As with any diagnostic tool, accurate utilization of ECG is critical—and that includes correct ECG lead placement on women and men. As a paper in Circulation notes, misplacements can lead to incorrect readings of waveforms, potentially causing false-positive or false-negative diagnoses of conditions such as arrhythmias or myocardial infarction.1 Positioning errors can also disrupt stratification and management efforts for patients with known cardiac disease.
Positioning problems are both well-documented and common, affecting waveform morphology, the potential for misreading, and the risk of misdiagnosis. While misplacement occurs across both sexes, anatomical differences can complicate correct ECG placement lead placement on women versus men. For instance, according to a review in Cardiology and Cardiovascular Medicine, challenges with lead placement can arise in cases where patients have large breast tissue or are overweight, as ECG professionals may not be able to locate bone landmarks in the chest.2
That same review also notes that paramedics could make errors in lead placement due to fears or embarrassment about exposing female patients' breast tissue, emphasizing the underlying dynamics of sex-based differences in cardiac care and their lasting impacts on women's health.
While electrode misplacement can and does affect most patients—occurring in more than 50 percent of cases, and often in V1 and V2, according to the papers in Circulation and Cardiology and Cardiovascular Medicine—certain errors linked to sex can drive inequities in cardiovascular medicine and worsen existing disparities. For this reason, ECG professionals should consider how physiological differences can affect lead placement as they look to position ECG leads for diagnostic accuracy.
ECG Lead Placement on Women: Nuances to Understand
Regardless of a patient's sex, the positioning of the electrodes remains the same: V1 and V2 flank the sternal borders at the fourth intercostal space; V4, V5, and V6 align starting at the fifth intercostal space; and V3 goes on the midway point between V2 and V4. However, errors can occur when placing chest electrodes on a female patient versus a male patient, owing to the location and amount of breast tissue.
Historical context has suggested a nuanced take. As cited in the Annals of Noninvasive Electrocardiology, it had previously been suggested (in 1998) that ECG waveforms were insignificantly affected by breast placement, indicating the need for breast placement with precordial leads for better positioning.3 Current guidelines suggest otherwise, however.
Recommendations from the Society for Cardiological Science and Technology (SCST) dictate that when breast tissue covers placement areas, ECG professionals should place electrodes V4, V5, and V6 under the breast, but those recommendations tend to clash with patient preference.4 According to research published in Emergency Medicine Journal, more than half of female patients who get an ECG find it preferable and less intrusive for the leads to be positioned on their breast tissue rather than under it, but if ECG professionals follow this patient preference, they may risk placing the leads too high or too low.5 This concern presents a good opportunity for additional study, training, and both patient and provider education. One option may be to explain the importance to patients and ask them to move up their breast for lead placement, or use the back of the operator's hand to do so.
These risks apply to all leads, though positioning inaccuracies in V4, V5, and V6 are more common than those in V1, V2, and V3, particularly in women who are older and larger in size. Misplacement of these commonly variable leads can lead to many recording problems, including simulation of anterior infarction and a modified voltage that could affect ventricular hypertrophy diagnosis.
