease.
Conditions when Triple Heart Sound is Produced
 Triple heart sound is produced in conditions like myocardial infarction and severe
hypertension.
ii) QUADRUPLE HEART SOUND
 Quadruple heart sound is an abnormal rhythm of heart, characterized by four clear heart sounds during each
 heart beat.
 It is also called quadruple rhythm.
 It is due to third and fourth heart sounds that are heard besides first and second heart sounds.
 It is also called quadruple gallop.
 Quadruple heart sound is also indicative of serious cardiovascular disease.
Conditions when Quadruple Heart Sound is Produced
 Quadruple heart sound is produced in patients with congestive heart failure.
Summation Gallop
 Whenever there is tachycardia in patients with quadruple heart sound, the third and fourth heart sounds merge
together a.nd give rise to a single sound. This sound is called summation gallop and it resembles gallop rhythm.

20. Cont….
Cardiac murmur :-
 Cardiac murmur is the abnormal or unusual heart sound.
 It is also called abnormal heart sound or cardiac bruit.
Cause of murmur
types of murmur causes
1. Systolic
Eg:- AS, PS, MR, TR
1. Incompetence of Atrioventricular valves
2. Stenosis of semilunar valves
3. Anemia
4. Septal defect
5. Coarctation of aorta
2. Diastolic
Eg :- AR, PR, MS, TS
1. Stenosis of atrioventricular valves
2. Incompetence of semilunar valves
3. Continous 1. Patent ductus arteriosus

21. CADIAC OUTPUT
 Cardiac output is the amount of blood pumped from each ventricle.
 Stroke volume is the amount of blood pumped out by each ventricle during each beat.
(Normal value is 70 ml)
 Minute volume is the amount of blood pumped out by each ventricle in one minute. (Normal
volume is 5 l/mt)
 Cardiac index is the amount of blood pumped out per ventricle/minute/ square meter of the
body surface area.( normal value is 2.8 ± 0.3 L/square meter of body surface area/minute)
 Ejection fraction is the fraction of end diastolic volume that is ejected out by each ventricle.
(Normal ejection fraction is 60% to 65%)
 Cardiac reserve is the maximum amount of blood that can be pumped out by heart above the
normal value. (In a normal young healthy adult, the cardiac reserve is 300% to 400%. In old
age, it is about 200% to 250%. It increases to 500% to 600% in athletes.)
Factor affecting cardiac output :-
a) Physiological variation b) pathological variation
Eg:- age, sex, diurnal variation, body build Eg:- Increase c.o fever, anemia, hyperthyroidism
Emotions, after meal, posture, exercise, sleep Decrease c.o hypothyroidism, CHF, AF
Pregnancy, high altitude, and temp. shock, hemorrhage
incomplete heart block

22. Contd…..
FACTORS MAINTAINING CARDIAC OUTPUT
:-
1. Venous return
2. Force of contraction
3. Heart rate
4. Peripheral resistance.
Venous return :-
Venous return in turn, depends upon five factors:
i. Respiratory pump
ii. Muscle pump
iii. Gravity
iv. Venous pressure
v. Sympathetic tone

23. Contd….
2. FORCE OF CONTRACTION :-
* cardiac output α F.O.C α initial Length of muscle fibers, before the onset of contraction.
* Preload is the stretching of the cardiac muscle fibers at the end of diastole, just before contraction.
it is due to increase in ventricular pressure caused by filling of blood during diastole.
(F.O.C α PRELOAD)
* Afterload is the force against which ventricles must
contract and eject the blood.
(F.O.C α C.O α afterload)
3. HEART RATE :-
* Cardiac output is directly proportional to heart rate.
4. PERIPHERAL RESISTANCE :-
* The cardiac output is inversely proportional to peripheral
resistance
Organs Amount
of blood
(ml/mt)
%
1. LIVER 1500 30
2. KIDNEY 1300 26
3. SKELETAL
MUSCLE
900 18
4. BRAIN 800 16
5. SKIN, BONE
AND GI TRACT
300 6
6. HEART 200 4
TOTAL 5000 100

24. E.C.G
*Electrocardiography is the technique by which electrical activities of the heart are
studied.
*Electrocardiogram is the record or graphical registration of electrical activities of the heart, which
occur prior to the onset of mechanical activities.
*USES OF ECG
Electrocardiogram is useful in determining and
diagnosing the following:
1. Heart rate
2. Heart rhythm
3. Abnormal electrical conduction
4. Poor blood flow to heart muscle (ischemia)
5. Heart attack
6. Coronary artery disease
7. Hypertrophy of heart chambers
IMP POINT R/T ECG PAPER :-
a) 1 mm = 0.04 second
b) 5 mm = 0.20 second
c) 1 mm = 0.1 mV
d) 5 mm = 0.5 mV
„e) speed of the paper 25 mm/second.
f) If heart rate is very high
speed of the paper is changed to 50 mm/second.

