Cardiomyopathies can generally be categorized into two groups, based on World Health Organization guidelines: extrinsic cardiomyopathies and intrinsic cardiomyopathies.[2]
Extrinsic cardiomyopathies
These are cardiomyopathies where the primary pathology is outside the myocardium itself. Most cardiomyopathies are extrinsic, because by far the most common cause of a cardiomyopathy is ischemia. The World Health Organization calls these specific cardiomyopathies:[2]
- Ischemic (or ischaemic) cardiomyopathy
- Hypertensive cardiomyopathy
- Valvular cardiomyopathy
- Inflammatory cardiomyopathy
- Cardiomyopathy secondary to a systemic disease
- Alcoholic cardiomyopathy
[edit] Ischemic cardiomyopathy
Ischemic cardiomyopathy is a weakness in the muscle of the heart due to inadequate oxygen delivery to the myocardium with coronary artery disease being the most common cause. Anemia and sleep apnea are relatively common conditions that can contribute to ischemic myocardium and hyperthyroidism can cause a 'relative' ischemia secondary to high output heart failure. Individuals with ischemic cardiomyopathy typically have a history of myocardial infarction (heart attack), although longstanding ischemia can cause enough damage to the myocardium to precipitate a clinically significant cardiomyopathy even in the absence of myocardial infarction. In a typical presentation, the area of the heart affected by a myocardial infarction will initially become necrotic as it dies, and will then be replaced by scar tissue (fibrosis). This fibrotic tissue is akinetic; it is no longer muscle and cannot contribute to the heart's function as a pump. If this akinetic region of the heart is substantial enough, the affected side of the heart (i.e. the left or right side) will go into failure, and this failure is the functional result of an ischemic cardiomyopathy.
[edit] Cardiomyopathy due to systemic diseases
Many diseases can result in cardiomyopathy. These include diseases like hemochromatosis, (an abnormal accumulation of iron in the liver and other organs), amyloidosis (an abnormal accumulation of the amyloid protein), diabetes, hyperthyroidism, lysosomal storage diseases and the muscular dystrophies.
[edit] Intrinsic cardiomyopathies
An intrinsic cardiomyopathy is weakness in the muscle of the heart that is not due to an identifiable external cause. To make a diagnosis of an intrinsic cardiomyopathy, significant coronary artery disease should be ruled out (amongst other things). The term intrinsic cardiomyopathy does not describe the specific etiology of weakened heart muscle. The intrinsic cardiomyopathies are a mixed-bag of disease states, each with their own causes.
Intrinsic cardiomyopathy has a number of causes including drug and alcohol toxicity, certain infections (including Hepatitis C), and various genetic and idiopathic (i.e., unknown) causes.
There are four main types of intrinsic cardiomyopathy:[2][3]
- Dilated cardiomyopathy (DCM), the most common form, and one of the leading indications for heart transplantation. In DCM the heart (especially the left ventricle) is enlarged and the pumping function is diminished. Approximately 40% of cases are familial, but the genetics are poorly understood compared with HCM. In some cases it manifests as peripartum cardiomyopathy, and in other cases it may be associated with alcoholism.
- Hypertrophic cardiomyopathy (HCM or HOCM), a genetic disorder caused by various mutations in genes encoding sarcomeric proteins. In HCM the heart muscle is thickened, which can obstruct blood flow and prevent the heart from functioning properly.
- Arrhythmogenic right ventricular cardiomyopathy (ARVC) arises from an electrical disturbance of the heart in which heart muscle is replaced by fibrous scar tissue. The right ventricle is generally most affected.
- Restrictive cardiomyopathy (RCM) is the least common cardiomyopathy. The walls of the ventricles are stiff, but may not be thickened, and resist the normal filling of the heart with blood. A rare form of restrictive cardiomyopathy is the obliterative cardiomyopathy, seen in the hypereosinophilic syndrome. In this type of cardiomyopathy, the myocardium in the apicies of the left and right ventricles become thickened and fibrotic, causing a decrease in the volumes of the ventricles and a type of restrictive cardiomyopathy.
[edit] Treatment
Treatment depends on the type of cardiomyopathy, but may include medical therapy and implanted artificial pacemakers. The goal of treatment is often symptom relief, with the underlying condition unaffected. Some patients may eventually require a heart transplant. Treatment of cardiomyopathy (and other heart diseases) using alternative methods such as stem cell therapy is commercially available but is not supported by convincing evidence.
--------------------------------------------------------------------------In medicine (cardiology), myocarditis is inflammation of the myocardium, the muscular part of the heart. It is generally due to infection (viral or bacterial). It may present with chest pain, rapid signs of heart failure, or sudden death.
