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13 Cards in this Set
- Front
- Back
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Name the two types of compensation to Ht failure. Characterize them.
Is apoptosis affected by Ht failure? |
Extrinsic:
- involves sympathetic nervous sys and renin-a-a system - baroreceptor rflx reset --> reduced baro input to vasomotor sys --> increased sym outflow, dec para => tachy, ^contractility, ^vascular tone... At first this ^CO, but then as ^AL due to vasotone, \CO. => \renal perfusion and ^sym outflow --> ^angII --> water and salt retention --> **edema** Intrinsic: - myocardial hypertrophy due to ^work and ^angII --> initially helps but later leads to performance decreases. Yes, increased. |
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Which of the following sx result directly from reduced CO, and which are from compensatory mechanisms?
- decreased exercise tolerance - tachycardia - edema - enlargement of the heart |
only decreased exercise tolerance is directly linked to reduced CO
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Cardiac failures primarily arise as a result of decreased _____ of the ht, particularly the ventricles.
What is the most common etiology? |
contractility
CAD |
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Drugs commonly used in heart failure include diuretics, ACE inhibitors, angiotensin receptor blockers, cardiac glycosides (^contractility), B-blockers, bipyridines, B-agonists, and vasodilators. Dietary salt restriction is also useful.
But! which targets (and which drug types) are the ones that have proven most useful? |
cardiac glycosides *were* the traditional drug
...but! it seems that things that target non-ht things are the only ones that improve outcomes: - ACE-inhib - B-blockers - sprinolactone Other drugs are good for the sx relief of the pt. |
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The term 'digitalis' is used synonymously with which class of drugs? What is the classic example of this class?
Is it's therapeutic index wide or narrow? Why? What is the primary target of this class? What does this cause? |
Cardiac Glycosides.
Digoxin. Narrow, b/c it's pretty much a poison that we're using as a drug. s. inhibit Na/K ATPase --> increase in intracellular Na, which decreases the gradient needed to get Calcium *out* of the cell --> ^[Ca]intra --> increase in contractility. -- also increase vagal tone. |
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Inamrinone, milrinone
- class? - mech? - primary basis for their usefulness in ht failure? - relative toxicity? |
- bipyridines
- selectively inhib PDE3 --> ^cAMP --> ^ inward Ca flux --> ^contractility act as **vasodilators** by ^cAMP --> ^PKA --> phos's myosin light chain kinase --> inactivated... this decreases the amnt of phos'd myosin. --> decreases the amnt of Ca sensitive smooth muscle ... also stim Ca sequestration by the SR. toxic, NOT the most preferred drugs for Tx of ht fail. |
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What is the most widely used B-agonist to tx ht failure? Mechanism?
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Dobutamine (B1-selective)
- increases cardiac contractility / CO bia PKA and increased intracellular Ca. |
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How are diuretics helpful in Heart failure?
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increase urine volume --> reduction of venous pressure and ventricular preload via lowered body fluid volume --> improved efficiency of the faltering pump.
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ACE inhibitors do what in ht failure? How might they actually be reducing mortaility? Example drug?
ARBs? |
reduce Peripheral resistance --> decrease AL. Also reduce salt and water retention via reducing aldosterone secretion.
captopril **reduce the long-term remodeling of the ht and vessels ARBs act similarly. |
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Are vasodilators high up on the list of useful drugs in Ht failure? How do they help?
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No, further down the list.
Reduce PL via venous dilation, and reduce AL via arterial dilation. |
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Beta blockers have pronounced _____ ionotropic and chronotropic effects. Do they increase or decrease mortaility in ht failure?
Which are helpful? (3) |
negative
decrease mortality; reasons unkonwn. Bisoprolol, carvedilol, metoprolol "meet buy carve" |
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What *was* the traditional remedy for Ht failure? (two drugs) Now?
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digitalis + diuretic
Now digitalis is reserved for those that don't respond to diuretics, ACE inhibitors, and B-blockers. |
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Order the following w.r.t. ***current*** ht failure therapy:
digitalis & beta-blockers ACE-inhib & ARBs control workload (HTN, etc.) B-agoinsts & Vasodilators Diet Na restrict / diuretics |
control workload (HTN, etc.)
Diet Na restrict / diuretics ACE-inhib & ARBs digitalis & beta-blockers B-agoinsts & Vasodilators |
