Normal Sinus Rhythm
The heart's natural rhythm, driven by the sinus node — the heart's built-in pacemaker. Each beat produces a coordinated P wave, QRS complex, and T wave in regular succession.
Patient Education
Understanding Your
Heart Rhythm
Each animation below shows the characteristic ECG pattern for common conditions treated by Dr Kyriacou. Click any card to learn more.
Click to enlarge
Normal
Normal Sinus Rhythm
The sinus node fires regularly at 60–100 beats per minute, producing a coordinated P wave, QRS complex, and T wave with each beat — the baseline for understanding all arrhythmias.
Arrhythmia
Atrial Fibrillation (AF)
Chaotic impulses from the pulmonary veins cause the left atrium to fibrillate rather than contract, producing an irregular pulse. AF increases stroke risk and can cause breathlessness and fatigue.
Arrhythmia
Atrial Flutter
A self-sustaining circuit loops counter-clockwise around the right atrium at 250–300 bpm. The ventricles beat at a fraction of this rate, typically 2:1. Curable with catheter ablation in >90% of cases.
Arrhythmia
Atrial Tachycardia
A single overactive focus in the atrium fires repetitively at a rapid rate, causing a regular but abnormally fast atrial rhythm. Often responds well to catheter ablation with high success rates.
Arrhythmia
Supraventricular Tachycardia (SVT)
An extra electrical connection creates a re-entrant circuit at the AV node, sustaining a rapid rate of 150–250 bpm. Most common in younger, otherwise healthy people. Curative ablation succeeds in >90%.
Arrhythmia
Ventricular Tachycardia (VT)
Fast, abnormal impulses from within the ventricular muscle produce wide, abnormal beats. Can cause dizziness or blackouts and may be life-threatening in patients with underlying heart disease.
Arrhythmia
Ventricular Ectopics (PVCs)
Premature beats from the ventricles interrupt a regular rhythm. Usually benign and cause a 'missed beat' sensation. Very frequent ectopics can occasionally affect heart function; catheter ablation is highly effective.
Device Therapy
Conduction System Pacing
A lead paces directly from the His bundle or left bundle branch, activating the heart's own conduction system and preserving natural, coordinated ventricular contraction. Dr Kyriacou has specialist expertise in this technique.
Device Therapy
Cardiac Resynchronisation Therapy (CRT)
Three pacing leads synchronise the right and left ventricles to correct mechanical dyssynchrony in heart failure, improving pumping efficiency, exercise capacity, and quality of life.
Supraventricular Tachycardia (SVT)
A common condition mostly affecting younger, otherwise healthy people. An extra electrical connection causes the heart to beat rapidly at 150–250 times per minute.
Atrial Flutter
An electrical circuit revolves repeatedly around the right atrium at 250–300 beats per minute. The ventricles respond at a regular fraction of this rate, typically 2:1.
Atrial Fibrillation (AF)
Chaotic electrical activation passes through the upper chambers, causing the atria to fibrillate rather than contract. This results in an irregular pulse and reduced pumping efficiency.
Ventricular Tachycardia (VT)
A fast rhythm originating from the lower chambers of the heart. It produces wide, abnormal beats on the ECG and can cause palpitations, dizziness, breathlessness or blackouts.
Ventricular Ectopics (PVCs)
Premature beats originating from the ventricles that interrupt an otherwise regular rhythm. Extremely common and usually benign in people with a structurally normal heart.
Conduction System Physiological Pacing
His bundle or left bundle branch pacing delivers impulses directly to the heart's natural wiring system, producing a narrow, physiological QRS — preserving coordinated contraction of both ventricles.
Cardiac Resynchronisation Therapy (CRT)
CRT uses three pacing leads to coordinate the timing of both ventricles in patients with heart failure and electrical conduction delay, improving the heart's pumping efficiency.
Cardiac Pacemakers
Blackouts and dizziness can result from problems with the heart's electrical system causing a very slow or paused heart rhythm. A pacemaker can restore a safe, reliable rhythm.