Term
When heart fails:
Objectives of therapy |
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Definition
-extend quality and support
-support failing heart
-manage the neurohumoral response
-manage vascular volume |
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Term
| Heart Failure: Mechanisms |
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Definition
-systolic failure (pump failure)
-diastolic failure (impeded diastolic filling)
-volume overload (excessive preload)
-pressure overload (excessive afterload) |
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Term
| Systolic Failure (diseases) |
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Definition
-DCM
-Muscular dystrophy
-taurine deficiency
-myocarditis
-arrhythmias |
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Term
| Diastolic Failure (diseases) |
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Definition
-HCM
-pericardial effusion
-pericarditis
-lymphosarcoma |
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Term
| Volume Overload (excessive preload) |
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Definition
-chronic valvular disease
-AV shunting |
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Term
| Pressure Overload (Excessive aterload) |
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Definition
-Lft Ventricle (systemic arterial hypertension/ aortic stenosis)
-Rt ventricle (pulmonary hypertension/ pulmonic stenosis) |
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Term
| Which of the following statements is correct? |
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Definition
| - pericardial effusion is most likely to cause a diastolic failure |
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Term
| Which of the following statements is correct? |
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Definition
| -Excessive preload would result in edema |
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Term
| Which of the following therapies would make the most sense for the following physiological dysfxns? |
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Definition
| -Diastolic failure may benefit from a drug that decreases the heart rate |
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Term
Goals of therapy:
Relieve edema and pleural effusion (reduce preload) |
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Definition
-Diuretics and aldosterone antagonists (spironolactone)
-ACE inhibitors and ARB's
-Venodilators (nitroglycerine) and O2 |
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Term
Goals of therapy:
Reduce cardiac workload (reduce afterload) |
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Definition
-ACE inhibitors and ARB's
-Peripherally-acting Ca channel blockers (Amlodipine)
-Arteriolar dilators in refractory cases (hydralazine, nitroprusside)
-Pulmonary hypertension reducers (sildenafil/ ACEI) |
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Term
Goals of therapy:
Improve pumping function (contractility) |
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Definition
Short term
-Catecholamines IV
-Phosphodiesterase IV (amrinone)
Long term
-Oral phosphodiesterase inhibitors (Pimobendan/milrinone)
-Digitalis glycosides (digoxin) |
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Term
Goals of therapy:
Improve filling fxn (diastolic filling) |
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Definition
Improve by reducing HR
-beta-blockers (propanolol,atenolol)
-Ca channel blockers (diltiazem/ verapamil)
Improve early diastolic relaxation
-Ca channel blockers |
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Term
ACE Inhibitors
Enalapril Factoid |
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Definition
-decreases atrial and ventricular filling pressures
-decreases peripheral vascular resistance
-increases CO and RBF
-good oral absorption
-RENAL ELIMINATION |
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Term
ACE Inhibitors
Benazepril and Ramipril Factoids |
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Definition
-RENAL & KIDNEY Elimination
-safer for animals with renal impairment
-SID/BID |
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Term
ACE Inhibtors
Side Effects |
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Definition
-GI distress, anorexia, vomiting, diarrhea
-hyperkalemia (uncommon)
-hypotension @ high doses or with other vasodilators
-renal dysfxn |
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Term
| Pimobendan (Vetmedin) Factoids |
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Definition
-phosphodiesterase III inhibitor
- (+) inotropic effects (sensitizes myofibrils to intracellular Ca)
-arterial and venous dilator
-reduction in plasma NE
-reduction in plasma cytokines |
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Term
Pimobendan (vetmedin)
Tx and contraindications |
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Definition
Tx
-CHF due to dilated cardiomyopathy/ Chronic MV insufficiency
Contraindicated in:
-HCM
-Valvular stenosis
-diastolic dysfxn |
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Term
Digitalis Glycosides
(Digoxin/ digitoxin)
Therapy |
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Definition
-(+) inotropic therapy
-variable PK and narrow therapeutic index |
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Term
Digitalis Glycosides
Therapy |
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Definition
- ^ myocardial contractility
- ^ vagal tone
- ^ diuresis and decreases edema secondary to inhibiting renal ATPase (inhibits renin release)
-decreases SNS tone
-normalize baroreceptor reflexes
- ^ myocardial O2 demand |
