Term
| • What is cardiogenic shock? |
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Definition
- Inadequate cellular metabolism secondary to cardiac dysfxn, despite adequate intravascular vol
- Dx based on clin demonstration of shock along w/ evidence of cardiac dysfxn
- Clin signs consis w/ global hypoperfusion
- Tx aims to restore cardiac output in order to normalize tissue perfusion and cellular metabolism |
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Term
| • What factors and parameters make up the cardiac output (CO) of patients? |
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Definition
- Product of stroke volume and heart rate SV x HR = CO
- Decrease in either can therefore lead to a reduction in cardiac output
- When pt has adequate intravascular vol but reduced cardiac output from cardiac dusfxn, a pt has forward failure. When forward flow failure is sufficient to cause inadequate tissue perfusion despite an adequate intravascular vol, the pt has cardiogenic shock |
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Term
| Response to a decrease in stroke vol |
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Definition
- Normal physio response is a compensatory increase in HR (and systemic vascular resistance) to maintain cardiac output
- This is due to a baroreceptor-mediated sympathetic stimulation to preserve BP and tissue perfusion
- A decrease in SV that cannot be reciprocally compensated for by a further increase in HR will lead to reduced cardiac output and forward flow failure
- Similarly, forward failure may result from a severe decrease in HR w/o a primary decrease in SV
- Cardiogenic shock will result if the forward flow failure leads to decreased tissue perfusion that does not meet cellular energy standards |
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Term
| • What factors make up cardiac stroke volume (SV)? |
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Definition
- Determined by preload, afterload and contractility
- Cardiogenic shock can ensue from alterations in any of these
- Systolic or diastolic dysfxn or arrhythmias can result in decreased SV, forward flow failure, and cardiogenic shock |
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Term
| • What are the most common causes of cardiogenic shock resulting from systolic dysfunction? |
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Definition
- Most common cause – dilated cardiomyopathy (DCM) (most common in dogs – dobie, boxer, Great Dane, Lab, Cocker – rarely seen in cats except w/ taurine deficiency)
- Sepsis
- Endomyocarditis |
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Term
| • What is the number one cause of cardiogenic shock in humans? |
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Definition
| - Myocardial infarction – rarely seen in dogs |
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Term
| • What is the number one cause of cardiogenic shock in humans? |
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Definition
| - Myocardial infarction (rarely in dogs) |
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Term
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Definition
- Due to inadequate ventricular filling
- Can result from hypovolemia, a physical restriction (cardiac tamponade), inability of the myocardium to relax (hypertrophic cardiomyopathy) or inadequate time for filling (tachycardia) |
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Term
| What will diastolic failure result in? |
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Definition
- A decreased preload and therefore a reduced stroke volume
- If pt unable to maintain cardiac output w/ an increase in HR, cardiogenic shock ensues |
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Term
| What is the most common cause of a decreased preload resulting in an inadequate cardiac output? |
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Definition
- Hypovolemia
- Corrected by restoration of intravascular vol and is therefore not truly cardiogenic shock |
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Term
| • What are the common clinical signs of congestive left heart failure? |
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Definition
- Tachypnea
- Dyspnea
- Coughing
- Orthopnea
- secondary to pulmonary edema |
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Term
| • Cats with congestive left heart failure commonly develop which condition or disease? |
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Definition
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Term
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Definition
- Present when the delivery of oxygenated blood is insufficient to meet the metabolic req of the body’s tissues
- May result from failure of any one or more of the various components of the circ; heart, vascular bed, the blood vol, or the conc of oxygenated hemoglobin (Hgb) in the blood |
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Term
| • What are the common causes of myocardial failure? |
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Definition
- Heart failure caused by a defect in myocardial contractility (systolic pump failure)
- Myocardial contractility is depressed in dogs/cats w/DCM. This is primary fxnl abnorm in these pts
- Not all pts w/ heart fail have decreased myo contr
- Acute rupture of a chordae tendineae
- Pericard effusion
- Constrictive pericarditits
- Acute PTE |
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Term
| • Which drugs would, and would not, be indicated in treating left heart failure? |
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Definition
| - IV furosemide or nitroprusside, w/ or w/o dobutamine |
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Term
| • If a patient with left heart failure is exercising, the production of which chemical in skeletal muscle results in the feeling of fatigue and forces the patient to stop? |
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Definition
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Term
| • Right sided vs left side heart failure |
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Definition
- w/ HF, congestion dev as a conseq of excessive venous pressure caused by the combined effects of increased plasma vol (sodium and water retention) and decreased venous capacitance (vasoconstriction)
