Therapies that support reverse remodeling have been investigated, and this may suggests a new approach to the prognosis of cardiomyopathies (see ventricular remodeling).

A significant number of people with hypertrophic cardiomyopathy do not have any symptoms and will have normal life expectancies, although they should avoid particularly strenuous activities or competitive athletics, and should be screened for risk factors for sudden cardiac death. In people with resting or inducible outflow obstructions, situations that will cause dehydration or vasodilation (such as the use of vasodilatory or diuretic blood pressure medications) should be avoided. Septal reduction therapy is not recommended in asymptomatic people.

Treatment may include suggestion of lifestyle changes to better manage the condition. Treatment depends on the type of cardiomyopathy and condition of disease, but may include medication (conservative treatment) or iatrogenic/implanted pacemakers for slow heart rates, defibrillators for those prone to fatal heart rhythms, ventricular assist devices (VADs) for severe heart failure, or ablation for recurring dysrhythmias that cannot be eliminated by medication or mechanical cardioversion. The goal of treatment is often symptom relief, and some patients may eventually require a heart transplant.

Due to non-compaction cardiomyopathy being a relatively new disease, its impact on human life expectancy is not very well understood. In a 2005 study that documented the long-term follow-up of 34 patients with NCC, 35% had died at the age of 42 +/- 40 months, with a further 12% having to undergo a heart transplant due to heart failure. However, this study was based upon symptomatic patients referred to a tertiary-care center, and so were suffering from more severe forms of NCC than might be found typically in the population. Sedaghat-Hamedani et al. also showed the clinical course of symptomatic LVNC can be severe. In this study cardiovascular events were significantly more frequent in LVNC patients compared with an age-matched group of patients with non-ischaemic dilated cardiomyopathy (DCM). As NCC is a genetic disease, immediate family members are being tested as a precaution, which is turning up more supposedly healthy people with NCC who are asymptomatic. The long-term prognosis for these people is currently unknown.

In patients with advanced disease who are refractory to medical therapy, heart transplantation may be considered. For these people 1-year survival approaches 90% and over 50% survive greater than 20 years.

A post-mortem following the death of popular TV presenter David Frost in 2013 showed he suffered from HCM, though it didn’t contribute to his death and his family wasn’t informed. The sudden cardiac death of his 31-year-old son in 2015 led the family to collaborate with the British Heart Foundation to raise funds for better screening.

One paper

has listed the various types of management of care that have been used for various types of NCC. These are similar to management programs for other types of cardiomyopathies which include the use of ACE inhibitors, beta blockers and aspirin therapy to relieve the pressure on the heart, surgical options such as the installation of pacemaker is also an option for those thought to be at a high risk of arrhythmia problems.

In severe cases, where NCC has led to heart failure, with resulting surgical treatment including a heart valve operation, or a heart transplant.

Cardiomyopathies are either confined to the heart or are part of a generalized systemic disorder, both often leading to cardiovascular death or progressive heart failure-related disability. Other diseases that cause heart muscle dysfunction are excluded, such as coronary artery disease, hypertension, or abnormalities of the heart valves. Often, the underlying cause remains unknown, but in many cases the cause may identifiable. Alcoholism, for example, has been identified as a cause of dilated cardiomyopathy, as has drug toxicity, and certain infections (including Hepatitis C). On the other hand, molecular biology and genetics have given rise to the recognition of various genetic causes. For example, mutations in the cardiac desmosomal genes as well as in the DES gene may cause arrhythmogenic right ventricular cardiomyopathy (ARVC).

A more clinical categorization of cardiomyopathy as 'hypertrophied', 'dilated', or 'restrictive', has become difficult to maintain because some of the conditions could fulfill more than one of those three categories at any particular stage of their development. The current American Heart Association definition divides cardiomyopathies into primary, which affect the heart alone, and secondary, which are the result of illness affecting other parts of the body. These categories are further broken down into subgroups which incorporate new genetic and molecular biology knowledge.

An ICD is the most effective prevention against sudden cardiac death. Due to the prohibitive cost of ICDs, they are not routinely placed in all individuals with ARVD.

Indications for ICD placement in the setting of ARVD include:

- Cardiac arrest due to VT or VF

- Symptomatic VT that is not inducible during programmed stimulation

- Failed programmed stimulation-guided drug therapy

- Severe RV involvement with poor tolerance of VT

- Sudden death of immediate family member

Since ICDs are typically placed via a transvenous approach into the right ventricle, there are complications associated with ICD placement and follow-up.

