Anticoagulant therapy is the mainstay of treatment. Acutely, supportive treatments, such as oxygen or analgesia, may be required. People are often admitted to hospital in the early stages of treatment, and tend to remain under inpatient care until the INR has reached therapeutic levels. Increasingly, however, low-risk cases are managed at home in a fashion already common in the treatment of DVT. Evidence to support one approach versus the other is weak.

Usually, anticoagulant therapy is the mainstay of treatment. Unfractionated heparin (UFH), low molecular weight heparin (LMWH), or fondaparinux is administered initially, while warfarin, acenocoumarol, or phenprocoumon therapy is commenced (this may take several days, usually while the patient is in the hospital). LMWH may reduce bleeding among people with pulmonary embolism as compared to UFH according to a systematic review of randomized controlled trials by the Cochrane Collaboration. According to the same review, LMWH reduced the incidence of recurrent thrombotic complications and reduced thrombus size when compared to heparin. There was no difference in overall mortality between participants treated with LMWH and those treated with unfractionated heparin.

Warfarin therapy often requires a frequent dose adjustment and monitoring of the international normalized ratio (INR). In PE, INRs between 2.0 and 3.0 are generally considered ideal. If another episode of PE occurs under warfarin treatment, the INR window may be increased to e.g. 2.5–3.5 (unless there are contraindications) or anticoagulation may be changed to a different anticoagulant e.g. LMWH.

In patients with an underlying malignancy, therapy with a course of LMWH is favored over warfarin; it is continued for six months, at which point a decision should be reached whether ongoing treatment is required.

Similarly, pregnant women are often maintained on low molecular weight heparin until at least six weeks after delivery to avoid the known teratogenic effects of warfarin, especially in the early stages of pregnancy.

Warfarin therapy is usually continued for 3–6 months, or "lifelong" if there have been previous DVTs or PEs, or none of the usual risk factors is present. An abnormal D-dimer level at the end of treatment might signal the need for continued treatment among patients with a first unprovoked pulmonary embolus. For those with small PEs (known as subsegmental PEs) the effects of anticoagulation is unknown as it has not been properly studied as of 2014.

Treatment is aimed at controlling symptoms and improving the interrupted blood flow to the affected area of the body.

Medications include:

- Antithrombotic medication. These are commonly given because thromboembolism is the major cause of arterial embolism. Examples are:

- Anticoagulants (such as warfarin or heparin) and antiplatelet medication (such as aspirin, ticlopidine, and clopidogrel) can prevent new clots from forming

- Thrombolytics (such as streptokinase) can dissolve clots

- Painkillers given intravenously

- Vasodilators to relax and dilate blood vessels.

Appropriate drug treatments successfully produces thrombolysis and removal of the clot in 50% to 80% of all cases.

Antithrombotic agents may be administered directly onto the clot in the vessel using a flexible catheter ("intra-arterial thrombolysis"). Intra-arterial thrombolysis reduces thromboembolic occlusion by 95% in 50% of cases, and restores adequate blood flow in 50% to 80% of cases.

Surgical procedures include:

- Arterial bypass surgery to create another source of blood supply

- Embolectomy, to remove the embolus, with various techniques available:

- Thromboaspiration

- Angioplasty with balloon catheterization with or without implanting a stent Balloon catheterization or open embolectomy surgery reduces mortality by nearly 50% and the need for limb amputation by approximately 35%.

- Embolectomy by open surgery on the artery

If extensive necrosis and gangrene has set in an arm or leg, the limb may have to be amputated. Limb amputation is in itself usually remarkably well tolerated, but is associated with a substantial mortality (~50%), primarily because of the severity of the diseases in patients where it is indicated.

How well a patient does depends on the location of the clot and to what extent the clot has blocked blood flow. Arterial embolism can be serious if not treated promptly.

Without treatment, it has a 25% to 30% mortality rate. The affected area can be permanently damaged, and up to approximately 25% of cases require amputation of an affected extremity.

Arterial emboli may recur even after successful treatment.

Acute cardiogenic pulmonary edema often responds rapidly to medical treatment. Positioning upright may relieve symptoms. Loop diuretics such as furosemide or bumetanide are administered, often together with morphine or diamorphine to reduce respiratory distress. Both diuretics and morphine may have vasodilator effects, but specific vasodilators may be used (particularly intravenous glyceryl trinitrate or ISDN) provided the blood pressure is adequate.

