From the Guidelines
The right side of the heart is indeed represented by the septal leads V1 and V2 on an electrocardiogram (ECG). These leads are placed on the chest wall over the right ventricle and provide information about electrical activity in the right side of the heart, particularly the right ventricle and interventricular septum.
Key Points
- V1 is positioned in the fourth intercostal space at the right sternal border, while V2 is positioned in the fourth intercostal space at the left sternal border 1.
- These leads are particularly useful for diagnosing right ventricular hypertrophy, right bundle branch block, and certain types of myocardial infarction affecting the right ventricle or interventricular septum.
- They also help in distinguishing between ventricular and supraventricular arrhythmias based on QRS morphology.
- Understanding the anatomical correlation between these leads and the right heart chambers is essential for accurate ECG interpretation in clinical practice, as emphasized by the American Heart Association electrocardiography and arrhythmias committee, council on clinical cardiology 1.
Clinical Implications
- Accurate placement of V1 and V2 electrodes is crucial for obtaining reliable ECG readings, as different placement of electrodes on the limbs can alter the ECG 1.
- The standard 12-lead ECG consists of 3 limb leads, 3 augmented limb leads, and 6 precordial leads, including V1 through V6, which are effectively “bipolar” 1.
- Skin preparation by cleaning and gentle abrasion before electrode application can reduce noise and improve the quality of the recorded ECG 1.
From the Research
Septal Leads
- The right side of the heart is associated with septal leads V1 and V2, as these leads are positioned to capture the electrical activity of the interventricular septum 2, 3.
- The interventricular septum is a wall of tissue that separates the left and right ventricles of the heart, and its electrical activity is an important aspect of the electrocardiogram (ECG) 3.
- Leads V1 and V2 are typically placed on the chest wall to the right of the sternum, and they are designed to capture the electrical activity of the septum as it depolarizes 2.
Lead Placement and Septal Activity
- The placement of leads V1 and V2 is critical for accurate interpretation of the ECG, as misplacement of these leads can lead to false diagnoses of septal infarction 2.
- The morphology of the P wave in lead V2 can be used to suspect erroneous right precordial lead placement in cases of apparent septal infarction 2.
- The initial electrical forces emanating from the interventricular septum are directed to the right and anteriorly, producing an initial positive deflection or R wave in leads V1 and V2 3.
Clinical Significance
- The septal leads V1 and V2 are important for diagnosing and monitoring various cardiac conditions, including left bundle branch block (LBBB) and left ventricular hypertrophy 3, 4, 5.
- Abnormal septal motion in LBBB can be influenced by regional left ventricular function and myocardial scar, and septal flash is associated with positive response to cardiac resynchronization therapy (CRT) 5.