Association of Fragmented QRS with Subclinical Left Ventricular Dysfunction in Patients with Obstructive Sleep Apnea

Abstract

Objective: We aimed to investigate whether fragmented QRS (fQRS) is associated with subclinical left ventricular (LV) dysfunction in patients with obstructive sleep apnea (OSA). Subjects and Methods: A total of 141 patients with OSA who had normal LV ejection fraction (LVEF) were included in the study. The fQRS was defined as the presence of an additional R wave, notching of R or S wave or the presence of fragmentation in 2 contiguous electrocardiography (ECG) leads. Subclinical LV dysfunction was defined as the presence of a tissue Doppler-derived Tei index of ≥0.5 in the absence of impaired LVEF (<50%) as assessed by transthoracic echocardiography. Results: Of the 141 patients, 71 (50.4%) had subclinical LV dysfunction. Overall, the prevalence of the fQRS was 61% (86/141). Patients with fQRS had significantly higher Tei indices than those without fQRS [median 0.66, interquartile range (IQR) 0.39 vs. median 0.40, IQR 0.15, p < 0.001]. The presence of fQRS on ECG predicted subclinical LV dysfunction in univariate logistic regression analysis [odds ratio (OR) 6.69, 95% confidence interval (CI) 3.10-14.43]. The association remained significant after adjusting for all potential confounders (OR 4.59, 95% CI 1.94-10.87). Conclusion: fQRS on ECG was an independent predictor of subclinical LV dysfunction in patients with OSA. This simple tool might help to identify OSA patients who could be at risk for developing overt cardiac dysfunction.

The relationship between presystolic wave and subclinical left ventricular dysfunction in asymptomatic hypertensive patients

“…Using this method, deterioration in LV function can be identified before overt heart failure [18]. Several studies have reported that the MPI is not affected by blood pressure, heart rate, valvular regurgitation, ventricular geometry, preload, and afterload in patients who are in a supine position [19,20].…”

The Influence of Sleep Apnea on 24-Hour and Nocturnal ECG and Blood Pressure Parameters in Patients with Acute Heart Failure

“…SA, both the obstructive and central types, is one of the most frequently occurring comorbidities in HF, being present in over 50% of patients, regardless of the type of HF (with reduced or preserved left ventricular ejection fraction) [6-8]. SA proved to be prevalent in our patient population (unselected cases hospitalized with acute HF), being predominantly of the obstructive type.…”

Ventricular Arrhythmias in Patients with Obstructive Sleep Apnea

“…Abnormal impulse conduction creates a milieu for VA through reentry mechanisms and fQRS complexes are a predictor of cardiovascular death in patients with structural heart disease [ 88 , 90 ]. Recent studies found fQRS in patients with OSA (independently of obesity), suggestive of electrical myocardial remodeling [ 87 , 91 , 92 ]. One of the mechanisms thought to be responsible for fQRS is cellular apoptosis and interstitial fibrosis in cardiac structure, which may be secondary to chronic hypoxia, metabolic abnormalities and oxidative stress [ 87 , 91 , 92 ].…”