[Arrhythmia].

Genetically transmitted diseases are an important cause of juvenile sudden cardiac death (SCD). In a considerable proportion of individuals in which a medicolegal investigation is performed, structural heart disease is absent, and the medical examiner fails to discover an adequate cause of death. In such cases, an inherited arrhythmogenic disease should be considered, which manifests with life-threatening ventricular tachycardia or SCD. Molecular diagnosis is progressively becoming an important tool for these questions. Therefore, postmortem genetic testing ("molecular autopsy") should be considered as a part of the comprehensive medicolegal investigation in SCD cases without apparent structural heart disease. It will have implications not only for the deceased individual but also for living family members in preventing (further) cardiac events by expert counseling, appropriate lifestyle adjustment, and adequate treatment, if available.

Arrhythmias, Cardiac↗

PubMed2006

Heart rate regularity analysis obtained from pulse oximetric recordings in the diagnosis of obstructive sleep apnea.

Approximate entropy (ApEn) is a technique that can be used to quantify the irregularity or variability of time series. We prospectively evaluated the validity of ApEn of heart rate data obtained from pulse oximetric recordings as a diagnostic test for obstructive sleep apnea (OSA) in patients clinically suspected of suffering this disease. A sample of 187 referred outpatients (147 men and 40 women), with a mean age of 57.9+/-12.8 years and a body mass index of 29.5+/-5.5 kg/m(2), clinically suspected of having OSA were studied using nocturnal pulse oximetric recording performed simultaneously with complete polysomnography. A diagnosis of OSA was confirmed in 111 (59.3%). Patients with OSA presented significantly higher ApEn levels than those without OSA (1.334+/-0.189 vs 1.167+/-0.182). Chronic obstructive pulmonary disease (COPD) was diagnosed for 42 patients. Among these patients, 22 (52.4%) were diagnosed with OSA. COPD patients with OSA showed significantly higher ApEn levels than COPD patients without OSA (1.337+/-0.193 vs 1.184+/-0.173; p=0.01). ApEn correlated significantly with apnea-hypopnea index (r=0.38; p=0.000). There was no significant correlation between ApEn and either age or body mass index. No significant changes were observed in ApEn throughout the night in OSA patients. Using receiver operating characteristic curve analysis, we obtained a diagnostic sensitivity of 71.2%, specificity of 78.9%, positive predictive value of 81.3%, and negative predictive value of 66% at a threshold of 1.272. We conclude that ApEn analysis of heart rate data obtained from pulse oximetric recordings could be a useful tool in the study of OSA.

Arrhythmias, Cardiac↗