In last week’s column, heart rhythm conditions were defined and categorised into fast versus slow arrhythmias, and those originating in the upper heart chambers versus the lower.

This week, diagnosis and management of cardiac rhythm abnormalities will be discussed.

Arrhythmia diagnosis

Your doctor will review your symptoms and medical history and will conduct a physical examination. They may ask about, or order tests for conditions that may trigger arrhythmias such as heart disease or thyroid gland dysfunction. They may also perform specific heart-monitoring tests like:

• Electrocardiogram: during an ECG, sensors (electrodes) that can detect the electrical activity of your heart are attached to your chest wall and limbs. An ECG measures the timing and duration of each electrical phase in your heartbeat.

• Holter monitor: this portable device can be worn for a day or more to record your heart’s activity.

• Event monitor: for sporadic arrhythmias, you keep this portable device available, attaching it to your body and pressing a button when you have events. This records your heart rhythm at the time of your symptoms. This type of monitor is also available in a patch form that you continuously apply to the skin. Event monitors could be worn up to 45 consecutive days.

• Implantable loop recorder: this device detects rare, but serious, abnormal heart rhythms and is implanted under the skin in the chest area. It may be left there for up to three years.

If your doctor does not find a rhythm problem during those tests, they may try to trigger your arrhythmia with other tests, which may include:

• Stress test: some arrhythmias are triggered or worsened by exercise. During a stress test, you’ll be asked to exercise on a treadmill while your heart activity is monitored.

• Tilt table test: your doctor may recommend this test if you’ve had fainting spells. Your heart rate and blood pressure are monitored, as you lie flat on a table. The table is then tilted as if you were standing up. Your doctor observes how your heart and the nervous system that controls it respond to the change.

• Electrophysiological testing: in this test, thin and flexible tubes tipped with electrodes (called catheters) are threaded through your blood vessels to a variety of spots within your heart. Once in place, they can map the spread of electrical impulses through your heart cavities. In addition, these electrodes could be used to stimulate your heart in order to beat at special rates, as during an arrhythmia. This allows defining the nature and location of the given arrhythmia.

Treating slow heartbeats

If severely slow heartbeats (bradycardias) are causing symptoms and do not have a reversible cause, like culprit medications or thyroid disease, a pacemaker is used. This is a small device usually implanted near your collarbone. One or more electrode-tipped wires run from the pacemaker through your blood vessels to your inner heart. If your rate is too slow or if it stops, the pacemaker sends out electrical impulses that stimulate your heart to beat at a steady rate.

Treating fast heartbeat

Here, treatment may include one or more of the following:

• Vagal manoeuvres: you may be able to stop some atrial arrhythmias by using particular manoeuvres such as holding your breath and straining, dunking your face in ice water, or coughing. These manoeuvres affect the nervous system that controls your heartbeat (vagus nerve), often causing your heart rate to slow down. However, vagal manoeuvres are not always successful.

• Medications: for many types of tachycardia, you may be prescribed medication to control your heart rate or restore a normal rhythm. It’s very important to take any anti-arrhythmic medication exactly as directed by your doctor in order to minimise complications.

• Cardioversion: if you have a certain type of arrhythmia, such as atrial fibrillation, your doctor may use cardioversion, where an electrical shock is delivered to your heart through patches on your chest. The current affects the electrical impulses in your heart and can restore a normal beat.

• Catheter ablation: it usually is combined with an electrophysiological testing (see above). In this part of the procedure, and once your fast arrhythmia is already localised, cold or hot energy is applied via a catheter, to a small spot of heart tissue in an effort to damage it (ablate it), and thence cure the arrhythmia.

• Implantable cardioverter-defibrillator: this permanent device is recommended if you developed or are at high risk of developing a dangerously fast or irregular rhythm in the lower half of your heart (ventricular tachycardia or ventricular fibrillation), which could lead to fainting or sudden death. Similar to a pacemaker, an ICD is a battery-powered unit that is implanted under the skin near the collarbone with one or more electrode-tipped wires running to the heart. The ICD continuously monitors your heart rhythm and, if it detects an abnormal one, sends out low- or high-energy shocks to reset it to a normal pattern.

• Joe Yammine is a cardiologist at Bermuda Hospitals Board. He trained at the State University of New York, Brown University and Brigham and Women’s Hospital. He holds five American Board certifications. He was in academic practice between 2007 and 2014, when he joined BHB. During his career in the US, he was awarded multiple teaching and patients’ care recognition awards. The information herein is not intended as medical advice nor as a substitute for professional medical opinion. Always seek the advice of your physician. You should never delay seeking medical advice, disregard medical advice or discontinue treatment because of any information in this article.