Due to the extreme thinning of the RV free wall, it is possible to perforate the RV during implantation, potentially causing pericardial tamponade. Because of this, every attempt is made at placing the defibrillator lead on the ventricular septum.

After a successful implantation, the progressive nature of the disease may lead to fibro-fatty replacement of the myocardium at the site of lead placement. This may lead to undersensing of the individual's electrical activity (potentially causing inability to sense VT or VF), and inability to pace the ventricle.

The goal of management of ARVD is to decrease the incidence of sudden cardiac death. This raises a clinical dilemma: How to prophylactically treat the asymptomatic patient who was diagnosed during family screening.

A certain subgroup of individuals with ARVD are considered at high risk for sudden cardiac death. Associated characteristics include:

- Young age

- Competitive sports activity

- Malignant familial history

- Extensive RV disease with decreased right ventricular ejection fraction.

- Left ventricular involvement

- Syncope

- Episode of ventricular arrhythmia

Management options include pharmacological, surgical, catheter ablation, and placement of an implantable cardioverter-defibrillator.

Prior to the decision of the treatment option, programmed electrical stimulation in the electrophysiology laboratory may be performed for additional prognostic information. Goals of programmed stimulation include:

- Assessment of the disease's arrhythmogenic potential

- Evaluate the hemodynamic consequences of sustained VT

- Determine whether the VT can be interrupted via antitachycardia pacing.

Regardless of the management option chosen, the individual is typically advised to undergo lifestyle modification, including avoidance of strenuous exercise, cardiac stimulants (i.e.: caffeine, nicotine, pseudoephedrine) and alcohol. If the individual wishes to begin an exercise regimen, an exercise stress test may have added benefit.

The condition itself does not need to be treated, but rather the underlying cause requires correction. Depending on the etiology the gallop rhythm may resolve spontaneously.

Left ventricular hypertrophy (LVH) is thickening of the heart muscle of the left ventricle of the heart, that is, left-sided ventricular hypertrophy.

The enlargement is not permanent in all cases, and in some cases the growth can regress with the reduction of blood pressure.

LVH may be a factor in determining treatment or diagnosis for other conditions. For example, LVH causes a patient to have an irregular ECG. Patients with LVH may have to participate in more complicated and precise diagnostic procedures, such as imaging, in situations in which a physician could otherwise give advice based on an ECG.

The cause should be identified and, where possible, the treatment should be directed to that cause. A last resort form of treatment is heart transplant.

Artificial pacemakers have been used in the treatment of sick sinus syndrome.

Bradyarrhythmias are well controlled with pacemakers, while tachyarrhythmias respond well to medical therapy.

However, because both bradyarrhythmias and tachyarrhythmias may be present, drugs to control tachyarrhythmia may exacerbate bradyarrhythmia. Therefore, a pacemaker is implanted before drug therapy is begun for the tachyarrhythmia.

It can result in many abnormal heart rhythms (arrhythmias), including sinus arrest, sinus node exit block, sinus bradycardia, and other types of bradycardia (slow heart rate).

Sick sinus syndrome may also be associated with tachycardias (fast heart rate) such as atrial tachycardia (PAT) and atrial fibrillation. Tachycardias that occur with sick sinus syndrome are characterized by a long pause after the tachycardia. Sick sinus syndrome is also associated with azygos continuation of interrupted inferior vena cava.

The third heart sound or S is a rare extra heart sound that occurs soon after the normal two "lub-dub" heart sounds (S and S). S3 is associated with heart failure.

An infant with dilated, failing heart was no rarity on the pediatric wards of hospitals in the mid-twentieth century. When such patients came to the autopsy table, most of the hearts showed the thickened endocardial layer noted above. This was thought to be a disease affecting both the heart muscle and the endocardium and it was given various names such as: idiopathic hypertrophy of the heart, endocardial sclerosis, cardiac enlargement of unknown cause, etc. Some of these hearts also had overt congenital anomalies, especially aortic stenosis and coarctation of the aorta.

