Independent evolution of heart autonomic function and insulin sensitivity during weight loss.

In order to investigate the improvement of insulin resistance and cardiac autonomic function along massive weight loss, 12 obese women were evaluated before, and 3 and 12 months after Roux-en-Y gastric bypass. The 12-month values were compared to those of BMI-matched controls. Insulin sensitivity was assessed by euglycemic clamp and the cardiac autonomic function by the analysis of the Heart Rate Variability (HRV). After surgery, glucose uptake progressively increased from 4.3 +/- 0.5 mg/kg lean body mass (LBM)/min preoperative (pre-op) to 4.9 +/- 0.5 and 7.0 +/- 0.5, 3- and 12-month postoperative (post-op) (P = 0.04 and P = 0.006 vs. pre-op), whereas the cardiac autonomic function showed a biphasic pattern. HRV values increased 3 months post-op, and decreased at 12 months, thus indicating an early sympathetic withdrawal followed by a later reactivation (e.g., the standard deviation of the normal-to-normal intervals was 116 +/- 7 ms in pre-op, 161 +/- 10 at 3 months, P = 0.008 vs. pre-op, and 146 +/- 15 at 12 months, P = 0.03 vs. pre-op and P = 0.02 vs. 3 m). Insulin sensitivity was significantly related to body weight (P = 0.02), whereas the cardiac indexes were significantly linked to the profile of energy intake (e.g., HRV triangular index vs. energy intake P = 0.003). No significant relationship linked insulin sensitivity to the cardiac autonomic indexes. Insulin sensitivity and cardiac parameters of the 12-month post-op patients were similar to their matched controls. During massive weight loss, the cardiac autonomic deregulation and insulin resistance improved concomitantly but independently from each other. Our results suggest that the extent of the improvement is associated with the final body weight.

Usefulness of ambulatory 7-day ECG monitoring for the detection of atrial fibrillation and flutter after acute stroke and transient ischemic attack.

BACKGROUND AND PURPOSE: Although atrial fibrillation is the most frequent cause of cardioembolic stroke, this arrhythmia remains underdiagnosed, as it is often asymptomatic or intermittent and, thus, may not be detected on standard 12-lead ECG or even 24-hour ECG recording (Holter). In this study, we hypothesized that 7-day ambulatory ECG monitoring using an event-loop recording (ELR) device would detect otherwise occult episodes atrial fibrillation and flutter (AF) after acute stroke or transient ischemic attack (TIA). METHODS: One hundred forty-nine consecutive patients admitted to our neurology department with an acute stroke or TIA were systematically screened for emboligenic arrhythmias using standard ECG. In the absence of AF on standard ECG, patients underwent 24-hour ECG recording (Holter), which was followed by a 7-day ambulatory ECG monitoring (ELR) in patients with a normal Holter. Patients with previously documented persistent AF, with primary hemorrhagic stroke, or with acute large vessel dissection were not included in the study. RESULTS: AF was detected in 22 patients. Standard ECG identified AF in 2.7% of the cases at admission (4/149 patients) and in 4.1% of remaining patients within 5 days (6/145). Holter disclosed AF in 5% of patients with a normal standard ECG (7/139 patients), whereas ELR detected AF in 5.7% of patients with a normal standard ECG and normal Holter (5/88 patients). CONCLUSIONS: Following acute stroke or TIA, ELR identified patients with AF, which remained undetected with standard ECG and with Holter. ELR should, therefore, be considered in every patient in whom a cardioembolic mechanism is suspected.