Atrial Tachycardia

The exact cause of AT is not always clear, but it can be triggered by:

• Structural heart disease (e.g., congenital heart defects, cardiomyopathy, or valve disease)

• Electrolyte imbalances (e.g., low potassium or magnesium)

• Inflammation or infection (e.g., myocarditis or pericarditis)

• Excessive caffeine, alcohol, or stimulant use

• Stress or anxiety

• Idiopathic (no identifiable cause)

In some cases, AT may occur in otherwise healthy hearts, especially in children and young adults.

• Children and young adults (sometimes as a congenital condition)

• Individuals with structural heart disease

• Those with a history of other arrhythmias or heart conditions

It is less common than other types of SVT, such as AVNRT (AV nodal reentrant tachycardia) or AVRT (accessory pathway-mediated tachycardia).

Palpitations (a sensation of rapid, fluttering, or pounding heartbeats)

Dizziness or lightheadedness

Shortness of breath

Chest discomfort

Fatigue

Some people may experience no symptoms at all, with the condition only detected during routine medical checks.

AT is diagnosed using:

• ECG (Electrocardiogram): AT typically appears as a regular, rapid rhythm with abnormal P waves (different in shape from normal sinus P waves).

• Holter or event monitor: A portable device worn to record heart rhythm over 24 hours or longer.

• Electrophysiological (EP) study: A procedure where thin, flexible wires (catheters) are inserted into the heart to initiate atrial tachycardia and can be used to distinguish AT from the other forms of SVT. It’s an electrical signal-based puzzle solver.

• 3D Mapping: Advanced imaging technology used during an EP study to create a detailed map of the heart’s electrical activity, helping to pinpoint the exact location of the abnormal focus. It creates a computer-generated model video of the heart’s impulses during tachycardia.

Medications

Medications may be prescribed to control heart rate or rhythm, including:

• Beta-blockers (e.g., bisoprolol, metoprolol)

• Calcium channel blockers (e.g., verapamil, diltiazem)

• Anti-arrhythmic drugs (e.g., flecainide, propafenone, or sotalol)

These medications can help manage symptoms but may not cure the condition.

Catheter Ablation

Catheter ablation is a procedure where the abnormal focus is targeted and destroyed using radiofrequency energy or cryoablation (freezing). This is often recommended if medications are ineffective or not tolerated.

What to Expect During Ablation:

• 3D Mapping: Used to create a precise map of the heart’s electrical activity, guiding the ablation catheter to the exact source of the abnormal rhythm.

• Non-Inducibility: After ablation, your doctor will attempt to induce the arrhythmia to confirm it has been successfully treated.

• Success Rates: Ablation for FAT has a lower success rate compared to other SVTs (such as AVNRT or AVRT), often due to the challenging location of the focus or the presence of multiple foci.

Multifocal Atrial Tachycardia (MAT) is a distinct type of SVT where multiple areas in the atria fire abnormal signals, leading to a rapid and irregular heart rhythm. It is most commonly seen in:

• Older adults

• People with chronic lung disease (e.g., COPD)

• Those with low oxygen levels or electrolyte imbalances

• ECG: Regular, rapid rhythm with abnormal P waves. Often the atria beat more than once for every ventricular beat (2:1 ratio or higher).

• Electrophysiological Testing: Confirms the origin of the tachycardia and maps the abnormal focus.

• 3D Mapping: Provides a visual map of the heart, showing the precise location of the abnormal electrical activity. Instead of mapping a whole short circuit, we usually see a bulls-eye area of earliest activity.