ECG lead misplacement: A brief review of limb lead misplacement

An unusual ECG lead reversal

Lead reversals are a common cause of electrocardiographic abnormality, which can lead to a false diagnosis like chamber enlargement, myocardial ischemia or infarction. Isolated limb lead reversals and chest lead reversals are common in clinical practice. This article reports a rare case where multiple limb and chest leads were reversed due to the reversal of cables leading to a false diagnosis of myocardial ischemia.

Wandering ST-Segment in Acute Coronary Syndrome: The Einthoven's Twist

Interpretation of the ST-segment axis in ST-elevation myocardial infarction (STEMI) plays a crucial role in identifying the culprit artery and optimizing revascularization strategies. In certain conditions, the ST-segment axis may abruptly change during management, creating diagnostic confusion, provoking unnecessary workups, and causing treatment delays. Some reported causes of wandering ST-segment include lead misplacement, progressive injury, coronary vasospasm, migration of the thrombus, and aortic dissection. Here we describe two exciting cases of wandering ST-segment axis in acute coronary syndrome and its management.

ECG lead misplacement in the frontal and horizontal plane mimicking A myocardial infarction

BACKGROUND/AIMS

Electrocardiogram (ECG) is an inexpensive, fundamental screening tool used in daily clinical practice. It is essential in the diagnosis of life-threatening conditions, such as acute myocardial infarctions, ventricular arrhythmias etc. However, ECG lead misplacement is a common technical error, which may translate into wrong interpretations, unnecessary investigations, and improper treatments.

METHODS/RESULTS

We report a case of a multiple ECG lead misplacement made across two different planes of the heart, resulting in a bizarre series of ECG, mimicking an acute high lateral myocardial infarction. Multiple ECGs were done as there were abrupt changes compared to previous ECGS. Patient was pain free and administration of potentially harmful procedures and treatments were prevented.

CONCLUSION

Our case demonstrated the importance of high clinical suspicion in diagnosing ECG lead misplacement. It is the responsibility of both the healthcare workers who are performing and interpreting the ECG to be alert of a possible lead malposition, to prevent untoward consequences to the patient.

Electrocardiographic lead reversals

Misplacement of cables during the recording of a 12-lead electrocardiogram [ECG] poses a non-negligible risk of creating panic and confusion at the bedside in daily clinical practice. Clinical awareness about the manifestations of commonly encountered electrode misplacements is imperative for avoiding misdiagnosis. A basic understanding of the electrophysiology behind these anomalous ECG tracings is likely to aid in prompt suspicion, accurate detection, and appropriate rectification in most cases. We discuss the abnormalities produced on 12-lead ECG tracings by the misplacement of electrode cables, with a focus on the clinical implications of the same. We suggest a mnemonic - 'SPIRAL' - as a quick screening criterion to detect commonly encountered lead reversals.

Incorrect Electrocardiogram Lead Placement in ST-Segment-Elevation Myocardial Infarction

This case report describes a patient in their 70s with acute onset waxing and waning chest pressure, which radiated to both arms and was accompanied by shortness of breath.

Reversal of Fortune: ECG STEMI Mimic

This column discusses what appears to be a lead reversal in a 12-lead electrocardiogram (ECG) of a routine low-risk chest pain evaluation in a 36-year-old man. A 12-lead ECG was completed and identified ST changes suggestive of ischemia in the inferior leads. Findings in the ECG suggested arm lead reversal that created an ST-segment elevation myocardial infarction (STEMI) mimic. Repeating the ECG and correcting the arm lead mistake identified a correction of these changes and identified an ECG more suggestive of benign early repolarization or J-point elevation. This case discusses the importance of identifying ECG findings that may suggest arm lead reversal and how sometimes misplaced leads could create the appearance of an STEMI. This is a review of the case, key points to interpreting ECGs for possible lead reversal and identifying the REVERSE mnemonic.

Sensitivity and Adjustment Model of Electrocardiographic Signal Distortion Based on the Electrodes' Location and Motion Artifacts Reduction for Wearable Monitoring Applications

Wearable vital signs monitoring and specially the electrocardiogram have taken important role due to the information that provide about high-risk diseases, it has been evidenced by the needed to increase the health service coverage in home care as has been encouraged by World Health Organization. Some wearables devices have been developed to monitor the Electrocardiographic in which the location of the measurement electrodes is modified respect to the Einthoven model. However, mislocation of the electrodes on the torso can lead to the modification of acquired signals, diagnostic mistakes and misinterpretation of the information in the signal. This work presents a volume conductor evaluation and an Electrocardiographic signal waveform comparison when the location of electrodes is changed, to find a electrodes’ location that reduces distortion of interest signals. In addition, effects of motion artifacts and electrodes’ location on the signal acquisition are evaluated. A group of volunteers was recorded to obtain Electrocardiographic signals, the result was compared with a computational model of the heart behavior through the Ensemble Average Electrocardiographic, Dynamic Time Warping and Signal-to-Noise Ratio methods to quantitatively determine the signal distortion. It was found that while the Einthoven method is followed, it is possible to acquire the Electrocardiographic signal from the patient’s torso or back without a significant difference, and the electrodes position can be moved 6 cm at most from the suggested location by the Einthoven triangle in Mason–Likar’s method.

