Daytime QT by Routine 12-Lead ECG Is Prolonged in Patients with Severe Obstructive Sleep Apnea

Table 2

QTc based on OSA severity.

OSA severity	Normal-mild (SD or 95% confidence limits)	Moderate (SD or 95% confidence limits)	Severe (SD or 95% confidence limits)	value
QTc (ms, unadjusted)	435.60 (29.36)	431.36 (27.88)	444.40 (30.86)	0.01, 0.03^†
QTc (ms, adjusted)	441.07 (433.26-448.88)	438.78 (431.3-446.26)	450.83 (444.05-457.6)	0.04, 0.007^‡, 0.63^¥

Adjusted and unadjusted mean QTc values. Classification of apnea-hypopnea index (AHI): mild: <15/hr, moderate: 15-30/hr, and severe: >30/hr. OSA = obstructive sleep apnea. Adjusted results are based on multivariable regression adjusting for body mass index, age, gender, presence of hypertension, and presence of heart failure. Analysis additionally adjusting for race, atrial fibrillation, and chronic obstructive pulmonary disease did not change the results (not shown). Severe compared to normal-mild OSA. ^‡Severe compared to moderate OSA. ^¥Moderate compared to normal-mild OSA. ^† value for linear trend (unadjusted) across OSA severity classes.