EKG Subtlety: Tall T-Wave in Lead V1

EKGs are a simple, cheap modality that can give an emergency physician quite a bit of information. Sometimes, in a busy ER, this information can be very subtle and almost overlooked without a second thought. A perfect example of this is a New Tall T-wave in lead V1 (NTTV1). This finding can be a normal variant, but can also be a precursor to badness.

What is a NTTV1?

• While a normal EKG has a flat or inverted T-wave in lead V1, a NTTV1 can be an early sign of an ischemic hyperacute T-wave
• Upright T-wave in lead V1 is abnormal if:

1. Height of upright T-wave in V1 taller than T-wave in V6, or
2. A NEW, upright T-wave in V1 (compare to old EKG)

What are the causes of a NTTV1?

• Ischemia (CAD)
• LVH
• LBBB
• High Left Ventricular Voltage (Young Athletes)
• Lead Misplacement

What is the significance of NTTV1?¹

• 84.4% of patients in a series of 218 patients undergoing cardiac catheterization had severe CAD (>75% stenosis)
• In patients with one vessel disease and NTTV1 >0.15mV, the lesion was:

1. Left circumflex artery disease (44%)
2. Right coronary artery (22%)
3. Left anterior descending artery (2%)

• In patients with two vessel disease and NTTV1 >0.15mV, the lesions were:

1. Left circumflex and right coronary artery disease (69%)
2. Left anterior descending and left circumflex arteries (7%)
3. Left anterior descending and right coronary arteries (17%)

EKGs From: Mattu A. ECG’s for the Emergency Physician 1. 2003.

Take Home Message

Assuming a patient doesn’t have LVH or LBBB, a new, upright, tall T-wave in lead V1 or a T-wave in lead V1 taller than V6 could signify hyperacute T-waves and precede acute myocardial infarction. Remember to always compare to prior EKGs.

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