Atrial fibrillation : clinical presentation and prevention of recurrences
Abstract: Atrial fibrillation (AF) is the most common sustained arrhythmia of clinical importance. AF is known to decrease quality of life and it is related to an increased morbidity and a risk of tromboembolic events. AF may also be asymptomatic, and to what extent patients actually are able to distinguish between sinus rhythm (SR) and AF is unknown. In some patients, due to symptoms, restoration of SR is an important therapeutic goal. Electrical cardioversion mostly restores SR, but recurrence of AF is frequent even with the use of antiarrhythmic treatment. The latter, furthermore, carry proarrhythmic properties and alternative treatment regimens are therefore required. The main purpose of the present studies was to investigate: the rate of conversion and recurrence after oral sotalol treatment in patients with direct current (DC) refractory AF, the predictive value and occurrence of episodes of AF after cardioversion, the perceived heart rhythm in relation to ECG findings after cardioversion and the ability of metoprolol CR in combination with early repetition of cardioversion to maintain SR. The rate of conversion and recurrence after oral sotalol treatment was investigated in 53 patients with persistent AF refractory at a first DC cardioversion. Oral sotalol treatment was started after the unsuccessful cardioversion. A comparative group of patients with AF not refractory at cardioversion was also studied. A total of 43 patients (81%) in the sotalol group regained SR, of whom 10 (19%) converted pharmacologically and 33 (62%) of a second cardioversion. After four weeks SR was present in 29 patients (67%). The comparative group included 132 patients. This group differed significantly from the refractory patients only concerning weight. After four weeks SR was maintained by 50 patients (37%) in this group. To evaluate the possibility to predict recurrence of AF and the incidence of self-limited episodes of AF 74 patients were followed with ambulatory ECG Holter monitoring (24 hours) one, three and six weeks after successful cardioversion. Six weeks after cardioversion 40 patients (54%) had SR and 34 patients (46%) had relapsed into persistent AF. Eight out of these 34 patients (24%) had episodes of AF at their first Holter recording compared with 12 patients out of 40 (30%) in SR at six weeks (p>0.05). On the first, second and third Holter recording 21 patients out of 51 (41%), 21 patients out of 43 (49%) and 15 out of 40 patients (38%) had self-limited bursts of AF, respectively. The incidence and duration of episodes did not vary over time during six weeks of follow-up. The relation between perceived heart rhythm and ECG-findings after cardioversion of persistent AF was studied in 356 patients. The patients were interviewed concerning perceived heart rhythm and symptoms. An ECG was obtained after the interview. Chance-corrected measure of agreement was calculated using Cohen´s kappa-test. One week after cardioversion 160 patients (45%) thought that they had SR, and the ECG showed SR in 222 patients (62%). In 130 patients who perceived SR the ECG showed SR, κ=0.34, fair agreement. Thirtyeight patients perceived AF in agreement with AF found on their ECG, κ=0.13, poor agreement. There was a strong association between perceived SR and improvement of symptoms. To evaluate the combination of metoprolol CR and early repeated cardioversion in patients with persistent AF cardioverted for the first time, a randomized double-blind placebo-controlled study was conducted. A careful medical history, clinical investigation, echocardiographic assay and 24-hour ECG was performed in all patients. Study treatment was started at least one week before cardioversion. Patients were followed once a week during the first six weeks after cardioversion, and in the case of relapse during this period a second cardioversion was performed within seven days. Total treatment and follow-up time was six months. In an intention to treat analysis 38 patients (46%) in the metoprolol group compared with 22 patients (26%) in the placebo group were in SR after six months (p=0.007). Accordingly, in patients with DC refractory AF oral pre-treatment with sotalol prior to repeated cardioversion results in a high rate of SR restoration. After successful cardioversion self-limited bursts of AF do not predict recurrence of persistent AF although such episodes are common and constant in incidence and duration six weeks after cardioversion. Agreement between perceived heart rhythm and ECG as well as between improvement of symptom and SR on ECG is no more than poor to fair after successful cardioversion of persistent AF. The association between perceived SR and improvement of symptoms is strong. In patients with first time persistent AF, a treatment strategy with metoprolol initiated before cardioversion and promptly repeated cardioversion in case of early relapse significantly increases the number of patients in SR during six months of follow-up. The described studies increase the understanding of symptoms of AF and maintenance of SR, and may hopefully contribute to improve the care of this large group of patients.
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