QuestionSBA
QuestionChoice
Ischaemic heart disease is a common cause of heart failure, however the absence of risk factors (smoking, diabetes, hypertension, ethnicity, etc.) and the history of breast cancer make this less likely.
10015719
d
Ischaemic heart disease
QuestionChoice
Bilateral pleural effusions would be an unusual presentation of pleural metastases. Bilateral alveolar oedema is more in keeping with heart failure.
10015717
b
Pleural metastases
QuestionChoice
Amyloidosis is a rare cause of heart failure.
10015720
e
Amyloidosis
QuestionChoice
Patients presenting with ARDS generally have a more acute course of illness.
10015718
c
Acute respiratory distress syndrome
QuestionChoice
Doxorubicin is commonly used in the treatment of breast cancer. Cardiotoxicity is an establised side-effect.
10015716
a
Dilated cardiomyopathy
QuestionComment
Just say heart failure. DEAR GOD!
45228
User
subscriber
Prone Ketone
QuestionComment
:0
55649
User
subscriber
Eris
QuestionComment
why is this not pleural metastases ?
59687
QuestionComment
Correct me if i'm wrong but pleural metastases from malignancy are typically unilateral
59945
User
subscriber
Transplant Tazocin
User
subscriber
Hypertension Kinase
Concept
Chapter
# Summary

Cardiomyopathy is a group of heart muscle diseases characterised by structural and functional abnormalities of the myocardium in the absence of other heart conditions. The four main types are dilated cardiomyopathy (DCM), restrictive cardiomyopathy, arrhythmogenic right ventricular cardiomyopathy (ARVC), and Hypertrophic Cardiomyopathy (HCM). DCM is the most common type and occurs when a patient has dilated ventricles and impaired systolic function, restrictive cardiomyopathy involves impaired diastolic filling and ARVC is characterised by fatty fibrous material replacing the myocardium, primarily in the right ventricle. HCM is discussed in a separate section. Takotsubo cardiomyopathy is a rare, non-ischemic form triggered by stress, resulting in transient apical ballooning of the heart muscle. Each type has different causes, symptoms, and management approaches.

# Definition 

Cardiomyopathies are a group of diseases that have structural and functional abnormalities of the myocardium usually in the absence of coronary artery disease, hypertension, valvular disease or congenital heart disease.  

# Epidemiology 

Cardiomyopathy can often go undiagnosed and the prevalence depends on the subtype. Dilated cardiomyopathy is the most common and impacts approximately 1 in 2500 people per year. Takotsubo cardiomyopathy is, however, rare and estimated to impact 1% of those who present with troponin positive chest pain. 

# Pathophysiology

The pathophysiology of cardiomyopathies depends on the subtype. 

# Classification 

There are four main types of cardiomyopathy:

1. Dilated (DCM): most common 
3. Restrictive
4. Arrhythmogenic right ventricular cardiomyopathy (ARVC)
5. Hypertrophic (HCM): discussed in separate section

Cardiomyopathies can also be considered as to whether they are primary, mixed, or secondary (although this is not a perfect system). Primary cardiomyopathies are disease processes confined to the heart (e.g. HOCM or ARVC). Mixed cardiomyopathies refer to those with a genetic disposition to a cardiomyopathy that is triggered by a secondary process (DCM or restrictive). Secondary cardiomyopathies refer to systemic or multi-organ processes that impact the myocardium (e.g. hyperthyroidism or sarcoidosis).

Takotsubo is a rare, acquired primary cardiomyopathy that will also be briefly discussed in this section. 

Each cardiomyopathy will be discussed separately. 

# Dilated Cardiomyopathy (DCM) 

Dilated cardiomyopathy refers to a dilated heart with impaired systolic function (HFrEF). It is the most common cardiomyopathy. Causes include idiopathic, alcohol, Cocksackie B virus (via an acute myocarditis), or wet beri beri. DCM can be found in association with cardiovascular disease, but in order to classify as a cardiomyopathy the the degree of myocardial dysfunction cannot be purely explained by hypertension, valve disease or ischaemic heart disease. 

## Causes 

Dilated cardiomyopathy (DCM) has a number of possible causes.

* Ischaemic changes, hypertension, or valvular disease can, with time, manifest with DCM. These individuals tend to have a genetic predisposition. 
* Genetic and congenital - may be related to familial dilated cardiomyopathy, however some sporadic gene mutations may be responsible for idiopathic cases.
* Toxin-related - excessive alcohol consumption leads to myocardial dysfunction and subsequent DCM. Cocaine is also associated with ischaemia and DCM. Other medications which lead to cardiomyopathy include anthracycline chemotherapy (Doxorubicin), Cyclophosphamide, antiretroviral drugs (Zidovudine), Chloroquine and Clozapine.
* Infiltrative - haemochromatosis, amyloidosis and sarcoidosis are known to cause DCM.
* Peripartum - a rare cause of DCM, with unclear aetiology.
* Thyrotoxicosis - the exact mechanism of this is uncertain, but thought to be related to the effects of thyroid hormone on cardiac function.
* Infectious - DCM can occur secondary to myocarditis, or as a direct result of infection from HIV, Lyme disease and Chagas disease.
* Idiopathic - when other potential causes have been ruled out

## Symptoms and Signs 

Common symptoms are those related to heart failure: 

* Exertional dyspnoea 
* Orthopnoea 
* Paroxysmal nocturnal dyspnoea
* Peripheral oedema

Other symptoms relate to consequences of the cardiomyopathy

* Palpitations (atrial fibrillation or ventricular tachycardia)
* Syncope/pre-syncope with conduction disturbance
* Sudden cardiac death

Common signs: 

* Displaced apex beat
* S3 gallop rhythm (rapid ventricular filling)
* Murmur of mitral regurgitation (due to displacement of the valve leaflets)
* Signs of heart failure (such as oedema, hepatomegaly, ascites, raised JVP).

