Mediastenum
space where heart is located, just behind the sterum
The top of the heart location
second intercostal
Base of the heart location
5th intercostal and mid clavicular line on the left
Endocardium
The innermost layer of the heart
chordae tendinae
connective tissue that keep the AV valves in place
Heart skeleton
Pericardium, parietal pericardium, visceral pericardium or epicardum and pericardial sac
Parietal pericardium
outside layer of the heart skeleton
Visceral pericardium or epicardium
the inner layer of the heart
Pericardial Sac
The layers and fluid between the two layers of the pericardium that prevent friction
septum
A wall of tissue that separates the left and right sides of the heart, The septum prevents oxygen rich and oxygen poor blood from mixing in the heart.
Right side of the heart
Pumps deoxygenated blood with low pressure from veins to the lungs; responsible for pulmonary circulation
Left side of the heart
Pumps oxygenated blood with high pressure toward the tissue through the arteries; responsible for systemic circulation
Number of chambers in the heart
four
Right and left atria
Smaller, thin walled chambers that are situated on top of the ventricles and receive blood from the lungs and veins
Right and left ventricles
Larger, more muscular chambers that eject blood to the systemic circulation and the two lungs
Right atrium RA
Receives deoxygenated blood returning to the heart from the body via the superior and inferior vena cava
Coronary Sinus
The largest vein that drains the heart muscle's deoxygenated blood received by the RA
Right Ventricle RV
Receives deoxygenated blood from the RA which is pumped to the lungs for oxygenation through the pulmonary trunk and the pulmonary arteries
Pulmonary arteries PA
The only arteries that carry deoxygenated blood
Left Atrium LA
Receives oxygenated blood from the lungs via the right and left pulmonary veins
Pulmonary Veins PV
The only veins that carry oxygenated blood
Left Ventricle LV
Receives the oxygenated blood from the LA and pumps it to the body through the aorta, the largest artery of the body
Blood Flow
Deoxygenated blood > superior vena cava> RA> tricuspid valve> RV> SL Pulmonary valves >PA> Pulmonary trunk> lungs>PV> LA> bicuspid or MV> LV> SL LV> systemic aortic valve
Heart valves
Prevents the back flow of blood ensuring uni-directional flow through the heart
Atrio-ventricular valves
Valves between the atria and ventricles that are have tough fibrous rings, long and strong leaflets cuspids, papillary muscles and chordae tendinae
Tricuspids valves
located between the right atria and right ventricle, it has three cusp
Bicuspids / mitral valves
located between the left atria and ventricle, two cusp
Pulmonic valve
located between the left ventricle and the pulmonary trunk
Aortic Valve
located between the left ventricle and the aorta
coronary arteries
located on the epicardium
Four vessels in coronary circulation
Left Anterior Descending (LAD), Left Circumflex (LCX) artery and the Left and Right Coronary
Systole
Contraction of both atrial and ventricles
diastole
Relaxation and filling of all cardiac chambers
Heart Sounds
Closure of the heart valves
S1 (Lubb)
During ventricular contraction and closure of AV valves
S2 (Dubb)
During ventricular relaxation when SL valves closes
Heart murmurs
Disease of the valves or any other abnormalities
Heart rate
Number of contractions per minute: 60-100 bpm
Chemo and Baro receptors
Controls the heart rate and is located in the aortic arch and carotoid arteries
Sympathetic nervous system
Affects both the atria and ventricles by increasing heart rate conduction and irritability
Parasympathetic Nervous system
Affects the atria only by decreasing heart rate conduction and irritability
Automaticity
The ability of the cardiac pacemaker cells to spontaneously initiate there own electrical impulse with out being stimulated from another source
Excitability
Cardiac cells and its ability to respond to external stimulus electrical chemical and mechanical
Conductivity
The ability of the cardiac cells to receive an electrical stimulus and transmit the stimilus to another cardiac cell
Contractility
The ability of the cardiac cells to shorten and cause cardiac muscle contraction in response to an electrical stimulus
Polarization
The heart resting
Depolarization
The heart when it is contracting. Systolic
Repolarization
The recovery of the heart, diastole
SA Node
Located in the upper posterior portion of the right atrial wall below the opening of the superior vena cava; It is the primary pacemaker of the heart
AV node
Located in the right atrium just above the tricuspid valve. electrical activity that allows blood flow from the atria to the ventricles
Bundle of His
located at the superior portion of the interventricular septum, the pathway leads to the SA Node
Purkinje fibers
located in the ventricular myocardium, it consist of small conduction fibers that delivers the electrical impulses to the ventricular myocardium
Bipolar leads
placed on the LA, RA, LL, RL this is the ground lead
Lead 1
LA - RA
Lead 2
LL - RA
Lead 3
LL - LA
Augmented Unipolar
needs only one electrode from one limb to make a lead; the machine records a midpoint between two other limbs
Lead aVR
Right arm is positive all other limbs are negative
Lead AvL
Left arm is positive and other are negative
Lead AVF
Left leg is positive and all others limbs is negative
Unipolar Precordial Leads
Six positive electrodes placed on the chest
V1
Forth intercostal space, right sternal border
V2
Forth intercostal space, left sternal border
V3
Equidistant between v2 and V4
V4
fifth intercostal space, left midclavicular line
V5
fifth intercostal space, anterior axillary line
V6
fifth intercostal space, midaxillary line
number of leads placed on the body
10 leads
number of readings
12
EKG paper
horizontal represents time; 1mm =0.04mm; 5mm = 0.2 seconds
vertical line represents amplitude 0.1 mV = 1mm
waveform
refers to the movement away from the isoelectric line either upward (positive) deflection or downward (negative)
Segment
line between two way forms
Interval
waveform plus a segment
complex
several waveforms
P wave
deflection of atrial depolarization. does not exceed 0.11s or 2.5mm in height
QRS complex
represents ventricular depolarization
Q Wave
initial negative deflection produced by ventricular depolarization
R wave
first positive deflection produced by ventricular depolarization
S wave
first negative deflection produced by the ventricular depolarization follows R wave
t wave
The deflection produced by ventricular repolarization
U wave
the deflection seen following the t wave but proceeds the P wave; shows hypokalemia low potassium, blood levels
RR interval
heart rate
PR interval
Normal interval is 0.12 -0.2
QRS interval
represents complete ventricular depolarization time. it should be no more than 0.1sec in limb leads and 0.11 sec in precordial leads
somatic tremors
patient's tremors or shaking the wires can poduce jittery patterns on the EKG tracing
Wandering baseline
sweat or lotion on patient's skin that interfere with the signal going to the EKG
60 cycle interference
deflection occurring at a rapid rate that may mimic atrial flutter
Stress test
Target heart rate is 220 - the persons age
arrhythmias
abnormal heart rate
tachcardia
heart rate over 100
brachcardia
heart rate under 60
myocardial ischemia
decrease in blood flow to a section of the heart
myocardial infraction
the actual death of the myocardial cells