Term
| What is the relationship between reduced exercise capacity and cardiac performance measured by hemodynamic parameters ie:EF? |
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Definition
| They do NOT correlate. Can have a low EF and still have good exercise tolerance. |
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Term
| Why do most HF pts discontinue exercise? |
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Definition
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Term
| What is VE/VCO2? What does it indicate? |
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Definition
| Minute ventilation/CO2 produced. For every unit of CO2 you produce, you need to increased your VE to get rid of it. |
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Term
| What does a steep VE/VCO2 curve mean? Why does this happen? (2) |
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Definition
| The more the increase in CO2, the steeper the rise in VE, and the worse it is for a pts prognosis. A person w/ a steep curve increases VE to blow of CO2 more than someone who doesn't have a steep curve. B/C of perfusion and how you get the CO2 in the blood back to the lungs, and also b/c of ability of lungs to exchange gas. |
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Term
| What are the major factors contributing to exercise intolerance? (9) |
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Definition
| 1. Abnormal ventilatory drive. 2. Altered skeletal muscle structure. 3. Poor tissue oxygenation - low CO. 4. Altered distribution of perfusion. 5. Low anaerobic threshold. 6. Chronotropic incompenence. 7. Altered skeletal muscle function. 8. Endothelial dysfunctions. 9. Fatigue. |
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Term
| Why does abnormal ventilatory drive impact exercise tolerance? |
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Definition
| There is inappropriate hyperventilaion, and a limite to VE so they'll reach VE too quickly and things start grinding to a halt. |
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Term
| WHy is there inappropriate hyperventilation in HF pts? |
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Definition
| Not clear why. But they HV easily. |
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Term
| What are the skeletal muscle changes that take place that impact exercise tolerance? (3) |
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Definition
| Inactivity leads to atrophy, Decr in type I fibers and incr in type 2 fibers. |
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Term
| Why is there a decrease in type I fibers? |
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Definition
| O2 is low. They use an oxidative energy system. If there's no fuel for them due to poor muscle perfusion, they can't run. |
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Term
| why is it a disadvantage to rely more on type 2 than type 1 fibers? |
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Definition
| b/c type two are fast twitch; easily fatiguable. |
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Term
| How is the distribution of perfusion altered in HF pts, and how does it impact their fn? |
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Definition
| only 50-60% CO goes to active muscles, vs 90% in normals. There is poor O2 distribution and also poor waste removal (lactic acid, etc...). And there are deceases in VO2peak, so they rarely get to VO2max. |
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Term
| What is Chronotropic incompentence? |
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Definition
| They can't increase their HR normally b/c of sympathetic overload and decreased sensitivity. |
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Term
| What are the endothelial dysfunctions that occure w/ HF, and why? |
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Definition
| Abnormal vascular bed tone - they don't dilate and constrict normally. Partly b/c of vasopressin, and partly b/c of decreased nitric oxide production. |
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Term
| What does NO do? What is its role in HF? |
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Definition
| it's a powerful vasodilator. There's decr NO in HF pts, so they can't vasodilate very well, which results in decreased perfusion. |
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Term
| How does the HF pt's exercise response at submax intensity compare to healthy? (6) |
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Definition
| Increased: HR, a-vO2 and VE. Decreased SV, CO and VO2. |
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Term
| How is the HF pt exercise response at peak exercise different from healthy? |
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Definition
| Decr: Power output, CO, VO2, SV, HR and VE. |
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Term
| In the case study w/ the pt who had Sx return 4yrs post PTCA who took part in aerobic and strength training, what were the results? (8) |
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Definition
| Decreased: Resting BP and angina. Increased: Peak: VO2, METs, Lactate Threshold, HR and strength. Didn't change EF - so there were no harmful effects on EF by doing weight training. |
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Term
| What types of meds are HF pts put on? (7) |
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Definition
| 1. Diuretics. 2. ACE inhibitors. 3. B Blockers. 4. Aldosterone antagonists. 5. Antiarrhythmics. 6. Vasodilators. 7. Digoxin. |
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Term
| Why are diuretics used w/ HF pts? What are some examples of diuretics? |
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Definition
| To maintain vascular volume within a reasonable level. Lasix/Furosemide. |
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Term
| What factors lead to the water retention that requires diuretic use? |
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Definition
| b/c of angiotensin and aldosterone and ADH, water is retained and sometimes too much - so need diuretics to get rid of excess. |
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Term
| What are the adverse effects of diuretics?(3) Can anything be done to help avoid them? |
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Definition
| 1. Cheap ones (like lasix) cause electrolyte depletion, so eat a banana/day. 2. Renal failure. 3. Activation of RAA and SNS. |
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Term
| what is the most important drug category for HF pts? Why? |
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Definition
| ACE in hibitors. B/C they break down chronic stimulation for vasopressin and aldosterone. |
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Term
| What are the benefits to ACE inhibitor use?(5) |
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Definition
| 1. Slows down/reverses some of the negative heart remodeling. 2. Increases survival. 3. Improves exercise tolerance. 4. Decreases hospitalization. 5. Improves Sx. |
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Term
| What's the adverse side effect of ACE inhibitors? |
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Definition
| They may cause a dry, chronic cough which can be really annoying. |
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Term
| What do B blockers do? (physiologically and functionally) What is an example of one? |
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Definition
| 1. Decrease HR. 2. Increased EF, 6 min walk, distance. Coreg. |
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Term
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Definition
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Term
| What are the benefits of vasodilating drugs? What are two examples of them? |
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Definition
| 1. Increase survival 2. Icnrease exercise tolerance. 3. Improves Sx (orthopnea, PND). Hydralazine and Nitrates. |
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Term
| What are the adverse effects of Hydralazine and Nitrates? (2each) |
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Definition
| Hydralazine: Nausia, Lupus. Nitrates: Tolerance if used all the time, and headaches. |
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Term
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Definition
| It improves cardiac contractility. |
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