Abstract
While the prognostic impact of QRS axis deviation has been assessed, it has never been investigated in patients without conduction block. Thus, we evaluated the prognostic impact of QRS-axis deviation in patients without conduction block. We retrospectively analyzed 3353 patients who had undergone both scheduled transthoracic echocardiography and electrocardiography in 2013 in a hospital-based population, after excluding patients with a QRS duration of ≥ 110 ms, pacemaker placement, and an QRS-axis − 90° to − 180° (northwest axis). The study population was categorized into three groups depending on the mean frontal plane QRS axis as follows: patients with left axis deviation (N = 171), those with right axis deviation (N = 94), and those with normal axis (N = 3088). The primary outcome was a composite of all-cause death and major adverse cardiovascular events. The cumulative 3-year incidence of the primary outcome measure was significantly higher in the left axis deviation group (26.4% in the left axis deviation, 22.7% in the right axis deviation, and 18.4% in the normal axis groups, log-rank P = 0.004). After adjusting for confounders, the excess risk of primary outcome measure remained significant in the left axis deviation group (hazard ratio [HR] 1.44; 95% confidence interval [CI] 1.07–1.95; P = 0.02), while the excess risk of primary outcome measure was not significant in the right axis deviation group (HR 1.22; 95% CI 0.76–1.96; P = 0.41). Left axis deviation was associated with a higher risk of a composite of all-cause death and major adverse cardiovascular events in hospital-based patients without conduction block in Japan.
Highlights
QRS axis deviation can be determined in electrocardiograms (ECGs)
While the prognostic impact of QRS axis deviation in patients including a wide QRS complex has been assessed from the 1980s in Western c ountries[11,13,14,15], it has never been investigated in patients without conduction block in Asian population
The cumulative 3-year incidence of the primary outcome measure was significantly higher in the left axis deviation group (Fig. 2A)
Summary
QRS axis deviation can be determined in electrocardiograms (ECGs). left axis deviation is often an age-related physiological change[1,2,3], it may indicate the presence of various conditions, such as left ventricular hypertrophy[4], left anterior fascicular b lock[5], inferior wall myocardial infarction6, emphysema[7], and mechanical shift due to elevated diaphragm because of obesity[8]. The study population comprised 3353 patients, who were categorized into three groups depending on the mean frontal plane QRS-axis as follows: left axis deviation (− 30° to − 90°), right axis deviation (90° to 180°), and normal axis (− 30° to + 90°). We compared the patient characteristics and 3-year clinical outcomes among the three groups with (1) left axis deviation, (2) right axis deviation, and (3) normal axis.
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