ST-Elevation Myocardial Infarction in a Patient Having Dextrocardia with Situs Inversus

BACKGROUND

Dextrocardia with situs inversus is a rare genetic condition in which the heart and internal organs are positioned on the opposite side of the body. Diagnosing and treating acute myocardial infarction correctly in a patient with dextrocardia is a difficult task.

CASE REPORT

We present the case of an acute anterior wall ST elevation myocardial infarction (STEMI) in a patient with dextrocardia with situs inversus diagnosed after a lead reversal electrocardiogram (ECG). The patient then successfully underwent percutaneous coronary intervention and subsequent multivessel coronary artery bypass grafting. We discuss the original diagnosis and decision-making, clinical features, ECG characteristics, and disposition of the patient, as well as a review of the relevant literature. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: Emergency physicians must identify and recognize the typical ECG of dextrocardia, especially when presenting with pathology, as its identification can lead to proper diagnosis and treatment.

Simulating Arbitrary Electrode Reversals in Standard 12-lead ECG

Electrode reversal errors in standard 12-lead electrocardiograms (ECG) can produce significant ECG changes and, in turn, misleading diagnoses. Their detection is important but mostly limited to the design of criteria using ECG databases with simulated reversals, without Wilson's central terminal (WCT) potential change. This is, to the best of our knowledge, the first study that presents an algebraic transformation for simulation of all possible ECG cable reversals, including those with displaced WCT, where most of the leads appear with distorted morphology. The simulation model of ECG electrode swaps and the resultant WCT potential change is derived in the standard 12-lead ECG setup. The transformation formulas are theoretically compared to known limb lead reversals and experimentally proven for unknown limb-chest electrode swaps using a 12-lead ECG database from 25 healthy volunteers (recordings without electrode swaps and with 5 unicolor pairs swaps, including red (right arm-C1), yellow (left arm-C2), green (left leg (LL) -C3), black (right leg (RL)-C5), all unicolor pairs). Two applications of the transformation are shown to be feasible: 'Forward' (simulation of reordered leads from correct leads) and 'Inverse' (reconstruction of correct leads from an ECG recorded with known electrode reversals). Deficiencies are found only when the ground RL electrode is swapped as this case requires guessing the unknown RL electrode potential. We suggest assuming that potential to be equal to that of the LL electrode. The 'Forward' transformation is important for comprehensive training platforms of humans and machines to reliably recognize simulated electrode swaps using the available resources of correctly recorded ECG databases. The 'Inverse' transformation can save time and costs for repeated ECG recordings by reconstructing the correct lead set if a lead swap is detected after the end of the recording. In cases when the electrode reversal is unknown but a prior correct ECG recording of the same patient is available, the 'Inverse' transformation is tested to detect the exact swapping of the electrodes with an accuracy of (96% to 100%).

Inter-lead correlation analysis for automated detection of cable reversals in 12/16-lead ECG

BACKGROUND AND OBJECTIVE

A crucial factor for proper electrocardiogram (ECG) interpretation is the correct electrode placement in standard 12-lead ECG and extended 16-lead ECG for accurate diagnosis of acute myocardial infarctions. In the context of optimal patient care, we present and evaluate a new method for automated detection of reversals in peripheral and precordial (standard, right and posterior) leads, based on simple rules with inter-lead correlation dependencies.

METHODS

The algorithm for analysis of cable reversals relies on scoring of inter-lead correlations estimated over 4s snapshots with time-coherent data from multiple ECG leads. Peripheral cable reversals are detected by assessment of nine correlation coefficients, comparing V6 to limb leads: (I, II, III, -I, -II, -III, -aVR, -aVL, -aVF). Precordial lead reversals are detected by analysis of the ECG pattern cross-correlation progression within lead sets (V1-V6), (V4R, V3R, V3, V4), and (V4, V5, V6, V8, V9). Disturbed progression identifies the swapped leads.

RESULTS

A test-set, including 2239 ECGs from three independent sources-public 12-lead (PTB, CSE) and proprietary 16-lead (Basel University Hospital) databases-is used for algorithm validation, reporting specificity (Sp) and sensitivity (Se) as true negative and true positive detection of simulated lead swaps. Reversals of limb leads are detected with Se = 95.5-96.9% and 100% when right leg is involved in the reversal. Among all 15 possible pairwise reversals in standard precordial leads, adjacent lead reversals are detected with Se = 93.8% (V5-V6), 95.6% (V2-V3), 95.9% (V3-V4), 97.1% (V1-V2), and 97.8% (V4-V5), increasing to 97.8-99.8% for reversals of anatomically more distant electrodes. The pairwise reversals in the four extra precordial leads are detected with Se = 74.7% (right-sided V4R-V3R), 91.4% (posterior V8-V9), 93.7% (V4R-V9), and 97.7% (V4R-V8, V3R-V9, V3R-V8). Higher true negative rate is achieved with Sp > 99% (standard 12-lead ECG), 81.9% (V4R-V3R), 91.4% (V8-V9), and 100% (V4R-V9, V4R-V8, V3R-V9, V3R-V8), which is reasonable considering the low prevalence of lead swaps in clinical environment.

CONCLUSIONS

Inter-lead correlation analysis is able to provide robust detection of cable reversals in standard 12-lead ECG, effectively extended to 16-lead ECG applications that have not previously been addressed.