Long-term evaluation of autonomic tone in patients below 50 years of age with unexplained cerebral infarction: relation to atrial vulnerability

Preliminary studies have described, in young patients with unexplained cere bral infarction, electrophysiological abnormalities similar to those observ ed in paroxysmal atrial fibrillation. Moreover, in young adults with 'norma l' hearts, increased susceptibility to paroxysmal atrial fibrillation with autonomic abnormalities as assessed by heart rate variability analysis have been reported. Methods The long-term time and frequency domain measures of heart rate vari ability were analysed prospectively from 24-h Holter ECG recordings in 25 p atients (39 +/- 8 years) with unexplained cerebral infarction, and in 25 ag e-, sex- and cigarette-smoking-matched healthy control subjects. The day fo llowing the Holter ECG recordings, 9 +/- 4 months (mean) after the stroke, stroke patients underwent an electrophysiological study in order to analyse the electrical characteristics of their right atria and also to determine their vulnerability to atrial fibrillation. The correlations between autono mic tone parameters and electrophysiological findings were therefore assess ed with linear regression analyses. Results All the measured components of heart rate variability either in tim e (SDNN, pNN50, SDANN/5, rMSSD) or frequency domains (total power, low-freq uency, high-frequency power, low-frequency/high-frequency power ratio) were similar between stroke patients and controls. During electrophysiological study, atrial fibrillation was induced in 80% of stroke patients. Among the se patients, atrial refractory periods were significantly shorter, local el ectrograms were longer, and latent atrial vulnerability index was markedly decreased when compared with patients having no inducible atrial fibrillati on. Concerning heart rate variability analysis, no difference was found bet ween patients with induced atrial fibrillation when compared with a matched subgroup of healthy control subjects. Furthermore, there was no statistica lly linear correlation between any of the measured autonomic tone parameter s and any of the discovered atrial vulnerability markers. Conclusions The long-term autonomic tone parameters of young patients prese nting with a history of unexplained cerebral infarction are similar to thos e of healthy control subjects and are not correlated with atrial vulnerabil ity parameters or atrial fibrillation inducibility. (Europace 2000; 2: 297- 303) (C) 2000 The European Society of Cardiology.