ECG lead V1

Introduction

Lead placement: right 4th intercostal space in the parasternal space.

Normally an S wave (downward deflection) in V1 from LV free wall depolarization. Septal R wave in V1 (if present) 25 msec. Q-wave not abnormal in V1.

Causes of R in V1:

• right bundle branch block - prolonged QRS
• posterior myocardial infarction
  • generally occurs in association with inferior wall MI
  • Q's in II, III, aVF from inferior wall MI
• Wolf Parkinson White (WPW) type A (accessory tract anterior to mitral valve)
• right ventricular hypertrophy

More general terms

• ECG lead

Additional terms

• electrocardiogram (ECG, EKG)