Left side
- w/ impairment on left side, pulmonary venous pressure increases
- resulting in pulm edema (pulm capillary wedge press >25mmHg)and signs of resp distress, left-sided CHF
Right side
- systemic venous pressures rise
- resulting in hepatomegaly and ascites (central venous press >15mmHg, right sided CHF |
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Term
| Modern concept of heart failure |
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Definition
- body responds to declining cardiac output and reduced tissue perfusion by
1. retaining sodium and water in order to increase the blood vol
2. increasing HR and contractility in order to augment CO
3. inducing generalized vasoconstriction to maintain BP and ensure perfusion of vital organs such as the brain and kidney
- these compensatory responses help some for pts w/ developing heart failure
- eventually result in excessive sodium and water retention (leading to congestion and edema)
- as well as excessive vascular resistance (resulting in mismatching of afterload to contractility and declining CO
- vicious cycle whereby the compensatory responses evoked by heart failure cause a progressive decline in cardiac fxn, leading to further activation of the same compensatory responses, leading to more decline |
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Term
| • What are the four basic types of feline cardiomyopathy? |
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Definition
- DCM
- Hypertrophic cardiomyopathy (HCM)
primary heart muscle dz – (genetic basis) ventricular hypertrophy dev in absence of hemodynamic or metabolic cause
gen hypertrophy of a nondilated ventricle , altho sys dysfxn and wall thinning occas occur w/ long-standing HCM
- Restrictive cardiomyopathy (RCM)
Disorder in which impaired ventricular filling occurs in the absence of myocardial hypertrophy or pericardial dz
Structural features of RCM varied and dx criteria not rigidly defined
Term gen applied when there is atrial enlargement assoc w/ a ventricle that has a normal or nearly normal appearance
Cause not known
Presumed explanations for dias dysfxn and resultant atrial enlargement – endomyocardial fibrosis and myocardial fxnl deficits that impair relaxation
May sometimes be the sequelae of endomyocardial inflammation
- Arrhythmogenic tight ventricular cardiomyopathy |
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Term
| • What accounts for almost all acquired cardiac disorders in the cat? |
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Definition
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Term
| • What effect does heart failure have on the heart rate of cats? |
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Definition
- Seldom higher than normal
- Occas bradycardia from a low sinus rate or AV conduction disturbances |
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Term
| • Which drugs are used in the acute treatment of feline HCM? |
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Definition
| - Diuretic tx – furosemide – high ceiling loop diuretic that inc urine prod and reduces intravascular vol and venous pressures |
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Term
| • Which drugs are used in the long-term management of feline HCM? |
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Definition
- Mgmt. of dias dysfxn - drugs that slow HR or speed myocardial relaxation or both
- B-adrenergic antagonists such as atenolol indirectly improve ventricular filling by lowering HR (bene when tachy contributes to dias dysfxn,when dynamic left ventricular outflow tract obstruction is caused by SAM – systolic anterior motion- of the mitral valve and when complicated by tachyarrhythmia)
- Diltiazem (benzothyiazepine calium channel antagonist)
Minor slowing effect on HR but speeds myocardial relaxation, resulting in reduced filling pressures
May also dilate coronary arteries and improve dias fxn by improving coronary perfusion
Little effect on outflow tract obstruction caused by SAM
- Enalapril (ACE inhibitor)
Interrupts the enzymatic conversion of angiotensin I to angiotensin II it has diverse neuroendocrine effects
> resultant drcrease in aldosterone activity may be bene by decreasing the renal retention of salt and water
? also, aldosterone and angiotensin II have been implicated as trophic factors that might be relevant to the development of hypertrophy and fibrosis
ACE inhibitors are vasodilators, altho weak effect |
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Term
| • Long-term therapy for feline myocardial disease is best guided which diagnostic findings? |
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Definition
| - Echocardiographic findings |
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Term
| • DCM typically affects which sized dogs? |
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Definition
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Term
| • What is the role of pleurocentesis and abdominocentesis in treating canine cardiomyopathy? |
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Definition
| - To relieve chronic signs |
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Term
| • What are the possible nutritional causes of canine DCM? |
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Definition
- L-Carnitine deficiency
- Taurine deficiency
- Vit E, selenium deficiency |
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Term
| • Which breeds and sizes of dogs most frequently develop atrial fibrillation? |
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Definition
| - Giant breeds w/ DCM such as Great Danes, Irish Wolfhounds, and Newfies |
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Term
| • What are the treatments of myocardial failure in canines? |
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Definition
- An emergency
- Needs low-stress environment
- O2
- Diuretics
- Vasodilators
- Inotropic support |
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Term
| • What are the signs and symptoms of acquired degenerative valvular disease in dogs? |
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Definition
- Aka MVD – myxomatous valvular degeneration
- Rarely feline
- Small dogs commonly
- Hx of cardiac murmur (often chronic)