Signs and symptoms
The signs and symptoms associated with myocardits are varied, and relate either to the actual inflammation of the myocardium, or the weakness of the heart muscle that is secondary to the inflammation. Signs and symptoms of myocarditis include:[1]
- Chest pain (often described as "stabbing" in character)
- Congestive heart failure (leading to edema, breathlessness and hepatic congestion)
- Palpitations (due to arrhythmias)
- Sudden death (in young adults, myocarditis causes up to 20% of all cases of sudden death)[2]
- Fever (especially when infectious, e.g. in rheumatic fever)
Since myocarditis is often due to a viral illness, many patients give a history of symptoms consistent with a recent viral infection, including fever, diarrhea, joint pains, and easy fatigueability.
Myocarditis is often associated with pericarditis, and many patients present with signs and symptoms that suggest concurrent myocarditis and pericarditis.
[edit] Diagnosis
Myocardial inflammation can be suspected on the basis of electrocardiographic results (ECG), elevated CRP and/or ESR and increased IgM (serology) against viruses known to affect the myocardium. Markers of myocardial damage (troponin or creatine kinase cardiac isoenzymes) are elevated.[1]
The ECG findings most commonly seen in myocarditis are diffuse T wave inversions; saddle-shaped ST-segment elevations may be present (these are also seen in pericarditis).[1]
The gold standard is still biopsy of the myocardium, generally done in the setting of angiography. A small tissue sample of the endocardium and myocardium is taken, and investigated by a pathologist by light microscopy and - if necessary - immunochemistry and special staining methods. Histopathological features are: myocardial interstitium with abundant edema and inflammatory infiltrate, rich in lymphocytes and macrophages. Focal destruction of myocytes explains the myocardial pump failure.
--------------------------------------------------------------------------lidocaine - local anesthetic, antiarrhythmic
Post MI, dressler's syndrome, treat with lidocaine
epinephrine - vasocontrict
beta blockers - estend lifespan of post MI, cardiac pt by
decreasing contractility, blood pressure and heart rate
two types:
selective
nonselective
don't give beta blockers to asthmatic pt, because it's gonna cause bronchospasm
in diabetics, beta blocker masks hyperglycemia, and also causes impotence
--------------------------------------------------------------------------
Dressler's syndrome is a form of pericarditis that occurs in the setting of injury to the heart or the pericardium (the outer lining of the heart).
Dressler's syndrome is also known as postmyocardial infarction syndrome and postcardiotomy pericarditis.
Presentation
The syndrome consists of a persistent low-grade fever, chest pain (usually pleuritic in nature), a pericardial friction rub, and /or a pericardial effusion.The symptoms tend to occur after a few weeks or even months after infarction and tend to subside in a few days. Signs include elevated ESR.
[edit] Causes
It is believed to result from an autoimmune inflammatory reaction to myocardial neo-antigens.
Dressler's syndrome is associated with myocardial infarction (heart attack), and with open heart surgery.
[edit] Differential diagnosis
In the setting of myocardial infarction, Dressler's syndrome occurs in about 7% of cases1, and typically occurs 2 to 10 weeks after the myocardial infarction occurred. This differentiates Dressler's syndrome from the much more common post myocardial infarction pericarditis that occurs in 17 to 25% of cases of acute myocardial infarction and occurs between days 2 and 4 after the infarction.
[edit] Treatment
Dressler's syndrome is typically treated with high-dose salicylates or NSAIDs.
--------------------------------------------------------------------------isth·mus (
s
m
s)
) --------------------------------------------------------------------------
Pulseless Electrical Activity (also known by the older term Electromechanical Dissociation or Non-Perfusing Rhythm) is a condition where the heart generates and conducts the electrical impulses required to stimulate itself but fails to produce mechanical contraction or an output. On electrocardiography (ECG) this may appear as any rhythm, whether slow, fast or regular.
The normal condition when electrical activation of muscle cells precedes mechanical contraction is known as Electromechanical Coupling.
Pulseless electrical activity will generally occur secondary to:
- Severe shock (severe blood loss or marked volume depletion)
- Severe trauma such as electrocution, cold water drowning and adverse drug reactions
- Myocardial infarction
- Cardiac arrest
- End-stage heart disease
- Cardiac tamponade (fluid surrounding the heart)
- Cardiac rupture
The approach in treatment of PEA is to treat the underlying cause. These possible causes are remembered as the 5 H's and the 5 P's.
