Multi-modal ECG Holter system for sleep-disordered breathing screening: a validation study

The high prevalence of sleep disordered breathing (SDB) among heart diseases patients becomes increasingly recognized. A reliable exploring tool of SDB well adapted to cardiologists practice would be very useful for the management of these patients.

We assessed a novel multi-modal electrocardiogram (ECG) Holter which incorporated both thoracic impedance and pulse oximetry signals. We compared in a home setting, a standard condition for Holter recordings, results from the novel device to a classical ambulatory polygraph in subjects with suspected SDB. The analysis of cardiac arrhythmias in relationship with SDB is also presented. A total of 118 patients clinically suspected of having SDB were evaluated (mean age 57 ± 14 years, mean body mass index [BMI] 32 ± 6 kg/m(2)). The new device allows calculating a new index called thoracic impedance (TI) disturbance index (TIDI+) evaluated from TI and SpO(2) signals recorded from a Holter monitor.

In the population under study, 93% had more than 70% of usable TI signal and 95% had more than 90% for SpO(2) during sleep time recording. Screening performance results based on automatic analysis is accurate: TIDI + demonstrates a high level of sensitivity (96.8%), specificity (72.3%) as well as positive (82.4%) and negative (94.4%) predictive value for the detection of SDB. Moreover, detection of SDB periods permits us to observe a possible respiratory association of several nocturnal arrhythmias.

The multi-modal Holter should be considered as a valuable evaluating tool for SDB screening and as a case selection technique for facilitating access to a full polysomnography for severe cases. Moreover, it offers a unique opportunity to study arrhythmia consequences with both respiratory and hypoxia disturbances.