Sokolow and Lyon described the electrocardiographic changes seen in patients with left ventricular hypertrophy.
Early abnormalities present in left ventricular hypertrophy:
(1) depressed RS-T segment with flat or low diphasic T waves
(2) abnormally high voltage in the QRS complex, and
(3) delayed onset of the intrinsicoid deflection.
Standard Limb Leads (SLL)
(1) (R in I) + (S in III) >= 25 mm
(2) RS-T in I depressed 0.5 mm or more
(3) T in I flat, diphasic, or inverted, particularly when associated with (SLL 2) and a prominent R wave
(4) T in II and T in III diphasic or inverted in the presence of tall R waves and (SLL 2)
(5) T in III > T in I, in the presence of left axis deviation and high voltage QRS complex in leads I and III
Precordial Leads (PL)
(1) R in V5 or V6 > 26 mm
(2) RS-T segment depressed more than 0.5 mm in V4, V5 or V6
(3) A flat, diphasic or inverted T wave in V4, V5 and V6 with normal R and small S waves and (PL 2)
(4) Ventricular activation time in V5 or V6 >= 0.06 seconds (delayed onset of intrinsic deflection), especially when associated with a tall R wave.
(5) (R in V5) + (S in V1) >= 35 mm
Unipolar Limb Leads (ULL)
(1) RS-T segment depressed more than 0.5 mm in aVL or aVF
(2) Flat, diphasic or inverted T wave in aVL or aVF with an R wave >= 6 mm, with (ULL 1)
(3) R in aVL > 11 mm
(4) upright T wave in aVR.
• 1 mm = 0.1 mV
The intrinsicoid deflection is the duration from the beginning of the earliest appearing Q or R wave to the peak of the R wave
• The end of the deflection represents the time of arrival of the electrical impulse at the epicardial surface located beneath the recording electrode.
• It is called intrinsic when the electrode is on the epicardial surface and intrinsicoid when the electrode is on the body surface.
• The intrinsicoid deflection for the right ventricle is measured in leads V1 and V2 and has an upper limit of 0.035 seconds.
• The intrinsicoid deflection for the left ventricle is measured in leads V5 and V6 and has an upper limit of 0.045 seconds.
• The intrinsicoid deflection may be increased either with ventricular hypertrophy or intraventricular conduction delay.
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Purpose: To identify left ventricular hypertrophy using the changes in the electrocardiogram described by Sokolow and Lyon.
Objective: criteria for diagnosis