Continuous positive airway pressure and bilevel positive airway pressure (BIPAP/NIPPV) has been demonstrated to reduce the need of mechanical ventilation in people with severe cardiogenic pulmonary edema, and may reduce mortality.

It is possible for cardiogenic pulmonary edema to occur together with cardiogenic shock, in which the cardiac output is insufficient to sustain an adequate blood pressure. This can be treated with inotropic agents or by intra-aortic balloon pump, but this is regarded as temporary treatment while the underlying cause is addressed.

The initial management of pulmonary edema, irrespective of the type or cause, is supporting vital functions. Therefore, if the level of consciousness is decreased it may be required to proceed to tracheal intubation and mechanical ventilation to prevent airway compromise. Hypoxia (abnormally low oxygen levels) may require supplementary oxygen, but if this is insufficient then again mechanical ventilation may be required to prevent complications. Treatment of the underlying cause is the next priority; pulmonary edema secondary to infection, for instance, would require the administration of appropriate antibiotics.

Arterial thrombosis is platelet-rich, and inhibition of platelet aggregation with antiplatelet drugs such as aspirin may reduce the risk of recurrence or progression.

Nitrates such as nitroglycerin are often used as part of the initial therapy for ADHF.

Another option is nesiritide, although it should only be considered if conventional therapy has been ineffective or contraindicated as it is much more expensive than nitroglycerine and has not been shown to be of any greater benefit.

Initial therapy of acute decompensated heart failure usually includes some combination of a vasodilator such as nitroglycerin, a loop diuretic such as furosemide, and non-invasive positive pressure ventilation (NIPPV).

Even if symptoms of heart failure are not present, medications can be used to treat the symptoms that are being experienced. These medicines work to control these symptoms as well as treat other health problems that might be present. They can work to improve the quality of life, slow down the progression of heart failure and reduce the risk for other complications that can occur due to heart failure. It is very important to take proper medicines exactly as prescribed by the physician.

A number of different medications are required for people who are experiencing heart failure. Common types of medications that are prescribed for heart failure patients include ACE inhibitors, vasodilators, beta blockers, aspirin, calcium channel blockers, and cholesterol lowering medications such as statins. Depending on the type of damage a patient has suffered and the underlying cause of the heart failure, any of these drug classes or a combination of them can be prescribed. Patients with heart pumping problems will use a different medication combination than those who are experiencing problems with the heart's ability to fill properly during diastole. Potentially dangerous drug interactions can occur when different drugs mix together and work against each other.

Warfarin and vitamin K antagonists are anticoagulants that can be taken orally to reduce thromboembolic occurrence. Where a more effective response is required, heparin can be given (by injection) concomitantly. As a side effect of any anticoagulant, the risk of bleeding is increased, so the international normalized ratio of blood is monitored. Self-monitoring and self-management are safe options for competent patients, though their practice varies. In Germany, about 20% of patients were self-managed while only 1% of U.S. patients did home self-testing (according to one 2012 study). Other medications such as direct thrombin inhibitors and direct Xa inhibitors are increasingly being used instead of warfarin.

Following a heart attack, nitrates, when taken for two days, and ACE-inhibitors decrease the risk of death. Other medications include:

Aspirin is continued indefinitely, as well as another antiplatelet agent such as clopidogrel or ticagrelor ("dual antiplatelet therapy" or DAPT) for up to twelve months. If someone has another medical condition that requires anticoagulation (e.g. with warfarin) this may need to be adjusted based on risk of further cardiac events as well as bleeding risk. In those who have had a stent, more than 12 months of clopidogrel plus aspirin does not affect the risk of death.

Beta blocker therapy such as metoprolol or carvedilol is recommended to be started within 24 hours, provided there is no acute heart failure or heart block. The dose should be increased to the highest tolerated. Contrary to what was long believed, the use of beta blockers does not appear to affect the risk of death, possibly because other treatments for MI have improved. When beta blocker medication is given within the first 24–72 hours of a STEMI no lives are saved. However, 1 in 200 people were prevented from a repeat heart attack, and another 1 in 200 from having an abnormal heart rhythm. Additionally, for 1 in 91 the medication causes a temporary decrease in the heart's ability to pump blood.

