CARDIAC-ARRHYTHMIAS, SNORING, AND SLEEP-APNEA

We investigated the frequency of cardiac arrhythmias in patients suspe cted of having sleep apnea, and related them to the severity of apnea, snoring, and nocturnal hypoxemia. We prospectively studied 458 patien ts who had nocturnal polysomnography which included objective measurem ent of snoring (quantified by the number of snores per hour of sleep [ snoring index (SI)] and maximum nocturnal sound intensity [(dBmax)], a s well as examination of the electrocardiogram (modified lead 2). We f ound 58 percent prevalence of arrhythmias in patients with sleep apnea (apnea/hypopnea index=AHI >10), vs 42 percent in nonapneic controls ( chi(2)=16.7, p<0.0001). Patients with arrhythmias had more severe apne a and nocturnal hypoxemia, but not snoring, than patients without arrh ythmias. To examine separately the relationship between the prevalence of arrhythmias and snoring, nocturnal oxygenation, and apnea-we selec ted subgroups of patients ''at the opposite ends of the spectrum'' wit h respect to the severity of snoring, hypoxemia, and apnea. We found t hat 38 percent of light snorers had arrhythmias vs 39 percent of heavy snorers, 82 percent of patients with mean nocturnal oxygen saturation <90 percent had arrhythmias vs 40 percent of patients with mean noctu rnal oxygen saturation >90 percent (chi(2)=7.4, p=0.006), and 70 perce nt of patients with AHI greater than or equal to 40 had arrhythmias vs 42 percent with AHI less than or equal to 10 (chi(2)=9.2, p=0.002). W e conclude that patients with sleep apnea as a group have higher preva lence of cardiac arrhythmias than nonapneic patients and that snoring alone, without concomitant sleep apnea, is not associated with increas ed frequency of cardiac arrhythmias.