ECG, Metabolism and Cardiodynamics Flashcards
What is cardiac output?
Its the volume of blood pumped out of the heart every minute
Give a normal reading for cardiac output.
Approximately 5 L per minute for a 70 kg male
What determines cardiac output?
Heart rate and stroke volume
Define heart rate.
The number of contractions (beats) the ventricles perform in one minute
Give a normal reading for heart rate.
74 bpm at rest
Define stroke volume.
The volume of blood pumped out of the ventricle during systole
Give a normal reading for stroke volume.
70 ml for a 70kg male
Define minute ventilation.
The volume of air brought into the lungs each minute
Give a normal reading for minute ventilation.
Approximately 6 L per minute for a 70 kg male
What is the equation for calculating minute ventilation?
V = Tidal volume x respiration rate
Define tidal volume.
The volume of air brought into the lungs with each breath
Give a normal reading for tidal volume.
Approximately 500-750ml at rest
Dependent on height
Define respiration rate.
The number of breaths per minute
Give a normal reading for respiration rate.
approximately 16 breaths per minute at rest
What are the three different ways of measuring cardiac output?
Stress test
VO2 max
Metabolic rate
What is the respiratory exchange ratio?
VCO2/VO2
What factors affect basal metabolic rate?
6
Gender
Age
Body mass/composition
Fasting state
Rested
Temperature
What is cardiodynamics?
Cardiodynamics refers to the movements and forces generated during cardiac contractions
What do conducting cells do?
They relay electrical depolarising charge through myocardium triggering the contractile cells
What do contractile cells do?
After they depolarise they contract and produce force causing the myocardium to drive blood
What is an ECG?
Electrocardiogram
Measure of electrical activity in the heart
What are the two types of cell involved in the spread of excitation throughout the myocardium?
Autorhythmic contractile
Conducting cells
List the different parts of an ECG
P wave
QRS wave
T wave
What happens to the heart during the P wave?
Atrial depolarization