ACE inhibitor therapy should be started within 24 hours, and continued indefinitely at the highest tolerated dose. This is provided there is no evidence of worsening kidney failure, high potassium, low blood pressure, or known narrowing of the renal arteries. Those who cannot tolerate ACE inhibitors may be treated with an angiotensin II receptor antagonist.

Statin therapy has been shown to reduce mortality and subsequent cardiac events, and should be commenced with the aim of lowering LDL cholesterol. Other medications, such as ezetimibe, may also be added with this goal in mind.

Aldosterone antagonists (spironolactone or eplerenone) may be used if there is evidence of left ventricular dysfunction after an MI, ideally after beginning treatment with an ACE inhibitor.

If PCI cannot be performed within 90 to 120 minutes in STEMI then fibrinolysis, preferably within 30 minutes of arrival to hospital, is recommended. If a person has had symptoms for 12 to 24 hours evidence for effectiveness of thrombolysis is less and if they have had symptoms for more than 24 hours it is not recommended. Thrombolysis involves the administration of medication that activates the enzymes that normally dissolve blood clots. These medications include tissue plasminogen activator, reteplase, streptokinase, and tenecteplase. Thrombolysis is not recommended in a number of situations, particularly when associated with a high risk of bleeding or the potential for problematic bleeding, such as active bleeding, past strokes or bleeds into the brain, or severe hypertension. Situations in which thrombolysis may be considered, but with caution, include recent surgery, use of anticoagulants, pregnancy, and proclivity to bleeding. Major risks of thrombolysis are major bleeding and intracranial bleeding. Pre-hospital thrombolysis reduces time to thrombolytic treatment, based on studies conducted in higher income countries, however it is unclear whether this has an impact on mortality rates.

Dressler syndrome is best treated with high dose aspirin. In some resistant cases, corticosteroids can be used but are not preferred (avoided) in first month due to the high frequency of impaired ventricular healing leading to increased rate of ventricular rupture. NSAIDs though once used to treat Dressler syndrome, are less advocated and should be avoided in patients with ischemic heart disease. One NSAID in particular, indomethacin, can inhibit new collagen deposition thus impairing the healing process for the infarcted region. NSAIDS should only be used in cases refractory to aspirin. Heparin in Dressler syndrome should be avoided because it can lead to hemorrhage into the pericardial sac leading to tamponade. The only time heparin could be used with pericarditis is with coexisting acute MI in order to prevent further thrombus formation.

First-line therapy for people with heart failure due to reduced systolic function should include angiotensin-converting enzyme (ACE) inhibitors (ACE-I) or angiotensin receptor blockers (ARBs) if the person develops a long term cough as a side effect of the ACE-I. Use of medicines from this class is associated with improved survival and quality of life in people with heart failure.

Beta-adrenergic blocking agents (beta blockers) also form part of the first line of treatment, adding to the improvement in symptoms and mortality provided by ACE-I/ARB. The mortality benefits of beta blockers in people with systolic dysfunction who also have atrial fibrillation (AF) is more limited than in those who do not have AF. If the ejection fraction is not diminished (HFpEF), the benefits of beta blockers are more modest; a decrease in mortality has been observed but reduction in hospital admission for uncontrolled symptoms has not been observed.

In people who are intolerant of ACE-I and ARBs or who have significant kidney dysfunction, the use of combined hydralazine and a long-acting nitrate, such as isosorbide dinitrate, is an effective alternate strategy. This regimen has been shown to reduce mortality in people with moderate heart failure. It is especially beneficial in African-Americans (AA). In AAs who are symptomatic, hydralazine and isosorbide dinitrate (H+I) can be added to ACE-I or ARBs.

In people with markedly reduced ejection fraction, the use of an aldosterone antagonist, in addition to beta blockers and ACE-I, can improve symptoms and reduce mortality.

Second-line medications for CHF do not confer a mortality benefit. Digoxin is one such medication. Its narrow therapeutic window, a high degree of toxicity, and the failure of multiple trials to show a mortality benefit have reduced its role in clinical practice. It is now used in only a small number of people with refractory symptoms, who are in atrial fibrillation and/or who have chronic low blood pressure.

Diuretics have been a mainstay of treatment for treatment of fluid accumulation, and include diuretics classes such as loop diuretics, thiazide-like diuretic, and potassium-sparing diuretic. Although widely used, evidence on their efficacy and safety is limited, with the exception of mineralocorticoid antagonists such as spironolactone. Mineralocorticoid antagonists in those under 75 years old appear to decrease the risk of death. A recent Cochrane review found that in small studies, the use of diuretics appeared to have improved mortality in individuals with heart failure. However, the extent to which these results can be extrapolated to a general population is unclear due to the small number of participants in the cited studies.

