Dilated Cardiomyopathy - Revision history

Lwilkie: /* Blood Tests */

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Blood Tests

Lwilkie: /* History and Physical Examination */

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History and Physical Examination

Lwilkie: /* Signalment */

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Signalment

Lwilkie: /* Signalment */

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Signalment

Lwilkie: /* Introduction */

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Introduction

Lwilkie: /* References */

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References

Lwilkie: /* Prognosis */

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Prognosis

Lwilkie: /* Treatment and Control */

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Treatment and Control

Lwilkie: /* Diagnosis */

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Diagnosis

Lwilkie: /* Clinical Signs */

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Clinical Signs

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 Changes on serum biochemistry analysis may include [[azotemia]], this is common in dogs receiving diuretic therapy and is usually pre-renal in nature. Electrolyte abnormalities, such as mild hyponatraemia and hypokalaemia, are also common in dogs with congestive heart failure.
-Taurine deficiency may contribute to a DCM phenotype in the American Cocker Spaniel, Dalmatian, Labrador Retriever and Golden Retriever. Most dogs with taurine-deficient DCM will have plasma taurine levels <25nmol/L. This is important to recognize, as in these cases cardiac function and prognosis can be substantially improved by taurine supplementation.
+'''Taurine''' deficiency may contribute to a DCM phenotype in the American Cocker Spaniel, Dalmatian, Labrador Retriever and Golden Retriever. Most dogs with taurine-deficient DCM will have plasma taurine levels <25nmol/L. This is important to recognize, as in these cases cardiac function and prognosis can be substantially improved by taurine supplementation.
 <br>

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 Asymptomatic (occult) phase
 * Soft, systolic heart murmur
 * Arrhythmia with pulse deficits

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 ==Signalment==
-Giant and large breeds are most at risk. Predisposed breeds include: Irish Wolfhound, Great Dane, Newfoundland, Leonberger, St. Bernard, Dobermann Pinscher, Boxer, Dogue de Bordeaux and the Portuguese Water dog.
+'''Giant and large breeds''' are most at risk. Predisposed breeds include: Irish Wolfhound, Great Dane, Newfoundland, Leonberger, St. Bernard, Dobermann Pinscher, Boxer, Dogue de Bordeaux and the Portuguese Water dog.
 Prevalence increases with age and the typical age at diagnosis is 6-8 years. A severe juvenile form is recognized in the Portuguese Water dog.

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 ==Signalment==
-Giant and large breeds (e.g. Doberman Pinscher, Irish Wolfhound and Great Dane) are most at risk.
+Giant and large breeds are most at risk. Predisposed breeds include: Irish Wolfhound, Great Dane, Newfoundland, Leonberger, St. Bernard, Dobermann Pinscher, Boxer, Dogue de Bordeaux and the Portuguese Water dog.
-Prevalence increases with age and the typical age at diagnosis is 6-8 years.
+Prevalence increases with age and the typical age at diagnosis is 6-8 years. A severe juvenile form is recognized in the Portuguese Water dog.
 Male dogs are more frequently affected than females, particularly in Doberman Pinschers.

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 == Introduction  ==
-Dilated cardiomyopathy (DCM) is characterized by progressive '''systolic dysfunction''' (loss of myocardial contractile function) and '''ventricular dilation''' (eccentric hypertrophy).
+Dilated cardiomyopathy (DCM) is characterized by progressive '''systolic dysfunction''' (loss of myocardial contractile function) and '''ventricular dilation''' (eccentric hypertrophy). This is the most common form of cardiomyopathy in dogs. There are breed predispositions and familial distributions, suggesting an underlying causal genetic mutation. An autosomal dominant inheritance pattern with incomplete and age-dependent penetrance has been reported.
 ==Signalment==

