Why Do Patients With Atrial Fibrillation Develop Symptoms?
Before treatment is prescribed for a patient with new-onset atrial fibrillation, a thoughtful analysis is required to examine why any symptoms or clinical deterioration might have occurred. Symptoms in a patient presenting with new-onset atrial fibrillation should not be attributed simply to the loss of the atrial contribution to ventricular filling, because other culprits may be the predominant factor, the most obvious of which is a rapid ventricular response associated with the untreated arrhythmia. In the absence of AV nodal blocking agents, the mean resting ventricular response to atrial fibrillation is 110 to 125 bpm,16 19 and this may increase considerably during exertion. As heart rate increases, the percentage of time spent in diastole is shortened. Because diastolic dysfunction is a feature of many diseases associated with atrial fibrillation,20 a rapid ventricular rate can precipitate or aggravate heart failure. If the rate remains uncontrolled for a longer period of time, ta