Chronic Heart Failure Flashcards
How does exercise training reduce peripheral resistance?
- Decreases circulating catecholamine levels therefore causing an anti-inflammatory and antioxidative effect
- Decreases natriuretic peptide concentrations therefore increasing shear stress and Nitric oxide formation
How could aerobic training increase LVEF?
Improve: preload, myocardial contractility and augmented vascular reserve
Is LV remodelling possible through exercise in stable HF patients?
Yes
What is a major problem in all HF patients when it comes to exercising?
Adherence
What mode is preferred in HF patients?
Cycling - because of the reproducible power output, the possible low workloads and reduced injury rate.
What is now accepted as the limit for prolonged aerobic exercise without additional risk for patients with HF?
VT - (65–90% of VO2peak)
True or False: HF patients with significantly reduced pre-training VO2peak and/or high exercise-related risks, aerobic training intensities as low as 40% of VO2peak is effective
True
True or False: The risk of a cardiovascular event is low after both high-intensity exercise and moderate-intensity exercise in a cardiovascular rehabilitation setting.
True
Why is sustained maximal isometric exercise contraindicated in HF patients?
Because of the excessive rise in blood pressure and the lowering of the stroke volume.
Patients with HF with preserved ejection fraction (HFPEF) present a combination of:
Systolic and diastolic abnormalities
HF with preserved ejection fraction is primarily due to:
- Reduced cardiac output, secondary to an inability to increase the end-diastolic and stroke volume via the Frank–Starling mechanism
What 2 factors contribute significantly to the exercise intolerance in HF patients?
- Reduced arteriovenous oxygen difference
2. Reduced cardiac output
True or False:
The arteriovenous oxygen reserve is an independent predictor of VO2peak, which strongly suggests that peripheral factors at least partly determine the limited exercise tolerance in these patients
True
True or False:
Activities with pronounced arm–shoulder movements should be avoided, especially during the first 2 months after implantation of an ICD.
True
Exercise training attenuates:
- Neurohormonal stimulation
- Production of proinflammatory cytokines
- Over-expression of natriuretic peptide
True or False:
Symptoms and disease progression in HF does NOT involve alteration of peripheral organs and neurohormonal activation
False - It does
What is the HR response in HF patients and what does this lead to?
- Increased at rest, decreased at peak exercise
Leads to a reduction of the chronotropic reserve, because of desensitisation of b-adrenergic receptors.
True or False:
Exercise training has a beneficial effect on the sympathetic nervous system, even in patients receiving a beta-blocker
True
True or False:
In HF patients - SV during exercise, increases less than in healthy subjects or, more often, decreases.
True
True or False
Interval training programme is NOT associated with a greater improvement in LVEF than a continuous or steady-state programme
False - It is
What limits exercise the most in HF patients central or peripheral factors?
It is usually the periphery
How does HF affect ventilation?
Increase in dead space and Ve/VCO2 slope
Reduces ventilatory efficiency
How does HF contribute to myopathy?
Decreased: muscle mass and oxidative muscle metabolism
True or False:
When CO during exercise is increased in patients with severe HF, maximal VO2 increases minimally because arteriovenous oxygen difference does not increase in parallel
True
What are the key phenomenon in the blunted vasodilatory response to exercise in CHF patients
Abnormalities in endothelium- and flow-dependent vasodilatation
How does exercise training reduce peripheral resistance in HF patients?
Improves both basal endothelial nitric oxide formation and agonist-mediated endothelium-dependent vasodilation
Muscle atrophy occurs because of:
Malnutrition, deconditioning
and the toxic action of cytokines
How does exercise training increase muscle capacity?
By increases in:
- myofibril cross-sectional area
- mitochondrial density
- volume density of cytochrome c oxidase-positive mitochondria
- capillary density
True or false:
A higher intensity level of exercise training (70% of peak VO2 ) seems to be necessary to obtain a significant reshift to type I fibre, with a
significant increase in type I fibre and a significant decrease
in type II fibre.
True
True or false:
The slope relating ventilation to oxygen uptake (VE/VCO2 slope) is decreased
in chronic HF patients and is a potent prognostic factor.
False - It is increased
True of false:
Both interval training and continuous training is associated with reverse left ventricular remodelling
False - Just interval training had significant LV remodelling
CHF is characterised by:
Inability of the heart to deliver oxygen to the working tissues (due to systolic and/or diastolic dysfunction)
Systolic Dysfunction:
Impaired ventricular CONTRACTION because of the loss of myocardium (from infarction) or loss of CONTRACTILITY.