Where an underlying systemic cause is unable to be determined in sufficient time pulseless electrical activity should receive treatment methods as if the patient were in asystole. Treatment is intravenous delivery Epinephrine 1 mg every 3-5 minutes, and, if the underlying rhythm is bradycardia, Atropine 1 mg IV up to .04 mg/kg (varies with regional protocols). Both these drugs should be administered along with appropriate CPR techniques. Defibrillators are not used for this rhythm, as the problem lies in the response of the myocardial tissue to electrical impulses. Resuscitation protocols (such as ALS), contain instructions on how to systemically consider the causes for PEA. These include hypoxia, acidosis, tension pneumothorax and various others.
---------------------------------------------------------------------------In anatomy, the Precordium is the portion of the body over the heart and stomach.
A precordial thump is a medical procedure used in the initial response to a witnessed cardiac arrest when no defibrillator is immediately available. It can be used as a small part of the provision of advanced cardiac life support (ACLS). About 25% of patients in cardiac arrest who received a thump on the precordium regained cardiac function (Scherf and Bornemann:, 1960)
To perform a precordial thump, a highly trained provider such as a paramedic or physician strikes a single very carefully aimed blow with the fist to the center of the patient's sternum. The intent is to possibly interrupt a heart-damaging rhythm. The precordial thump is thought to produce an electrical depolarization of 2 to 5 Joules. However, the thump is effective only if used at the onset of ventricular fibrillation or pulseless ventricular tachycardia and so should be used only when the arrest is witnessed or monitored. There is no evidence that precordial thump improves recovery in unwitnessed cardiac arrest.
A precordial thump may be given just once. While the odds of success are poor, if a precordial thump is done properly little time is lost. The provider will immediately continue with other ACLS skills, or CPR if the needed ACLS drugs and equipment (such as a defibrillator) are unavailable.
The performance of a precordial thump is outside the scope of first aid and requires at minimum training in advanced cardiac life support. ACLS is performed primarily by physicians, paramedics and nurses with advanced training in emergency care.
---------------------------------------------------------------------------Compartment syndrome is characterized by increased pressure within one or more fascial compartments so that vascular perfusion is compromised. Without prompt treatment, the resulting tissue hypoxia can lead first to nerve damage and eventually muscle death.
Causes
Because the connective tissue that defines the compartment does not stretch, a small amount of bleeding into the compartment, or swelling of the muscles within the compartment can cause the pressure to rise greatly. Common causes of compartment syndrome include tibial or forearm fractures, ischemic-reperfusion following injury, haemorrhage, vascular puncture, intravenous drug injection, casts, prolonged limb compression, crush injuries, and burns.
When compartment syndrome is caused by repetitive heavy use of the muscles, as in a runner, it is known as chronic compartment syndrome (CCS). This is usually not an emergency, but the loss of circulation can cause temporary or permanent damage to nearby nerves and muscle.
[edit] Pathophysiology
Any condition that results in an increase in compartment contents or reduction in a compartment’s volume could lead to the development of an acute compartment syndrome. When pressure is elevated capillary blood flow is compromised. Edema of the soft tissue within the compartment further raises the intra-compartment pressure, which compromised venous and lymphatic drainage of the injured area. Pressure if further increased in a reinforcing vicious cycle until arteriole perfusion in compromised leading to further tissue ischemia.
Tissue pressure is normally below 10 mm Hg and is usually approximately zero. Blood flow through capillaries is at risk at pressures above 20 mm Hg and nerves and muscles may undergo necrosis at pressures greater than 30 – 40 mm Hg. Arteries and arterioles are stable at these pressures, however the tissues within the compartment dependent on the capillaries for nutrients suffer hypoxia.
Untreated compartment syndrome mediated ischemia of the muscles and nerves lead to eventual irreversible damage and death of the tissues within the compartment.
[edit] Symptoms and Signs
Pain is often reported early and almost universally. The description is usually of deep, constant, and poorly localized and is sometimes described as out of proportion with the injury. The pain is aggravated by stretching the muscle group within the compartment. Paresthesia (loss of sensation) in the cutaneous nerves of the affected compartment is another typical sign. A lack of pulse in areas distal to the compartment as well as paralysis of the limb are usually late findings. The compartment may feel very tense as well.
[edit] Diagnosis
CCS can be tested for using by gauging the pressure within the muscle compartments. If the pressure is sufficiently high, a fasciotomy may be required.
--------------------------------------------------------------------------in EKG,
leads II, III, aVF show R coronary artery, posterior infarct
leads V1-V6 reflect circumflex of L coronary artery
--------------------------------------------------------------------------
Myocardial Infarction (MI)
The pathogenesis can include:
Occlusive intracoronary thrombus - a thrombus overlying an ulcerated or fissured stenotic plaque causes 90% of transmural acute myocardial infarctions.