The term "endocardial fibroelastosis" was introduced by Weinberg and Himmelfarb in 1943. In their pathology laboratory they noted that usually the endocardium was pearly white or opaque instead of normally thin and transparent and microscopically showed a systematic layering of collagenous and elastic fibers. they felt their new term was more adequately descriptive, and, indeed it was quickly and widely adopted. Clinicians began applying it to any infant with a dilated, failing heart, in spite of the fact that the only way to definitively establish the presence of EFE was to see it at autopsy. EFE had quickly become the name of a disease, and it continues to be used by many physicians in this way, though many patients with identical symptoms do not have the endocardial reaction of EFE.

In the latter decades of the twentieth century new discoveries and new thinking about heart muscle disease gave rise to the term "cardiomyopathy". Many of the cases of infantile cardiac failure were accordingly called "primary cardiomyopathy" as well as "primary EFE", while those with identifiable congenital anomalies stressing the heart were called "secondary EFE". In 1957 Black-Schaffer proposed a unitary explanation that stress on the ventricle, of any kind, may trigger the endocardial reaction, so that all EFE could be thought of as secondary. This prescient paper convinced few readers at the time.

Evidence gradually accumulated as to the role of infection as one such type of stress. The studies of Fruhling and colleagues in 1962 were critical. They followed a series of epidemics of Coxsackie virus infection in their part of France. After each epidemic there were increased numbers of cases with EFE coming to autopsy. On closer study there were cases of pure acute myocarditis, cases of mixed myocarditis and EFE, and cases where myocarditis had healed, leaving just EFE. They were able to culture Coxsackie virus from the tissues of many of the cases at all stages of this apparent progression. A similar progression from myocarditis to EFE was later observed at Johns Hopkins but no virology was done.

Noren and colleagues at University of Minnesota, acting on an idea floated at a pediatric meeting, were able to show a relation between exposure to maternal mumps in fetal life, EFE, and a positive skin test for mumps in infants. This brought on a large ongoing controversy and finally prompted a virologist colleague of theirs to inject embryonated eggs with mumps virus. The chicks at first showed the changes of myocarditis, about a year later, typical EFE, and transitional changes in between. Despite this, the controversy about the role of mumps continued as the actual incidence of EFE plummeted. The proponents of mumps as a cause pointed to this as the effect of the recent implementation of widespread mumps immunization.

Evidence that viral infection may play a role as a cause or trigger of EFE was greatly reinforced by the study directed by Towbin in the virus laboratory of Texas Children's Hospital. They applied the methods of today's genetics to old preserved specimens from autopsies of patients with EFE done well before mumps immunization began and found mumps genome in the tissues of over 80% of these patients. It seems undeniable that transplacental mumps infection had been in the past the major cause of EFE, and that immunization was indeed the cause of EFE having become rare.

Non-infectious causes of EFE have also been studied, spurred by the opening of new avenues of genetics research. Now there are specific named genes associated with certain cardiomyopathies, some of which show the characteristic reaction of EFE. A typical example is Barth syndrome and the responsible gene, tafazzin.

Developments in echocardiography, both the technology of the machines and the skill of the operators, have made it no longer necessary to see the endocardium at autopsy. EFE can now be found non-invasively by the recording of increased endocardial echos. Fetal echocardiography has shown that EFE can begin to accumulate as early as 14 weeks of gestation, and increase with incredible rapidity and even that it can be reversed if the stress can be removed early in fetal life.

The North American Pediatric Cardiomyopathy Registry was founded in 2000 and has been supported since by the National Heart, Lung and Blood Institute. Because of the logic of the diagnostic tree, where EFE applies to many branches of the tree and thus cannot occupy a branch, it is not listed by the Registry as a cause but rather, "with EFE" is a modifier that can be applied to any cause.

Thus, the past half century has seen EFE evolve from a mysterious but frequently observed disease to a rare but much better understood reaction to many diseases and other stresses.

Pulsus paradoxus, also paradoxic pulse or paradoxical pulse, is an abnormally large decrease in stroke volume, systolic blood pressure and pulse wave amplitude during inspiration. The normal fall in pressure is less than 10 mmHg. When the drop is more than 10 mmHg, it is referred to as pulsus paradoxus. Pulsus paradoxus is not related to pulse rate or heart rate and it is not a paradoxical rise in systolic pressure. The normal variation of blood pressure during breathing/respiration is a decline in blood pressure during inhalation and an increase during exhalation. Pulsus paradoxus is a sign that is indicative of several conditions, including cardiac tamponade, chronic sleep apnea, croup, and obstructive lung disease (e.g. asthma, COPD).

