The diagnostic tests in cardiology are methods of identifying

heart The heart is a muscular Organ (biology), organ found in humans and other animals. This organ pumps blood through the blood vessels. The heart and blood vessels together make the circulatory system. The pumped blood carries oxygen and nutrie ...

conditions associated with healthy vs. unhealthy, pathologic heart function.

Bedside

History

Obtaining a

medical history The medical history, case history, or anamnesis (from Greek: ἀνά, ''aná'', "open", and μνήσις, ''mnesis'', "memory") of a patient is a set of information the physicians collect over medical interviews. It involves the patient, and ev ...

is always the first "test", part of understanding the likelihood of significant disease, as detectable within the current limitations of clinical medicine. Yet heart problems often produce no symptoms until very advanced, and many symptoms, such as palpitations and sensations of extra or missing heart beats correlate poorly with relative heart health ''vs'' disease. Hence, a history alone is rarely sufficient to diagnose a heart condition.

Auscultation

Auscultation Auscultation (based on the Latin verb ''auscultare'' "to listen") is listening to the internal sounds of the body, usually using a stethoscope. Auscultation is performed for the purposes of examining the circulatory system, circulatory and resp ...

'' employs a

stethoscope The stethoscope is a medicine, medical device for auscultation, or listening to internal sounds of an animal or human body. It typically has a small disc-shaped resonator that is placed against the skin, with either one or two tubes connected t ...

to more easily hear various normal and abnormal sounds, such as normal heart beat sounds and the usual heart beat sound changes associated with breathing versus heart murmurs.

Laboratory

Blood tests

A variety of ''

blood test A blood test is a medical laboratory, laboratory analysis performed on a blood sample that is usually extracted from a vein in the arm using a hypodermic needle, or via fingerprick. Multiple tests for specific blood components, such as a glucose ...

s'' are available for analyzing

cholesterol Cholesterol is the principal sterol of all higher animals, distributed in body Tissue (biology), tissues, especially the brain and spinal cord, and in Animal fat, animal fats and oils. Cholesterol is biosynthesis, biosynthesized by all anima ...

transport behavior, HDL, LDL,

triglyceride A triglyceride (from '' tri-'' and '' glyceride''; also TG, triacylglycerol, TAG, or triacylglyceride) is an ester derived from glycerol and three fatty acids. Triglycerides are the main constituents of body fat in humans and other vertebrates ...

s, lipoprotein little a, homocysteine, C-reactive protein, blood sugar control: fasting, after eating or averages using glycated albumen or hemoglobin,

myoglobin Myoglobin (symbol Mb or MB) is an iron- and oxygen-binding protein found in the cardiac and skeletal muscle, skeletal Muscle, muscle tissue of vertebrates in general and in almost all mammals. Myoglobin is distantly related to hemoglobin. Compar ...

creatine kinase Creatine kinase (CK), also known as creatine phosphokinase (CPK) or phosphocreatine kinase, is an enzyme () expressed by various tissues and cell types. CK catalyses the conversion of creatine and uses adenosine triphosphate (ATP) to create phos ...

troponin Troponin, or the troponin complex, is a complex of three regulatory proteins (troponin C, troponin I, and troponin T) that are integral to muscle contraction in skeletal muscle and cardiac muscle, but not smooth muscle. Measurements of cardiac-spe ...

, brain-type natriuretic peptide, etc. to assess the evolution of

coronary artery disease Coronary artery disease (CAD), also called coronary heart disease (CHD), or ischemic heart disease (IHD), is a type of cardiovascular disease, heart disease involving Ischemia, the reduction of blood flow to the cardiac muscle due to a build-up ...

and evidence of existing damage. A great many more physiologic markers related to

atherosclerosis Atherosclerosis is a pattern of the disease arteriosclerosis, characterized by development of abnormalities called lesions in walls of arteries. This is a chronic inflammatory disease involving many different cell types and is driven by eleva ...

and heart function are used and being developed and evaluated in research. (*) due to the high cost, LDL is usually calculated instead of being measured directly
source: Beyond Cholesterol, Julius Torelli MD, 2005

Electrophysiology

Electrocardiogram

Electrocardiography Electrocardiography is the process of producing an electrocardiogram (ECG or EKG), a recording of the heart's electrical activity through repeated cardiac cycles. It is an electrogram of the heart which is a graph of voltage versus time of t ...

'' (ECG/EKG in German vernacular. Elektrokardiogram) monitors

electrical Electricity is the set of physical phenomena associated with the presence and motion of matter possessing an electric charge. Electricity is related to magnetism, both being part of the phenomenon of electromagnetism, as described by Maxwel ...

activity of the heart, primarily as recorded from the skin surface. A 12 lead recording, recording the electrical activity in three planes, anterior, posterior, and lateral is the most commonly used form. The ECG allows observation of the heart electrical activity by visualizing waveform beat origin (typically from the sinoatrial or SA node) following down the bundle of HIS and ultimately stimulating the ventricles to contract forcing blood through the body. Much can be learned by observing the QRS morphology (named for the respective portions of the polarization/repolarization waveform of the wave, P,Q,R,S,T wave). Rhythm abnormalities can also be visualized as in slow heart rate

bradycardia Bradycardia, also called bradyarrhythmia, is a resting heart rate under 60 beats per minute (BPM). While bradycardia can result from various pathological processes, it is commonly a physiological response to cardiovascular conditioning or due ...

