Changes

== Introduction ==

== Introduction ==

 

Endocardiosis is a valvular insufficiency. The most commonly affected site is the mitral valve. The condition results in slowly developing [[:Category:Heart Failure|heart failure]] as the valves become swollen and shortened/misshapen, so the heart cannot pump blood effectively from the left ventricle to the circulation.  

Endocardiosis is a valvular insufficiency. The most commonly affected site is the mitral valve. The condition results in slowly developing [[:Category:Heart Failure|heart failure]] as the valves become swollen and shortened/misshapen, so the heart cannot pump blood effectively from the left ventricle to the circulation.  

Blood passes back into the left atrium, compromising the filling from the pulmonary vein, which leads to back pressure on the pulmonary capillaries. Resultant [[Oedema|oedema]] forms in the lungs, and can be heard as moist sounds on auscultation. This reduces the oxygenation of blood leading to exercise intolerance. Failure of the left side eventually compromises the function of the right side. In [[Heart Failure, Right-Sided|right sided heart failure]] there is a pooling of blood in the venous system i.e. in the [[Liver - Anatomy & Physiology|liver]]. In some cases a jet lesion can occur, where a small stream of blood passes back into the left atrium and contacts the atrial wall.  

Blood passes back into the left atrium, compromising the filling from the pulmonary vein, which leads to back pressure on the pulmonary capillaries. Resultant [[Oedema|oedema]] forms in the lungs, and can be heard as moist sounds on auscultation. This reduces the oxygenation of blood leading to exercise intolerance. Failure of the left side eventually compromises the function of the right side. In [[Heart Failure, Right-Sided|right sided heart failure]] there is a pooling of blood in the venous system i.e. in the [[Liver - Anatomy & Physiology|liver]]. In some cases a jet lesion can occur, where a small stream of blood passes back into the left atrium and contacts the atrial wall.  

Mitral valve dysplasia is a congenital malformation or degeneration of the mitral valve leaflets and its supporting structures (''chordae tendinae'', papillary muscles, valvular leaflets, annulus) resulting in valvular regurgitation (insufficiency). It is common in dogs and cats and rare in other species.

Mitral valve dysplasia is a congenital malformation or degeneration of the mitral valve leaflets and its supporting structures (''chordae tendinae'', papillary muscles, valvular leaflets, annulus) resulting in valvular regurgitation (insufficiency). It is common in dogs and cats and rare in other species.

Chronic mitral regurgitation leads to volume overload of the left heart, which results in dilatation (eccentric hypertrophy) of the left ventricle and atrium. When mitral regurgitation is severe, cardiac output decreases, which results in signs of left sided cardiac failure (LCHF) and pulmonary venous congestion. Dilatation of the left-sided chambers predisposes affected animals to [[:Category:Arrhythmia|arrhythmias]]. In some cases, malformation of the mitral valve complex causes a degree of valvular stenosis as well as insufficiency.

Chronic mitral regurgitation leads to volume overload of the left heart, which results in dilatation (eccentric hypertrophy) of the left ventricle and atrium. When mitral regurgitation is severe, cardiac output decreases, which results in signs of [[Heart Failure, Left-Sided|left sided cardiac failure]] (LCHF) and pulmonary venous congestion. Dilatation of the left-sided chambers predisposes affected animals to [[:Category:Arrhythmia|arrhythmias]]. In some cases, malformation of the mitral valve complex causes a degree of valvular stenosis as well as insufficiency.

In advanced cases, signs of right sided congestive heart failure may follow due to an increased pressure load on the right ventricle as a result of long standing pulmonary congestion.  

In advanced cases, signs of right sided congestive heart failure may follow due to an increased pressure load on the right ventricle as a result of long standing pulmonary congestion.  

==Signalment==

==Signalment==

Endocardiosis tends to affect middle-aged and older dogs, with males being predisposed. Breeds with particular predisposition to the disease include smaller breeds  

Endocardiosis tends to affect middle-aged and older dogs, with males being predisposed. Breeds with particular predisposition to the disease include smaller breeds  

such as Chihuahuas, Boston Terriers, Poodles, Pomeranians, Cavalier King Charles Spaniels and larger breeds such as the German Shepherd. It is the most common heart condition in dogs. In dogs over 9 years old 97% show lesions, of which approximately 40% are clinically significant. The condition is often found at post mortem as an incidental age related change. The disease is rare in cats.

such as Chihuahuas, Boston Terriers, Poodles, Pomeranians, Bull Terriers, Cavalier King Charles Spaniels and larger breeds such as the German Shepherd and Great Danes. It is the most common heart condition in dogs. In dogs over 9 years old 97% show lesions, of which approximately 40% are clinically significant. The condition is often found at post mortem as an incidental age related change. The disease is rare in cats.

 

Typically in middle aged to older small breed dogs. Genetically predisposed breeds include Cavalier King Charles Spaniel, Bull Terriers, German Shepherds, and Great Danes.

===History===

===History===

== Clinical Signs ==

== Clinical Signs ==

Signs depend on stage of disease, but may include coughing, syncope, weight loss, pale or cyanotic mucus membranes and prolonged capillary refill time. If [[Heart Failure, Left-Sided|left sided heart failure]] is present then signs will also include exercise intolerance, weakness, dyspnoea, inappetance and lethargy. If right sided heart failure is present then signs including hepatomegaly, jugular pulses & distension, pleural effusion, ascites and peripheral oedema will occur.  