- Cough, dyspnea, exercise intolerance, syncope, collapse
- PE findings w/ left-sided failure attributable to pulm edema
Dyspnea, orthopnea, cyanosis and abnormal lung sounds
Poss tachyarrhythmias ( sinus tachy, atrial premature contractions or atrial fibrillation may also be noted
- PE findings w/ right- sided failure
May result in the accumulation of pleural effusion or ascites, w/ dereased ventral lung sounds or abdo distention, respectively
Jugular distension or pulsation |
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Term
| • What is the prognosis for MVD compared to other cardiovascular diseases in dogs? |
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Definition
- In general, more favorable
- 1 – 2 yr preclinical phase w/ excellent quality of life, few clinical signs
- When CHF signs dev, prog worsens
- Med therapt poss approx. 1 yr of good-quality life after CHF onset
- Pts w/ ruptured major chordae tendineae or a ruptured left atrium poor or grave prog
- When pts decompensate after long term oral meds, aggressive parenteral tx may result in partial recovery and home w/ oral meds |
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Term
| • Virtually all patients with acquired degenerative valve disease that have congestive heart failure will have an audible cardiac murmur in which cardiac position? |
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Definition
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Term
| • What are the goals of emergency therapy in patents with MVD? |
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Definition
- Relieve signs of congestion
- Improve forward cardiac output
- Improve tissue oxygenation and nutrient delivery |
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Term
| • What are the most common physiologic consequence of myocardial injury in dogs and humans? |
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Definition
- arrhythmias
- Conduction defects |
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Term
| • Arrhythmias associated with myocardial injury may be delayed in onset up to how many hours? |
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Definition
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Term
| • Which findings and cardiac chemical levels on admission in traumatized human patients are an efficient way to rule out myocardial injuries and arrhythmias associated with trauma? |
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Definition
| - Normal ECG findings and cardiac troponin levels |
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Term
| • Which cardiac-specific proteins are effective biomarkers of myocardial injury in dogs? |
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Definition
| - Normal ECG findings and cardiac troponin levels |
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Term
| • What is the role and indications for Holter monitoring, or continuous electrocardiographic monitoring, in high-risk patients? |
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Definition
| - Most sensitive and least invasive but has long turnaround time |
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Term
| • What are the class I antiarrhythmic agents that are used commonly to manage ventricular ectopy associated with myocardial injury? |
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Definition
| - Lidocaine and procainamide |
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Term
| • What are the most commonly reported physical examination findings in dogs with myocardial infarction? |
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Definition
| - Dyspnea, tachycardia, arrhythmias, cardiac murmurs and signs attributable to other concurrent systemic dz |
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Term
| • What are the most common arrhythmias associated with myocardial infarction? |
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Definition
| - Sinus tachycardia, followed by ventricular tachy, a-fib and VPCs |
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Term
| • What is the prognosis for animals with severe acute myocardial infarction? |
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Definition
- Poor
- Largely dependent on severity of clinical signs, underlying dz process, response to therapy |
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Term
| • What is the most definitive confirmation of myocardial infarction in dogs? |
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Definition
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Term
| • The goal of antihypertensive therapy is to reduce the magnitude, severity, and likelihood of further end-organ damage. That is generally recognized to reduce systolic BP from how many to how many mm Hg? |
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Definition
| - 110 to 150 mm Hg, generally w/in 4 – 12 hrs |
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Term
| • What are the possible physiological consequences of high BP measurements in small animal patients? |
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Definition
- Usually eyes, brain
- Ocular lesions
- Neurologic clin signs incl hypertensive encephalopathy, altered mentation, disorientation, lethargy, seizures, head tilt, nystagmus, behavioral abnormalities and focal neuro deficits
- Renal - enhanced rate of decline of renal fxn, early renal death and proteinuria
- Cardiovascular – cardiac changes incl systolic murmurs and cardiac gallops and left ventricular hypertrophy |
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Term
| • What are the diagnostic and treatment parameters, and criteria, for hypertension in small animals? |
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Definition
| - Based on measurement of the patient’s BP following a standard protocol, and a thorough PE concurrently to assess end-organ damage |
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Term
| • The diagnosis and treatment of hypertension must be based on the patient's BP. That BP is measured by which means? |
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Definition
- Directly by intraarterial means or indirectly by devices w/ compressive cuff
- 3 – 7 consecutive indirect measurements (to avoid false readings from stress or anxiety).
