Cardiology overview electrophysiology

Cardiology Overview
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]

STEMI and Arrhythmias

Implantable Cardiac Defibrillator

• Should not be implanted within 40 days of STEMI
• A patient should wear a defibrillator vest while awaiting AICD implantation
• Amiodarone improves CV survival but not all cause survival in patients with an LVEF of <40%
• If someone with an ICD has refractory arrhythmias then radiofrequency ablation of the VT focus can be attempted
• Sotalol also reduces the frequency of shocks in patients with CAD

Atrial Fibrillation

Cardioversion

• In a patient with new onset atrial fibrillation, an attempt at cardioversion should be made. The patient should be anticoagulated with Coumadin for three weeks before the cardioversion and four weeks after the cardioversion. The anticoagulation after the cardioversion is due to the electrical mechanical dissociation that occurs in these patients.

Anticoagulation

• Patients with a CHADS2 score of two or higher should be anticoagulated with warfarin. Some clinicians believe that any patient with congestive heart failure should also be anticoagulated with warfarin.

Anticoagulation based on the CHADS₂ score

The following treatment strategies are recommended in the table below entitled Anticoagulation based on the CHADS2 score:

Score	Risk	Anticoagulation Therapy	Considerations
0	Low	Aspirin	Aspirin daily
1	Moderate	Aspirin or Warfarin	Aspirin daily or INR to 2.0-3.0, depending on factors such as patient preference
2 or greater	Moderate or High	Warfarin	INR to 2.0-3.0, unless contraindicated (e.g. clinically significant GI bleeding, inability to obtain regular INR screening)

Rate Control vs Rhythm Control

• Rhythm control offers no benefit over rate control in survival
• Rate control is very important in preventing the tachycardia cardiomyopathy syndrome. Patients who are hyperthyroid should be treated with Lopressor until they are euthyroid.
• Dronedarone reduces hospitalization for atrial fibrillation by about a quarter

Radiofrequency Ablation

• A complication of radio frequency ablation is left atrial tachycardia or flutter. This complication may itself require treatment.
• Anticoagulation should be continued after radiofrequency ablation.
• In patients who have a rapid ventricular response rate in atrial fibrillation and who develop a tachycardia induced cardiomyopathy, AV junctional ablation can be undertaken with permanent pacemaker placement.

QT prolongation

• QT prolongation can be treated with metoprolol

WPW

Complications

These patients are at risk of rapid conduction of atrial fibrillation and VT / VF

Treatment

• EP study and RF ablation of the bypass tract
• Do not use drugs that might block AV node and send conduction down accessory pathway