Joji Ishikawa1, Shizukiyo Ishikawa2, Kazuomi Kario3. 1. Division of Cardiovascular Medicine, Department of Medicine, Jichi Medical University, School of Medicine, Tochigi, Japan. Electronic address: george@jichi.ac.jp. 2. Division of Community and Family Medicine, Center for Community Medicine, Jichi Medical University, Tochigi, Japan. 3. Division of Cardiovascular Medicine, Department of Medicine, Jichi Medical University, School of Medicine, Tochigi, Japan.
Abstract
BACKGROUND: We attempted to evaluate whether the relationship between the QTc interval and mortality (including sudden cardiac death) is linear or J-shaped in the general Japanese population, who tend to be at greater risk of strokes than cardiac events. METHODS: We classified 10,804 subjects according to their Bazett QTc interval quartiles (determined by electrocardiography) at the baseline and followed them up for a mean period of 141.9±28.3 months (127,712 person-years). RESULTS: In total, 878 subjects died during the study period, including 104 from cardiovascular events, 100 from stroke, and 46 from sudden cardiac death. In a Cox proportional hazards regression model adjusted for conventional cardiovascular risk factors, the risk of cardiovascular mortality increased progressively with the QTc interval quartile [Q2, hazard ratio (HR)=0.94 (0.43-2.03); Q3, HR=1.11 (0.53-2.34); Q4, HR=2.21 (1.12-4.36); HR are vs. Q1]. A parallel analysis found that the risk of stroke mortality was marginally increased in the highest Bazett QTc interval quartile [HR=1.93 (0.97-3.85)]. On the other hand, the risk of sudden cardiac death exhibited a J-shaped relationship with the Bazett QTc interval quartile [Q1, HR=8.58 (1.07-69.05); Q3, HR=7.17 (0.88-58.73); Q4, HR=13.18 (1.72-101.03); HR are vs. Q2]. CONCLUSION: In the general Japanese population, cardiovascular and stroke mortality increase progressively with the Bazett QTc interval quartile, while the risk of sudden cardiac death exhibits a J-shaped relationship with the latter variable.
BACKGROUND: We attempted to evaluate whether the relationship between the QTc interval and mortality (including sudden cardiac death) is linear or J-shaped in the general Japanese population, who tend to be at greater risk of strokes than cardiac events. METHODS: We classified 10,804 subjects according to their Bazett QTc interval quartiles (determined by electrocardiography) at the baseline and followed them up for a mean period of 141.9±28.3 months (127,712 person-years). RESULTS: In total, 878 subjects died during the study period, including 104 from cardiovascular events, 100 from stroke, and 46 from sudden cardiac death. In a Cox proportional hazards regression model adjusted for conventional cardiovascular risk factors, the risk of cardiovascular mortality increased progressively with the QTc interval quartile [Q2, hazard ratio (HR)=0.94 (0.43-2.03); Q3, HR=1.11 (0.53-2.34); Q4, HR=2.21 (1.12-4.36); HR are vs. Q1]. A parallel analysis found that the risk of stroke mortality was marginally increased in the highest Bazett QTc interval quartile [HR=1.93 (0.97-3.85)]. On the other hand, the risk of sudden cardiac death exhibited a J-shaped relationship with the Bazett QTc interval quartile [Q1, HR=8.58 (1.07-69.05); Q3, HR=7.17 (0.88-58.73); Q4, HR=13.18 (1.72-101.03); HR are vs. Q2]. CONCLUSION: In the general Japanese population, cardiovascular and stroke mortality increase progressively with the Bazett QTc interval quartile, while the risk of sudden cardiac death exhibits a J-shaped relationship with the latter variable.
Authors: Jani Pirinen; Jukka Putaala; Karoliina Aarnio; Aapo L Aro; Satu Mustanoja; Juha Sinisalo; Markku Kaste; Elena Haapaniemi; Turgut Tatlisumak; Mika Lehto Journal: Eur Stroke J Date: 2017-03-01