Prognostic significance of low QRS voltage on the admission electrocardiogram in acute coronary syndromes.
OBJECTIVE
To examine the prognostic significance of low QRS voltage in a large contemporary cohort of patients with a broad spectrum of acute coronary syndromes (ACS).


METHODS
12409 patients with STEMI or NSTE-ACS from the Global Registry of Acute Coronary Events (GRACE) and Canadian ACS I registries were stratified based on the presence of low QRS voltage (<0.5 mV in all limb leads and <1.0 mV in all precordial leads) on the admission ECG. We performed multivariable logistic regression to assess the independent association between low voltage and in-hospital and 6-month mortality, and tested for its interaction with ST-segment deviation for these outcomes.


RESULTS
Patients with low voltage (3.2%) had higher GRACE risk scores, rates of prior myocardial infarction, and pathological Q waves, with less prevalent ST-segment deviation and ST-segment depression. They had worse left ventricular function and higher unadjusted rates of in-hospital and 6-month mortality. After adjustment for established prognosticators in the GRACE risk models in multivariable analysis, low voltage was independently associated with higher in-hospital mortality (adjusted OR 1.77, 95% CI 1.13-2.78, P=0.013) and mortality/re-infarction (adjusted OR 1.42, 95% CI 1.05-1.93, P=0.023), but not 6-month mortality (adjusted OR 1.25, 95% CI 0.85-1.84, P=0.27). There was no significant interaction between low voltage and ST-segment deviation for any endpoint (interaction P>0.10 for all endpoints).


CONCLUSIONS
Low QRS voltage was associated with previous myocardial infarction and adverse hemodynamic variables at presentation. After adjusting for other prognosticators, low voltage independently predicted higher in-hospital mortality. This increased risk was not modulated by concomitant ST-segment deviation.
Terrence Donnelly Heart Centre, St Michael's Hospital, Toronto, ON, Canada; University of Toronto, Toronto, ON, Canada.
Nigel S
NS
Tan
Terrence Donnelly Heart Centre, St Michael's Hospital, Toronto, ON, Canada; University of Toronto, Toronto, ON, Canada; Canadian Heart Research Centre, Toronto, ON, Canada.
Shaun G
SG
Goodman
University of Toronto, Toronto, ON, Canada.
Raymond T
RT
Yan
Canadian Heart Research Centre, Toronto, ON, Canada.
Mary K
MK
Tan
Centre for Cardiovascular Science, The University of Edinburgh, Edinburgh, UK.
Keith A A
KA
Fox
Department of Medicine, University of Massachusetts Medical School, Worcester, MA, United States.
Joel M
JM
Gore
Coronary Care Unit, Concord Hospital, Sydney, Australia.
David
D
Brieger
DHU FIRE, Université Paris Diderot, AP-HP, Hôpital Bichat, INSERM, U1148 Paris, France.
Ph Gabriel
PG
Steg
University of Toronto, Toronto, ON, Canada; Canadian Heart Research Centre, Toronto, ON, Canada.
Anatoly
A
Langer
Terrence Donnelly Heart Centre, St Michael's Hospital, Toronto, ON, Canada; University of Toronto, Toronto, ON, Canada. Electronic address: yana@smh.ca.
Andrew T
AT
Yan
D054058:Acute Coronary Syndrome / Q000175:diagnosis* / Q000453:epidemiology / Q000503:physiopathology*; D000368:Aged; D002170:Canada / Q000453:epidemiology; D004562:Electrocardiography / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010343:Patient Admission; D011379:Prognosis; D012042:Registries; D016037:Single-Blind Method
Acute coronary syndrome; Electrocardiogram; Low QRS voltage; Prognosis