Lesson 67 - Congestive Heart Failure

A patient experiences severe blood loss after an injury. As a response, the body increases heart rate, but the stroke volume decreases significantly because there is less blood returning to the heart.

What is the most likely effect on cardiac output?

Cardiac output decreases because the drop in stroke volume is larger than the increase in heart rate.

What is the equation for cardiac output?

stroke volume x heart rate

A patient receives a large amount of intravenous fluids, which increases the amount of blood returning to the heart.

Based on Frank-Starling Mechanism, what is the most likely effect on the heart?

The ventricles fill more, stretch more, and contract more forcefully, increasing stroke volume.

What are the hearts priorities?

1. maintain normal systemic arterial pressure

2. maintain normal tissue blood flow

3. maintain normal systemic and pulmonary capillary pressures

A patient is given a drug that causes strong vasoconstriction in the arteries. What is the most likely immediate effect on stroke volume?

Stroke volume decreases because the ventricle must overcome greater resistance to eject blood.

What are the basic concepts to remember?

1. bad hearts get big

2. you can pace a heart to death

3. hearts like to fail backward

A middle-aged dog presents with coughing, exercise intolerance, and mild labored breathing. On physical exam, you hear a soft heart murmur and notice mild pulmonary crackles. Which diagnostic test would be most appropriate to run first?

thoracic radiographs

What can be evaluated or detected on thoracic radiographs?

1. cardiomegaly

2. vascular abnormalities

3. congestive heart failure

4. lungs

5. pleural space

What lung pattern can be seen on this radiograph?

air bronchogram/alveolar pattern

What organs are at risk with an elevated BP?

1. eyes

2. brain

3. kidneys

4. heart

What does doppler evaluate?

systolic blood pressure

What heart rate changes would you expect to see with cardiac disease?

tachycardia

Which diagnostic test would you use to directly evaluate the heart's internal structures?

echocardiography

A veterinarian wants to precisely measure a dog's left ventricular chamber dimensions during diastole and systole to calculate fractional shortening and assess contractility.

Which diagnostic test would be most appropriate for this purpose?

M-mode echocardiography

A veterinarian suspects a dog has mitral valve thickening and chamber enlargement. They want to visualize the overall structure of the heart, valves, and chamber shapes in real time.

Which diagnostic test would be most appropriate for this purpose?

B-mode echocardiography

A young dog is suspected of having a patent ductus arteriosus (PDA). The veterinarian wants to visualize abnormal blood flow between the aorta and pulmonary artery, including direction and turbulence.

Which diagnostic test would be most appropriate?

Color doppler echocardiography

A dog presents with coughing, labored breathing, and exercise intolerance. You perform a thoracic ultrasound and see this.

What is the most likely clinical interpretation of this Echocardiogram?

pulmonary edema from congestive heart failure

A dog presents for a routine check-up and has no respiratory signs. A thoracic ultrasound shows this.

What is the most likely interpretation of this echocardiogram?

normal aerated lung

What are the blue labeled arrows?

rib shadows

What is the green labeled arrow?

pleural line

What are the unlabeled arrows?

A-lines

What are common cardiac conditions in horses?

1. arrhythmias

2. AV blocks

3. atrial fibrillation

A dog is presented with episodes of fainting and irregular heartbeats noted by the owner. On physical exam, the heart rate is irregular, but heart murmurs are absent.

Which diagnostic test would be most appropriate to evaluate the electrical activity of the heart in this dog?

electrocardiogram

What are common cardiac conditions of ruminants?

1. ventricular septal defect

2. high mountain disease

3. endocarditis

4. lymphosarcoma of right atrium

5. pericardial disease

6. electrolyte abnormalities

7. selenium deficiency

What are the common cardiac conditions with cats?

hypertrophic cardiomyopathy phenotype

What are the common cardiac conditions with dogs?

1. mitral valve disease

2. dilated cardiomyopathy

3. arrhythmogenic right cardiomyopathy

4. arrhythmias

5. congenital issues

What cardiac condition is most common with old small-mid sized dogs?

mitral valve disease

What cardiac condition is most common with big dogs and possibly dietary effects?

dilated cardiomyopathy

What cardiac condition is most common in boxers?

arrhythmogenic right cardiomyopathy

What can cause HCM phenotype in cats?

1. hypertension

2. reduced preload

3. neoplastic infiltration

4. transient myocardial thickening

5. acromegaly

6. hyperthyroidism

A middle-aged dog presents with coughing, exercise intolerance, and labored breathing. On thoracic auscultation, you hear crackles in the lung fields. Thoracic radiographs show pulmonary edema and mild cardiomegaly.

Which side of the heart is most likely failing?

Left-sided heart failure

A cow presents with abdominal distension and swelling of the hind limbs. On physical exam, you notice jugular vein distension and hepatic enlargement. The animal has no cough and lungs sound normal.

Which side of the heart is most likely failing?

Right-sided heart failure

What can be seen with congestive heart failure?

