Class Notes (836,589)
Canada (509,861)
Biology (2,229)
BIO120H1 (1,171)
Lecture 2

Lecture 2 Notes.pdf

10 Pages
Unlock Document

Stephen Reid

1Lecture 2 The Electrocardiogram ECG1 Uses of the ElectrocardiogramAn electrocardiogram or ECG also in some places called an EKG is a measurement of electrical activity from the heart that spreads to the surface of the body allowing you to quantify heart rate as well as see how this activity changes under different conditions over time Thus the ECG is a powerful diagnostic toolThe electrocardiogram produces the wellknow trace seen on the screen of a heart monitor There are several important components to the trace produced by an ECG recording there are generally three deflections above baseline and there are also segments between deflectionsand all of these tell us about heart function One of the things we can look at with an ECG is the electrical axis of the heart which we will talk about more in the next lecture However in brief whilst electrical activity occurs throughout the heart in all directions there is a mean axis in which electrical activity flows titled at about 60 degrees through the middle of the heart and how it shifts left or right can tell us about various disease state in the heart The ECG can also be used to measure heart rate including analysing either bradychardia a slow heart beat or tachycardia an elevated one Sometimes these terms are rather rigidly defined the former being less than 60 beatsminute the latter more than 100 beatsminute but they can also be used in the very general sense used here ie a slowing or speedingup of heart rate in general We will look also at arrhythmias and we will see how the heart has a normal rhythm that can be disrupted This disruption can be either superventricular above the ventricles or ventricularit is the ventricular arrhythmias that are particularly dangerous to the health of the heartWe will look at sequence activation disorders In other words an ECG trace can reveal abnormalities in the conduction of the waves of depolarisation through the heart or disruptions in the normal transit of electrical activity in the heart eg abnormalities in movement through the AV node or branch bundles An ECG can tell us whether the heart has undergone hypertrophy which is a particular problem because a heart that has grown too much muscle will have difficulty pumping blood properly There are changes in the ECG when the coronary circulation is disrupted and the heart becomes ischemic There are also changes in the ECG if heart tissue dies or if there is a heart infarction a heart attack Drugs such as digitalis can have effects on
More Less

Related notes for BIO120H1

Log In


Join OneClass

Access over 10 million pages of study
documents for 1.3 million courses.

Sign up

Join to view


By registering, I agree to the Terms and Privacy Policies
Already have an account?
Just a few more details

So we can recommend you notes for your school.

Reset Password

Please enter below the email address you registered with and we will send you a link to reset your password.

Add your courses

Get notes from the top students in your class.