Heart Rhythm Disorders: When They Matter, and How Surgery Treats Them

How the rhythm is normally produced

Each heartbeat begins in the sinus node, a cluster of cells in the right atrium that acts as a natural pacemaker. The impulse spreads across the atria, pauses briefly at the atrioventricular node — allowing the ventricles to fill — then travels down specialised fibres to make the ventricles contract.

An arrhythmia is a fault anywhere in that sequence: the signal starts in the wrong place, travels along an abnormal path, or is blocked.

Which palpitations matter

Almost everyone experiences palpitations. Most are benign — isolated extra beats, or sinus tachycardia from caffeine, anxiety, fever or anaemia.

Features that warrant assessment:

• Palpitations with fainting or near-fainting — the most concerning combination;
• Palpitations with chest pain or significant breathlessness;
• A sustained fast, regular racing that starts and stops abruptly;
• An irregular pulse that does not settle;
• Palpitations in someone with known heart disease, previous cardiac surgery, or impaired ventricular function;
• A family history of sudden unexplained death at a young age.

That last point is worth emphasising because it is often not asked about, and inherited rhythm disorders are a recognised cause of sudden death in otherwise healthy young people.

The common disorders

• Atrial fibrillation — the commonest sustained arrhythmia. The atria quiver chaotically, the pulse is irregular, and blood stagnating in the atrium can form clot, which is why stroke prevention is central. It is strongly associated with valve disease, hypertension and enlarged atria, and it commonly appears after cardiac surgery — see atrial fibrillation after heart surgery.
• Atrial flutter — a fast but organised atrial circuit, often treatable definitively by catheter ablation.
• Supraventricular tachycardia — sudden-onset regular racing, frequently in young people with structurally normal hearts, and often curable by ablation.
• Ventricular tachycardia and fibrillation — arising in the ventricles and potentially fatal. Usually associated with previous heart attack, cardiomyopathy or heart failure.
• Bradycardia and heart block — too slow, or conduction blocked, causing fatigue, dizziness or blackouts and often requiring a pacemaker.

Diagnosis

The central difficulty is capturing the rhythm while symptoms are occurring. A resting ECG is often normal between episodes. Ambulatory monitoring over 24 hours to several weeks, event recorders, and implantable loop recorders for infrequent symptoms are used accordingly. Echocardiography looks for underlying structural disease, and blood tests exclude thyroid disease and electrolyte disturbance — both reversible causes worth finding.

Treatment

Medical and catheter-based

Rate-controlling or rhythm-controlling drugs, anticoagulation where stroke risk warrants it, cardioversion, and catheter ablation — which cures many supraventricular arrhythmias and is widely used in atrial fibrillation. Pacemakers treat slow rhythms; implantable defibrillators protect patients at risk of life-threatening ventricular arrhythmia.

Surgical treatment: the Maze procedure

This is where rhythm disorder meets cardiac surgery, and it is not widely understood by patients.

Atrial fibrillation is sustained by disorganised electrical wavelets circulating through atrial tissue. The Maze procedure creates a deliberate pattern of lines of scar in the atrial wall — historically by cutting and sewing, now usually by radiofrequency or cryotherapy. Scar does not conduct electricity, so the lines act as barriers that block the chaotic circuits while leaving one corridor for the normal impulse to travel. Hence the name.

It is most often performed as a concomitant procedure — added during an operation being done for another reason, such as mitral valve surgery or bypass grafting, in a patient who also has atrial fibrillation. Adding it costs relatively little operative time and substantially improves the chance of leaving hospital in normal rhythm.

Surgical left atrial appendage closure is frequently performed at the same time. The appendage is a small pouch off the left atrium where most clots in atrial fibrillation form, and closing it reduces stroke risk.

Realistic expectations matter: success is higher in shorter-duration atrial fibrillation and in less dilated atria, some patients still need medication or a later ablation, and anticoagulation decisions are made on individual stroke risk rather than automatically stopped.

What patients can control

Treat the triggers: control blood pressure, treat sleep apnoea, reduce alcohol and caffeine, correct thyroid disease and anaemia, manage weight, and take medication consistently. Report fainting immediately rather than waiting for a routine appointment.

Further reading

NHS: arrhythmia, MedlinePlus: arrhythmia, and MedlinePlus: pacemakers and implantable defibrillators.

On this site: cardiac surgery.

General education, not advice about your own rhythm. Palpitations with fainting, chest pain or severe breathlessness require emergency assessment.