## Investigations 

* ECG: poor R wave progression. 
* Echocardiogram: diagnostic, showing a globular, dilated heart with reduced ejection fraction. 
* Role for cardiac MRI and endomyocardial biopsy. 

## Management 

Management of DCM involves addressing the trigger (e.g. alcohol abstinence in alcohol-induced DCM). Further medical management surrounds HFrEF optimisation with diuretics (symptom relief) and beta-blockers, ACE-I, and mineralocorticoid antagonists. 

# Restrictive cardiomyopathy

Restrictive cardiomyopathy involves non-dilated, non-hypertrophied ventricles with impaired diastolic filling but with normal or near-normal systolic function.   

## Causes 

* Familial non-infiltrative cardiomyopathy (inherited genetic disorders)
* Infiltrative:
  * Amyloidosis
  * Sarcoidosis
  * Gaucher disease
  * Hurler syndrome
  * Fatty infiltration
* Storage:
  * Haemochromatosis
  * Fabry disease
  * Glycogen storage disorders
* Others:
  * Diabetic cardiomyopathy
  * Scleroderma
  * Hypereosinophilic syndrome (Loeffler's)
  * Radiation
  * Chemotherapy (anthracyclines like Doxorubicin and Daunorubicin)

## Symptoms and Signs 

Presentation is often similar to heart failure or can be difficult to clinically distinguish from constrictive pericarditis. Patients may present with predominantly right ventricular failure symptoms due to reduced venous return. Up to 75% of patients will have associated atrial fibrillation. 

## Investigation 

* Echocardiogram: shows thickened ventricular walls and valves, with impaired ventricular filling and preserved systolic function. 
* Cardiac MRI: useful in distinguishing between restrictive cardiomyopathy and constrictive pericarditis. 

## Management

Management of restrictive cardiomyopathy also revolves around addressing the underlying cause (e.g. steroids for sarcoidosis). There is no specific treatment for restrictive cardiomyopathy but involves diuretics for symptom relief and anticoagulation for atrial fibrillation. 

# Arrhythmogenic Right Ventricular Cardiomyopathy (ARVC)

In ARVC, fatty fibrous material replaces the myocardium. It is caused by genetic defects in desmosomes. It is usually inherited in an autosomal dominant fashion. It primarily involves the right ventricle and can be seen on echocardiogram with hypokinetic segments of the free wall of the right ventricle. As suggested by the name, the main symptoms of ARVC relate to palpitations, syncope or cardiac sudden death due to the development of dangerous arrhythmias. 


# Takotsubo Cardiomyopathy 

Takotsubo (octopus pot) cardiomyopathy refers to a non-ischaemic cardiomyopathy associated with transient, apical ballooning of the myocardium usually triggered by stress ('Broken Heart' syndrome). It is suspected in those with troponin-positive chest pain, who have a history of a significant stressor, ST elevation on ECG, and normal coronary arteries on angiogram. Echocardiogram reveals classical apical ballooning due to severe hypokinesis of mid and apical segments with preservation of basal segments. The treatment is largely supportive and most patients completely recover within two months. 

# NICE Guidelines
[NICE Guidance on Chronic Heart Failure](<https://www.nice.org.uk/guidance/ng106>)

# References
[National Institute of Health Information on Cardiomyopathies](<https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4072838/>)
633
659
Other Cardiomyopathies
Topic
35
Cardiology
15687
Chemotherapy drugs such as doxorubicin can cause dilated cardiomyopathy leading to breathlessness, cardiomegaly, bilateral infiltrates, and pleural effusions.
Presentation
112
Breathlessness
UkmlaTopic
1
Acute and emergency
Presentation
113
Breathlessness
UkmlaTopic
3
Cancer
Presentation
114
Breathlessness
UkmlaTopic
4
Cardiovascular
Presentation
116
Breathlessness
UkmlaTopic
12
General practice and primary healthcare
Presentation
117
Breathlessness
UkmlaTopic
17
Neurosciences
Presentation
118
Breathlessness
UkmlaTopic
18
Obstetrics and gynaecology
Presentation
119
Breathlessness
UkmlaTopic
21
Perioperative medicine and anaesthesia
Presentation
120
Breathlessness
UkmlaTopic
23
Respiratory
A 65-year-old woman with a history of breast cancer (managed with surgery and Doxorubicin chemotherapy) presents with a 6-month history of breathlessness on exertion. A chest x-ray shows cardiomegaly, bilateral infiltrates and pleural effusions.

What is the most likely cause of her clinical condition?
a