Author + information
- Burak Hünük1,
- Özgür Çağaç2,
- Okan Erdoğan2,
- Alper Kepez2,
- Bülent Mutlu2,
- Muzaffer Değertekin3 and
- Çetin Erol4
The prolongation of QT interval/rate corrected QT interval (QT/QTc) is associated with cardiovascular (CV) mortality and morbidity. Anemia is an independent risk factor for CV outcomes. Effects of age and gender on QT interval have been well documented. However, the impact of anemia on QT remains to be elucidated.
ECGs were obtained from the HAPPY (Heart Failure Prevalence and Predictors in Turkey) study including randomly selected 4650 subjects ≥35 years with laboratory and clinical data from Turkey. After the exclusion of subjects with missing data, ECG abnormalities effecting QT, anti arrhythmic use or established coronary artery disease; 3374 subjects ([mean±SD]age, 51±11, [range]35-100 years) were enrolled in the study (female n [overall%]:1943 [57,6%]). Anemia was defined according to the WHO criteria (hemoglobin[Hgb] <13 g/dl in men, <12 g/dl in women). Long QTc was defined if interval was >440 ms for men and >460 ms for women. ECGs were interpreted by two experienced cardiologists for baseline ECG parameters and automated QTc analysis (Bazett's formula) values.
Long QTc was detected in 1,8% of the population. Three hundred eighty one women (19,6% of females) and 150 men (10,5% of males) were anemic. The incidence of anemia was higher in long QTc group vs normal QTc group (31,6% vs 16,2%, p=0,003). QTc values were significantly longer in patients with anemia (Data±SEM, 408±0,8 vs 406±0,3, p=0,02). Hgb levels were negatively correlated with QTc in univariate analyses (r=-0,101, p<0,001). In multivariate regression analyses, Hgb was found as an independent predictor of QTc durations after adjusting for age, gender and BMI (Table-1).
Anemia seems to prolong QT interval in subjects without a manifest heart disease. Our findings might be attributed to a probable subendocardial ischemia caused by a demand/supply mismatch in the coronary physiology of anemic subjects.
|r||p||β||p||Confidence Interval (95%)|
|Age (years)||0,100||< 0,001||0,107||< 0,001||(0,111 - 0,216)|
|Gender||0,092||< 0,001||0,087||0,001||(0,970 - 3,937)|
|BMI (kg/m2)||0,029||0,040||0,003||0,850||(-0,116 - 0,141)|
|Hgb (g/dl)||-0,101||< 0,001||-0,059||0,005||(-1,129 - -0,202)|
Multivariate regression model for QTc