Evaluation and Treatment of Arrhythmias

Abnormal cardiac arrhythmias may be due to reentry, abnormal automaticity, or triggered activity. Reentrant rhythms may be microreentrant or macroreentrant. Ambulatory (Holter) monitoring is useful for the evaluation of both symptomatic and asymptomatic rhythm disturbances and their relationship to daily activity. Treadmill exercise testing is very useful in the evaluation of patients who present with bradycardia and symptoms of palpitations because it allows both documentation of the adequacy of heart rate response to exercise and the recording of the cardiac rhythm during exercise in a controlled setting with ECG monitoring. An electrophysiologic study is useful for assessing sinus node function and the cardiac conduction system and for attempting to induce atrial or ventricular arrhythmias that could explain the clinical presentation. Electrophysiologic study requires placement of electrode catheters in the heart to record and to stimulate heart rhythm. Several therapeutic options are available for heart rhythm disorders, including drug therapy, radiofrequency ablation, and device therapy.