Particulate matter has been studied for its short- and long-term exposure effects on cardiovascular disease. Currently, PM is the major focus, in which gradients are used to determine CVD risk. For every 10 μg/m of PM long-term exposure, there was an estimated 8–18% CVD mortality risk. Women had a higher relative risk (RR) (1.42) for PM induced coronary artery disease than men (0.90) did. Overall, long-term PM exposure increased rate of atherosclerosis and inflammation. In regards to short-term exposure (2 hours), every 25 μg/m of PM resulted in a 48% increase of CVD mortality risk. In addition, after only 5 days of exposure, a rise in systolic (2.8 mmHg) and diastolic (2.7 mmHg) blood pressure occurred for every 10.5 μg/m of PM. Other research has implicated PM in irregular heart rhythm, reduced heart rate variability (decreased vagal tone), and most notably heart failure. PM is also linked to carotid artery thickening and increased risk of acute myocardial infarction.

Cardiovascular disease affects low- and middle-income countries even more than high-income countries. There is relatively little information regarding social patterns of cardiovascular disease within low- and middle-income countries, but within high-income countries low income and low educational status are consistently associated with greater risk of cardiovascular disease. Policies that have resulted in increased socio-economic inequalities have been associated with greater subsequent socio-economic differences in cardiovascular disease implying a cause and effect relationship. Psychosocial factors, environmental exposures, health behaviours, and health-care access and quality contribute to socio-economic differentials in cardiovascular disease.

The cause of cardiomegaly is not well understood and many cases of cardiomegaly are idiopathic (having no known cause). Prevention of cardiomegaly starts with detection. If a person has a family history of cardiomegaly, one should let one's doctor know so that treatments can be implemented to help prevent worsening of the condition. In addition, prevention includes avoiding certain lifestyle risk factors such as tobacco use and controlling one's high cholesterol, high blood pressure, and diabetes. Non-lifestyle risk factors include family history of cardiomegaly, coronary artery disease (CAD), congenital heart failure, Atherosclerotic disease, valvular heart disease, exposure to cardiac toxins, sleep disordered breathing (such as sleep apnea), sustained cardiac arrhythmias, abnormal electrocardiograms, and cardiomegaly on chest X-ray. Lifestyle factors which can help prevent cardiomegaly include eating a healthy diet, controlling blood pressure, exercise, medications, and not abusing alcohol and cocaine. Current research and the evidence of previous cases link the following (below) as possible causes of cardiomegaly.

The most common causes of Cardiomegaly are congenital (patients are born with the condition based on a genetic inheritance), high blood pressure which can enlarge the left ventricle causing the heart muscle to weaken over time, and coronary artery disease that creates blockages in the heart's blood supply, which can bring on a cardiac infarction (heart attack) leading to tissue death which causes other areas of the heart to work harder, increasing the heart size.

Other possible causes include:

- Heart Valve Disease

- Cardiomyopathy (disease to the heart muscle)

- Pulmonary Hypertension

- Pericardial Effusion (fluid around the heart)

- Thyroid Disorders

- Hemochromatosis (excessive iron in the blood)

- Other rare diseases like Amyloidosis

- Viral infection of the heart

- Pregnancy, with enlarged heart developing around the time of delivery (peripartum cardiomyopathy)

- Kidney disease requiring dialysis

- Alcohol or cocaine abuse

- HIV infection

- Diabetes

Although estimates vary, the annual incidence of clinically significant neuroendocrine tumors is approximately 2.5–5 per 100,000; two thirds are carcinoid tumors and one third are other NETs.

The prevalence has been estimated as 35 per 100,000, and may be considerably higher if clinically silent tumors are included. An autopsy study of the pancreas in people who died from unrelated causes discovered a remarkably high incidence of tiny asymptomatic NETs. Routine microscopic study of three random sections of the pancreas found NETs in 1.6%, and multiple sections identified NETs in 10%. As diagnostic imaging increases in sensitivity, such as endoscopic ultrasonography, very small, clinically insignificant NETs may be coincidentally discovered; being unrelated to symptoms, such neoplasms may not require surgical excision.

A number of medications may cause or worsen the disease. This includes NSAIDS, a number of anesthetic agents such as ketamine, thiazolidinediones, a number of cancer medications, salbutamol, and tamsulosin among others.

