Cardiomyopathies comprise a group of diseases of the myocardium that affect the mechanical (hypertrophic, arrhythmogenic right ventricular, dilated and restrictive cardiomyopathy) or electrical function (conduction system disease and ion channelopathies, e.g. long QT syndrome) of the heart. Diagnosis of myocardial disease is usually by imaging (echocardiogram and cardiac MR).
Hypertrophic cardiomyopathy (HCM)
HCM is characterized by marked ventricular hypertrophy in the absence of abnormal loading conditions such as hypertension and valvular disease. There is usually disproportionate involvement of the interventricular septum. The hypertrophic non-compliant ventricles impair diastolic filling, so that stroke volume is reduced. Most cases are familial, autosomal dominant, and caused by mutations in genes encoding sarcomeric proteins, e.g. troponin T and β-myosin. It is the most common cause of sudden cardiac death in young people.
Clinical features
Patients may be symptom-free (and detected through family screening) or have breathlessness, angina or syncope. Complications include sudden death, atrial and ventricular arrhythmias, thromboembolism, infective endo-carditis and heart failure. The carotid pulse is jerky because of rapid ejection and sudden obstruction to the ventricular outflow during systole. An ejection systolic murmur occurs because of left ventricular outflow obstruction, and the pansystolic murmur of functional mitral regurgitation may also be heard.
Investigations
■ ECG is almost always abnormal. A pattern of left ventricular hypertrophy with no discernible cause is diagnostic.
■ Cardiac imaging shows ventricular hypertrophy (on echo and MR) and fibrosis (on MR).
■ Genetic analysis may confirm the diagnosis and provide prognostic information.
Management
Amiodarone reduces the risk of arrhythmias and sudden death. Individuals at highest risk are fitted with an implantable cardiac defibrillator. Chest pain and dyspnoea are treated with β-blockers and verapamil. In selected cases outflow tract gradients are reduced by surgical resection or alcohol ablation of the septum, or by dual-chamber pacing.
Dilated cardiomyopathy (DCM)
DCM is characterized by a dilated left ventricle which contracts poorly. Inheritance is autosomal dominant in the familial disease.
Clinical features
Shortness of breath is usually the first complaint; less often patients present with embolism (from mural thrombus) or arrhythmia. Subsequently there is progressive heart failure with the symptoms and signs of biventricular failure.
Investigations
■ Chest X-ray may show cardiac enlargement.
■ ECG is often abnormal. The changes are non-specific and include arrhyth-mias and T-wave flattening.
■ Cardiac imaging shows dilated ventricles with global hypokinesis. Cardiac MR may show other aetiologies of left ventricular dysfunction, e.g. previ-ous myocardial infarction.
Other tests such as coronary angiography, viral and autoimmune screen and endomyocardial biopsy may be needed to exclude other diseases (Table 10.15) that present with the clinical features of DCM.
Management
Heart failure and atrial fibrillation are treated in the conventional way (pp. 440, 429). Cardiac resynchronization therapy and implantable cardiac defi-brillators are used in patients with NYHA III/IV grading. Severe cardiomyopa-thy is treated with cardiac transplantation.
Primary restrictive cardiomyopathy
The rigid myocardium restricts diastolic ventricular filling and the clinical features resemble those of constrictive pericarditis (see later). In the UK the most common cause is amyloidosis. The ECG, chest X-ray and echocardio-gram are often abnormal, but the findings are non-specific. Diagnosis is by cardiac catheterization, which shows characteristic pressure changes. An endomyocardial biopsy may be taken during the catheter procedure, thus providing histological diagnosis. There is no specific treatment and the prog-nosis is poor, with most patients dying less than a year after diagnosis. Cardiac transplantation is performed in selected cases.
Arrhythmogenic right ventricular cardiomyopathy
There is Progressive fibro-adipose replacement of the wall of the right ven-tricle. The typical presentation is ventricular tachycardia or sudden death in a young man.
Table 10.15 Heart muscle disease presenting with features of dilated cardiomyopathy |
