There is a large crossover between the lifestyle and activity recommendations to prevent a myocardial infarction, and those that may be adopted as secondary prevention after an initial myocardial infarct. Recommendations include stopping smoking, a gradual return to exercise, eating a healthy diet, low in saturated fat and low in cholesterol, and drinking alcohol within recommended limits, exercising, and trying to achieve a healthy weight. Exercise is both safe and effective even if people have had stents or heart failure, and is recommended to start gradually after 1–2 weeks. Counselling should be provided relating to medications used, and for warning signs of depression. Previous studies suggested a benefit from omega-3 fatty acid supplementation but this has not been confirmed.

Statins, drugs that act to lower blood cholesterol, decrease the incidence and mortality rates of myocardial infarctions. They are often recommended in those at an elevated risk of cardiovascular diseases.

Aspirin has been studied extensively in people considered at increased risk of myocardial infarction. Based on numerous studies in different groups (e.g. people with or without diabetes), there does not appear to be a benefit strong enough to outweigh the risk of excessive bleeding. Nevertheless, many clinical practice guidelines continue to recommend aspirin for primary prevention, and some researchers feel that those with very high cardiovascular risk but low risk of bleeding should continue to receive aspirin.

After return of heart function, there has been a moderately higher risk of death in the hospital when compared to MI patients without PVF. Whether this still holds true with the recent changes in treatment strategies of earlier hospital admission and immediate angioplasty with thrombus removal is unknown. PVF does not affect the long-term prognosis.

The survival of PVF largely depends on the promptness of defibrillation. The success rate of prompt defibrillation during monitoring is currently higher than 95%. It is estimated that the success rate decreases by 10% for each additional minute of delay.

Aggressive risk factor modification is required for effective treatment of microvascular angina where exercise plays a major role. Several other treatment strategies including b-blockers, angiotensin-converting enzyme inhibitors, ranolazine, l-arginine, statin drugs and potentially estrogen replacement therapy have been shown to relieve anginal symptoms as well as improve vascular function. Nitrates may be effective for symptom relief. Further studies are required to determine whether specific treatments are associated with improved survival as well as decreased symptoms.

The most specific medicine to treat angina is nitroglycerin. It is a potent vasodilator that decreases myocardial oxygen demand by decreasing the heart's workload. Beta blockers and calcium channel blockers act to decrease the heart's workload, and thus its requirement for oxygen. Nitroglycerin should not be given if certain inhibitors such as sildenafil, tadalafil, or vardenafil have been taken within the previous 12 hours as the combination of the two could cause a serious drop in blood pressure. Treatments for angina are balloon angioplasty, in which the balloon is inserted at the end of a catheter and inflated to widen the arterial lumen. Stents to maintain the arterial widening are often used at the same time. Coronary bypass surgery involves bypassing constricted arteries with venous grafts. This is much more invasive than angioplasty.

The main goals of treatment in angina pectoris are relief of symptoms, slowing progression of the disease, and reduction of future events, especially heart attacks and death. Beta blockers (e.g., carvedilol, propranolol, atenolol) have a large body of evidence in morbidity and mortality benefits (fewer symptoms, less disability and longer life) and short-acting nitroglycerin medications have been used since 1879 for symptomatic relief of angina. Calcium channel blockers (such as nifedipine (Adalat) and amlodipine), isosorbide mononitrate and nicorandil are vasodilators commonly used in chronic stable angina. A new therapeutic class, called If inhibitor, has recently been made available: Ivabradine provides pure heart rate reduction leading to major anti-ischemic and antianginal efficacy. ACE inhibitors are also vasodilators with both symptomatic and prognostic benefit. Statins are the most frequently used lipid/cholesterol modifiers, which probably also stabilize existing atheromatous plaque. Low-dose aspirin decreases the risk of heart attack in patients with chronic stable angina, and was part of standard treatment. However, in patients without established cardiovascular disease, the increase in hemorrhagic stroke and gastrointestinal bleeding offsets any benefits and it is no longer advised unless the risk of myocardial infarction is very high.

Exercise is also a very good long-term treatment for the angina (but only particular regimens - gentle and sustained exercise rather than intense short bursts), probably working by complex mechanisms such as improving blood pressure and promoting coronary artery collateralisation.

Though sometimes used by patients, evidence does not support the use of Traditional Chinese Herbal Products (THCP) for angina

Identifying and treating risk factors for further coronary heart disease is a priority in patients with angina. This means testing for elevated cholesterol and other fats in the blood, diabetes and hypertension (high blood pressure), and encouraging smoking cessation and weight optimization.

