Chap 5. Chronic Heart Failure Flashcards
Exercise response to chronic heart failure
Alterations in central/peripheral and ventilatory abnormalities
- reduction of cardiac output
- leg fatigue due to inadequate blood flow
- altered catecholamine levels
Central abnormalities
- systolic dysfuction
- pulmonary hemodynamics
- diastolic dysfunction
- neurohumoral mechanisms
Peripheral Abnormality
- Blood flow abnormalities
- vasodilatory capacity
- skeletal muscle biochemistry
Ventilatory Abnormality
Pulmonary pressure Physiologic dead space Ventilation-perfusion mismatch Respiratory contro Breathing patterns
Ventilatory Inefficiency
VE/VCO2 slope V02 Kinetics Ventilatory Threshold VO2 in recovery Exercise periodic (oscillatory) breathing during exercise
An increase in VCO2
Ventilatory/perfusion mismatching Early lactate accumulation Deconditioning Hyperventilation CHF patients have a higher slope (VE/VCO2) than normal subjects
Exercise Testing considerations for CHF (VE/CO2)
VE/VCO2 slope ≥34 indicates poor prognosis
HR (exercise test conditions)
20-30% of CHF patients have chronotropic incompetence
it is associated with decreased myocardial beta receptor sensitivity (HRpeak should exceed ≥80% of age predicted HRreserve)
BP (exercise test conditions)
may be low or fail to rise due to LV dysfunction, afterload reducing medications or both
VO2peak (exercise test conditions)
inversely related to mortality <18ml/kg/min or significant drop with testing is a concern
Other exercise testing conditions
- Atrial/ventricular arrhythmias, bundle branch block
- Left ventricular hypertrophy
Exercise Programming (CHF)
- Referral to cardiac rehabilitation
- Follow basic recommendations
- Re-evaluate frequently
- Pro-long warm-up and cool-down
- Perceived exertion and dyspnea scales should take precedence over heart rate targets
- Isometric exercises should be avoided
- Electrocardiogram monitoring is required for persons with a history of ventricular tachycardia, cardiac arrest (sudden cardiac death), and exertional hypotension
- resistance training appears safe in persons with HRrEF
Systolic Heart Failure
- Less blood pumped out of ventricles
- Weakened heart muscle can’t squeeze as well
Diastolic Heart Failure
Less blood fills the ventricles
Stiff heart muscle can’t relax normally
Left Side Heart Failure
Failure to properly pump out blood to the body (Systolic and diastolic fall under this category)
Right Side Heart Failure
back-ups in the area that collects ‘used’ blood
CHF occurs when
cardiac output is reduced systolic dysfunction (impairment of left ventricle) diastolic dysfunction (due to resistance to filling of one or both ventricles)
Most common cause of CHF
coronary artery disease, HTN and myocardial infarction
Pathophysiology of Heart Failure
Impaired Contractility
Increased afterload
both lead to reduced ejection fraction then heart failure
Impaired diastolic filling leads to preserved ejection fraction
Heart failure with preserved ejection fraction
aortic stenosis
hypertension due to increased diastolic filling and compensatory ventricular hypertrophy
Pathophysiology of CHF
Myocardial Injury –>reduced Cardiac Output—->decrease in carotid baroreceptor stimulation, decrease in renal perfusion—> activation of the SNS and the RAAS—
BNP
secreted by the ventricles in response to excessive stretching of cardiomyocytes
decrease TPR and central venous pressure
ANP
Secreted by atria in response to high blood volume
decrease TPR and central venous pressure
Vasoconstriction increases
afterload
Hemodynamic alterations increases
preload
SNA
has do to with SV and TVC
PNA
has to do with HR
Adrenal Gland cortex
releases aldosterone
Angiotension>Angiotension 1
Renin
Angiotension1>Angiotension2
ACE
Pituitary Gland
ADH secretion (vassopressin)
Regulation of Stroke Volume
EDV
Aortic Blood Pressure
Contractility
Contractility refers to
the strength of the ventricular contraction
Stroke Volume vs afterload
decreasing graph
Stoke volume vs EDV
increasing
Higher values of EDV if there is greater contractility
Coronary Artery Disease
CAD
Build up of plaque in the coronary arteries
Leads to ischemia and heart attack
The most common cause of death
Ischemia
limited blood flow to the heart
Risk factors of CAD
High LDL, Low HDL, Hypertension, family history, diabetes, smoking, obesity, etc
