Usefulness of notched duration to predict response to cardiac resynchronization therapy.
OBJECTIVE
The presence of notches in the biventricular paced QRS complex (BiP-QRS) from the posterolateral cardiac vein displays delays in the activation of the left ventricle and may consequently be linked with longer times of stimulus conduction. Our objective was to determine the relationship between the notch duration ≥ 0.1 mV in the BiP-QRS and the effectiveness of cardiac resynchronization therapy (CRT).


METHODS
A total of 210 patients, who underwent de novo CRT implantation previously and had ≥ 1 follow-up between August 2009 and February 2014, were enrolled in the study. Echocardiographic response to CRT was defined as "an increase of ≥ 5% in ejection fraction" and clinical response to CRT was defined as "an improvement ≥ 1 in New York Heart Association class without heart failure hospitalization after 6 months of CRT implantation."


RESULTS
At a mean follow-up of 9.2 ± 2.1 months, 142 patients (67%) were classified as responders to CRT. BiP-QRS duration was significantly longer among non-responders compared with responders (p = 0.036). More of the non-responders have notched in their BiP-QRS than responders (63% vs. 40%, p = 0.002). Median duration of notch was significantly higher among non-responders (80 ms vs. 67.5 ms, p = 0.041). Notch duration > 67.5 ms was associated with 2.8 times higher non-response to therapy (odds ratio: 2.8; 95% confidence interval: 1.075-7.588, p = 0.035).


CONCLUSIONS
Patients with notch duration greater than 67.5 ms are associated with poor response to CRT. Notch duration > 67.5 ms predicts non-response to therapy with 50.0% specificity and 72.1% sensitivity.
Department of Cardiology, Turkiye Yuksek Ihtisas Research and Education Hospital , Ankara , Turkey.
Mustafa Mücahit
MM
Balci
Kevser Gülcihan
KG
Balci
Fatih
F
Sen
Orhan
O
Maden
Sefa
S
Unal
Mehmet Timur
MT
Selcuk
Hatice
H
Selcuk
D000200:Action Potentials; D000368:Aged; D058406:Cardiac Resynchronization Therapy / Q000009:adverse effects; D058409:Cardiac Resynchronization Therapy Devices; D004562:Electrocardiography; D005260:Female; D006333:Heart Failure / Q000175:diagnosis / Q000503:physiopathology / Q000628:therapy*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D020127:Recovery of Function; D012189:Retrospective Studies; D012307:Risk Factors; D013318:Stroke Volume; D013997:Time Factors; D016896:Treatment Outcome; D016277:Ventricular Function, Left
cardiac resynchronization therapy; electrocardiography; heart failure