concordance
ECG pattern where QRS complexes in precordial leads all have same polarity, suggesting ventricular origin.
Full Definition
An electrocardiographic pattern observed in wide complex tachycardia where all QRS complexes in the precordial leads (V1-V6) demonstrate the same polarity - either all positive (positive concordance) or all negative (negative concordance). This finding is highly specific for ventricular tachycardia, as normal supraventricular conduction typically produces a transition from negative to positive deflections across the precordial leads. Negative concordance in particular is considered pathognomonic for ventricular tachycardia and should prompt immediate treatment as such in the emergency setting.
Usage
Usage note: Specify whether positive or negative concordance when documenting this finding.
In Context
- "Negative concordance across all precordial leads confirmed ventricular tachycardia." — ECG interpretation
- "The absence of concordance did not rule out ventricular origin of the wide complex tachycardia." — Emergency cardiology note