Q waves are the strongest electrocardiographic variable associated with primary prophylactic implantable cardioverter-defibrillator benefit: a prospective multicentre study
Authors: Pelli Ari , Junttila M Juhani , Kenttä Tuomas V , Schlögl Simon , Zabel Markus , Malik Marek , Reichlin Tobias , Willems Rik , Vos Marc A , Harden Markus , Friede Tim , Sticherling Christian , Huikuri Heikki V ,   the EU-CERT-ICD Study Investigators, Arbelo Elena , Bauer Axel , Braunschweig Frieder , Brugada Josep , Conen David , Cygankiewicz Iwona , Dommasch Michael , Eick Christian , Flevari Panagiota , Friede Tim , Galuszka Jan , Hansen Jim , Hatala Robert , Harden Markus , Hnatkova Katerina , Huikuri Heikki V , Junttila Juhani M , Kääb Stefan , Kaliska Gabriela , Kasprzak Jaroslaw D , Katsimardos Andreas , Kozak Milan , Kuczejko Tomasz , Lubinski Andrzej , Martinek Jozef , Merkely Béla , Novotný Tomáš , Malik Marek , Perge Peter , Pieske Burkert , Platonov Pyotr , Ptaczyński Pawel , Qavoq Dariusz , Rotkvić L , Sallo Zoltan , Schlögl Simon , Schmidt Georg , Sinner Moritz , Sritharan Rajeeva , Stefanow Stefan , Sticherling Christian , Svendsen Jesper Hastrup , Svetlosak Martin , Szavits-Nossan Janko , Taborsky Milos , Tuinenburg Anton , Vandenberk Bert , Vos Marc A , Willems Rik , Willich Stefan N , Wolpert Christian , Zabel Markus , Anic Ante , Bakotic Zoran , Behrens Steffen , Bimmel Dieter , Brusich Sandro , Dissmann Rüdiger , Grönefeld Gerian , Guzik Przemyzlav , Iovev Svetoslav , Jurisic Zrinka , Klingenheben Thomas , Pavlović Nikola , Seegers Joachim , Schwinger Robert H G , Shalganov Tchavdar , Traykov Vassil , Velchev Vasil 
Published: September 2021

Abstract

Aim
The association of standard 12-lead electrocardiogram (ECG) markers with benefits of the primary prophylactic implantable cardioverter-defibrillator (ICD) has not been determined in the contemporary era. We analysed traditional and novel ECG variables in a large prospective, controlled primary prophylactic ICD population to assess the predictive value of ECG in terms of ICD benefit.

Methods and results
Electrocardiograms from 1477 ICD patients and 700 control patients (EU-CERT-ICD; non-randomized, controlled, prospective multicentre study; ClinicalTrials.gov Identifier: NCT02064192), who met ICD implantation criteria but did not receive the device, were analysed. The primary outcome was all-cause mortality. In ICD patients, the co-primary outcome of first appropriate shock was used. Mean follow-up time was 2.4 ± 1.1 years to death and 2.3 ± 1.2 years to the first appropriate shock. Pathological Q waves were associated with decreased mortality in ICD patients [hazard ratio (HR) 0.54, 95% confidence interval (CI) 0.35–0.84; P &lt; 0.01] and patients with pathological Q waves had significantly more benefit from ICD (HR 0.44, 95% CI 0.21–0.93; P = 0.03). QTc interval increase taken as a continuous variable was associated with both mortality and appropriate shock incidence, but commonly used cut-off values, were not statistically significantly associated with either of the outcomes.

Conclusion
Pathological Q waves were a strong ECG predictor of ICD benefit in primary prophylactic ICD patients. Excess mortality among Q wave patients seems to be due to arrhythmic death which can be prevented by ICD.