1. pulmonary edema

2. pleural effusion in cats

3. hepatic congestion/ascites

4. jugular vein distension/pulses

5. cachexia

You suspect congestive heart failure in a horse presenting with exercise intolerance and abdominal distension. Which physical exam parameter would be most useful to evaluate to support your suspicion?

Jugular vein distension

A veterinarian evaluates two dogs with respiratory distress:

Scenario 1:

Dog is coughing and breathing rapidly

Auscultation: diffuse crackles in all lung fields

Percussion: normal resonance

Thoracic ultrasound: multiple vertical B-lines in lung parenchyma

Scenario 2:

Dog has labored breathing and lethargy

Auscultation: lung sounds diminished ventrally, louder dorsally

Percussion: dull over ventral thorax

Thoracic radiographs: fluid layering in pleural space with partial lung collapse

Which scenario corresponds to pulmonary edema and which to pleural effusion?

scenario 1: pulmonary edema, scenario 2: pleural effusion

What will happen to CO with HCM?

decreases

What valve opens at the end of isovolumetric contraction?

pulmonic and aortic

What valve opens at the end of isovolumetric relaxation?

mitral and tricuspid

What valve closes at the beginning of isovolumetric contraction?

mitral and tricuspid

What valve closes at the beginning of isovolumetric relaxation?

aortic and pulmonic

What is the end stage result with many cardiac diseases?

congestive heart failure

A middle-aged dog presents with difficulty breathing that worsens when lying down. The owner notes the dog prefers to stand with its elbows abducted and neck extended.

Which term best describes this clinical sign?

orthopnea

A dog presents with rapid, shallow breathing and labored inspiration. What is the most appropriate immediate diagnostic or therapeutic procedure?

thoracocentesis

What can cause dyspnea?

pulmonary edema

What can cause hyperpnea?

hypoxia, hypercarbia

A dog presents with rapid and deep breathing after strenuous exercise. Which term best describes this breathing pattern?

hyperpnea

What clinical signs coincide with a restrictive breathing pattern?

short and shallow breaths, tachypnea

What can cause increased venous pressure?

1. right sided failure

2. pericardial disease

3. volume overload

4. cranial mediastinal mass

What can cause right sided heart failure?

1. tricuspid disease

2. pulmonary hypertension

3. caval syndrome

On physical exam, what is something you can look at to see if the patient has any weakness in their limbs?

toenails to see if they are dragging their feet

What are the main clinical signs owners will notice with cardiac disease?

1. syncope

2. exercise intolerance

3. cough

What can cause a patient to cough?

1. mainstem bronchi compression from enlarged heart

2. congestive heart failure

3. respiratory and parasitic disease

4. pneumonitis, HWD, lungworms

5. non-cardiac disease

A 7-year-old cat presents with rapid breathing and exercise intolerance. On physical exam:

Lung auscultation reveals diffuse crackles and wheezes

Heart sounds are normal

Thoracic radiographs show patchy interstitial and alveolar patterns throughout the lungs

What is the most likely system affected and cause of the clinical signs?

Respiratory - primary lung disease

A 6-year-old dog collapses briefly during exercise. The owner reports the dog recovers quickly and seems normal afterward. On physical exam:

Heart rate is irregular

Auscultation reveals a systolic murmur

No neurological deficits are noted

What is the most likely cause of these episodes?

Syncope due to cardiac arrhythmia

A 5-year-old dog is brought in after having a sudden episode of collapsing, stiffening, and paddling of all four limbs. During the episode:

The dog loses consciousness

There is urination and salivation

After the episode, the dog is disoriented for 5-10 minutes

What is the most likely cause of this event?

Seizure due to idiopathic epilepsy

What are key signs of syncope?

1. occurs with excitement or exercise

2. rear limb weakness

What mucous membrane change can be seen with PDA?

red head and blue butt

What do we want to evaluate on physical exam for cardiac patients

1. mucous membranes and CRT

2. abdominal palpation

3. jugular pulses

4. palpate the chest

5. arterial pulse abnormalities

6. palpate the thyroid

7. retinal exam

A 12-year-old cat presents with sudden blindness. On ophthalmic exam:

Retinal hemorrhages are visible

Retinal detachment is noted

Pupillary light reflexes are slow, but the cornea is normal

Which systemic condition is the most likely underlying cause?

systemic hypertension

What animals more commonly get pleural effusion?

cats

What can be seen in this radiograph?

pleural effusion

You hear a left sided holosystolic or pansystolic murmur. What might be the cause?

mitral valve insufficiency

You hear a right sided holosystolic or pansystolic murmur. What might be the cause?

tricuspid valve insufficiency

You hear a crescendo-decrescendo murmur with the point of maximum intensity at the 3rd intercostal space on the left. What might be the cause?

pulmonic stenosis

You hear a crescendo-decrescendo murmur with the point of maximum intensity at the 4th intercostal space on the left. What might be the cause?

aortic stenosis

You hear a continuous murmur that sounds like machinery. What might be the cause?

patent ductus arteriosus

A 1-year-old dog presents for a wellness exam. Auscultation reveals a soft murmur that is audible consistently. No thrill is palpated, and the dog is asymptomatic.

