Cardiac arrhythmias can be diagnosed in a physician’s office. By studying the characteristic wave pattern of a series of heartbeats, physicians can determine what kind of arrhythmia is present. The most common diagnostic tool is the electrocardiogram (ECG or EKG) (NHLBI 2011b).
Diagnosis may include one or more of the following:
History and physical examination. The presence of heart disease or a history of heart disease, thyroid problems, or high blood pressure in the patient or in family members is associated with increased risk; family history of sudden death, diabetes, or other illnesses also increases risk (NHLBI 2011b). Listening to the heart and measuring the rate and rhythm of the heartbeat, listening for heart murmurs, checking for swelling in the feet, and taking the pulse can all aid in the diagnosis of arrhythmias (NHLBI 2011a).
Electrocardiogram (ECG or EKG). The ECG is a test that detects and records the heart’s electrical activity (MayoClinic 2011a).
- An ECG may be performed at a doctor’s office; however, in case the arrhythmia is intermittent, a portable ECG monitor (eg, Holter monitor) that is attached to the patient may be employed. The Holter monitor can record the heart’s electrical signals for a period of 24-48 hours, after which the doctor may be able to detect the arrhythmia and reach a diagnosis (Abbott 2005).
- Another ECG monitoring method is an implantable loop recorder, a device that performs continuing ECG monitoring and can detect abnormal heart rhythms. The device is placed under the skin on the left chest area through minor surgery performed under local anesthesia. It can be used for as long as 12-24 months and allows prolonged continual monitoring (Cumbee 1990; Parry 2010; NHLBI 2011b; Edvardsson 2011).
Intracardiac electrophysiology study (EPS). EPS is a procedure used to test the heart’s electrical system. It is typically used in cases of serious arrhythmia to pinpoint the location and cause of the arrhythmia and to plan the therapeutic strategy. EPS involves directing a thin, flexible wire through a vein in the upper thigh/groin or arm to the heart to record the heart’s electrical signals (NHLBI 2011b).
Echocardiography. Echocardiography is a test that uses sound waves for the dynamic visualization of the heart and to observe the flow of blood. It can provide information about the size and shape of the heart and its chambers and valves, and it can identify heart areas that do not function normally (such as areas with poor blood flow, areas that are not contracting normally, or areas with previous injury) (NHLBI 2011b).
Stress test. Some arrhythmias are triggered or worsened by exercise, and certain heart problems are easier to diagnose when the heart is working hard. The stress test involves testing for arrhythmias while the patient is exercising on a treadmill or a stationary bicycle. In patients who have difficulty exercising, the test involves being injected with a drug, such as adenosine, to stimulate the heart to mimic exercise. Heart activity is monitored during the test (Faulds 1991; MayoClinic 2011a; NHLBI 2011b).
Coronary angiography. This procedure uses dye and X-rays to visualize the inside of the coronary arteries (NHLBI 2011b).
Tilt table test. This test is recommended in patients who have fainting spells. Heart rate and blood pressure are measured while the patient is lying flat on a table. Subsequently, the table is tilted, and the heart and nervous system are monitored during the change in the angle (MayoClinic 2011a).
Blood tests. Thyroid hormone and electrolyte levels may be measured as abnormal levels are associated with increased risk of arrhythmia (NHLBI 2011b).
Electromechanical wave imaging – a novel diagnostic technique
Electromechanical wave imaging (EWI) is a newer non-invasive technique based on ultrasound imaging that can map the electrical circuitry of the heart. Unlike previously available diagnostic techniques, EWI can detect minute changes/deformations in the heart and be performed with real-time feedback. Moreover, this technique is adaptable to already existing ultrasound imaging machines (Provost 2011b).
A study conducted on mice demonstrated the feasibility of EWI use as a non-invasive technique to visualize the electrical circuitry of the heart and enable the early detection of arrhythmias (Konofagou 2010; Provost 2011a). Additional exploratory experiments showed that EWI may be viable for mapping heart rhythms in canines and humans (Konofagou 2012; Provost 2011a).
EWI technology may enable doctors to precisely evaluate arrhythmias in real time, diagnose them, and design treatments appropriate for each patient (Provost 2011a).