The calcium channel blocker nifedipine prolongs cardiovascular event- and procedure-free survival in patients with coronary artery disease. New overt heart failures were reduced by 29% compared to placebo; however, the mortality rate difference between the two groups was statistically insignificant.

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.

One of the most important features differentiating ischemic cardiomyopathy from the other forms of cardiomyopathy is the shortened, or worsened all-cause mortality in patients with ischemic cardiomyopathy. According to several studies, coronary artery bypass graft surgery has a survival advantage over medical therapy (for ischemic cardiomyopathy) across varied follow-ups.

A complication that may occur in the acute setting soon after a myocardial infarction or in the weeks following is cardiogenic shock. Cardiogenic shock is defined as a hemodynamic state in which the heart cannot produce enough of a cardiac output to supply an adequate amount of oxygenated blood to the tissues of the body.

While the data on performing interventions on individuals with cardiogenic shock is sparse, trial data suggests a long-term mortality benefit in undergoing revascularization if the individual is less than 75 years old and if the onset of the acute myocardial infarction is less than 36 hours and the onset of cardiogenic shock is less than 18 hours. If the patient with cardiogenic shock is not going to be revascularized, aggressive hemodynamic support is warranted, with insertion of an intra-aortic balloon pump if not contraindicated. If diagnostic coronary angiography does not reveal a culprit blockage that is the cause of the cardiogenic shock, the prognosis is poor.

Restoring adequate blood flow to the heart muscle in people with heart failure and significant coronary artery disease is strongly associated with improved survival, some research showing up to 75% survival rates over 5 years. A stem cell study indicated that using autologous cardiac stem cells as a regenerative approach for the human heart (after a heart attack) has great potential.

American Heart Association practice guidelines indicate (ICD) implantable cardioverter-defibrillator use in those with ischemic cardiomyopathy (40 days post-MI) that are (NYHA) New York Heart Association functional class I. LVEF of >30% is often used to differentiate primary from ischemic cardiomyopathy, and a prognostic indicator. At the same time, people who undergo ventricular restoration on top of coronary artery bypass show improved postoperative ejection fraction as compared to those treated with only coronary artery bypass surgery. Severe cases are treated with heart transplantation.

Secondary prevention is preventing further sequelae of already established disease. Lifestyle changes that have been shown to be effective to this goal include:

- Weight control

- Smoking cessation

- Avoiding the consumption of trans fats (in partially hydrogenated oils)

- Decrease psychosocial stress.

- Exercise. Aerobic exercise, like walking, jogging, or swimming, can reduce the risk of mortality from coronary artery disease. Aerobic exercise can help decrease blood pressure and the amount of blood cholesterol (LDL) over time. It also increases HDL cholesterol which is considered as "good cholesterol". Separate to the question of the benefits of exercise; it is unclear whether doctors should spend time counseling patients to exercise. The U.S. Preventive Services Task Force, found "insufficient evidence" to recommend that doctors counsel patients on exercise, but "it did not review the evidence for the effectiveness of physical activity to reduce chronic disease, morbidity and mortality", it only examined the effectiveness of the counseling itself. The American Heart Association, based on a non-systematic review, recommends that doctors counsel patients on exercise.

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.

There are a number of treatment options for coronary artery disease:

- Lifestyle changes

- Medical treatment – drugs (e.g., cholesterol lowering medications, beta-blockers, nitroglycerin, calcium channel blockers, etc.);

- Coronary interventions as angioplasty and coronary stent;

- Coronary artery bypass grafting (CABG)

A myocardial infarction may compromise the function of the heart as a pump for the circulation, a state called heart failure. There are different types of heart failure; left- or right-sided (or bilateral) heart failure may occur depending on the affected part of the heart, and it is a low-output type of failure. If one of the heart valves is affected, this may cause dysfunction, such as mitral regurgitation in the case of left-sided coronary occlusion that disrupts the blood supply of the papillary muscles. The incidence of heart failure is particularly high in patients with diabetes and requires special management strategies.

Unstable angina (UA) is a type of angina pectoris that is irregular. It is also classified as a type of acute coronary syndrome (ACS).