Ischaemia Hypertension Congenital heart disease Peripartum cardiomyopathy Iníections, e.g. cytomegalovirus, HIV Alcohol excess Muscular dystrophy Amyloidosis Haemochromatosis |
1. Ethics and communication
2. Infectious diseases
3. Gastroenterology and nutrition
Gastroenterology and nutrition
4. Liver, biliary tract and pancreatic disease
Liver, biliary tract and pancreatic disease
LIVER BIOCHEMISTRY AND LIVER FUNCTION TESTS
SYMPTOMS AND SIGNS OF LIVER DISEASE
JAUNDICE
HEPATITIS
NON - ALCOHOLIC FATTY LIVER DISEASE (NAFLD)
CIRRHOSIS
COMPLICATIONS AND EFFECTS OF CIRRHOSIS
LIVER TRANSPLANTATION
TYPES OF CHRONIC LIVER DISEASE AND CIRRHOSIS
PRIMARY SCLEROSING CHOLANGITIS
BUDD - CHIARI SYNDROME
LIVER ABSCESS
LIVER DISEASE IN PREGNANCY
LIVER TUMOURS
GALLSTONES
THE PANCREAS
CARCINOMA OF THE PANCREAS
NEUROENDOCRINE TUMOURS OF THE PANCREAS
5. Haematological disease
Haematological disease
ANAEMIA
Assessment and treatment of suspected neutropenic sepsis
HAEMOLYTIC ANAEMIA
INHERITED HAEMOLYTIC ANAEMIAS
ACQUIRED HAEMOLYTIC ANAEMIA
MYELOPROLIFERATIVE DISORDERS
THE SPLEEN
BLOOD TRANSFUSION
THE WHITE CELL
HAEMOSTASIS AND THROMBOSIS
THROMBOSIS
THERAPEUTICS
6. Malignant disease
Malignant disease
MYELOABLATIVE THERAPY AND HAEMOPOIETIC STEM CELL TRANSPLANTATION
THE LYMPHOMAS
THE PARAPROTEINAEMIAS
PALLIATIVE MEDICINE AND SYMPTOM CONTROL
7. Rheumatology
Rheumatology
COMMON INVESTIGATIONS IN MUSCULOSKELETAL DISEASE
COMMON REGIONAL MUSCULOSKELETAL PROBLEMS
BACK PAIN
OSTEOARTHRITIS
INFLAMMATORY ARTHRITIS
THE SERONEGATIVE SPONDYLOARTHROPATHIES
Clinical features, Investigations
INFECTION OF JOINTS AND BONES
AUTOIMMUNE RHEUMATIC DISEASES
SYSTEMIC INFLAMMATORY VASCULITIS
DISEASES OF BONE
THERAPEUTICS
8. Water, electrolytes and acid–base balance
WATER AND ELECTROLYTE REQUIREMENTS
BODY FLUID COMPARTMENTS
REGULATION OF BODY FLUID HOMEOSTASIS
PLASMA OSMOLALITY AND DISORDERS OF SODIUM REGULATION
DISORDERS OF POTASSIUM REGULATION
DISORDERS OF MAGNESIUM REGULATION
DISORDERS OF ACID - BASE BALANCE
THERAPEUTICS
9. Renal disease
Renal disease
INVESTIGATION OF RENAL DISEASE
GLOMERULAR DISEASES
NEPHROTIC SYNDROME
URINARY TRACT INFECTION
TUBULOINTERSTITIAL NEPHRITIS
HYPERTENSION AND THE KIDNEY
RENAL CALCULI AND NEPHROCALCINOSIS
URINARY TRACT OBSTRUCTION
ACUTE RENAL FAILURE/ACUTE KIDNEY INJURY
CHRONIC KIDNEY DISEASE
RENAL REPLACEMENT THERAPY
CYSTIC RENAL DISEASE
TUMOURS OF THE KIDNEY AND GENITOURINARY TRACT
DISEASES OF THE PROSTATE GLAND
TESTICULAR TUMOUR
URINARY INCONTINENCE
10. Cardiovascular disease
COMMON PRESENTING SYMPTOMS OF HEART DISEASE
INVESTIGATIONS IN CARDIAC DISEASE
CARDIAC ARRHYTHMIAS
HEART FAILURE
ISCHAEMIC HEART DISEASE
RHEUMATIC FEVER
VALVULAR HEART DISEASE
PULMONARY HEART DISEASE
MYOCARDIAL DISEASE
CARDIOMYOPATHY
PERICARDIAL DISEASE
SYSTEMIC HYPERTENSION
ARTERIAL AND VENOUS DISEASE
ELECTRICAL CARDIOVERSION
DRUGS FOR ARRHYTHMIAS
DRUGS FOR HEART FAILURE
DRUGS AFFECTING THE RENIN - ANGIOTENSIN SYSTEM
NITRATES, CALCIUM - CHANNEL BLOCKERS AND POTASSIUM - CHANNEL ACTIVATORS
11. Respiratory disease
Respiratory disease
TUBERCULOSISnd
DIFFUSE DISEASES OF THE LUNG PARENCHYMA
OCCUPATIONAL LUNG DISEASE
CARCINOMA OF THE LUNG
DISEASES OF THE CHEST WALL AND PLEURA
DISORDERS OF THE DIAPHRAGM
12. Intensive care medicine
13. Drug therapy, poisoning, and alcohol misuse
Drug therapy, poisoning, and alcohol misuse
14. Endocrine disease
Endocrine disease
PITUITARY HYPERSECRETION SYNDROMES
THE THYROID AXIS
MALE REPRODUCTION AND SEX
FEMALE REPRODUCTION AND SEX
THE GLUCOCORTICOID AXIS
THE THIRST AXIS
DISORDERS OF CALCIUM METABOLISM
DISORDERS OF PHOSPHATE CONCENTRATION
ENDOCRINOLOGY OF BLOOD PRESSURE CONTROL
DISORDERS OF TEMPERATURE REGULATION
THERAPEUTICS
15. Diabetes mellitus and other disorders of metabolism
DIABETES MELLITUS
DIABETIC METABOLIC EMERGENCIES
COMPLICATIONS OF DIABETES
SPECIAL SITUATIONS
HYPOGLYCAEMIA IN THE NON - DIABETIC
DISORDERS OF LIPID METABOLISM
THE PORPHYRIAS
16. The special senses
THE EAR
THE NOSE AND NASAL CAVITY
THE THROAT
THE EYE
17. Neurology
COMMON NEUROLOGICAL SYMPTOMS
COORDINATION OF MOVEMENT
THE CRANIAL NERVES
COMMON INVESTIGATIONS IN NEUROLOGICAL DISEASE
UNCONSCIOUSNESS AND COMA
STROKE AND CEREBROVASCULAR DISEASE
EPILEPSY AND LOSS OF CONSCIOUSNESS
NERVOUS SYSTEM INFECTION AND INFLAMMATION
HYDROCEPHALUS
HEADACHE, MIGRAINE AND FACIAL PAIN
SPINAL CORD DISEASE
DEGENERATIVE NEURONAL DISEASES
DISEASES OF THE PERIPHERAL NERVES
MUSCLE DISEASES
MYOTONIAS
DELIRIUM
THERAPEUTICS
18. Dermatology