25. Contd….
* Bipolar Lead
lead I
lead II
lead III
* Unipolar Limb Lead
avR lead
avF lead
avL lead
* Cheast Lead
V1 :- Over 4th intercostal space near right sternal
margin
V2 :- Over 4th intercostal space near left sternal
margin
V3 :- In between V2 and V4
V4 :- Over left 5th intercostal space on the mid
clavicular line
V5 :- Over left 5th intercostal space on the mid
clavicular line
V6 :- Over left 5th intercostal space on the mid
clavicular line

26. Contd…..

27. Contd…..
i) Normal duration of ‘P’ wave is 0.1 second
ii) Normal amplitude of ‘P’ wave is 0.1 to 0.12 mV.
Iii) Normal duration of ‘QRS’ complex is between 0.08 and 0.10 second
iv) Amplitude of ‘Q’ wave = 0.1 to 0.2 mV.
v) Amplitude of ‘R’ wave = 1 mV.
Vi) Amplitude of ‘S’ wave = 0.4 mV.
Vii) Normal duration of ‘T’ wave is 0.2 second.
Viii) Normal amplitude of ‘T’ wave is 0.3 mV.
ix) Normal duration of ‘P-R interval’ is 0.18 second and varies between 0.12 and 0.2 second
x) Normal duration of Q-T interval is between 0.4 and 0.42 second
xi) Normal duration of ‘S-T’ segment is 0.08 second
xii) Normal duration of ‘R-R’ interval is 0.8 second


28. HEART RATE
 NORMAL HEART RATE
Normal heart rate is 72/minute. It ranges between 60 and 80 per minute.
a) TACHYCARDIA b) BRADYCARDIA
Tachycardia is the increase in heart rate above 100/mt Bradycardia is decrease in heart rate below 60/ mt minute.
Physiological Conditions when pathological condition when bradycardia occur
Tachycardia Occurs 1. Sleep
1. Childhood 2. Athletes.
2. Exercise pathological condition when bradycardia occur
3. Pregnancy 1. Hypothermia
4. Emotional conditions such as anxiety. 2. Hypothyroidism
Pathological Conditions when 3. Heart attack
Tachycardia Occurs 4. Congenital heart disease
1. Fever 5. Degenerative process of aging
2. Anemia 6. Obstructive jaundice
3. Hypoxia 7. Increased intracranial pressure
4. Hyperthyroidism Drugs which Induce Bradycardia
5. Hypersecretion of catecholamines 1. Beta blockers
6. Cardiomyopathy 2. Channel blockers
7. Diseases of heart valves. 3. Digitalis and other antiarrhythmic drugs

29. Cont….
 Heart rate is regulated by the nervous mechanism, which consists of three components:
A. Vasomotor center
B. Motor (efferent) nerve fibers to the heart
C. Sensory (afferent) nerve fibers from the heart.
A) Vasomotor center is bilaterally situated in the reticular formation of medulla oblongata and lower part of pons
Vasomotor center is formed by three areas:
1. Vasoconstrictor area
2. Vasodilator area
3. Sensory area.
1. VASOCONSTRICTOR AREA OR CARDIOACCELERATOR CENTER
 Situation
Vasoconstrictor area is situated in the reticular formation of medulla in floor of IV ventricle
 Function
Vasoconstrictor area increases the heart rate and constriction of blood vessels.
 Control
Vasoconstrictor area is under the control of hypothalamus and cerebral cortex.
2. VASODILATOR AREA OR CARDIOINHIBITORY CENTER
 Situation
Vasodilator area is also situated in the reticular formation of medulla oblongata in the floor of IV ventricle.
 Function
Vasodilator area decreases the heart rate dilatation of blood vessels.
 Control
Vasodilator area is under the control of cerebral cortex and hypothalamus. It is also controlled by the impulses
from baroreceptors, chemoreceptors and other sensory impulses via afferent nerves.

30. Cont….
3. „SENSORY AREA
 Situation
nucleus of tractus solitarius in medulla and pons.
 Function
Sensory area receives sensory impulse via glossopharyngeal nerve and vagus nerve from periphery, particularly, from the
baroreceptors. In turn, this area controls the vasoconstrictor and vasodilator areas
B) MOTOR (EFFERENT) NERVE FIBERS TO HEART
FEATURES PARASYMPATHETIC SYMPATHETIC
1. Origin dorsal nucleus of vagus. arise from lateral gray horns of the T1
to T4 segments of the spinal cord.
2.Distribution *right vagus terminate in sinoatrial (SA) node.
Remaining fibers supply the atrial muscles and
atrioventricular (AV) node
*left vagus supply AV node and some fibers
supply the atrial muscle and SA node.
*Ventricles do not receive the vagus nerve
supply.
1. Superior cervical sympathetic nerve,
which innervates larger arteries and
base of the heart
2. Middle cervical sympathetic nerve,
which supplies the rest of the heart
3. Inferior cervical sympathetic nerve,
which serves assensory (afferent)
nerve from the heart.
3. Function cardioinhibitory cardioaccelerators
4. Mode of action Vagus nerve inhibits the heart by secreting the
neurotransmitter substance known as
acetylcholine.
Cardioacceleration by sympathetic
stimulation is
due to the release of neurotransmitter
substance,
noradrenaline.

31. Contd….
C) SENSORY (AFFERENT) NERVE FIBERS FROM HEART
These nerve fibers carry sensations of stretch and pain from the heart to brain via spinal cord.
„# FACTORS AFFECTING VASOMOTOR CENTER – REGULATION OF VAGAL TONE :-
MAREY’S REFLEX BAINBRIDGE REFLEX

32. I HOPE YOU
UNDERSTAND