Overview of Various Arrhythmias and Electrophysiology Issues
The most common abnormal cardiac arrhythmia leading to hospitalization with a major cause of strokes is atrial fibrillation. The upper chamber beats very rapidly and irregular and can be associated with significant symptoms at times due to the irregular rhythm with fast and or slow rates and in some patients due to loss of the atrial kick. Treatment options include rate control in some patients and rhythm control using medication and or ablation therapy (catheter as well as surgical). The major treatment issue is prevention of strokes or other embolism by utilizing anti-platelet therapy (aspirin, or plavix) or with anticoagulation with warfarin or newer agents such as dabigatran (Pradaxa). Another treatment option for embolic protection is occlusion of a structure called the left atrial appendage where clots can form. This can be accomplished with catheter based approach (still investigational) or minimally invasive surgical procedure (performed at BHH).
This is a more organized but a very rapid rhythm of the upper chambers of the heart. This arrhythmia does not respond well to medical therapy but can be managed using a relatively straight forward low risk catheter ablation and does require attention with regard to the risk for stroke.
“Other” Supraventricular Tachycardias
Rapid tachycardias originating from the upper chambers of the heart can be caused due to an abnormal focus in the heart or due to a “short circuit” in the normal conduction system and in some patients an extra connection (bypass tract / Wolf Parkinson White) of muscle between the upper and lower chambers. These arrhythmias can at times be managed with medical therapy but in some cases may require electrophysiology study and catheter ablation therapy.
Ventricular Tachycardia / Ventricular Fibrillation
These are arrhythmias from the lower chambers of the heart. In some patients they produce only symptoms and in others they can cause cardiac arrest or be markers for a risk of cardiac arrest. Patients may require testing to exclude coronary artery blockages, to evaluate valvular function and overall “pump” function of the heart. Some patients may require medical therapy while others may require a defibrillator (ICD) implantation.