The Cardiovascular System: Impact of Exercise on the Heart with Cardiac Ultrasound Demonstration Flashcards
Define cardiac arrest
Sudden unexpected loss of contractile function of the heart.
Can be different to a heart attack (blockage of coronary arteries).
What is the first step in ‘evaluation of a collapsed athlete’?
Assess their consciousness the assess for pulse.
This determines 1 of 2 paths; one being much more serious.
What if an athlete does not have a pulse?
Cardiac arrest = life support measure.
CPR
State a key determining factor for cardiac arrest
Time to initiate chest compressions
What is the O2 consumption equation?
Oxygen consumption = cardiac output x A-V oxygen difference
During exercise there is an increased metabolic need for O2. Blood flow delivery to exercising skeletal muscle is increased via 2 mechanisms:
1) Increased CO
2) A redistribution of blood flow from inactive organs to the working skeletal muscle.
Cardiac output increase during exercise is directly proportional to..?
The metabolic rate required to perform the exercise.
At rest, what is the difference in Cardiac output between trained and untrained individuals?
CO is very similar (between 4.5-5 l/min).
- HR is higher in untrained, and SV is higher in trained.
During exercise, is there a difference in CO between trained and untrained individuals?
Yes, there is a significant increase in CO. E.g., CO:UNT = 22.0 l/min, TRN =34.2 l/min
Trained = increased SV = HR affords to rest, more time for diastole = heart is more efficient.
What is strength of ventricular contraction enhanced by?
- Circulating epinephrine & norepinephrine
- Direct sympathetic stimulation of the heart.
What is echocardiography?
A non-invasive imaging technique using ultrasound to create detailed images of heart structure, function and blood flow helping to diagnose and monitor various CV conditions.