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Term
|
Definition
-IV and oral
-RENAL Elimination (variable depending on age, renal fxn, eddema, lean mass) |
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Term
|
Definition
-low
-tox common (cats)
-TDM
-drug interactions |
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Term
Digitalis Glycosides
TX and contraindications |
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Definition
Tx
-CHRONIC therapy of HF
-myocardial failure
-symptomatic supraventricular tachyarrhythmias
Contraindications
-hypertrophic cardiomyopathy
-cond with diastolic dysfxn
-Sinus or AV node dysfxn |
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Term
| Which of the following drugs would be contraindicated in the treatment of diastolic dysfxn? |
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Definition
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Term
|
Definition
-oral arterial dilator
-reduces afterload
-admin BID
-sig first-pass HEPATIC metabolism
-Alternative to ACEI |
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Term
|
Definition
-Hypotension/tachycardia
-serious GI disturbances |
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Term
|
Definition
-Ca-channel blocker (add-on)
-peripheral vasodilator |
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Term
|
Definition
-use in hypertensive or normotensive with refractory HF
-useful for FELINE hypertension
-use in DOGS refractory to ACEI + diruetics |
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Term
|
Definition
-venodilators
-preload reducer
-Oral and IV
-ACUTE tx of cardiogenic pulmonary edema
-improves coronary circulation and decreases myocardial oxygen demand |
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Term
|
Definition
Very potent afterload and preload reducer
-increases CO
-lowers arterial pressure
-lowers pulmonary capillary wedge pressure |
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Term
|
Definition
-FIRST CHOICE for emergency reduction of arterial BP (afterload)
-used wit dobutamine in cardiogenic shock secondary to DCM
-Constant IV rate infusion (m arterial BP)
-FAST-ACTING & SHORT-lived |
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Term
Catecholamines
Epinephrine |
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Definition
| -FIRST choice for cardiac arrest |
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Term
Catechlolamines
Epinephrine effects |
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Definition
Increases
-cardiac contractility
-HR
-BP
-CO |
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Term
|
Definition
Low Doses
-acute oliguric RF (renal vasodilation)
High doses
-cardiogenic shock |
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Term
Catecholamines
Dobutamine |
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Definition
| Limited to cases of severe intractable heart failure caused by myocardial failure |
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Term
Class 1 Antiarrhythmics
Na Channel Blockers |
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Definition
Slow down phase 0
-increase threshold for excitability
-inhibits spontaneous depolarizations |
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Term
Class 1A Antirrhythmics
Quinidine |
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Definition
-supraventricular and ventricular arrhythmias
-negative ionotrope
-ORAL USE ONLY |
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Term
Class 1A Antiarrhythmics
Procainamide |
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Definition
-supraventricular and ventricular arrhythmias
-IV
-short 1/2 life |
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Term
Class 1A Antiarrhythmics
Disopyramide |
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Definition
SECOND LINE
-refractory arrhythmia
-contraindicated in CHF
-potent (-) ionotrope |
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Term
Class 2A Antiarrhythmics
Lidocaine |
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Definition
-ACUTE life-threatening ventricular arrhythmias
-minimal effect on ionotropy
-IV ONLY |
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Term
Class 2A Antiarrhythmics
Tocainide |
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Definition
-follow up therapy to LIDOCAINE
-ORAL
-can cause renal in Dobies |
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Term
Class 2A Antiarrhythmics
Mexiletine |
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Definition
-follow up therapy to LIDOCAINE
-ORAL
-side effects less common |
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Term
Class 2 Antiarrhythmics
Beta-Blockers MOA |
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Definition
-inhibit sympathoadrenal excitation of the heart
-decreases myocardial O2 requirement
Negative
-ionotropic
-chronotropic
-dromotrophic |
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Term
Class 2 Antiarrhythmics
Beta Blockers
Non-selective |
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Definition
-Proponolol (p digitalized first)
-Carvedilol (vasodilator; used in CHF)
-Sotalol (also blocks K channels) |
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Term
Class 2 Antiarrhythmics
Beta Blockers
Selective (B1) |
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Definition
Inappropriate for animals with PULMONARY issues
-Atenolol
-Metoprolol
-Esmolol (IV) |
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Term
Class 2 Antiarrhythmics
Beta Blockers
Uses |
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Definition
-supraventricular tachycardias
-A-fib