Anemia is an independent factor in mortality in people with chronic heart failure. The treatment of anemia significantly improves quality of life for those with heart failure, often with a reduction in severity of the NYHA classification, and also improves mortality rates. The latest European guidelines (2012) recommend screening for iron-deficient anemia and treating with parenteral iron if anemia is found.

The decision to anticoagulate people with HF, typically with left ventricular ejection fractions <35% is debated, but generally, people with coexisting atrial fibrillation, a prior embolic event, or conditions which increase the risk of an embolic event such as amyloidosis, left ventricular noncompaction, familial dilated cardiomyopathy, or a thromboembolic event in a first-degree relative.

After an AMI, people should be treated to prevent LVT formation. Aspirin plus an oral anticoagulant such as warfarin are suggested for individuals at risk for thromboembolic events. Anticoagulants are also shown to reduce the risk of embolisms when a thrombus is already formed. Heparin, an injectable, fast-acting anticoagulant, is effective in high doses for preventing LVT formation after AMI.

The definitive treatment for constrictive pericarditis is pericardial stripping, which is a surgical procedure where the entire pericardium is peeled away from the heart. This procedure has significant risk involved, with mortality rates of 6% or higher in major referral centers.

A poor outcome is almost always the result after a pericardiectomy is performed for constrictive pericarditis whose origin was radiation-induced, further some patients may develop heart failure post-operatively.

There are also surgical procedures for removal of a thrombus (thrombectomy).

In acute decompensated heart failure (ADHF), the immediate goal is to re-establish adequate perfusion and oxygen delivery to end organs. This entails ensuring that airway, breathing, and circulation are adequate. Immediate treatments usually involve some combination of vasodilators such as nitroglycerin, diuretics such as furosemide, and possibly noninvasive positive pressure ventilation (NIPPV).

Treatment for Thrombotic Storm may include lifelong anticoagulation therapy and/or thrombolytic therapy, plasmapherisis, and corticosteroids. Studies have shown that when anticoagulant therapy is withheld recurrence of thrombosis usually follows. INR is closely monitored in the course of treatment.

Depending on the type of cardiogenic shock, treatment involves infusion of fluids, or in shock refractory to fluids, inotropic medications. In case of an abnormal heart rhythm several anti-arrhythmic agents may be administered, e.g. adenosine.

Positive inotropic agents (such as dobutamine or milrinone), which enhance the heart's pumping capabilities, are used to improve the contractility and correct the low blood pressure. Should that not suffice an intra-aortic balloon pump (which reduces workload for the heart, and improves perfusion of the coronary arteries) or a left ventricular assist device (which augments the pump-function of the heart) can be considered. Finally, as a last resort, if the person is stable enough and otherwise qualifies, heart transplantation, or if not eligible an artificial heart, can be placed. These invasive measures are important tools- more than 50% of patients who do not die immediately due to cardiac arrest from a lethal abnormal heart rhythm and live to reach the hospital (who have usually suffered a severe acute myocardial infarction, which in itself still has a relatively high mortality rate), die within the first 24 hours. The mortality rate for those still living at time of admission who suffer complications (among others, cardiac arrest or further abnormal heart rhythms, heart failure, cardiac tamponade, a ruptured or dissecting aneurysm, or another heart attack) from cardiogenic shock is even worse around 85%, especially without drastic measures such as ventricular assist devices or transplantation.

Cardiogenic shock may be treated with intravenous dobutamine, which acts on β receptors of the heart leading to increased contractility and heart rate.

Nitroglycerin can be used immediately to widen the coronary arteries and help increase blood flow to the heart. In addition, nitroglycerin causes peripheral venous and artery dilation reducing cardiac preload and afterload. These reductions allow for decreased stress on the heart and therefore lower the oxygen demand of the heart's muscle cells.

Antiplatelet drugs such as aspirin and clopidogrel can help reduce the progression of atherosclerotic plaque formation, as well as combining these with an anticoagulant such as a low molecular weight heparin.

Oxygen consumption of skeletal muscle is approximately 50 times larger while contracting than in the resting state. Thus, resting the affected limb should delay onset of infarction substantially after arterial occlusion.

