EKG Flashcards
what is electrocardiogram?
it is a graphic recording from the body surface of the electrical currents generated by the heart
what are arrhythmias?
they are abnormalities in the heart’s electrical activity
what does the cardiac conduction system responsible for?
the cardiac conduction system is responsible for initiating and transmitting the electrical impulse that causes the heart to contract
where is the sinoatrial node ( sinus node) located?
the sinoatrial node locates in the rt atrium near the entrance of the superior vena cava also known as the heart’s normal pacemaker.
how many sinoatrial nodes discharges electrical impulses per minute?
60-100 times per minute
where is the atrioventricular node located?
it is located on the rt side of the heart. beneath the surface of the interventricular septum
what does the atrioventricular node also know as?
AV junctional tissue
how many impulses does the atrioventricular node discharge?
40-60 impulse per minute
where is the atrioventricular bundle located?
a band of nerve fibers that original at the AV node then passes along the interventricular septum to the ventricles
what does the atrioventricular bundle also known as?
BUNDLE of HIS
what are bundle branches?
bundle branches are continuation of the bundle of HIS they proceed along the rt and lt sides of the interventricular septum to the tip of the two ventricle
What is Purkinje fiber?
Purkinje fiber are tree-like branches of the rt and lt bundles extending across ventricular wall
how many electrical impulses do the Purkinje fibers discharge?
20-40 impulse per minute
how the electrical conduction system of the heart work?
sinoatrial node (SA) -> atrioventricular node (AV) -> bundle of HIS -> lt and rt bundle -> purkinje fibers
what is the P wave?
atrial depolarization causes atrial contraction
What does the PR interval represent?
start of P wave to start of QRS
what does the PR segment represent?
end of P-wave to start of QRS
what does QRS complex present?
ventricular depolarization causes ventricular contraction
what does the ST segment present?
end of QRS to the beginning of T wave
what does the QT interval present?
start of QRS complex to end of T wave
what does T wave present?
ventricular repolarization causes ventricular relaxation
what is cardiac cycle?
the events and time between one heartbeat and the next successive heartbeat
what is systole?
the period of ventricular contraction
what is diastole?
the period of ventricular relaxation
what is end-diastole volume?
the quantity of blood in the ventricle at the end of diastole about 150 ml in adults
what is cardiac output?
the amount of blood ejected from the left ventricle over a 1 minute interval
what is the stroke volume?
the amount of blood ejected in a single beat. normal in adult stroke volume 80-100ml
stroke volume formula
end diastolic volume - end systolic volume
what is ejection fraction?
the fraction of the total ventricular filling volume that is ejected during each ventricular contraction
ejection fraction fomula
(end diastolic - end systolic) / ( end diastolic - background)
what is normal ejection fraction in LV?
50-75%
what is normal ejection fraction in RV?
35-50%
What is normal adult resting heart rate?
60-100 beats per minute (BPM)
what is normal adult stress or exercising heart rate?
140 bpm or more
what is normal wave form EKG is called?
sinus rhythm
what is sinus tachycardia?
rapid heart rate with 100-150 bpm, average 125bpm
what is sinus bradycardia?
abnormally slow hear beat
what is hypertrophic cardiomyopathy?
Abnormal increase in the thickness of myocardium due to either a congenital abnormality or prolonged hypertension
what is dilated cardiomyopathy?
reduced ability of the myocardium to contract effectively, despite having sufficient blood supply
