Reversal of Atrial Remodeling after Cardioversion of Persistent Atrial Fibrillation Measured with Magnetocardiography

Background : Atrial fibrillation (AF) causes electrical, functional, and structural changes in the atria. We examined electrophysiologic remodeling caused by AF and its reversal noninvasively by applying a new atrial signal analysis based on magnetocardiography (MCG).
Methods : In 26 patients with persistent AF, MCG, signal-averaged electrocardiography (SAECG), and echocardiography were performed immediately after electrical cardioversion (CV), and repeated after 1 month in 15 patients who remained in sinus rhythm (SR). Twenty-four matched subjects without history of AF served as controls. P-wave duration (Pd) and dispersion (standard deviation of Pd values in individual channels) and root mean square amplitudes of the P wave over the last 40 ms portions (RMS40) were determined.
Results : In MCG Pd was longer (122.8 ± 18.2 ms vs 101.5 ± 14.6 ms, P < 0.01) and RMS40 was higher (60.4 ± 28.2 vs 46.9 ± 19.1 fT) in AF patients immediately after CV as compared to the controls. In SAECG Pd dispersion was increased in AF patients. Mitral A-wave velocity and left atrial (LA) contraction were decreased and LA diameter was increased (all P < 0.01). After 1 month, Pd in MCG still remained longer and LA diameter greater (both P < 0.05), while RMS40 in MCG, Pd dispersion in SAECG, mitral A-wave velocity, and LA contraction were recovered.
Conclusions : Magnetocardiographically detected atrial electrophysiologic alterations in persistent AF diminish rapidly although incompletely during maintained SR after CV. This might be related to the known early high and late lower, but still existent tendency to AF relapses.     

ELEVATED RESTING HEART RATE IN RHEUMATOID ARTHRITIS: POSSIBLE ROLE OF PHYSICAL DECONDITIONING

Thirty-four patients with RA, 76 diabetic subjects (DM) and67 healthy controls (CR) were studied in order to study cardiovascularautonomic function in RA. Valsalva manoeuvre, deep breathingtest and active orthostatic test were used. Resting heart rate(resting HR) was markedly elevated in the RA and DM groups.Therefore, the groups were compared using analysis of variancewith age and resting HR as covariates. The analyses showed nodifferences in cardiovascular responses between the RA groupand CR group but cardiovascular responses were significantlydiminished in the DM group compared with both the CR group andRA group. Our data indicate that the parasympathetic efferentpathway mediating cardiovascular reflexes via the nervus vagusis intact in RA. Thus elevated resting HR in RA does not seemto be due to peripheral parasympathetic damage. Physical deconditioningmay explain the elevation of resting HR in patients with RA. KEY WORDS: Cardiovascular reflexes, Rheumatoid arthritis, Diabetes mellitus, Autonomic nervous system, Resting heart rate, Physical deconditioning