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.

While lead misplacement can impact ECG performance, ECG professionals should also keep in mind that some sex-based factors can affect accuracy even when the electrodes are in the right place. For example, as a paper from the European Society of Cardiology explains, breast implants have been known to block voltage pathways and result in a T-wave inversion and ST depression that could be wrongly interpreted as coronary artery disease and myocardial infarction.6

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Ensuring Equitable Care Through Practice and Training

Variances in electrode placement between male and female patients can delay critical care and ultimately impact patient outcomes. ECG professionals should remain wary of potential lead misplacement and work to implement the correct positioning by using bone landmarks. Doing so can help reduce the chances of inaccuracies showing up on the ECG and informing misdiagnoses.

Because breast size or shape can complicate anatomical reference points, it's recommended that ECG professionals continue to place electrodes beneath the breast when necessary, though research to determine what impact alternative placement may have on ECG recordings is ongoing. SCST guidelines note that ECG professionals can minimize physical contact with the breast by raising it with the back of the hand. This protocol may help mitigate negative impacts on care that could arise from a desire to preserve modesty.

Concerns around sex-based differences in cardiology outcomes emphasize the need not only for increased diligence in caring for patients but also for changes in medical education. Notably, one example in Gender in the Genome details a textbook that advises removing patients' neckties in cases of acute MI but does not mention bras.7 As sex-based disparities become more apparent in cardiovascular medicine, it will take widespread and consistent efforts in practice and in training to highlight opportunities for improvement, including opportunities that relate to ECG placement.

With a commitment to equal and equitable care delivery throughout the care continuum, cardiologists can play an active role in improving diagnostic accuracy and deploying prompt interventions for all patients, regardless of their sex, race, or any other differentiating factor.



  1. Davis LL, Funk M, Fennie KP, et al. Abstract 16195: Does accuracy of V lead electrode placement differ based on gender of patient: results of the practical use of the latest standards of electrocardiography (PULSE) trial. Circulation. 2016;134(1).

  2. Hadjiantoni A, Oak K, Mengi S, et al. Is the correct anatomical placement of the electrocardiogram (ECG) electrodes essential to diagnosis in the clinical setting: A systematic review. Fortune Journals. Accessed November 11, 2021.

  3. García-Niebla J, Llontop-García P, Valle-Racero JI, et al. Technical mistakes during the acquisition of the electrocardiogram. Ann Noninvasive Electrocardiol. 2009;14(4):389-403.
  4. Campbell B, Richley D, Ross C, et al. Clinical guidelines by consensus: recording a standard 12-lead electrocardiogram. Society for Cardiological Science and Technology. Accessed November 11, 2021.
  5. Wallen R, Tunnage B, Wells S. The 12-lead ECG in the emergency medical service setting: how electrode placement and paramedic gender are experienced by women. Emergency Medicine Journal. 2014;31:851-852.

  6. European Society of Cardiology. Breast implants may impede ECG and lead to false heart attack diagnosis. Accessed November 11, 2021.

  7. Hiltner S, Oertelt-Prigione S. Sex and gender representations of myocardial infarction in German medical books. Gender and the Genome. June 2017:68-75.