Usefulness of the Sum Absolute QRST Integral to Predict Outcomes in Patients Receiving Cardiac Resynchronization Therapy.
Cardiac resynchronization therapy (CRT) reduces mortality and morbidity in selected patients with heart failure (HF), but up to 1/3 of patients are nonresponders. Sum absolute QRST integral (SAI QRST) recently showed association with mechanical response on CRT. However, it is unknown whether SAI QRST is associated with all-cause mortality and HF hospitalizations in patients undergoing CRT. The study population included 496 patients undergoing CRT (mean age 69 ± 10 years, 84% men, 65% left bundle branch block [LBBB], left ventricular ejection fraction 23 ± 6%, 63% ischemic cardiomyopathy). Preimplant digital 12-lead electrocardiogram was transformed into orthogonal XYZ electrocardiogram. SAI QRST was measured as an arithmetic sum of areas under the QRST curve on XYZ leads and was dichotomized based on the median value (302 mV ms). All-cause mortality served as the primary end point. A composite of 2-year all-cause mortality, heart transplant, and HF hospitalization was a secondary end point. Cox regression models were adjusted for known predictors of CRT response. Patients with preimplant low mean SAI QRST had an increased risk of both the primary (hazard ratio [HR] 1.8, 95% CI 1.01 to 3.2) and secondary (HR 1.6, 95% CI 1.1 to 2.2) end points after multivariate adjustment. SAI QRST was associated with secondary outcome in subgroups of patients with LBBB (HR 2.1, 95% CI 1.5 to 3.0) and with non-LBBB (HR 1.7, 95% CI 1.0 to 2.6). In patients undergoing CRT, preimplant SAI QRST <302 mV ms was associated with an increased risk of all-cause mortality and HF hospitalization. After validation in another prospective cohort, SAI QRST may help to refine selection of CRT recipients.
Department of Cardiology, Clinical Sciences, Lund University and Arrhythmia Clinic, Skåne University Hospital, Lund, Sweden.
Jonatan
J
Jacobsson
Department of Cardiology, Clinical Sciences, Lund University and Arrhythmia Clinic, Skåne University Hospital, Lund, Sweden; Cardiology Division, Massachusetts General Hospital, Boston, Massachusetts.
Rasmus
R
Borgquist
Department of Cardiology, Clinical Sciences, Lund University and Arrhythmia Clinic, Skåne University Hospital, Lund, Sweden.
Christian
C
Reitan
Electrophysiology Chapter, Knight Cardiovascular Institute, Oregon Health and Science University, Portland, Oregon.
Elyar
E
Ghafoori
Cardiology Division, Massachusetts General Hospital, Boston, Massachusetts.
Neal A
NA
Chatterjee
Electrophysiology Chapter, Knight Cardiovascular Institute, Oregon Health and Science University, Portland, Oregon.
Muammar
M
Kabir
Department of Cardiology, Clinical Sciences, Lund University and Arrhythmia Clinic, Skåne University Hospital, Lund, Sweden.
Pyotr G
PG
Platonov
Department of Cardiology, Clinical Sciences, Lund University and Arrhythmia Clinic, Skåne University Hospital, Lund, Sweden.
Jonas
J
Carlson
Cardiology Division, Massachusetts General Hospital, Boston, Massachusetts.
Jagmeet P
JP
Singh
Electrophysiology Chapter, Knight Cardiovascular Institute, Oregon Health and Science University, Portland, Oregon. Electronic address: tereshch@ohsu.edu.
Larisa G
LG
Tereshchenko
D000368:Aged; D002037:Bundle-Branch Block / Q000150:complications / Q000503:physiopathology / Q000628:therapy*; D058406:Cardiac Resynchronization Therapy; D002423:Cause of Death; D015331:Cohort Studies; D004562:Electrocardiography; D005260:Female; D006333:Heart Failure / Q000150:complications / Q000401:mortality / Q000503:physiopathology / Q000628:therapy*; D006760:Hospitalization / Q000706:statistics & numerical data*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009026:Mortality; D015999:Multivariate Analysis; D017202:Myocardial Ischemia / Q000503:physiopathology; D016016:Proportional Hazards Models; D012189:Retrospective Studies; D018570:Risk Assessment; D013318:Stroke Volume; D016896:Treatment Outcome