Side Effect: Arrhythmia

An arrhythmia is an irregular heartbeat. It occurs when the electrical impulses that coordinate the heartbeats do not work properly, causing the heart to beat too fast (tachycardia), too slow (bradycardia), or with an irregular rhythm. Arrhythmias can range from harmless to life-threatening.

On an electrocardiogram (ECG or EKG), arrhythmias may appear as irregularities in the normal sinus rhythm of the heart. Arrhythmias can present with various symptoms, including:

• Palpitations
• Dizziness or lightheadedness
• Shortness of breath
• Chest pain
• Fatigue or weakness
• Fainting or near-fainting spells

Certain factors that increase the risk of arrythmias include:

• Age
• History of heart disease, heart attack, or heart surgery
• Medications that affect heart rhythm
• High blood pressure
• Diabetes
• Smoking 
• Stress

Risk factors that can be seen in patients with cancer include:

• Cardiotoxic cancer therapies
• Cancer therapies that affect heart rhythm
• Cancer cells directly affecting heart tissue

Preventing arrhythmias involves managing risk factors:

• Eat a balanced diet
• Exercise regularly
• Avoid excessive alcohol and caffeine
• Manage underlying medical conditions
• Avoid medications that can affect heart rhythm when possible

Treatment for arrhythmias depends on the cause. Risk factors can be modified as above. Medications may need to be stopped or adjusted if they are contributing to the arrythmia. Prompt treatment of the cancer can help symptoms if the disease is the cause. If necessary, treatments can be initiated depending on the cause and severity:

• Medications
  
  • Beta-blockers
    
    • Metoprolol (Lopressor®, Toprol®)
    • Carvedilol (Coreg®)
    • Atenolol (Tenormin®)
  • Calcium channel blockers
    
    • Diltiazem (Cardizem®)
    • Verapamil (Calan®)
  • Antiarrhythmic drugs
    
    • Amiodarone (Cordarone®)
    • Dronedarone (Multaq®)
    • Dofetilide (Tikosyn®)
    • Sotalol (Betapace®)
• Lifestyle changes
  
  • Dietary adjustments
  • Exercise
  • Stress management
• Medical procedures
  
  • Cardioversion
  • Catheter ablation
  • Pacemakers or implantable cardioverter-defibrillators (ICDs)