The "paradox" in "pulsus paradoxus" is that, on physical examination, one can detect beats on cardiac auscultation during inspiration that cannot be palpated at the radial pulse. It results from an accentuated decrease of the blood pressure, which leads to the (radial) pulse not being palpable and may be accompanied by an increase in the jugular venous pressure height (Kussmaul's sign). As is usual with inspiration, the heart rate is slightly increased, due to decreased left ventricular output.

Pulsus paradoxus can be caused by several physiologic mechanisms. Anatomically, these can be grouped into:

- "cardiac causes",

- "pulmonary causes" and

- "non-pulmonary and non-cardiac causes".

Considered physiologically, PP is caused by:

- decreased right heart functional reserve, e.g. myocardial infarction and tamponade,

- right ventricular inflow or outflow obstruction, e.g. superior vena cava obstruction and pulmonary embolism, and

- decreased blood to the left heart due to lung hyperinflation (e.g. asthma, COPD) and anaphylactic shock.

The Infarct Combat Project (ICP) is an international nonprofit organization founded in 1998 to fight ischemic heart diseases through education and research.

Early treatment is essential to keep the affected limb viable. The treatment options include injection of an anticoagulant, thrombolysis, embolectomy, surgical revascularisation, or amputation. Anticoagulant therapy is initiated to prevent further enlargement of the thrombus. Continuous IV unfractionated heparin has been the traditional agent of choice.

If the condition of the ischemic limb is stabilized with anticoagulation, recently formed emboli may be treated with catheter-directed thrombolysis using intraarterial infusion of a thrombolytic agent (e.g., recombinant tissue plasminogen activator (tPA), streptokinase, or urokinase). A percutaneous catheter inserted into the femoral artery and threaded to the site of the clot is used to infuse the drug. Unlike anticoagulants, thrombolytic agents work directly to resolve the clot over a period of 24 to 48 hours.

Direct arteriotomy may be necessary to remove the clot. Surgical revascularization may be used in the setting of trauma (e.g., laceration of the artery). Amputation is reserved for cases where limb salvage is not possible. If the patient continues to have a risk of further embolization from some persistent source, such as chronic atrial fibrillation, treatment includes long-term oral anticoagulation to prevent further acute arterial ischemic episodes.

Decrease in body temperature reduces the aerobic metabolic rate of the affected cells, reducing the immediate effects of hypoxia. Reduction of body temperature also reduces the inflammation response and reperfusion injury. For frostbite injuries, limiting thawing and warming of tissues until warmer temperatures can be sustained may reduce reperfusion injury.

Cardiomyopathies are generally inherited as autosomal dominants, although recessive forms have been described, and dilated cardiomyopathy can also be inherited in an X-linked pattern. Consequently, in addition to tragedy involving an athlete who succumbs, there are medical implications for close relatives. Among family members of index cases, more than 300 causative mutations have been identified. However, not all mutations have the same potential for severe outcomes, and there is not yet a clear understanding of how these mutations (which affect the same myosin protein molecule) can lead to the dramatically different clinical characteristics and outcomes associated with hypertrophic cardiomyopathy (HCM) and dilated cardiomyopathy (DCM).

Since HCM, as an example, is typically an autosomal dominant trait, each child of an HCM parent has a 50% chance of inheriting the mutation. In individuals without a family history, the most common cause of the disease is a "de novo" mutation of the gene that produces the β-myosin heavy chain.

After a disease-causing mutation has been identified in an index case (which is not always accomplished conclusively), the main task is genetic identification of carriers within a pedigree, a sequential process known as "cascade testing". Family members with the same mutation may show different severities of disease, a phenomenon known as "variable penetrance". As a result, some may remain asymptomatic, with little lifelong evidence of disease. Nevertheless, their children remain at risk of inheriting the disorder and potentially being more severely affected.

The best treatment is avoidance of conditions predisposing to attacks, when possible. In athletes who wish to continue their sport or do so in adverse conditions, preventive measures include altered training techniques and medications.

Some take advantage of the refractory period by precipitating an attack by "warming up," and then timing competition such that it occurs during the refractory period. Step-wise training works in a similar fashion. Warm up occurs in stages of increasing intensity, using the refractory period generated by each stage to reach a full workload.