Low molecular weight heparin is used to reduce or at least prevent enlargement of a thrombus, and is also indicated before any surgery. In the legs, below the inguinal ligament, percutaneous aspiration thrombectomy is a rapid and effective way of removing thromboembolic occlusions. Balloon thrombectomy using a Fogarty catheter may also be used. In the arms, balloon thrombectomy is an effective treatment for thromboemboli as well. However, local thrombi from atherosclerotic plaque are harder to treat than embolized ones. If results are not satisfying, another angiography should be performed.

Thrombolysis using analogs of tissue plasminogen activator (tPA) may be used as an alternative or complement to surgery. Where there is extensive vascular damage, bypass surgery of the vessels may be necessary to establish other ways to supply the affected parts.

Swelling of the limb may cause inhibited flow by increased pressure, and in the legs (but very rarely in the arms), this may indicate a fasciotomy, opening up all four leg compartments.

Because of the high recurrence rates of thromboembolism, it is necessary to administer anticoagulant therapy as well. Aspirin and low molecular weight heparin should be administered, and possibly warfarin as well. Follow-up includes checking peripheral pulses and the arm-leg blood pressure gradient.

Patients with uncomplicated acute pericarditis can generally be treated and followed up in an outpatient clinic. However, those with high risk factors for developing complications (see above) will need to be admitted to an inpatient service, most likely an ICU setting. High risk patients include the following:

- subacute onset

- high fever (> 100.4 F/38 C) and leukocytosis

- development of cardiac tamponade

- large pericardial effusion (echo-free space > 20 mm) resistant to NSAID treatment

- immunocompromised

- history of oral anticoagulation therapy

- acute trauma

- failure to respond to seven days of NSAID treatment

Pericardiocentesis is a procedure whereby the fluid in a pericardial effusion is removed through a needle. It is performed under the following conditions:

- presence of moderate or severe cardiac tamponade

- diagnostic purpose for suspected purulent, tuberculosis, or neoplastic pericarditis

- persistent symptomatic pericardial effusion

NSAIDs in "viral" or "idiopathic" pericarditis. In patients with underlying causes other than viral, the specific etiology should be treated. With idiopathic or viral pericarditis, NSAID is the mainstay treatment. Goal of therapy is to reduce pain and inflammation. The course of the disease may not be affected. The preferred NSAID is ibuprofen because of rare side effects, better effect on coronary flow, and larger dose range. Depending on severity, dosing is between 300–800 mg every 6–8 hours for days or weeks as needed. An alternative protocol is aspirin 800 mg every 6–8 hours. Dose tapering of NSAIDs may be needed. In pericarditis following acute myocardial infarction, NSAIDs other than aspirin should be avoided since they can impair scar formation. As with all NSAID use, GI protection should be engaged. Failure to respond to NSAIDs within one week (indicated by persistence of fever, worsening of condition, new pericardial effusion, or continuing chest pain) likely indicates that a cause other than viral or idiopathic is in process.

Colchicine, which has been essential to treat recurrent pericarditis, has been supported for routine use in acute pericarditis by recent prospective studies. Colchicine can be given 0.6 mg twice a day (0.6 mg daily for patients <70 kg) for 3 months following an acute attack. It should be considered in all patients with acute pericarditis, preferably in combination with a short-course of NSAIDs. For patients with a first episode of acute idiopathic or viral pericarditis, they should be treated with an NSAID plus colchicine 1–2 mg on first day followed by 0.5 daily or twice daily for three months. It should be avoided or used with caution in patients with severe renal insufficiency, hepatobiliary dysfunction, blood dyscrasias, and gastrointestinal motility disorders.

Corticosteroids are usually used in those cases that are clearly refractory to NSAIDs and colchicine and a specific cause has not been found. Systemic corticosteroids are usually reserved for those with autoimmune disease.

Splenic infarction can be induced for the treatment of such conditions as portal hypertension or splenic injury. It can also be used prior to splenectomy for the prevention of blood loss.

Individuals can benefit from a variety of physical therapy interventions. Persons with neurological/neuromuscular abnormalities may have breathing difficulties due to weak or paralyzed intercostal, abdominal and/or other muscles needed for ventilation. Some physical therapy interventions for this population include active assisted cough techniques, volume augmentation such as breath stacking, education about body position and ventilation patterns and movement strategies to facilitate breathing.