High Voltage

High voltage – probable left ventricular hypertrophy (LVH); criteria:

• S in V1 plus R in V5-6 (whichever is the larger) ≥ 35 mm
  • sensitive  but not specific; the larger the sum the more specific         
• or R in aVL ≥ 13 mm
  • specific but not sensitive                                                                    
• or R in I plus S in III ≥ 27 mm
  • intermediate sensitivity-specificity
• LAE, LAD, ST-T abnormalities (strain pattern): LVH more likely
• QRS voltages may be higher in normal young and thin individuals
• Unexplained high voltage: check amplification (r/o 20 mm/mV)

Low Voltage

• QRS amplitude <5 mm in all  limb leads; <10 mm in all chest leads

Variable Voltage

• Proceed to alternans

High Voltages

Low Voltage

Alternans