A person's risk of developing heart failure is inversely related to their level of physical activity. Those who achieved at least 500 MET-minutes/week (the recommended minimum by U.S. guidelines) had lower heart failure risk than individuals who did not report exercising during their free time; the reduction in heart failure risk was even greater in those who engaged in higher levels of physical activity than the recommended minimum.

Hypertension or high blood pressure affects at least 4 billion people worldwide. Hypertensive heart disease is only one of several diseases attributable to high blood pressure. Other diseases caused by high blood pressure include ischemic heart disease, stroke, peripheral arterial disease, aneurysms and kidney disease. Hypertension increases the risk of heart failure by two or three-fold and probably accounts for about 25% of all cases of heart failure. In addition, hypertension precedes heart failure in 90% of cases, and the majority of heart failure in the elderly may be attributable to hypertension. Hypertensive heart disease was estimated to be responsible for 1.0 million deaths worldwide in 2004 (or approximately 1.7% of all deaths globally), and was ranked 13th in the leading global causes of death for all ages. A world map shows the estimated disability-adjusted life years per 100,000 inhabitants lost due to hypertensive heart disease in 2004.

Pheochromocytoma is seen in between two and eight in 1,000,000, with approximately 1000 cases diagnosed in United States yearly. It mostly occurs in young or middle age adults, though it presents earlier in hereditary cases.

- About 10% of adrenal cases are bilateral (suggesting hereditary disease)

- About 10% of adrenal cases occur in children (also suggesting hereditary disease)

- About 15% are extra-adrenal (located in any orthosympathetic tissue): Of these 9% are in the abdomen, and 1% are located elsewhere. Some extra-adrenal pheochromocytomas are probably actually paragangliomas, but the distinction can only be drawn after surgical resection.

- About 11.1% of adrenal cases are malignant, but this rises to 30% for extra-adrenal cases

- About 15–20% are hereditary

- About 5% are caused by VHL disease

- About 3% recur after being resected

- About 14% of affected individuals do not have arterial hypertension (Campbell's Urology)

Carcinoid Syndrome is multiple in 1/5 cases.

Incidence of Gastric Carcinoid is increased in Achlorhydria,Hashimoto's thyroiditis,Pernicious anemia.

Coronary artery disease has a number of well determined risk factors. These include high blood pressure, smoking, diabetes, lack of exercise, obesity, high blood cholesterol, poor diet, depression, family history, and excessive alcohol. About half of cases are linked to genetics. Smoking and obesity are associated with about 36% and 20% of cases, respectively. Lack of exercise has been linked to 7–12% of cases. Exposure to the herbicide Agent orange may increase risk. Both rheumatoid arthritis and systemic lupus erythematosus are independent risk factors as well.

Job stress appears to play a minor role accounting for about 3% of cases.

In one study, women who were free of stress from work life saw an increase in the diameter of their blood vessels, leading to decreased progression of atherosclerosis. In contrast, women who had high levels of work-related stress experienced a decrease in the diameter of their blood vessels and significantly increased disease progression. Having a type A behavior pattern, a group of personality characteristics including time urgency, competitiveness, hostility, and impatience is linked to an increased risk of coronary disease.

Metastasis of carcinoid can lead to carcinoid syndrome. This is due to the over-production of many substances, including serotonin, which are released into the systemic circulation, and which can lead to symptoms of cutaneous flushing, diarrhea, bronchoconstriction, and right-sided cardiac valve disease. It is estimated that less than 6% of carcinoid patients will develop carcinoid syndrome, and of these, 50% will have cardiac involvement.

The massive release of catecholamines in pheochromocytoma can cause damage to heart cells. This damage may be due to either compromising the coronary microcirculation or by direct toxic effects on the heart cells.

Genetic changes are very high in SCLC and LCNEC, but usually low for TC, intermediate for AC.

Idiopathic giant-cell myocarditis (IGCM) is a cardiovascular disease of the muscle of the heart (myocardium).

The condition is rare; however, it is often fatal and there is no proven cure because of the unknown nature of the disorder.