, or fast heart rate

tachycardia Tachycardia, also called tachyarrhythmia, is a heart rate that exceeds the normal resting rate. In general, a resting heart rate over 100 beats per minute is accepted as tachycardia in adults. Heart rates above the resting rate may be normal ...

Fasegram

A '' Fasegraphy'' allows expanding the system of

diagnostic features, based on the evaluation of the speed characteristics of the process, and thereby increasing the sensitivity and specificity of ECG-diagnostics. Fasegraphy allows determining the initial features of changes in the

cardiac muscle Cardiac muscle (also called heart muscle or myocardium) is one of three types of vertebrate muscle tissues, the others being skeletal muscle and smooth muscle. It is an involuntary, striated muscle that constitutes the main tissue of the wall o ...

, even on a single-channel ECG, which are underestimated in traditional ECG diagnostics.

Holter monitor

A '' Holter monitor'' records a continuous EKG rhythm pattern (rarely a full EKG) for 24 hours or more. These monitors are used for suspected frequent rhythm abnormalities, especially ones the wearer may not recognize by symptoms. They are more expensive than event monitors.

Event monitor

An '' event monitor'' records short term EKG rhythm patterns, generally storing the last 2 to 5 minutes, adding in new and discarding old data, for 1 to 2 weeks or more. There are several different types with different capabilities. When the wearer presses a button on the monitor, it quits discarding old and continues recording for a short additional period. The wearer then plays the recording, via a standard phone connection, to a center with compatible receiving and rhythm printing equipment, after which the monitor is ready to record again. These monitors are used for suspected infrequent rhythm abnormalities, especially ones the wearer does recognize by symptoms. They are less expensive than Holter monitors.

Cardiac stress testing

Cardiac stress testing A cardiac stress test is a cardiological examination that evaluates the cardiovascular system's response to external stress within a controlled clinical setting. This stress response can be induced through physical exercise (usually a treadmill) o ...

'' is used to determine to assess cardiac function and to disclose evidence of exertion-related cardiac hypoxia. Radionuclide testing using

thallium Thallium is a chemical element; it has Symbol (chemistry), symbol Tl and atomic number 81. It is a silvery-white post-transition metal that is not found free in nature. When isolated, thallium resembles tin, but discolors when exposed to air. Che ...

technetium Technetium is a chemical element; it has Symbol (chemistry), symbol Tc and atomic number 43. It is the lightest element whose isotopes are all radioactive. Technetium and promethium are the only radioactive elements whose neighbours in the sense ...

can be used to demonstrate areas of perfusion abnormalities. With a maximal stress test the level of exercise is increased until the person's heart rate will not increase any higher, despite increased exercise. A fairly accurate estimate of the target heart rate, based on extensive clinical research, can be estimated by the formula 220 beats per minute minus patient's age. This linear relation is accurate up to about age 30, after which it mildly underestimates typical maximum attainable heart rates achievable by healthy individuals. Other formulas exist, such as that by Miller (217 - (0.85 × Age)) and others. Achieving a high enough heart rate at the end of exercise is critical to improving the sensitivity of the test to detect high grade heart artery

stenosis Stenosis () is the abnormal narrowing of a blood vessel or other tubular organ or structure such as foramina and canals. It is also sometimes called a stricture (as in urethral stricture). ''Stricture'' as a term is usually used when narrowing ...

. High frequency analysis of the QRS complex may be useful for detection of coronary artery disease during an exercise stress test.

Electrophysiology study

The

electrophysiology study A cardiac electrophysiology study (EP test or EP study) is a Invasiveness of surgical procedures, minimally invasive procedure using catheters introduced through a vein or artery to record electrical activity from within the heart. This electric ...

or EP study is the end all of electrophysiological tests of the heart. It involves a catheter with electrodes probing the endocardium, the inside of the heart, and testing the conduction pathways and electrical activity of individual areas of the heart.

Medical imaging

Cardiac imaging techniques include

coronary catheterization A coronary catheterization is a minimally invasive procedure to access the coronary circulation and blood filled chambers of the heart using a catheter. It is performed for both diagnostic and interventional (treatment) purposes. Coronary cathet ...

echocardiogram Echocardiography, also known as cardiac ultrasound, is the use of ultrasound to examine the heart. It is a type of medical imaging, using standard ultrasound or Doppler ultrasound. The visual image formed using this technique is called an echo ...

intravascular ultrasound Intravascular ultrasound (IVUS) or intravascular echocardiography is a medical imaging methodology using a specially designed catheter with a miniaturized ultrasound probe attached to the distal end of the catheter. The proximal end of the cathe ...

, retinal vessel analysis and the coronary calcium scan.

References

{{Cardiac procedures Diagnostic cardiology