Signs depend on stage of disease, but may include coughing, syncope, weight loss, pale or cyanotic mucus membranes and prolonged capillary refill time. If left sided heart failure is present then signs will also include exercise intolerance, weakness, dyspnoea, inappetance and lethargy. If right sided heart failure is present then signs including hepatomegaly, jugular pulses & distension, pleural effusion, ascites and peripheral oedema (pulmonary crackles) will occur.  

There may be resting tachycardia, pale mucous membranes, prolonged capillary refill time (CRT) and jugular filling time, cool extremities, loss of sinus arrhythmia and new cardiac arrhythmias e.g. [[Atrial Fibrillation|Atrial Fibrillation]] or [[Supraventricular Premature Complexes|atrial premature complexes]].

**Pale Mucous membranes

** Prolonged Capillary refill time (CRT)

** Prolonged Jugular filling time

** Cool extremities

** Loss of sinus arrhythmia

** Cardiac arrhythmias e.g. Atrial fibrillation, Atrial premature complexes

== Diagnosis ==

== Diagnosis ==

Clinical signs plus signalment of the dog are indicative of the disease. Upon physical examination a '''murmur over the left heart apex''' may be heard. Snaps, crackles, pops will also be heard if pulmonary edema is present. Muffled heart sounds in the presence of pleural/pericardial fluid will be auscultated.

Clinical signs plus signalment of the dog are indicative of the disease. Upon physical examination a '''systolic murmur over the left heart apex''' may be heard. Snaps, crackles, pops will also be heard if pulmonary edema is present. Muffled heart sounds in the presence of pleural/pericardial fluid will be auscultated.

 

Upon '''radiography''' there will be visible signs of left sided heart enlargement. There will possibly be none, some or all of the following radiographic signs - left atrial enlargement (DV view appears at 2-3 o'clock position), left ventricular enlargement, dorsal displacement of trachea, bronchial compression, pulmonary venous congestion and/or edema and right-sided signs (distended caudal vena cava, ascites, pleural effusion, hepatomegaly).  

===Diagnostic Imaging===

 

 

===Diagnostic imaging===

====Radiography====

====Radiography====

Left lateral, right lateral and ventrodorsal views of the thorax are needed. The key radiographic signs associated with mitral valve dysplasia and resulting left sided congestive heart failure are cardiomegaly, pulmonary venous congestion (enlarged pulmonary arteries and veins) and pulmonary oedema. Cardiomegaly may lead to dorsal displacement of the trachea.  

Left lateral, right lateral and ventrodorsal views of the thorax are needed. The key radiographic signs associated with mitral valve dysplasia and resulting left sided congestive heart failure are cardiomegaly leading to possible dorsal displacement of trachea. There will possibly be none, some or all of the following radiographic signs - left atrial enlargement (DV view appears at 2-3 o'clock position), left ventricular enlargement, bronchial compression, pulmonary venous  

congestion (enlarged pulmonary arteries and veins) and/or pulmonary oedema.  

Evidence of right sided congestive heart failure maybe evident in severe cases e.g. distended caudal vena cava, hepatomegaly, ascites, pleural effusions.

Evidence of right sided congestive heart failure maybe present in severe cases e.g. distended caudal vena cava, hepatomegaly, ascites, pleural effusions.

====Echocardiography====

====Echocardiography====

Evidence of left atrial and left ventricular enlargement is visible on echocardiography. The 'fractional shortening' is also increased which is measured as the percentage change in the left ventricular diameter during systole and is used as a measure of systolic function. It is also possible to see structural changes in the valve leaflets in some cases. The regurgitant jet of blood can be detected using colour doppler and evidence of turbulent flow.

Evidence of left atrial and left ventricular enlargement is visible on echocardiography. The 'fractional shortening' on M wave echography is also increased which is measured as the percentage change in the left ventricular diameter during systole and is used as a measure of systolic function. It is also possible to see structural changes in the valve leaflets in some cases. It may detail irregularities of the valves affected (e.g. thickening, shortening, and/or prolapse of the valve leaflets), abnormal valve movements &  valve regurgitation, left atrial enlargement (wide P wave) and left ventricular dilation (tall R wave, wide QRS complex). The regurgitant jet of blood can be detected using colour doppler and evidence of turbulent flow.  

===Electrocardiogram (ECG)===

===Electrocardiogram (ECG)===

A resting ECG trace may show evidence of an enlarge left atrium (wide P wave), an enlarged left ventricle (tall R wave, wide QRS complex, shift of mean electrical axis to the left) and rhythm disturbances such as sinus tachycardia, atrial fibrillation, atrial premature complexes and atrial tachycardia.

A resting ECG trace may show evidence of an enlarge left atrium (wide P wave), an enlarged left ventricle (tall R wave, wide QRS complex, shift of mean electrical axis to the left) and rhythm disturbances such as sinus tachycardia, [[Atrial Fiblrillation|atrial fibrillation]], [[Supraventricular Premature Complexes|atrial premature complexes]] and atrial tachycardia.

===Laboratory Tests===

===Laboratory Tests===

Pro-brain natriuretic peptide (N-BNP) is a newly described cardiac hormone considered to be an effective marker of severity and prognosis of acute coronary syndromes and congestive heart failure. Circulating levels of the hormone increase in peripheral blood with increased myocardial stress. Commercial assays are not currently available.

Pro-brain natriuretic peptide (N-BNP) is a newly described cardiac hormone considered to be an effective marker of severity and prognosis of acute coronary syndromes and congestive heart failure. Circulating levels of the hormone increase in peripheral blood with increased myocardial stress. Commercial assays are not currently available.

== Treatment ==

== Treatment ==