Left ventricular hypertrophy is a common echocardiographic abnormality in severe obstructive sleep apnea and reverses with nasal continuous positive airway pressure.
OBJECTIVE
To determine cardiac structural abnormalities by echocardiography in subjects with severe obstructive sleep apnea (OSA), and to determine the long-term effects of nasal continuous positive airway pressure (CPAP) on such abnormalities.


METHODS
Polysomnography was conducted on oximetry-screened patients who showed a desaturation index > 40/h and > or = 20% cumulative time spent below 90%. From these, 25 patients with severe OSA but without daytime hypoxemia underwent echocardiography prior to, then 1 month and 6 months following initiation of CPAP treatment.


METHODS
Outpatient sleep disorders center.


RESULTS
Of the 25 patients, 13 patients (52%) had hypertension by history or on physical examination. Baseline echocardiograms showed that severe OSA was associated with numerous cardiovascular abnormalities, including left ventricular hypertrophy (LVH) [88%], left atrial enlargement (LAE) [64%], right atrial enlargement (RAE) [48%], and right ventricular hypertrophy (16%). In all patients (intent to treat) as well as those patients compliant with CPAP therapy (84% > 3 h nightly), there was a significant reduction in LVH after 6 months of CPAP therapy as measured by interventricular septal distance (baseline diastolic mean, 13.0 mm; 6-month mean after CPAP, 12.3 mm; p < 0.02). RAE and LAE were unchanged after CPAP therapy.


CONCLUSIONS
LVH was present in high frequency in subjects with severe OSA and regressed after 6 months of nasal CPAP therapy.
Cloward
Tom V
TV
Intermountain Sleep Disorders Center, LDS Hospital, Salt Lake City, Utah 84143, USA. ldtclowa@ihc.com
Walker
James M
JM
Farney
Robert J
RJ
Anderson
Jeffrey L
JL
D000328:Adult; D000368:Aged; D001784:Blood Gas Analysis; D005260:Female; D006801:Humans; D017379:Hypertrophy, Left Ventricular / Q000150:complications* / Q000000981:diagnostic imaging; D000860:Hypoxia / Q000150:complications*; D008297:Male; D008875:Middle Aged; D017286:Polysomnography; D011175:Positive-Pressure Respiration / Q000379:methods*; D020181:Sleep Apnea, Obstructive / Q000150:complications / Q000175:diagnosis / Q000628:therapy; D014463:Ultrasonography