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Biomedical subjects

I C Van Gelder

Publications and source records attributed to I C Van Gelder.

7 recordsLinked to original sources
PubMed1992

Low-dose amiodarone for maintenance of sinus rhythm after cardioversion of atrial fibrillation or flutter.

OBJECTIVE: To study efficacy and safety of low-dose amiodarone for maintenance of sinus rhythm after electrical cardioversion of atrial fibrillation or flutter. DESIGN: Nonrandomized trial; mean duration of follow-up, 20.7 months. SETTING: Referral center; institutional practice; both hospitalized and ambulatory care. PATIENTS: Eighty-nine consecutive patients having chronic atrial fibrillation or flutter and eligible for cardioversion. Patients had failed previous treatment aimed at maintaining sinus rhythm. During follow-up one patient was withdrawn because of side effects; all patients were available for follow-up. INTERVENTION: Before cardioversion, patients received 600 mg of amiodarone daily during a 4-week loading period. After conversion, the daily maintenance dose was 204 +/- 66 mg (mean +/- SD). MAIN OUTCOME MEASURES: Arrhythmia recurrence and adverse effects causing drug discontinuation. RESULTS: During loading, 15 patients (16%) converted, and after electrical cardioconversion, 90% of all patients had sinus rhythm. Actuarially, 53% of these patients were still in sinus rhythm after 3 years. In patients with compromised left ventricular function, 93% maintained sinus rhythm after 6 months. One patient died due to congestive heart failure. Intolerable side effects occurred in one patient. No proarrhythmia was observed. Logistic regression analysis revealed that amiodarone was ineffective in patients with mitral stenosis or chronic arrhythmia. CONCLUSIONS: Low-dose amiodarone is effective for maintaining sinus rhythm in patients with difficult to treat chronic atrial fibrillation or flutter and is associated with a low incidence of serious side effects.

Amiodarone↗
PubMed1991

Serial antiarrhythmic drug treatment to maintain sinus rhythm after electrical cardioversion for chronic atrial fibrillation or atrial flutter.

The sequential use of different types of antiarrhythmic drugs may improve arrhythmia prognosis in chronic atrial fibrillation or flutter after successful electrical cardioversion. The rationale for serial treatment is that the arrhythmogenic mechanism may vary between patients, leading to different responses to 1 specific drug. To investigate this issue prospectively, 127 patients having chronic fibrillation or flutter exclusively, underwent serial drug treatment with flecainide (stage I) followed by sotalol or, if contraindicated, quinidine (stage II) and eventually amiodarone (stage III). Stages II and III were entered after electrical recardioversion for a recurrence during stages I or II, respectively. Calculated on an actuarial basis, the 2-year cumulative percentage of patients free of the arrhythmia increased from 31% after stage I to 63% at the end of serial treatment. To reach this result, a mean of 1.8 +/- 0.8 cardioversions per patient were needed, with 53 patients progressing to stage II and 34 to stage III. Sixteen patients stopped serial treatment prematurely and 15 patients were considered to have intractable atrial fibrillation at the end of stage III. Incidence of proarrhythmia was low. Multivariate analysis disclosed that an older age, in combination with a large number of previous episodes of arrhythmia, a long previous duration of arrhythmia and presence of mitral valve disease, were predictive for medical refractoriness during serial treatment. It is concluded that serial treatment may improve arrhythmia prognosis in atrial fibrillation or flutter, with an acceptable incidence of proarrhythmic events.

Actuarial Analysis↗
PubMed1991

Prediction of uneventful cardioversion and maintenance of sinus rhythm from direct-current electrical cardioversion of chronic atrial fibrillation and flutter.

The present study was undertaken to reassess prospectively the immediate and long-term results of direct-current electrical cardioversion in chronic atrial fibrillation or atrial flutter, and to determine factors predicting clinical outcome of the arrhythmia after direct-current cardioversion. Two-hundred forty-six patients underwent direct-current electrical cardioversion and were followed during a mean of 260 days. Multivariate analysis was used to identify factors predicting short- and long-term arrhythmia outcome. Cardioversion was achieved in 70% of patients with atrial fibrillation and in 96% of patients with atrial flutter. Stepwise logistic regression analysis revealed that arrhythmia duration (p less than 0.001), type of arrhythmia (fibrillation vs flutter, p less than 0.02) and age (p less than 0.05) independently influenced conversion rate. On an actuarial basis, 42 and 36% of patients remained in sinus rhythm during 1 and 2 years, respectively. Multivariate regression analysis revealed that the type of arrhythmia (p = 0.0008), low precardioversion functional class (p = 0.002) and the presence of nonrheumatic mitral valve disease (p = 0.03) independently increased the length of the arrhythmia-free episode. Rheumatic heart disease shortened this period (p = 0.03). In conclusion, patients having a high probability of conversion together with a prolonged post-shock arrhythmia-free episode can be identified. This may improve the cost-benefit ratio of cardioversion.

Adult↗
PubMed1991

Incidence and clinical significance of ST segment elevation after electrical cardioversion of atrial fibrillation and atrial flutter.

To study the incidence and clinical significance of postshock ST segment elevations, we recorded 12-lead ECGs immediately after transthoracic direct-current electrical cardioversion in 146 patients with atrial fibrillation or flutter. Among 23 patients (19%), acute ST segment elevations amounted to 1.4 +/- 0.8 mV (mean +/- SD) and occurred after 243 +/- 114 joules (cumulative dose) in the precordial leads only in 14, concomitantly in precordial and inferior leads in two, and in the precordial and anterolateral leads in seven. They normalized within 1.5 +/- 0.8 minutes. Occurrence of ST segment elevation was related to previous pericardiotomy (p less than 0.00001) and age (p = 0.01). Estimation of myocardial enzyme release did not show evidence of myocardial damage. Patients with ST segment elevations had a lower conversion rate (48% versus 76%, p = 0.005). Long-term maintenance of sinus rhythm was also diminished (35% versus 59%, p = 0.03). Results of this study show that postcardioversion ST segment elevation occurs predominantly in postpericardiotomy patients and may be associated with an unfavorable arrhythmia prognosis.

Age Factors↗
PubMed1989

Efficacy and safety of flecainide acetate in the maintenance of sinus rhythm after electrical cardioversion of chronic atrial fibrillation or atrial flutter.

The efficacy and safety of flecainide were studied in the maintenance of sinus rhythm after electrical cardioversion for chronic atrial fibrillation or atrial flutter. Eighty-one patients were randomized to flecainide treatment or no treatment. Baseline characteristics of both groups were comparable. Compared to previous studies, patients could be classified as difficult-to-treat patients. Multiple regression analysis showed New York Heart Association class I for exercise tolerance (p = 0.0004) and flecainide treatment (p = 0.01) to be the main factors increasing the arrhythmia-free episode. However, Mantel-Cox lifetable analysis did not reveal significant differences between arrhythmia-free survival curves of both treatment groups. In the flecainide-treated group, 9% of patients experienced side effects, mostly related to negative dromotropic effects. The incidence of ventricular proarrhythmia in this group of patients was low. Thus, flecainide may be effective in postponing arrhythmia recurrence, even in difficult-to-treat patients. Caution should be excercised in treating patients with underlying conduction disturbances, sick sinus syndrome or characteristics favoring development of ventricular proarrhythmia.

Adolescent↗