Transport in Animals - Electrocardiogram Traces Flashcards
what does an ECG measure
the tiny electrical differences in your skin which result from the electrical activity of your heart
what does the height of the wave correspond to
strength of contraction
what does the P-wave represent
electrical activity causing the atria to contract
what does the QRS complex represent
electrical activity causing the ventricles to contract
what does the QT interval represent
ventricles contracting and relaxing
what does the T-wave represent
ventricular repolarisation
what does the TP interval represent
filling time- diastole
why do the peaks and troughs of the ECG happen just before the peaks and troughs of a pressure graph
electrical signal causes contraction, which squeezes atria and ventricles, which causes a change in pressure.
- it is a sequence of events so cannot be instantaneous
what are the features of bradycardia
- long TP interval
- slow heart rate (below 60bpm)
what may severe bradycardia require
pacemaker
what are the features of tachycardia
- short TP interval
- fast heart rate (over 100bpm)
- may occur during exercise, fever or stress
what are the features an ectopic heartbeat
- heartbeat is regular apart from one ectopic heartbeat, where the ventricle has contracted too soon and does not show normal pattern
- followed by a compensatory pause
what are the features of atrial fibrillation
- many P-waves but none clear
- rapid, irregular electrical impulses in the atria, where they contract too fast but not fully
- only some of the impulses are passed on to the ventricles
what are the features of ventricular fibrillation
- rapid and irregular electrical activity
- ventricles unable to contract in a synchronised manner
- immediate loss of cardiac output