IGCM frequently leads to death with a high rate of about 70% in first year. A patient with IGCM typically presents with symptoms of heart failure, although some may present initially with ventricular arrhythmia or heart block. Median age from the time the disease is diagnosed to the time of death is approximately 6 months. 90% of patients are either deceased by the end of 1 year or have received a heart transplant. Diagnosis is made by endomyocardial biopsy during heart catheterization. Biopsy shows multinucleated giant cells and thus the name. While previously cases universally required heart transplantation, recent studies show that two thirds of patients can survive past one year with high doses of immunosuppressants such as prednisone and cyclosporine. The transplanted heart has a high chance of disease recurrence. Compared to lymphocytic (presumed viral) myocarditis, giant cell myocarditis is much more severe with much more rapid progression.

It is suggested to be caused by T-lymphocytes.

There are more women than men with hypertension, and, although men develop hypertension earlier in life, hypertension in women is less well controlled. The consequences of high blood pressure in women are a major public health problem and hypertension is a more important contributory factor in heart attacks in women than men. Until recently women have been under-represented in clinical trials in hypertension and heart failure. Nevertheless, there is some evidence that the effectiveness of antihypertensive drugs differs between men and women and that treatment for heart failure may be less effective in women.

Depending on source, the overall 5-year survival rate for medullary thyroid cancer is 80%, 83% or 86%, and the 10-year survival rate is 75%.

By overall cancer staging into stages I to IV, the 5-year survival rate is 100% at stage I, 98% at stage II, 81% at stage III and 28% at stage IV. The prognosis of MTC is poorer than that of follicular and papillary thyroid cancer when it has metastasized (spread) beyond the thyroid gland.

The prognostic value of measuring calcitonin and carcinoembryonic antigen (CEA) concentrations in the blood was studied in 65 MTC patients who had abnormal calcitonin levels after surgery (total thyroidectomy and lymph node dissection). The prognosis correlated with the rate at which the postoperative calcitonin concentration doubles, termed the calcitonin doubling time (CDT), rather than the pre- or postoperative absolute calcitonin level:

- CDT less than 6 months: 3 patients out of 12 (25%) survived 5 years. 1 patient out of 12 (8%) survived 10 years. All died within 6 months to 13.3 years.

- CDT between 6 months and 2 years: 11 patients out of 12 (92%) survived 5 years. 3 patients out of 8 (37%) survived 10 years. 4 patients out of 12 (25%) survived to the end of the study.

- CDT more than 2 years: 41 patients out of 41 (100%) were alive at the end of the study. These included 1 patient whose calcitonin was stable, and 11 patients who had decreasing calcitonin levels.

The calcitonin doubling time was a better predictor of MTC survival than CEA but following both tests is recommended.

Prognosis varies from individual to individual. It ranges from a 95% 5-year survival for localized disease to an 80% 5-year survival for those with liver metastases. The average survival time from the start of octreotide treatment has increased to about 12 years.

A diet high in fruits and vegetables decreases the risk of cardiovascular disease and death. Vegetarians have a lower risk of heart disease, possibly due to their greater consumption of fruits and vegetables. Evidence also suggests that the Mediterranean diet and a high fiber diet lower the risk.

The consumption of trans fat (commonly found in hydrogenated products such as margarine) has been shown to cause a precursor to atherosclerosis and increase the risk of coronary artery disease.

Evidence does not support a beneficial role for omega-3 fatty acid supplementation in preventing cardiovascular disease (including myocardial infarction and sudden cardiac death). There is tentative evidence that intake of menaquinone (Vitamin K), but not phylloquinone (Vitamin K), may reduce the risk of CAD mortality.

Although in many cases no cause is apparent, dilated cardiomyopathy is probably the result of damage to the myocardium produced by a variety of toxic, metabolic, or infectious agents. It may be due to fibrous change of the myocardium from a previous myocardial infarction. Or, it may be the late sequelae of acute viral myocarditis, such as with Coxsackie B virus and other enteroviruses possibly mediated through an immunologic mechanism.

Other causes include:

- Chagas disease, due to "Trypanosoma cruzi". This is the most common infectious cause of dilated cardiomyopathy in Latin America

- Pregnancy. Dilated cardiomyopathy occurs late in gestation or several weeks to months postpartum as a peripartum cardiomyopathy. It is reversible in half of cases.

- Alcohol abuse (alcoholic cardiomyopathy)

- Nonalcoholic toxic insults include administration of certain chemotherapeutic agents, in particular doxorubicin (Adriamycin), and cobalt.