Diastolic Dysfunction:
Impaired ventricular FILLING, increased diastolic pressure and reduced COMPLIANCE
4 main central haemodynamic changes in CHF include:
- Decreased CO during exercise or rest
- High LV diastolic pressure
- Ventricular volume overload
- Elevated pulmonary and central venous pressure
Hallmark signs and symptoms of CHF:
Fatigue, dyspnea and reduced exercise tolerance
Hyperventilation and early onset of fatigue in individuals with CHF is largely due to:
Inadequate BF to the working muscles as well as an early accumulation of lactate in the blood at low work rates
Contractility is reduced in CHF because:
Elevated levels of catecholomines and less sensitive beta-adernergic receptors alter normal inotropic regulation of the heart.
How is exercise capacity affected by abnormal skeletal muscle abnormalities?
- Reduced mitochondrial enzyme activities
- Reduced Type 1 aerobic fibres, more Type 2 fibres
These cause glycolysis, reduced oxidative phosphorylation and greater metabolic acidosis
True or False:
Improvements in exercise capacity are due to cardiac changes not peripheral adaptations in patients with CHF?
False - Mainly because of peripheral adaptations ( improvements in muscle metabolism, endothelial function, vasodilation capacity and CO)
CHF is managed in two ways:
1: Identify cause (eg stenosis, HTN)
2: Reduce overload with drugs
Why are diuretics prescribed for CHF patients?
To reduce salt and water retention
What drugs would reduce after-load?
ACE inhibitors and Vasodilators
How do B-Blockers help patients with CHF?
Slows the sympathetic system therefore reduces the risk of damage to the failing heart due to adernergic stimulation
How does medication differ between diastolic and systolic dysfunction?
Diastolic doesn’t need positive inotropic drugs, but CCB’s help with ventricular realxation and increase EDV, therefore increase functional capacity.
ICD’s and CRT are used in CHF to:
Synchronise left and right ventricular contraction (to increase CO)
Why is the CPX information more helpful compared to the ECG during testing?
- Can see gas exchange in response to exercise
- quantify exercise tolerance
- may be able to identify pathophysiological abnormalities that limit exercise capacity
How are CPx values different during exericse in CHF patients compared to healthy people?
Lower CO Peripheral vascular resistance is high High ventilation Decreased EF, SV Exertional hypotension
Considerations to exercise testing in CHF:
Symptoms come on at lower MET levels (usually
True or False:
Target HR should be used as a criteria to terminate exercise testing
False - Should focus on haemodynamic responses and standard termination criteria
Modes of testing recommended in CHF:
Cycle (ramp - 10-15 W increments)
6MWT
Functional test similar to ADL’s
Exercise Recommendations for CHF:
Aerobic:
Large muscle activities 40-70% VO2peak, 4-7 days/week, 20-60min a session or broken up in smaller bouts
RT:
Circuit, High reps low weight
Flexibility:
2-3 days/week
Functional:
Activity specific
What causes HF?
It develops after other conditions have damaged or weakened your heart. It can also occur if the heart becomes too stiff.
Ejection Fraction is:
An important measurement of how well your heart is pumping and is used to help classify heart failure and guide treatment.
What is the Ejection Fraction in a healthy heart?
50% or more (This means that 50 percent of the blood in the heart is pumped out with each beat)
Describe Left-sided heart failure:
Fluid may back up in your lungs, causing shortness of breath.
Describe Right-sided heart failure
Fluid may back up into your abdomen, legs and feet, causing swelling.
Systolic heart failure:
The left ventricle can’t contract vigorously, indicating a pumping problem.
Diastolic heart failure:
(also called heart failure with preserved ejection fraction) The left ventricle can’t relax or fill fully, indicating a filling problem.
How can CAD lead to HF?
A heart attack occurs if plaques formed by the fatty deposits in your arteries rupture. This causes a blood clot to form, which may block blood flow to an area of the heart muscle, weakening the heart’s pumping ability and leaving permanent damage.
How can HTN lead to HF?
If your blood pressure is high, your heart has to work harder than it should to circulate blood throughout your body.
Over time, the heart muscle may become thicker to compensate for the extra work it must perform. Eventually, your heart muscle may become either too stiff or too weak to effectively pump blood.
How can abnormal heart rhythms (heart arrhythmias) lead to HF?
It may cause your heart to beat too fast, which creates extra work for your heart. Over time, your heart may weaken, leading to heart failure. A slow heartbeat may prevent your heart from getting enough blood out to the body and may also lead to heart failure.