- Based on systolic BP
- Gen rule is at least 2 measurement sessions at least 30 min apart brfore starting therapy, unless presence of ocular or neuro end-organ damage (emergency) |
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Term
| ACVIM system for classification of systolic BP levels based on risk for further end-organ damage |
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Definition
- I - <150 – minimal
- II – 150-159 – mild
- III – 160-179 – moderate
- IV - >/= 180 severe |
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Term
| • Which drugs are indicated for the emergency management of hypertension? |
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Definition
- Rapid onset of action
- Hydralazine IV/IM
- Enalaprilat IV
- Labetalol IV
- Esmolol IV
- Amlodipine Oral
- Many prefer oral calcium channel blockers, lower w/in 4 – 6 hrs, limited risk of hypotension or BP instability |
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Term
| • What are the characteristic echocardiographic findings with cardiac tamponade? |
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Definition
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Term
| • What is the immediate treatment of choice for cardiac tamponade? |
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Definition
| - Immed pericardiocentesis |
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Term
| What are the best methods to immediately diagnose cardiac tamponade in a trauma patient? |
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Definition
- thoracic rads and esp echocardiogram
- often already suspected from the hx/PE |
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Term
| • What are the most common causes of pericardial effusion in dogs? |
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Definition
- Hemangiosarcoma
- Idiopathic pericardial effusion
- Malignant mesothelioma (MM)
- Heart base tumors |
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Term
| • What is the main immediate clinical tool for diagnosing pericardial effusion and/or cardiac masses? |
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Definition
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Term
| • Which procedure allows the definitive detection of any cardiac-associated masses and provides pericardial tissue for histopathologic analysis? |
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Definition
| - Exploratory thoracotomy |
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Term
| • Slowed conduction through the AV conduction system results in a prolongation in which interval, or first-degree AV block? |
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Definition
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Term
| • What are, and are not, examples of cardiac bradyarrhythmias? |
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Definition
- Sinus bradycardia – tx unneeded unless clinical signs, underlying signs. If symptomatic, chronic anticholinergic tx
- Sinoatrial block
- Sinus arrest
- Escape beats
- Sick sinus syndrome – tx – gen pacemaker to prevent syncope |
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Term
- Sinus bradycardia – tx unneeded unless clinical signs, underlying signs. If symptomatic, chronic anticholinergic tx
- Sinoatrial block
- Sinus arrest
- Escape beats
- Sick sinus syndrome – tx – gen pacemaker to prevent syncope |
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Definition
- AV block refers to conduction disturbances that alter conduction of the cardiac elec impulse from the sinus node to the ventricles
- Altered intratrial conduction, altered AV junctional conduction, altered bundle of His conduction and altered conduction in both bundle branches simultaneously can alter AV conduction. |
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Term
| • How are AV blocks classified? |
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Definition
| - First-degree, second-degree, and third-degree AV blocks |
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Term
| • Second-degree AV block occurs when and is divided into which types? |
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Definition
- Occurs when some sinus depolarizations conduct through the AV junction to reach the ventricles and others don’t. Heard as “dropped beats” produces an abnormal heart rhythm
- Divided into
Type I (Mobitz Type I), or Wenckebach, second-degree AV block, the PR interval progressively prolongs before the blocked beat. PR interval before the block may be normal or too long (1st degree0
Type II (Mobitz Type II) second degree AV block – sudden failure of conduction w/o alteration in the PR interval. Interval may be normal or prolonged
Second degree AV blocks commonly labeled w/ the # of P waves followed by the # of QRS complexes generated.
Ex: if q other sinus deploraization is blocked from reaching the ventricles, called a 2:1 second degree AV block.
Ex: if q fourth P wave is not followed by a QRS complex, called a 4:3 AV block (4 P waves, 3 QRS complexes)
3rd type of block is high-grade block – any block that is 2:1 or gtr cant be classified as type I or type ii because there is ni chance to determine whether progressive prolongation is occuring |
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Term
| • What are third-degree AV blocks? |
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Definition
- Third degree (complete heart block) occurs when there is no conduction between the sinus node and the ventricles.
- Sinus node depolarizes at its own inherent rate, depolarizing the atria and producing P waves, whereas the ventricles are depolarized by a subsidiary pacemaker (either the AV node or Purkinje fibers) that depolarizes at a slower rate, depolarizing the ventricles and producing QRS complexes. On ECG no relationship between the P waves and QRS complexes (AV dissociation) so varying PR intervals from beat to beat, atrial rate and vent rate often constant in that the P-P intervals and R-R intervals are constant |
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Term
| • What is the preferred treatment of third-degree AV blocks? |
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Definition
| - Implantation of an external pacing generator and lead (artificial pacemaker) |
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Term
| • What is the most effective vagal maneuver in small animals for the treatment of SVTs? |
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Definition
- SVTs (supraventricular tachyarrythmias) – rapid rhythms from or dep on tissues above the ventricles
- Carotid sinus massage |
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Term
| • What are the signs and symptoms of SVTs? |
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Definition
- Decreased exercise intolerance
- Weakness
- Collapse
- GI signs (esp V/anorexia)
- Very rapid HR (esp in lat recumb)
- Dyspnea
- Tachypnea
- Abdo distention
- Pulsing of the ears or bobbing of the head with each beat |
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