from the body superior and inferior vena cavas right atrium tricuspid valve right ventricle semilunar valve pulmonary artery lungs pulmonary veins left atrium bicuspid valve left ventricle semilunar valve aorta to the body
the P wave represents the electrical activity associated with the contraction of the atria, or atrial depolarization
Time required for conduction from the SA node to AV node. The time between atrial and ventricular depolarization. This is normally 0.12 to 0.2 seconds.
The first portion of the QRS complex that is seen with a downward deflection and is usually not obvious on the EKG of the normal heart. Often the first portion of the deflection is positive, signifying no Q wave. This is the beginning of ventricular depolarization.
Represents ventricle depolarization. The QRS Interval is measured from the start of the Q wave or from the beginning of the R wave if no Q wave is present. If no Q wave is present, a normal QRS interval should be less than 0.12 seconds in all leads.
Indicates that ventricle depolarization is complete and that repolarization is about to begin. Also called early ventricle repolarization. The ST Segment is measured from the end of the QRS to the beginning of the T wave, and represents a portion of ventricular repolarization. The normal segment is usually flat, or isoelectric. The absolute measurement of this segment is not as clinically important as is the configuration, whether depressed or elevated.
the T wave represents the electrical recovery of the ventricles, or ventricle repolarization. the muscle cells are recovering in preparation for another impulse
duration of ventricular cardiac cycle (an indicator of ventricular rate)
heart rate x stroke volume, Total blood volume pumped from the left ventricle per minute. Can be increased by increasing heart rate or stroke volume. SV X HR= CO
the volume of blood pumped out by a ventricle with each heartbeat
Volume of blood in the ventricles at the end of diastole, immediately before ventricular contraction.
the pressure that must be exceeded before ejection of blood from the ventricles can occur
relaxation phase of the cardiac cycle, the widening of the chambers of the heart between two contractions when the chambers fill with blood
the contraction of the chambers of the heart (especially the ventricles) to drive blood into the aorta and pulmonary artery
located in the heart + ionotrphic and chronotrophic, also in kidneys renin release in blood helping regulation of bp causing vasoconstriction
denotes mimicking of the actions of the sympathetic nervous system (EPI & Nor-EPI)
drug or other substance that blocks the actions of the sympathetic nervous system (also call antiadrenergic). (Clonidine)
DRUGS USED TO DECREASE HEART RATE AND ACT ON SMOOTH AND SKELETAL MUSCLES (Parasympathetic System)
Block the action of acetylcholine in the parasympathetic nervous system; also known as cholinergic blocking agents, antispasmodics, and parasympatholytic agents (Atropine)
Sympathetic Nervous System
the division of the autonomic nervous system that arouses the body, mobilizing its energy in stressful situations (Fight or Flight) EPI and NorEPI
Parasympathetic Nervous System
the division of the autonomic nervous system that calms the body, conserving its energy (Feed or Breed)
affects arousal and memory; raises blood pressure by causing blood vessels to become constricted, but also carried by bloodstream to the anterior pituitary which relaxes ACTH thus prolonging stress response (levophed)
anti-cholinergic drug that acts on muscarinic receptors. anti-parasympathetic drug, blocks the Parasympathetic NS not stimulating the Sympathetic NS
Bundle Branch Block
heart block; occurs when electrical impulse is blocked from traveling down the bundle branches; results in the ventricles beating at a different rate than the atria
Right Bundle Branch Block
widened QRS (>0.12s); double peaked QRS in V1 (best to look in V1 and V2); T wave can look abnormal – inverted (does not indicate ischemia)
Right Bundle Branch
carry electricity through right ventricle 20 – 40 bpm
Left Bundle Branch
carries electricity through left ventricle 20 – 40 bpm
Right Coronary Artery
supplies blood to right atrium, portions of both ventricles and cells of AV nodes and SA node.
Left Coronary Artery
Branches into two arteries: 1. Anterior interventricular artery – also called the left anterior descending artery, supplies the anterior surface of both ventricles and most of the interventricular septum 2. Circumflex artery – supplies the left atrium and ventricle
the pace-maker of the heart; where the impulse conduction of the heart usually starts; located in the top of the right atrium
an area of specialized tissue between the atria and the ventricles of the heart, which conducts the normal electrical impulse from the atria to the ventricles.
End of the conduction system; sends impulses through the ventricles, causing them to contract
Bundle of HIS
neurological fibers, extending from the AV node to the right and left bundle branches, that fire the impulse from the AV node to the Purkinje fibers
The atrioventricular junction; the portion of the electric conduction system of the heart located in the upper part of the interventricular septum that conducts the excitation impulse from the atria to the bundle of His
the upper chambers of the heart
the two lower chambers of the heart, and they pump blood out to the lungs and body.
When the SA node fires at a rate of less than 60 beats per minute. The P wave and the QRS complex are normal.
a heart rhythm established by impulses from the SA node. Irregularities include sinus bradycardia, sinus tachycardia, sinus arrest, and sinus arrhythmia
P Waves present, constant, each constant P Wave is followed by a constant QRS complex (normal width – slim), constant intervals between QRS Complexes are equal, heart rate is 100-150 BPM
irregularly irregular. rate varies and depends on the conduction rate. no identifiable P waves. Baseline shows fibrillartory waves.
Characterized by a “saw-toothed” wave formation with a slower ventricular rate. The atrial rate generally ranges form 220 to 350 beats/min. Cardioversion may be used.
the SA node is nonfunctional, P waves are absent, and heart is paced by the AV node at 40-60 beats/min
Accelerated Junctional Rhythm
regular rhythm, rate 60-100, p waves inverted or occur before during or after QRS, PRI measured if p before QRS <0.12
A heart rate of over 150 bpm caused above the ventricle, either the atria, SA node, or AV junction.
is a syndrome of pre-excitation of the ventricles of the heart due to an accessory pathway known as the bundle of Kent. This accessory pathway is an abnormal electrical communication from the atria to the ventricles. WPW is a type of atrioventricular reentrant tachycardia. Has a “Delta Wave” on the EKG
Rhythm: Regular Rate: 100-250 bpm P-waves: Absent PR-Interval: Absent QRS complex: Wide and bizarre *rhythm is unstable, compromises BP and CO
parts of the myocardium contract random, no blood is pumped, treated with direct-current shock
The SA node will fail momentarily and will not initiate an impulse
Multi-focal Atrial Tachycardia
Rate 100-250/bpm P wave two or more ectopic P waves with different morphologies QRS normal Rhythm irregular
records the heart’s voltage difference between the right arm and the left arm LA+ RA-
records the dfference between the right arm and left leg; shows the heart’s rhythm more clearly than the other two RA- LL+
records the difference between the left arm and the left leg LA- LL+
fourth intercostal space just right of sternum
fourth intercostal space just left of sternum
halfway between v2 and v4
fifth intercostal space midclavicular
5th intercostal space, midway between V4 & V6
midaxillary line at the same level as v4 (5th intercostal space)
Leads II,III, aVF Look at electrical activity from the vantage point of the inferior surface
Leads I, aVL, V5 and V6 Look at the electrical activity from the vantage point of the lateral wall of left ventricle.
V1 and V2 Look at electrical activity from the vantage point of the septal wall of the ventricles
leads V3 and V4, which are positioned over the front (anterior) of the left ventricle