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Atrial fibrillation (AF) has been linked with an increased risk for cognitive impairment and dementia, but whether this risk was due to stroke has been uncertain. This systematic review of 21 studi...

Atrial fibrillation (AF) has been linked with an increased risk for cognitive impairment and dementia.To complete a meta-analysis of studies examining the association between AF and cognitive impairment.Search of MEDLINE, PsycINFO, Cochrane Library, CINAHL, and EMBASE databases and hand search of article references.Prospective and nonprospective studies reporting adjusted risk estimates for the association between AF and cognitive impairment.Two abstracters independently extracted data on study characteristics, risk estimates, methods of AF and outcome ascertainment, and methodological quality.Twenty-one studies were included in the meta-analysis. Atrial fibrillation was significantly associated with a higher risk for cognitive impairment in patients with first-ever or recurrent stroke (relative risk [RR], 2.70 [95% CI, 1.82 to 4.00]) and in a broader population including patients with or without a history of stroke (RR, 1.40 [CI, 1.19 to 1.64]). The association in the latter group remained significant independent proof of clinical stroke history (RR, 1.34 [CI, 1.13 to 1.58]). However, there was significant heterogeneity among studies of the broader population (I2 = 69.4%). Limiting the analysis to prospective studies yielded similar results (RR, 1.36 [CI, 1.12 to 1.65]). Restricting the analysis to studies of dementia eliminated the significant heterogeneity (P = 0.137) but did not alter the pooled estimate substantially (RR, 1.38 [CI, 1.22 to 1.56]).There is an inherent bias because of confounding variables in observational studies. There was significant heterogeneity among included studies.Evidence suggests that AF is associated with a higher risk for cognitive impairment and dementia, with or without a history of clinical stroke. Further studies are required to elucidate the association between AF and subtypes of dementia as well as the cause of cognitive impairment.

Objective To assess the short-term efficacy and safety of moricizine in patients receiving electrophysiologically guided therapy for sustained ventricular arrhythmias refractory to treatment with class IA antiarrhythmic agents. Design Uncontrolled clinical trial. Setting Referral-based teaching medical center. Patients Twenty-one patients (18 of whom had coronary artery disease) with a mean left ventricular ejection fraction of 32% +/- 11% who presented with sustained ventricular tachycardia (13 patients), syncope (4 patients), or cardiac arrest (4 patients). Interventions Moricizine, 743 +/- 85 mg daily. Measurements Electrophysiologic testing in the drug-free state and after administration of moricizine unless sustained arrhythmias occurred. Main results Sustained ventricular tachycardia was inducible in the absence of antiarrhythmic drugs in 20 patients and was not suppressed by moricizine in any patient. Four patients had six episodes of spontaneous ventricular tachycardia while receiving moricizine. A probable proarrhythmic response occurred in four patients. Conclusion In patients with compromised left ventricular function caused by coronary artery disease in whom class IA antiarrhythmics were ineffective, moricizine was ineffective in suppressing sustained ventricular arrhythmias and resulted in proarrhythmic effects in some patients.

After the administration of verapamil for rapid tachycardias, five patients developed ventricular fibrillation or required urgent cardioversion. All episodes occurred in hospital emergency rooms, and each patient was resuscitated. Examination of electrocardiograms confirmed the presence of the Wolff-Parkinson-White syndrome. In four patients, the presenting tachyarrhythmia was atrial fibrillation with preexcited ventricular complexes, and in one patient a narrow QRS complex tachycardia was initially recorded. Acceleration of atrioventricular conduction occurred within 10 minutes of administration of verapamil, 5 to 10 mg intravenously. Subsequently, intracardiac electrophysiologic studies confirmed the presence of accessory atrioventricular pathways capable of rapid antegrade conduction in each patient. Because of this potentially fatal adverse response, verapamil should not be used in patients with atrial fibrillation and preexcited ventricular complexes.

A patient with symptomatic primary pulmonary artery hypertension underwent therapeutic trials with parenteral and oral phentolamine. Before drug therapy, he manifested marked increases in pulmonary artery pressure and pulmonary arteriolar resistance during exercise. This hypertensive response to exercise was significantly attenuated by parenteral phentolamine. He also manifested sustained hemodynamic improvement with the same degree of attenuation of exercise-induced increases in pulmonary artery pressure and pulmonary arteriolar resistance 7 months after initiation of therapy with oral phentolamine. Twenty months after initiation of therapy, the patient continues to enjoy symptomatic improvement with a marked increase in exercise tolerance.

Excerpt Amiodarone, an investigational antiarrhythmic drug, has been reported to be effective in treating various cardiac tachyarrhythmias (1). Pharmacokinetic interactions with digoxin, warfarin, ...

Complications were seen in 20 of 359 patients having programmed electrical stimulation during 1062 cardiac electrophysiologic procedures. No deaths occurred. Direct current countershock was used to end arrhythmias with serious hemodynamic consequences on 107 occasions. Countershock was effective in all cases and not associated with morbidity. The complications in 20 patients were related to intravascular catheterization and included thromboembolism (nine patients), local or systemic infections (six patients), and pneumothorax (five patients). All 20 patients recovered from these complications without long-term sequelae. Intracardiac electrophysiologic procedures can be done with an acceptably low risk in patients with life-threatening or disabling arrhythmias.

Excerpt Various innovative drug, surgical, and electrical treatments have been used recently for patients with ventricular tachyarrhythmias (1-8). Each approach has enthusiastic advocates who compa...

Twenty-five patients with recurrent episodes of syncope, unexplained despite thorough medical and neurologic evaluation, underwent intracardiac electrophysiologic study with programmed stimulation. Electrophysiologic study yielded a presumptive diagnosis in 17 patients: nine with rapid ventricular tachycardia by programmed stimulation, three with intra-His conduction delays, one with symptomatic atrial flutter, one with sick sinus syndrome, and three with persistent hypervagotonia manifested as atropine-reversible prolongation of atrioventricular nodal refractoriness. Therapy based on these findings provided complete symptomatic relief in 14 and improvement in one of these 17 patients during a mean follow-up of 18 +/- 10 months. Therapy based on electrophysiologic testing was ineffective in two of the 17 patients. Syncope persisted in four of the eight patients in whom electrophysiologic study did not define a probable arrhythmic mechanism. These observations indicate that full electrophysiologic evaluation with programmed stimulation is useful in the diagnosis and therapy of recurrent unexplained syncope.