Vasospasm - with or without coronary atherosclerosis and possible association with platelet aggregation.
Emboli - from left sided mural thrombosis, vegetative endocarditis, or paradoxic emboli from the right side of heart through a patent foramen ovale.
The gross morphologic appearance of a myocardial infarction can vary. Patterns include:
Transmural infarct - involving the entire thickness of the left ventricular wall from endocardium to epicardium, usually the anterior free wall and posterior free wall and septum with extension into the RV wall in 15-30%. Isolated infarcts of RV and right atrium are extremely rare.
Subendocardial infarct - multifocal areas of necrosis confined to the inner 1/3-1/2 of the left ventricular wall. These do not show the same evolution of changes seen in a transmural MI.
Arrhythmias and conduction defects, with possible "sudden death"
Extension of infarction, or re-infarction
Congestive heart failure (pulmonary edema)
Cardiogenic shock
Pericarditis
Mural thrombosis, with possible embolization
Myocardial wall rupture, with possible tamponade
Papillary muscle rupture, with possible valvular insufficiency
Ventricular aneurysm formation
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A myxoma (Myxo- = Latin for mucus) is the most common primary tumor of the heart. Myxomas are usually located in either the left or right atrium of the heart; about 86 percent occur in the left atrium.[1]
Myxomas are typically pedunculated, with a stalk that is attached to the interatrial septum. The most common location for attachment of the stalk is the fossa ovalis region of the interatrial septum.
The phrase "myxomatous degeneration" refers to the process in which connective tissue becomes filled with mucus. However, the word "myxoma" is rarely used outside of the context of the cardiac skeleton.
Diagnosis
It is most seen on echocardiography, as a pedunculated mass that is heterogeneous in appearance.
The differential diagnosis include other cardiac tumors such as lipomas and rhabdomyomas. These other tumors of the heart are typically not pedunculated, however, and are more likely to infiltrate the muscle of the heart. Cardiac Magnetic resonance Imaging can help non-invasively diagnose cardiac tumors.
[edit] Symptoms
Symptoms associated with cardiac myxomas are typically due to the effect of the mass of the tumor obstructing the normal flow of blood within the chambers of the heart.
Some symptoms of myxoma may be associated with the release of interleukin 6 (IL-6) by the myxoma.[2][3] High levels of IL-6 may be associated with a higher risk of embolism of the myxoma.[4]
Symptoms of a cardiac myxoma include[5]:
- Dyspnea on exertion
- Paroxysmal dyspnea
- Fever
- Weight loss
- Lightheadedness or syncope (Loss of consciousness)
- Hemoptysis
- Sudden death
Reperfusion injury refers to damage to tissue caused when blood supply returns to the tissue after a period of ischemia. The absence of oxygen and nutrients from blood creates a condition in which the restoration of circulation results in inflammation and oxidative damage from the oxygen rather than restoration of normal function.
Mechanisms of reperfusion injury
The damage of reperfusion injury is due in part to the inflammatory response of damaged tissues. White blood cells carried to the area by the newly returning blood release a host of inflammatory factors such as interleukins as well as free radicals in response to tissue damage [1].The restored blood flow reintroduces oxygen within cells that damages cellular proteins, DNA, and the plasma membrane. Damage to the cell's membrane may in turn cause the release of more free radicals. Such reactive species may also act indirectly in redox signaling to turn on apoptosis. Leukocytes may also build up in small capillaries, obstructing them and leading to more ischemia[1].
Reperfusion injury plays a part in the brain's ischemic cascade, which is involved in stroke and brain trauma. Repeated bouts of ischemia and reperfusion injury also are thought to be a factor leading to the formation and failure to heal of chronic wounds such as pressure sores and diabetic foot ulcers[2]. Continuous pressure limits blood supply and causes ischemia, and the inflammation occurs during reperfusion. As this process is repeated, it eventually damages tissue enough to cause a wound[2].
In prolonged ischemia (60 minutes or more), hypoxanthine is formed as breakdown product of ATP metabolism. The enzyme xanthine dehydrogenase is converted to xanthine oxidase as a result of the higher availability of oxygen. This oxidation results in molecular oxygen being converted into highly reactive superoxide and hydroxyl radicals. Excessive nitric oxide produced during reperfusion reacts with superoxide to produce to produce the potent free radical peroxynitrite. These radicals attack cell membrane lipids, proteins, and glycosaminoglycans, causing further damage.
