Cardiac Exercise Flashcards
What does cardiac rehab consist of?
Exercise training Counselling Dietary advice Medication/treatment advice Risk factor modification Social reintegration
What are the percentage reductions in mortality, cardiac mortality and hospital re admission for cardiac rehab?
13-26
26-46
23-56
What are the four stages of cardiac rehab and when are they?
Phase 1 - pre discharge - assess needs, make plan, give info and advise
Phase II - early post discharge - assess risk and needs, review plan, provide lifestyle advice and interventions
Phase III - same as above plus structured exercise sessions
Phase IV - long term maintenance - follow up, support groups, refer to specialists as needed
How much is peak VO2 reduced in CAD patients?
50%
What would a 1ml VO2 increase and 1 MET in fitness increase do for survival?
10% reduction in cardiac mortality
15%
Why is peak VO2 reduced in cardiac patients?
Cardiac output is decreased due to a decrease in stroke volume
At what intensity does stroke volume become reduced and why?
60%
TPR is increased as there is poorer sympathetic regulation and less NO thus increasing afterload
Why may HR increase be blunted?
Right coronary artery stenosis
Decreased SNS
Why can exercise cause coronary vasoconstriction and what are the consequences?
Reduced NO and increased endothelium
Less blood to myocardium causes heart to become hypokinetic
How is blood redistribution during exercise different in cardiac patients?
It is impaired to more goes to viscera and less to muscles
What are the exclusion criteria for cardiac rehab? (9)
Unstable angina >200/110 BP >120bpm ST depression at rest Uncontrolled arrhythmia Aortic stenosis Febrile illness Embolism Congestive heart failure
What is the cardiac effect of aerobic training normally?
Increase stroke volume via an increase in contractility due to more calcium proteins
Increased LV volume - eccentric - myocyte elongation
Increased LV mass - concentric - more myocytes
Increase plasma volume by 10%
What is La Place’s law? How does this apply to the heart?
Tension = (pressure difference x radius) / wall thickness
If the hearts volume increases, so too must the thickness
What affects myocardial oxygen consumption?
Heart rate
Contractility
Tension development
What stimulates an increase in LV mass?
GH, IGF, cortisol, thyroxine, Noradrenaline, RAAS
How do IGF and thyroxine get produced and how do they work?
IGF is produced in response to stretch and increases the hearts sensitivity to Ca2+
TSH is produced in response to exercise which produces thyroxine which stimulates hypertrophy
How does mechanical stress cause the heart to grow?
Increased pressure causes hypertrophy
Increased volume causes lengthening
Explain pathological hypertrophy
LV grows as a result of chronic overload (high BP) and greater preload
Reduced contractility and no Ca2+ sensitivity increased
Why does contractility improve after aerobic training?
Increased % shortening, quicker time to peak shortening and relaxing More calcium binding sites More NCX speeds up calcium removal Greater calcium stores in SR Increased sensitivity
What are the overall changes a cardiovascular patient may expect to see after aerobic training?
0-18% increase in SV due to increased blood volume, hypertrophy, contractility, ejection fraction Reduced viscosity as less fibrinogen More coronary collaterals and blood flow May regress vascular stenosis Less endothelial dysfunction
How may myocardial hypertrophy differ in a cardiac patient compared to a normal adult?
May shorten the myocyte length to return it to a normal length and thus increase contractility
How else does exercise improve cardiovascular health?
Lower resting HR Increase maximal SV Reduced systolic BP response due to increased NO Reduce myocardial demand Increase A-VO2 difference
How does exercise affect muscles in cardiac patients?
Increased A-VO2 difference More mitochondria and enzymes More aerobic Less blood flow as oxygen used more efficiently but higher maximum Increased fibre recruitment Low lactate concentration
What are the percentage changes in VO2, exercise capacity and angina threshold after cardiac rehab?
10-50% mean 20%
18-35%
10-20%
How is mortality affected by a 1000 calorie per week increase and decrease in exercise?
Reduced by 19%
Increased by 24%
Why does the angina threshold increase?
In submax exercise there is lower Q and TPR, lowering systolic BP and a lower HR. This means the myocardial oxygen demand is lower
What are the priorities for cardiac rehab in the first 48 hours?
Self care
Establish range of motion
Low resistance
Very minimal
What are the priorities for cardiac rehab before discharge?
Establish safe activities
Exercise plan
What are the broad benefits of cardiac rehab?
Physiological benefits
Increase self confidence
Decrease dependency
For weeks 1-6 how far (miles) and how often (days per week) should people walk?
1/4 - 4 1/2 - 4 3/4 - 4-5 3/4 - 4-5 1 - 5 1 - 5
What are the rules for walking?
Walk at a comfortable pace - RHR +20 Take GTN spray Know chest pain rules Flat route Go with someone at first and let others know the route later
For the Bruce exercise stress test what are the VO2 and MET requirements for the 6 stages
15 and 3-4 20 and 5-7 35 and 7-9 45 and 9-11 55 and 11-13 70
What are the MET values for: walking, cycling, dancing, gold, jogging, football, tennis and swimming?
3-10 3-8 4-8 4-7 8-10 5-12 4-9 4-8
What is the equation for predicting max HR with and without beta blockers?
B blocked: 203-(1.49*age)
252-(1.91*age)
How much exercise should they do?
3 days a week 10-15 at the start up to 30-60 with 10 minutes of warm up and 10 of cool down
50% peak HR, HRR, 5 METs
How much resistance training should be done?
60% of 1RM 6-10 exercises 8-20 reps 2-3 days Light Alternate legs/arms and sit/stand
How should aerobic and resistance training progress?
10% increase every 2 weeks
Duration then intensity
Reps then intensity
What are the improvements from strength training?
20-30% increase in strength
Increased efficiency and VO2
What are the advantages and disadvantages of water based exercise?
Less joint compression and good for overweight individuals
Increased BP, diuretic effect. Can cause arrhythmias and ST depression due to increased SNS
So be careful!!
What should someone’s MET capacity be to do a white collar job?
7
For what conditions is cardiac rehab indicated?
Post MI Pre/post CABG Pre/post PTCA Angina Valve replacement