Medical treatment for CAD
Angioplasty/coronary stent
Coronary bypass grafting
Medicines: beta-blockers, anti platelet drugs, calcium channel blockers, statins (lower cholesterol)
Balloon Angioplasty
minimally invasive,
widens the arteries, deflated balloon goes through catheter and then you inflate it
Coronary Stent
stent uses balloon to widen the artery and compress the plaque
Myocardial Infarction
Occurs when the blood flow stops to a part of the heart causing damage to the cardiac muscle
Most commonly happens due to CAD
Pathophysiology of MI
Atherosclerotic plaque
Inflammation: high sensitivity C-reactive protein (hs-CRP), calcification from calcium deposit as a part of plaque formation (can see this in CT scans)
Elevated CRP
predicts the risk of MI and stroke
CRP
c reactive protein
synthesized by the liver in response to factors released by macrophages and adipocytes
A heart (CT) scan
can show calcification (bright white spots on the CT scan)
Signs of a myocardial infarction
Discomfort in the center of the chest that lasts more than a few minutes (or goes away and comes back)
Uncomfortable pressure, squeezing, fullness or pain
pain/discomfort in arms, back, neck, jaw or stomach
Shortness of breath with or without chest discomfort
Breaking out in cold sweat, nausea or lightheadedness
True positive
positive exercise test and CVD
False Negative
negative exercise test and CVD
False Positive
Positive exercise test and no CVD
True Negative
Negative exercise test and no CVD
Alpha receptor blockers (exercise)
significantly lower BP
Minimal effects on HR and metabolic responses to exercise
CNS active drugs (exercise)
ex. clonidine, guanfacine, guanabenz
attenuating effects on HR and BP during exercise
Calcium Channel Blockers (exercise)
some may decrease HR response at rest and during exercise
Vasodilators, ACE inhibitors and angiotensin receptor blockers (exercise)
do not effect HR response
patients might experience hypotension
Beta-Blockers (exercise)
decreased submax and max hr
sometimes decreased exercise capacity
In Patient aerobic prescription (CAD and MI)
first 2-4 times/day for the 1st 3 days in the hospital
then 2 times/day beginning day 4 in hospital
to tolerance of intensity if they are asymptomatic (RPE ≤13 on 6 - 20 scale)
Post-MI/CHF: HR ≤120 bpm or HRrest +20 bpm
Postsurgery: HRrest +30 bpm
bouts of 3-5 min
rest=slower walk
2:1 exercise/rest ratio
progress to 10-15 min
Aerobic Prescription (CAD and MI)
4-7 days/wk multiple short bouts of 1-10 min RPE 11 to 16 (6 – 20 scale) 40 to 80% HRR or VO2R HR below ischemic threshold Warm up 5-10 min and then 20-60 min workout to toleration
Muscular Strength/endurance prescription(CAD and MI)
3-4 days /wk
2-4 sets; 12-15 reps; 8-10 various exercises
take as much time as needed
functional movements, circuit training, avoid straining and holding breath
Effects of exercise training
increased maximal oxygen consumption
improved ventilatory response
improved anaerobic and ventilatory threshold
relief of angina
modest decreases in bw, fat stores, bp, total cholesterol, serum triglycerides and LDL
Increases in HDL
Improved psychosocial well-being and self-efficacy
Protection against triggering MI by vigorous physical exertion
Decreased coronary inflammatory markers
increases numbers of endothelial progenitor cells and cells that promote angiogensis and vascular regeneration
Increased vagal tone and decreases adrenergic activity
Neurohumoral effects of exercise
decrease in norepinephrine, decrease in vasopressin, decrease in ang 2, decrease in aldostersone
Musculature effects of exercise
increase oxidative enzymes, increase mitochondria content, increase IGF-1. decrease proinflammatory cytokines, decrease oxidative stress
Inflammatory response of exercise
decrease in iNOS, TNF, IL-1B, IL-6, IL-10, CD4OL, P-selectin, GM-CSF, MCP-1, ICAM-1, VCAM-1
Cardiac Function effects of exercise
Increase Ca2+ sensititvity
Decrease myocyte contractility, improved hemodynamic, restoration of IP
Vasculature effects of exercise
increase in eNOS, NO, SOD, Endothelial function
Decrease in ROS, Oxidative Stress
Vascular reflex effects of exercise
increase of arterial baroreceptors, decrease in chemoreceptors
Nervous System effects of exercise
Decrease in Ang 2, decrease in AT1, decrease in ROS, increase in NO, decrease SNA, Increase in vagal activity