It can be difficult to distinguish unstable angina from non-ST elevation (non-Q wave) myocardial infarction (NSTEMI). They differ primarily in whether the ischemia is severe enough to cause sufficient damage to the heart's muscular cells to release detectable quantities of a marker of injury (typically troponin T or troponin I). Unstable angina is considered to be present in patients with ischemic symptoms suggestive of an ACS and no elevation in troponin, with or without ECG changes indicative of ischemia (e.g., ST segment depression or transient elevation or new T wave inversion). Since an elevation in troponin may not be detectable for up to 12 hours after presentation, UA and NSTEMI are frequently indistinguishable at initial evaluation.

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.

There is low-quality evidence that stem cell therapy may help. Although this evidence positively indicated benefit, the evidence was of lower quality than other evidence that does not indicate benefit.

A previous claim, which came from a 2012 article published by the British Journal "Heart", stated that a low salt diet increased the risk of death in those with congestive heart failure. This claim has since been withdrawn. The paper was retracted by the journal in 2013 because two of the cited studies contained duplicate data that could not be verified, and the data have since been lost.

A 2016 Cochrane review found tentative evidence of longer life expectancy and improved left ventricular ejection fraction in persons treated with bone marrow-derived stem cells.

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.

The prognosis of myocardial rupture is dependent on a number of factors, including which portion of the myocardium is involved in the rupture. In one case series, if myocardial rupture involved the free wall of the left ventricle, the mortality rate was 100.0%. The chances of survival rise dramatically if the patient: 1. has a witnessed initial event; 2. seeks early medical attention; 3. has an accurate diagnosis by the emergentologist; and 4. happens to be at a facility that has a cardiac surgery service (by whom a quick repair of the rupture can be attempted). Even if the individual survives the initial hemodynamic sequelae of the rupture, the 30‑day mortality is still significantly higher than if rupture did not occur.

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.

In cardiology, stunned myocardium is a state when some section of the myocardium (corresponding to area of a major coronary occlusion) shows a form of contractile abnormality. This is a segmental dysfunction which persists for a variable period of time, about two weeks, even after ischemia has been relieved (by for instance angioplasty or coronary artery bypass surgery). In this situation, while myocardial blood flow (MBF) returns to normal, function is still depressed for a variable period of time.

Myocardial stunning is the reversible reduction of function of heart contraction after reperfusion not accounted for by tissue damage or reduced blood flow.

After total ischemia occurs, the myocardium switches immediately from aerobic glycolysis to anaerobic glycolysis resulting in the reduced ability to produce high energy phosphates such as ATP and Creatinine Phosphate. At this point, the lack of the energy and lactate accumulation results in cessation of contraction within 60 seconds of ischemia (i.e. Vessel Occlusion). Subsequent to this is a period of "myocardial stunning," in which reversible ischemic damage is taking place. At approximately 30 minutes after the onset of total ischemia the damage becomes irreversible, thereby ending the phase of myocardial stunning.

Clinical situations of stunned myocardium are:

- acute myocardial infarction (AMI)

- after percutaneous transluminal coronary angioplasty (PTCA)

- after cardiac surgery

- 'neurogenic' stunned myocardium following an acute cerebrovascular event such as a subarachnoid hemorrhage

People who do not respond to conventional therapy are candidates for bridge therapy with left ventricular assist devices. Heart transplantation is reserved for people who fail to improve with conventional therapy.

Extracorporeal membrane oxygenation may be used in those who are about to go into cardiac arrest.

The prevalence of LVT with AMI is 5-15%. The rates of AMI associated with LVT is declining due to the use of better therapies and percutaneous coronary intervention used to treat myocardial infarction. LVT formation has been found to be higher in anterior wall AMI than other types of AMI.

The effectiveness and safety of ACE inhibitors and angiotensin receptor blockers acutely in ADHF have not been well studied, but are potentially harmful. A person should be stabilized before therapy with either of these medication classes is initiated. Individuals with poor kidney perfusion are especially at risk for kidney impairment inherent with these medications.

Beta-blockers are stopped or decreased in people with acutely decompensated heart failure and a low blood pressure. However, continuation of beta-blockers may be appropriate if the blood pressure is adequate.

Inotropes are indicated if low blood pressure ( SBP < 90 mmHg ) is present.

Opioids have traditionally been used in the treatment of the acute pulmonary edema that results from acute decompensated heart failure. A 2006 review, however, found little evidence to support this practice.

Ultrafiltration can be used to remove fluids in people with ADHF associated with kidney failure. Studies have found that it decreases health care utilization at 90 days.