← Older revision		Revision as of 12:42, 15 April 2016
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	== References==		== References==
		+	Tilley, L.P, Smith, F.W.K., Oyama, M.A, Sleeper, M.M (2008) '''Manual of Canine and Feline Cardiology''' (Fourth Edition) ''W.B. Saunders Company''
		+
		+	{{citation
		+	\|initiallast = Summerfield
		+	\|initialfirst = N.J.
		+	\|initiallast = Boswood
		+	\|initialfirst = A.
		+	\|initiallast = O'Grady
		+	\|initialfirst = M.R.
		+	\|initiallast = Gordon
		+	\|initialfirst = S.G.
		+	\|initiallast = Dukes-McEwan
		+	\|initialfirst = J.
		+	\|initiallast = Oyama
		+	\|initialfirst = M.A.
		+	\|initiallast = Smith
		+	\|initialfirst = S.
		+	\|initiallast = Patteson
		+	\|initialfirst = M.
		+	\|initiallast = French
		+	\|initialfirst = A.T.
		+	\|initiallast = Culshaw
		+	\|initialfirst = G.J.
		+	\|initiallast = Braz-Ruivo
		+	\|initialfirst = L.
		+	\|initiallast = Estrada
		+	\|initialfirst = A.
		+	\|initiallast = O'Sullivan
		+	\|initialfirst = M.L.
		+	\|initiallast = Loureiro
		+	\|initialfirst = J.
		+	\|initiallast = Willis
		+	\|initialfirst = R.
		+	\|initiallast = Watson
		+	\|initialfirst = P.
		+	\|year = 2012
		+	\|jtitle = Efficacy of Pimobendan in the Prevention of Congestive Heart Failure or Sudden Death in Doberman Pinschers with Preclinical Dilated Cardiomyopathy (The PROTECT Study)
		+	\|jor = Journal of Veterinary Internal Medicine
		+	\|vol = 26(6)
		+	\|Range = 1337–1349
		+	}}
		+

−	~~Ettinger, S.J. and Feldman, E. C. (2000) '''Textbook of Veterinary Internal Medicine Diseases of the Dog and Cat''' Volume 2 (Fifth Edition) ''W.B. Saunders Company''~~

−	~~Ettinger, S.J, Feldman, E.C. (2005) '''Textbook of Veterinary Internal Medicine '''(6th edition, volume 2) ''W.B. Saunders Company''~~

−	~~Fossum, T. W. et. al. (2007) '''Small Animal Surgery''' (Third Edition) ''Mosby Elsevier ''~~

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 == Prognosis ==
-'''Dogs: '''
+Prognosis from the onset of occult DCM is variable and can be years. Once clinical signs have developed, the prognosis is poor with a median survival time of 3-6 month depending on the breed. Death is usually due to refractory congestive heart failure or sudden death. The prevalence of sudden death is particularly high in Doberman Pinschers with DCM (30-50%).
 <br>

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 == Treatment and Control ==
-Treat congestive heart failure (reduce preload & afterload; improve systolic function; control cardiac arrhythmias), therapeutic thoracocentesis (to remove pleural effusion in cats) and taurine supplementation (cats).
+===Clinical phase===
 <br>

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 == Diagnosis ==
-History and clinical signs suggest [[:Category:Heart Failure|heart failure]].
+Asymptomatic (occult) phase
-Physical examination will show presence of a systolic murmur, a gallop rhythm, S3 heart sound, arrhythmias, pulse deficits and pulmonary crackles.
+Overt clinical phase
-Blood tests will show [[azotemia]], elevated liver enzymes (+ liver congestion), signs of congestive heart failure, signs of [[thromboembolism]] (cats) and plasma taurine reduction (cats).
+===Thoracic Radiographs===
-Radiography will show left ventricular hypertrophy (seen in Dobermans & Boxers), left atrial enlargement (seen in Dobermans & Boxers), generalised cardiomegaly (seen in giant breeds), [[Heart Failure, Left-Sided|left sided congestive heart failure]] signs e.g. pulmonary congestion & edema and [[Heart Failure, Right-Sided|right sided congestive heart failure]] signs e.g. pleural effusion and ascites.
+===Electrocardiography (ECG)===
-Electrocardiography (ECG) will show rhythm disturbances e.g. [[Atrial Fibrillation|atrial fibrillation]] (giant breeds), ventricular arrhythmias (Doberman Pinchers, Boxers), conduction disturbances and characteristic signs of hypertrophy.
+During the clinical phase, the following may be detected:
-Echocardiography will show a hypokinetic left ventricle (i.e. reduced fractional shortening therefore reduced contractility), reduced ejection fraction (i.e. % end diastolic volume ejected at systole), decreased ventricular wall thickness, left atrial enlargement and mitral regurgitation.
+===Echocardiography===
 <br>

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 == Clinical Signs ==
-Can be asymptomatic (Occult) DCM: Seen in predisposed breeds (e.g. Doberman Pinschers).
+The natural history of the disease is described in two phases.
-Clinical signs include syncope, weight loss, dyspnoea, lethargy, weakness and hindlimb paresis (cats with saddle thrombi).
+The '''asymptomatic (occult) phase''' is when no clinical signs are apparent, but there may be structural, functional or electrical abnormalities. These include increased left ventricular and left atrial internal diameter, reduced myocardial contractility and ventricular premature contractions. The duration of this occult phase is variable and can last from months to years.
-<br>
+The '''overt clinical phase''' is when clinical signs, such as congestive heart failure (CHF), syncope and exercise intolerance, develop. Arrhythmias are common in this stage.
 == Diagnosis ==