Electrocardiography Data Analysis in Sleep Disorders
Condition: Sleep Disorders; Sleep Apnea; Sleep Disordered Breathing
MeSH terms: Sleep Apnea Syndromes; Sleep Wake Disorders; Parasomnias
Study type: Observational

Summary: 
      The objective of this study is to determine if a non-invasive technique, using an innovative
      analysis of electrocardiogram (ECG) data, would allow for detection of respiratory events
      during sleep and discrimination between central and obstructive apnea. Obstructive Sleep
      Apnea (OSA) is the most common respiratory disturbance seen during sleep, with an estimated
      prevalence of 10 % in the population and is strongly associated with the development of
      cardiovascular disease. In patients with underlying cardiac disease, particularly in heart
      failure (HF), central respiratory events such as Cheyne-Stokes Respiration (CSR) are often
      seen during sleep. The presence of CSR is also associated with increased cardiovascular
      morbidity and mortality. Currently, the identification and classification of sleep related
      respiratory disturbances is performed during over-night sleep studies (polysomnography),
      which are labor-intensive, time-consuming, expensive and difficult for patients. Thus, the
      development of alternative techniques to assist in the identification of those events in the
      outpatient setting is of marked importance for widespread screening of sleep apnea.
    

Detailed description: 
      This study aims to use novel analyses of electrocardiogram data to detect the presence and
      type of respiratory event observed in patients during sleep. Our specific aims include:
      determining the accuracy of using a non-invasive electrocardiogram (ECG) to detect sleep
      apnea and to distinguish between obstructive sleep apnea (OSA) and Cheyne-Stokes Respiration
      (CSR). For this investigator-initiated study, data from approximately 400 consecutive
      patients presenting to the Weill Cornell Center for Sleep Medicine for polysomnography will
      be collected. A sample size of 45 subjects in each group will be needed to quantify mean
      amplitude change in the ECG derived respiratory signal. Study procedures are outlined below.
      Standard and novel, research measurements from the ECG will be correlated with findings from
      polysomnography and used to assess the presence and severity of a variety of ECG-based
      measures of cardiovascular disease, such as left ventricular hypertrophy and prior Q-wave
      myocardial infarction. Subjects will also have to complete a Questionnaire prior to their ECG
      at their visit.

      Detailed procedures:

        1. Subjects will be asked to complete a brief questionnaire (see attached). This
           questionnaire will ask questions relating to subjects' sleep patterns, etc. Potential
           risks include possible discomfort while completing the questionnaire.

        2. Continuous 12-lead ECG recordings, using torso-located electrodes, will be obtained with
           Mortara Instrument H12+ recorders. An MTA Agreement has been established for the use of
           this equipment for the duration of this study. Electrocardiograms will be obtained in
           standard clinical fashion using GE Medical Systems equipment. Patients will be asked to
           lie in the supine position and 10 recording electrodes will be applied. With the patient
           lying quietly, a 10 second digital ECG will be recorded and then downloaded via analog
           modem to the MUSE ECG analysis and storage system at New York Presbyterian Hospital
           where it will be stored on a dedicated site of our password protected MUSE server. ECG
           information:12-lead ECGs will be downloaded from the MUSE system to a secure network
           drive and then copied to the hard drive of a password protected computer where they will
           be batch-analyzed using an ECG research analysis program, Magellan, provided by GE
           Medical Systems. Magellan will generate a series of measurements from each ECG and will
           then export these measurements to an Excel file which will be converted to SPSS files
           for data analysis. Deidentified ECG data may be downloaded to the Electrocardiography
           data center and transferred using a secure file transfer system, such as Cornell's file
           transfer website, to an outside company (Mortara, Inc.) for further analysis as needed.

        3. Standard polysomnography will be performed for 12 hours at approximately the patients
           regular sleep time. Sleep data will be recorded in a digitized system and analyzed using
           Grass Twin software ® (Middleton, WI) for the determination and classification of
           respiratory events and other sleep related parameters. The Apnea-Hypopnea Index (AHI)
           will be calculated by computing the average number of obstructive apneas plus
           obstructive hypopneas per hour of sleep. Obstructive sleep apnea (OSA) is here defined
           by an AHI &#8805;5. Intermittent hypoxemia (IH) will be determined by the number of
           periods &#8805;6 sec with SaO2 drops &#8805;4%. Cheyne-Stokes Respiration will be
           determined by the typical crescendo-decrescendo pattern on the respiratory flow signal,
           chest and thoracic impedance, using standard criteria. Total duration of CSR will be
           calculated for the determination of the % of sleep time on CSR. Data regarding
           percentage of sleep time at SaO2 &#8804;90% (%TST&lt;90) and lowest saturation level
           (LowSaO2) will also be recorded.

      Upon completion of data attainment some de-identified data will be remote analyzed.
    

Intervention name(s): Polysomnography
Intervention type(s): Procedure
Intervention description(s): Polysomnography, also called a sleep study, is a test used to diagnose sleep disorders. Polysomnography records your brain waves, the oxygen level in your blood, heart rate and breathing, as well as eye and leg movements during the study.
Observational model: Cohort
Time perspective: Cross-Sectional
Sampling method: Non-Probability Sample
Study population: 
        patients undergoing overnight sleep studies