Consultant Cardiologist

Dr Louisa Malcolme-Lawes

Specialised in heart rhythm disturbances. Her NHS practice is based at Imperial College Healthcare NHS Trust and West Herts NHS Trust. She performs all types of catheter ablation and specialises in zero fluoroscopy ablation which is particularly beneficial in young patients or pregnant women wishing to avoid radiation exposure. She also performs all types of device implantation, including conduction system pacemakers and sub-cutaneous ICDs. She has special research interest in atrial fibrillation and the autonomic nervous system, and is undertaking the new technique of cardio neural ablation for vasovagal syncope at Hammersmith Hospital.

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Portrait of Dr Louisa Malcolme-Lawes

Symptoms

Palpitations

Palpitations are sensations where you feel your heart beating unusually fast, hard, or irregularly. They can be felt in your chest, throat, or neck and may be alarming, but they are often harmless. Common causes include stress, anxiety, caffeine, nicotine, or vigorous exercise. However, they can sometimes indicate an underlying heart condition, so it’s important to discuss them with your doctor if they occur frequently or are accompanied by other symptoms like dizziness, shortness of breath, or chest pain.

Conditions

Atrial Fibrillation (AF)

Illustration of the heart

Atrial fibrillation is a common heart condition where the heart beats irregularly and often rapidly. This irregular rhythm occurs because the upper chambers of the heart (the atria) beat out of sync with the lower chambers (the ventricles). This can lead to poor blood flow and various symptoms and in a small percentage of patients if left untreated can cause heart failure.

Symptoms

  • Palpitations (feeling of a fast, fluttering, or pounding heart)
  • Shortness of breath
  • Fatigue
  • Dizziness or light-headedness
  • Chest pain

Causes

AF can be caused by various factors, including:

  • High blood pressure
  • Heart disease
  • Thyroid problems
  • Excessive alcohol consumption
  • Stress
  • Sleep apnoea

Diagnosis

AF is typically diagnosed through an electrocardiogram (ECG), which records the electrical activity of the heart. Other tests may include blood tests, echocardiogram, or a Holter monitor.

Treatment

The treatment for AF aims to control the heart rate, restore a normal rhythm, and reduce the risk of stroke. Treatment options include:

Treatment for atrial fibrillation

Medications

  • Rate control medications: These help slow down the heart rate.
  • Rhythm control medications: These help restore and maintain a normal heart rhythm.
  • Anticoagulants: These are blood thinners that reduce the risk of stroke by preventing blood clots.

Other treatments

  • Cardioversion This is a procedure where an electric shock is delivered to the heart to restore a normal rhythm.
  • Catheter Ablation This is a minimally invasive procedure where areas of the heart causing the irregular rhythm are destroyed using radiofrequency energy.
  • Lifestyle Changes
    • Reducing alcohol and caffeine intake
    • Managing stress
    • Maintaining a healthy weight
    • Regular physical activity

Procedures

Cardioversion

Cardioversion is a medical procedure used to restore a normal heart rhythm in people with certain types of abnormal heartbeats (arrhythmias). It is often performed when the heart is beating too fast or irregularly, such as in atrial fibrillation or atrial flutter.

There are two main types of cardioversion:

Electrical cardioversion

Electrical Cardioversion

This involves delivering a controlled electric shock to the heart through paddles or patches placed on the chest. The shock momentarily stops the heart’s electrical activity, allowing it to restart in a normal rhythm. This procedure is usually done under sedation to ensure comfort.

Pharmacological cardioversion

Pharmacological Cardioversion

This involves using medications to restore the heart’s normal rhythm. These medications can be administered orally or intravenously.

Cardioversion is generally a safe procedure, but like any medical intervention, it carries some risks, including the potential for blood clots, stroke, or other complications. Your doctor will discuss these risks with you and take steps to minimise them, such as prescribing blood thinners if necessary.

The decision to undergo cardioversion will depend on your specific condition, symptoms, and overall health. Your cardiologist will provide detailed information and guidance tailored to your situation.

Many thanks for the excellent care you and your team gave me during the AT ablation procedure at Hammersmith Hospital last Friday. You have a calm and reassuring demeanour, and an impressive collective competence. For that many thanks.

Mr RM, April 2025

Research & Publications

As an Honorary Clinical Lecturer at Imperial College Dr Malcolme-Lawes continues to be closely involved in ongoing research studies and is Principal Investigator at West Herts NHS Trust for the Protect HF study which is a national study of conduction system pacing being run by Imperial College. She also participates in research activities within Imperial College including student vivas and teaching programmes, regularly teaching on the BCS Mayo Clinic Cardiology Board Review Course.