-Refractory ventricular tachyarrhythmias
HCM |
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Term
Class 3 Antiarrhythmics
K+ channel blockers |
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Definition
-K channel inhibitors
-prolong AP
-prolong refractory period
-increase fibrillation threshold |
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Term
Class 3 Antiarrhythmics
Amiodarone |
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Definition
-supraventricular arrhythmias
-refractory ventricular arrhythmias
-combined with 1A/1C
-long 1/2 life after repeated doses |
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Term
Class 3 Antiarrhythmics
Sotalol |
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Definition
-Class 2 and 3 effects
-supraventricular and ventricular arrhytmias
-(-) ionotrope |
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Term
Class 4 Antiarrhythmias
Ca-channel blockers |
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Definition
Inhibit entry of Ca+ into cells in Phase 1 and 2
-contractile depression
-reduced CO |
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Term
Class 4 Antiarrhythmias
Diltiazem |
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Definition
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Term
Antiarrhythmic Therapy
Supraventricular arrhythmias |
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Definition
Acute
-diltiazem IV
-Esmolol IV
-Procainamide IM
Chronic
-Digoxin + B-blockers
-Digoxin + Ca channel blockers
-Digoxin + procainamide |
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Term
Antiarrhythmic Therapy
Ventricular tachycardias |
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Definition
Acute
-Lidocaine IV (life-threatening)
-Procainamide IV (2nd choice)
Chronic
-Mexiletine + atenolol
-Mexiletine + Procainamide
-Mexiletine + sotalol
-Mexiletine + atenolol |
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Term
| Which of the following drug combinations makes the most sense for the chronic treatment of DCM in a dog? |
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Definition
| ACEI + Furosemide + Pimobendan |
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Term
| Which of the following drug combos makes the most sense for the chronic tx of HCM in a cat? |
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Definition
ACEI + Furosemide
Nitroglycerine + Dobutamine + ACEI (acute) |
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Term
|
Definition
Mechanism of Chronic HF
-progressive diastolic dysfxn
-decreased myocardial contractility
-decreased stroke volume
Consequences
-CO insufficient to serve the needs of body
-Hypertension with pulmonary edema and ascites
-Arrhythmias may be present
ACUTE Therapeutic priorities
-Relieve fluid accumulation: diuretics (Furosemide IV)
-Improve pumping fxns: ionotropes (DOBUTAMINE/digoxin)
-Decrease hypertension: vasodilators (NITROGLYCERINE/ AceI)
-Acute antiarrhythmics (LIDOCAINE)
-OXYGEN supplementation |
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Term
| Chronic tx of DCM in a dog |
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Definition
-Relieve fluid accumulation: diuretics (furosemide/spironolactone)
-Improve pumping fxn: inotropes (pimobendan/digoxin)
-Decrease hypertension: vasodilators (ACEI/hydralazine)
-possible antiarrhythmics
-Taurine or L-carnitine supplementation |
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Term
|
Definition
-Diastolic dysfxn
-Myocardial fibrosis
-concentric hypertrophy lft ventricle |
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Term
|
Definition
-Decreased CO
-Excessive activation of RAAS
-excessive preload
-pulmonary and peripheral congestion
-pleural effusion
-Ventricular blood stasis
-thromboembolism |
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Term
HCM in Cats
Principles of Therapy
Asymptomatic Cats |
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Definition
-Empirical tx common
-ACEI, spironolactone, diltiazem, atenolol
Objective: slow/prevent dz progression |
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Term
HCM in Cats
Principles of Therapy
Cats with Symptoms: Resolve signs of Congestion (Option 1) |
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Definition
Furosemide
-inhibits Na/Cl resorption
-blocks kidney's ability to concentrate or dilute urine
-ACUTE setting
-IV/IM to relieve severe pulmonary edema
-fluid admin - discontinue use
Chronic
-maintenance therapy for life |
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Term
HCM in Cats
Principles of Therapy
Cats with Symptoms:Resolve signs of congestion (option 2) |
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Definition
Nitroglycerine
-preload reducer
-very short 1/2 life |
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Term
HCM in Cats
Principles of Therapy
Cats with Symptoms: Resolve Signs of Congestion (option 3) |
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Definition
Na Nitroprusside
-preload reducer
-very short 1/2 life (CRI) |
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Term
HCM in Cats
Principles of Therapy
Cats with Symptoms: Counteract RAAS activation |
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Definition
ACEI
-preload and afterload reducers
-prevent excessive RAAS activation |
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Term
HCM in Cats
Principles of Therapy
Cats with Symptoms: Improve diastolic fxn |
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Definition
B- Blockers
-Atenolol
-reduce HR
-reduce systolic anterior motion
Ca Channel Blockers (SECOND choice)
-Diltiazem |
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