Makindo Medical Notes.com

Related Subjects: Chronic Heart Failure |Acute Heart Failure and Pulmonary Oedema |Loop Diuretics |Entresto Sacubitril with Valsartan |Ivabradine |Furosemide |Angiotensin Converting Enzyme Inhibitors |Cardiac Resynchronisation Therapy (CRT) Pacemaker |Arrhythmogenic Right Ventricular Cardiomyopathy |Dilated Cardiomyopathy |Hypertrophic cardiomyopathy (HCM - HOCM) |Peripartum cardiomyopathy |Restrictive Cardiomyopathy |Takotsubo Cardiomyopathy

About

• This can affect young people
• Dilated poorly contracting ventricle and echo shows poor systolic function
• Most cases are idiopathic but often assumed to follow an undiagnosed viral myocarditis.
• Exclude IHD and hypertension as causes

Causes

• Idiopathic (Unknown) accounts for most
• Alcoholism, Cocaine, Herceptin
• Drugs: Anthracycline - dose-related, patients treated for childhood cancers
• Post Viral myocarditis, Daunorubicin, Adriamycin
• Tachycardia mediated cardiomyopathy
• Chagas Disease (South America), HIV infection - less now with HAART
• Familial, Peripartum, Autoimmune, Thiamine and Selenium deficiency
• Amyloidosis (Avoid Digoxin as it causes toxicity and increased risk of ventricular arrhythmias)
• Acromegaly, Thyrotoxicosis, Myxoedema, Diabetes mellitus
• Mitochondrial myopathies, Friedreich's ataxia, Muscular dystrophy

Genetics

• 25% have evidence for familial disease which may be autosomal dominant
• Family members may have had sudden cardiac death
• X linked diseases such as Becker's and Duchenne's muscular dystrophies
• Ask about mitochondrial disease or phenotypes e.g. familial diabetes, deafness, epilepsy, maternal inheritance

Clinical

• Sudden cardiac death
• Progressive heart failure with breathlessness, reduced exercise tolerance
• Atrial fibrillation may be a cause of decompensation
• Sinus Tachycardia, S3 or S4 and displaced dyskinetic apex beat
• Signs of functional MR and TR
• Systemic Cardioembolic phenomena - stroke, peripheral emboli
• Raised JVP and Pleural effusion
• Hepatomegaly and Oedema of Right heart failure
• Arrhythmias e.g. AF, VT, Ectopics
• Determine alcohol intake and drug usage and family history
• Ask about Cocaine, HIV and Hepatitis C

Investigations

• FBC, U&E, LFT, ESR, CRP, CK, Troponin where indicated
• Viral serology (if acute presentation)
• Serum ferritin/iron/transferrin - haemochromatosis
• 12 lead ECG: may be normal. Also AF, Left Bundle branch block. Q waves. About 25% have Non sustained VT
• Check TFT's, Elevated BNP
• HIV and Hep C test: in those with suspected infection
• CXR: dilated heart, Kerley B lines
• ECG - AF, VT, LV ST changes
• Angiography - normal coronaries + poor LV
• Echocardiogram: globular heart, thin walls and dilated ventricular cavities, mural thrombus. Ejection fraction < 0.45 and/or a fractional shortening of < 25%, and a left ventricular end-diastolic dimension of > 112% predicted value corrected for age and body surface area.
• Cardiac MRI may be needed

Severe dilation of heart chambers

Criteria to diagnose Idiopathic DCM

• Ejection fraction < 0.45 and/or a fractional shortening of < 25%, and a left ventricular end diastolic dimension of > 112% predicted value corrected for age and body surface area.
• Exclusion criteria
  • Systemic hypertension (> 160/100 mm Hg)
  • Coronary artery disease (> 50% in one or more major branches)
  • Chronic excess alcohol (> 40 g/day female, > 80 g/day male for more than five years after six month abstinence
  • Systemic disease known to cause IDC
  • Pericardial diseases
  • Congenital heart disease
  • Cor pulmonale

Complications

• End stage cardiac failure
• Arrhythmias
• Sudden cardiac death
• Emboli - stroke

Management

• There are no specific treatments for most patients with IDC. The focus is on managing heart failure and preventing sudden death, and thromboembolism. Where there is a secondary cause then abstention from alcohol or other interventions may help.
• Some have an inexorable decline with rapidly worsening ventricular function, and cardiac transplantation might be required.
• Surgically implanted left ventricular assist devices (LVADs) are becoming increasingly common as a bridge to either recovery or transplantation.
• Anticoagulate if very poor LV, mural thrombus or AF or embolic event or AF or PE
• Treat heart failure - Diuretics, Digoxin, ACEI/ARB, beta-blockers etc. ACEI in particular is important. They also prevent or slow disease progression in asymptomatic patients. If ACEI is contraindicated then consider hydralazine-nitrate combinations. Beta-blockers starting at low doses carvedilol 3.125 mg twice daily, bisoprolol 1.25 mg once daily, Metoprolol SR 12.5 mg once daily should be trialled. Spironolactone should be considered in all patients presenting with moderate to severe heart failure symptoms.
• Manage arrhythmias - drugs and reasonable to consider ICDs in patients with sustained haemodynamically unstable ventricular tachycardia/fibrillation.
• Genetic counselling where there is familial disease.
• Surgery: Partial left ventriculectomy ("Batista procedure") is limited to very few centres
• Influenza and Pneumococcal vaccination

References

• Diagnosis and management of dilated cardiomyopathy. Perry Elliott