Peak T Wave Definition
A "peaked" T wave is a qualitative descriptor referring to a T wave with abnormally increased amplitude and often a narrow, pointed morphology, most commonly seen in hyperkalemia or as a normal variant in precordial leads V2-V3. 1
Electrocardiographic Characteristics
The term "peaked" describes the morphology and amplitude characteristics of the T wave rather than a specific quantitative measurement:
Normal T wave amplitude is typically most positive in leads V2 or V3, with upper normal thresholds of 1.0-1.4 mV in men (up to 1.6 mV in ages 18-29) and 0.7-1.0 mV in women 1
"Peaked" is used as a qualitative descriptor alongside other terms like symmetrical, biphasic, flat, and inverted to characterize T wave morphology 1
The T wave corresponds to the rapid ventricular repolarization phase (phase 3) of the ventricular action potential, representing transmural dispersion of repolarization in the ventricles 2
Clinical Context and Significance
The interpretation of peaked T waves depends heavily on clinical context:
Hyperkalemia is the most important pathological cause of peaked T waves, characterized by tall, narrow, symmetrical T waves with a pointed apex, typically appearing first in precordial leads 1
Normal variant peaked T waves can occur in healthy individuals, particularly in precordial leads V2-V3 where T wave amplitude is physiologically highest 1
Early repolarization patterns may show prominent T waves in association with J-point elevation, particularly in young males and athletes 2
Distinguishing Features from Other T Wave Abnormalities
When evaluating peaked T waves, consider these distinctions:
Peaked vs. tall T waves: While related, "peaked" specifically implies a narrow, pointed morphology rather than simply increased amplitude 1
Avoid confusion with U waves: In conditions with increased U wave amplitude (hypokalemia, certain drugs), the U wave may merge with or exceed the T wave, which differs from true T wave peaking 1, 3
Differentiate from T wave alternans: This represents beat-to-beat amplitude variations in an ABABAB pattern, distinct from consistently peaked morphology 1
Common Pitfalls in Recognition
Failure to correlate with serum potassium: Peaked T waves without checking electrolytes can lead to missed hyperkalemia, a life-threatening condition requiring immediate intervention 1
Misinterpreting normal variants as pathology: Prominent T waves in V2-V3 within normal amplitude ranges should not automatically trigger extensive workup in asymptomatic patients 1
Overlooking associated ECG findings: Peaked T waves in hyperkalemia typically progress to include PR prolongation, QRS widening, and eventually sine wave pattern as potassium rises 1
Confusing with hyperacute T waves of acute MI: Hyperacute T waves in acute myocardial infarction are typically broader-based and associated with ST elevation, whereas peaked T waves are narrower and more symmetrical 1