- Thyroid disease

- Inflammatory diseases such as sarcoidosis and connective tissue diseases

- Tachycardia-induced cardiomyopathy

- Muscular dystrophy

- Tuberculosis - 1 to 2% of TB cases.

- Autoimmune mechanisms

Recent studies have shown that those subjects with an extremely high occurrence (several thousands a day) of premature ventricular contractions (extrasystole) can develop dilated cardiomyopathy. In these cases, if the extrasystole are reduced or removed (for example, via ablation therapy) the cardiomyopathy usually regresses.

Although the disease is more common in African-Americans than in Caucasians, it may occur in any patient population.

Atypical pulmonary carcinoid tumour is a subtype of pulmonary carcinoid tumor. It is an uncommon low-grade malignant lung mass that is most often in the central airways of the lung. It is also known as "atypical lung carcinoid tumour", " atypical lung carcinoid" or "moderately differentiated neuroendocrine carcinoma".

It is a more aggressive than typical carcinoid tumors: nodal metastases in 70% vs. 5%. The 5 year survival is 49-69%.

Atypical carcinoid tumors have increased mitotic activity (2-10 per 10 HPF), nuclear pleomorphism or foci of necrosis.

Several issues help define appropriate treatment of a neuroendocrine tumor, including its location, invasiveness, hormone secretion, and metastasis. Treatments may be aimed at curing the disease or at relieving symptoms (palliation). Observation may be feasible for non-functioning low grade neuroendocrine tumors. If the tumor is locally advanced or has metastasized, but is nonetheless slowly growing, treatment that relieves symptoms may often be preferred over immediate challenging surgeries.

Intermediate and high grade tumors (noncarcinoids) are usually best treated by various early interventions (active therapy) rather than observation (wait-and-see approach).

Treatments have improved over the past several decades, and outcomes are improving. In malignant carcinoid tumors with carcinoid syndrome, the median survival has improved from two years to more than eight years.

Detailed guidelines for managing neuroendocrine tumors are available from ESMO, NCCN and a UK panel. The NCI has guidelines for several categories of NET: islet cell tumors of the pancreas, gastrointestinal carcinoids, Merkel cell tumors and pheochromocytoma/paraganglioma.

Pulmonary carcinoid tumour is a neuroendocrine tumour of the lung.

There are two types:

- Typical pulmonary carcinoid tumour

- Atypical pulmonary carcinoid tumour

Cardiomegaly is a condition affecting the cardiovascular system, specifically the heart. This condition is strongly associated with congestive heart failure. Within the heart, the working fibers of the myocardial tissue increase in size. As the heart works harder the actin and myosin filaments experience less overlap which increases the size of the myocardial fibers. If there is less overlap of the protein filaments actin and myosin within the sarcomeres of muscle fibers, they will not be able to effectively pull on one another. If the heart tissue (walls of left and right ventricle) gets too big and stretches too far, then those filaments cannot effectively pull on one another to shorten the muscle fibers, thus impacting the heart's sliding filament mechanism. If fibers cannot shorten properly, and the heart cannot contract properly, then blood cannot be effectively pumped to the lungs to be re-oxygenated and to the body to deliver oxygen to the working tissues of the body.

A total thyroidectomy with bilateral neck dissection is the gold standard for treating medullary thyroid cancer, and is the most definitive means of achieving a cure in patients without distant metastases or extensive nodal involvement. Due to the extreme level of difficulty in successfully performing the neck dissection without extensive morbidity, it is very important for patients to seek care under an experienced surgeon at a Center of Excellence who operates on MTC patients at least several times a year. Risks of surgery include loss of vocal control, irreparable nerve damage, death or the need for second operation to clean out residual diseased lymph nodes left behind if the sentinel node biopsy was positive for cancerous spread. Extensive surgery can be effective when the condition is detected early, but a risk for recurrence remains, particularly in patients with multiple positive lymph nodes or extracapsular invasion. About half of patients have metastasis to regional lymph nodes at the time of diagnosis.

The European Society of Endocrine Surgeons has published recommendations for managing this condition in gene carriers. The timing of surgery depends on the type of mutation present. For those in the highest risk group, surgery is recommended in the first year of life. In lower risk cases surgery may be delayed up to the age of ten years, the precise timing depending on the mutation and other factors.