Electrocardiogram voltage discordance: Interpretation of low QRS voltage only in the precordial leads.

OBJECTIVES: To define clinical correlates of low voltage isolated to precordial leads on the surface electrocardiogram (ECG).

INTRODUCTION: Low voltage (V) on the ECG is defined as QRS V<5mm in all limb leads and <10mm in all precordial leads. The diagnostic use of ECGs with low voltage isolated to the precordial leads with normal limb lead voltages is unclear.

METHODS: Twelve-lead ECGs with QRS V>5mm in one or more limb leads and <10mm in all precordial leads were collected. Associated clinical conditions were determined from clinical data, echocardiograms, and chest radiographs.

RESULTS: Low precordial voltage was found in 256 of 150,000 ECGs (~0.2%). 50.4% of patients had discordant ECGs that correlated with classic etiologies, with a higher incidence of LV dilation in those with classic etiologies than those without.

CONCLUSION: Low precordial voltage is associated with classic etiologies and LV dilation.