Cardiac enzymes ― also known as cardiac biomarkers ― include myoglobin, troponin and creatine kinase. Historically, lactate dehydrogenase, or LDH, was also used but is non-specific. Cardiac enzymes are released into the circulation when myocardial necrosis occurs, as seen in myocardial infarction.
Troponins are the most widely recognized and important cardiac enzymes used in the diagnosis of acute myocardial ischemia in modern medicine. The majority of patients with an acute MI will have elevation in troponins within 2 to 3 hours of arrival at the emergency department, versus 6 to 12 hours with creatine kinase.
cTnI and cTnT are the two isoforms expressed in the cardiac muscle only (cTnC is also expressed in the skeletal muscle), and they have been verified to be specific and sensitive biomarkers of myocardial damage [16–18], which is particularly important in asymptomatic patients, when combined with other biomarkers and ...
Troponin (I or T)—this is the most commonly ordered and most specific of the cardiac markers. It is elevated (positive) within a few hours of heart damage and remains elevated for up to two weeks. Rising levels in a series of troponin tests performed over several hours can help diagnose a heart attack.
Cardiac troponin.
This protein is by far the most commonly used biomarker. It has the highest known sensitivity. It enters into your bloodstream soon after a heart attack.
Cardiac troponin (cTn) has established itself firmly as the “gold standard” in the diagnosis of ACS.
Molecular, histologic, radiographic, or physiologic characteristics are types of biomarkers.
People with heart disease who experience mental stress induced-ischemia tend to have higher levels of troponin -- a protein whose presence in the blood that is a sign of recent damage to the heart muscle -- all the time, independently of whether they are experiencing stress or chest pain at that moment.
Currently the natriuretic peptides are the most commonly used biomarker and help in the diagnosis and prognostication of patients with heart failure.
Triglyceride-to-high-density lipoprotein cholesterol ratio
Triglyceride (TG) to high-density lipoprotein cholesterol ratio (HDLC) and total cholesterol (TC)-to-HDLC ratio, as well as a low ankle branchial pressure index (ABPI), are vital biomarkers for CVD [160].
Cardiac Risk Markers Profile estimates the levels of cardiac risk markers in the body, which help in evaluating the functioning of the heart. The test also evaluates lipids in the body, abnormal levels of which can lead to heart attacks or other severe heart conditions.
Cardiac markers are used for the diagnosis and risk stratification of patients with chest pain and suspected acute coronary syndrome (ACS) and for management and prognosis in patients with acute heart failure, pulmonary embolism, and other disease states.
TnI levels are typically considered elevated if they're above 40 ng/L in a high-sensitivity test. TnT levels may be considered high if they're above 14 ng/L for women and 22 ng/L for men in a high-sensitivity test.
Those patients with a very high troponin level had high mortality up to one month later. Beyond that, mortality was similar to that of patients with troponin levels within the normal range.
While troponin levels do reflect the extent of myocardial damage, they do not necessarily indicate myocardial ischemia in a subset of patients. Elevated troponin levels can be due to a wide array of mechanisms in the absence of myocardial ischemia and injury.
Tocolytic drugs Fenoterol and Verapamil increased troponin level in a prospective cohort study of 22 women. Thirty-two percent and 40% of women had troponin elevation at day 1 and day 3 of treatment, respectively [54].
Prognostic versus predictive biomarkers
Prognostic biomarkers are associated with differential disease outcomes, but predictive biomarkers discriminate those who will respond or not respond to therapy.
Low: Less than a 5% risk. Borderline: A 5% to 7.4% risk. Intermediate: A 7.5% to 19.9% risk. High: More than a 20% risk.
A coronary angiogram is a type of X-ray used to examine the coronary arteries supplying blood to your heart muscle. It's considered to be the best method of diagnosing coronary artery disease - conditions that affect the arteries surrounding the heart.
A troponin test measures the levels of troponin T or troponin I proteins in the blood. These proteins are released when the heart muscle has been damaged, such as occurs with a heart attack. The more damage there is to the heart, the greater the amount of troponin T and I there will be in the blood.
A CT coronary angiogram can reveal plaque buildup and identify blockages in the arteries, which can lead to a heart attack. Prior to the test, a contrast dye is injected into the arm to make the arteries more visible. The test typically takes 30 minutes to complete.