What murmur grade is most consistent with this scenario?

Grade II

A 2-year-old dog is presented with exercise intolerance. Auscultation reveals a loud systolic murmur at the left heart base, and the veterinarian can palpate a thrill over the area.

Which murmur grade is most appropriate?

Grade IV

A 4-month-old puppy is presented for a routine check-up. On auscultation, the veterinarian hears a very faint intermittent murmur only detectable after careful listening. The puppy is otherwise healthy and energetic.

What is the most likely grade of this murmur?

Grade I

A 6-year-old dog is presented with severe exercise intolerance and collapse during activity. On auscultation, a loud murmur with palpable thrill is detected, and the murmur is audible even when the stethoscope is lifted completely off the thoracic wall.

Which murmur grade is this?

Grade VI

A 5-year-old dog is brought in for coughing. On auscultation, a moderately loud systolic murmur is heard at the left apex. There is no palpable thrill.

Which murmur grade fits this description?

Grade III

A 3-year-old dog presents for evaluation of exercise intolerance. A very loud murmur is heard over the left heart base and a palpable thrill is present.

Which murmur grade is this?

Grade V

Which animals are arrhythmias expected in?

horses

What four diagnostics are the basics of a cardiac workup?

1. radiographs

2. electrocardiogram

3. echocardiogram

4. blood pressure

What is a common first line diagnostic test for large animal basic cardiac workups?

serum chemistry

What are some additional tests we can run for a cardiac workup?

1. thyroid function

2. heartworm test

3. complete neuro exam

4. holter monitoring

5. event monitoring

What is some evidence of brain damage from high bp?

1. encephalopathy

2. stroke

What is some evidence of heart damage from high bp?

1. left ventricular hypertrophy

2. cardiac failure

What can happen to the eyes with high bp?

1. acute blindness

2. retinal detachment

3. vessel tortuosity

4. perivascular edema

5. papilledema

6. hyphema

7. secondary glaucoma

What is a radiographic method to measure heart size?

vertebral heart score

What is the normal vertebral heart score in dogs?

8.7-10.7

A 7-year-old dog is presented for exercise intolerance and coughing. Lateral thoracic radiographs are taken, and measurements are as follows: Heart long axis = 5.5 vertebrae

Heart short axis = 4.0 vertebrae

The vertebral heart score (VHS) is calculated as the sum of the long and short axes. What does this VHS indicate?

Heart size is normal

A dog in respiratory distress arrives. On imaging, you see B-lines and LA enlargement. What are you going to treat for?

congestive heart failure

A dog in respiratory distress arrives. On imaging, you see ascites and RA enlargement. What are you going to treat for?

congestive heart failure

A dog in respiratory distress arrives. On imaging, you see ascites and RV hypertrophy. What are you going to treat for?

pulmonary hypertension

A cat in respiratory distress arrives. On imaging, you see B-lines, LA enlargement, and pleural/pericardial effusion. What are you going to treat for?

congestive heart failure

A 10-year-old dog presents with coughing, exercise intolerance, and mild tachypnea. Thoracic radiographs show mild cardiomegaly. The clinician orders NT-proBNP testing to aid in diagnosis.

What is the most clinically relevant interpretation of an elevated NT-proBNP in this patient?

Suggests cardiac myocyte stretch or volume overload, supporting a cardiac origin for the symptoms

What species is NT-proBNP better in?

cats

What can sending a NT-proBNP help with in dogs?

ruling out cardiac disease

A 7-year-old dog presents with lethargy and exercise intolerance. Blood is submitted for cardiac troponin I (cTnI) measurement. The result shows markedly elevated cTnI.

Which statement best describes the clinical significance of this finding?

Confirms acute myocardial injury, but does not indicate the underlying cause

What are the therapeutic uses for cardiac catheterization and CT?

1. presurgical/ballooning

2. pulmonic stenosis in bulldogs

What physiologic changes can cause cardiac damage?

1. pressure

2. volume

3. neurohormones

4. cytokines

A 5-year-old dog has chronic aortic stenosis. Over time, the left ventricle faces increased afterload. Echocardiography shows thickened left ventricular walls with reduced chamber size.

Which type of cardiac remodeling is most consistent with these findings?

concentric hypertrophy

A 4-year-old dog is diagnosed with a chronic patent ductus arteriosus (PDA). Over time, echocardiography shows:

Enlarged left ventricular chamber

Normal to mildly thickened ventricular walls

Evidence of increased end-diastolic volume

Which type of cardiac remodeling is most consistent with these findings?

Eccentric hypertrophy

Two dogs present with heart disease.

Dog A: Dilated left ventricle, thin walls, reduced ejection fraction Dog B: Thickened left ventricular walls, small chamber, normal ejection fraction

What type of heart failure do they have?

Dog A = Systolic; Dog B = Diastolic

What is key about starting a patient on cardiac therapies?

frequent reassessment

What drug helps with preload?

furosemide

What drug helps with afterload?

enalapril

What drug helps with contractility?

pimobendan

What drug changes conduction?

1. digoxin

2. diltiazem