Negative P wave in V1 is the key to identifying high placement of V1-V2 electrodes in nonpathological subjects

PATCH (Preferred Attachment Strategy for Optimal Electrocardiograms)-1 Study

12-Lead electrocardiography (ECG) is among the most frequently performed tests in medical practice. Despite its pivotal role in diagnostic and treatment decisions, baseline artifacts and errors in lead placement are common. The PATCH (Preferred Attachment Strategy for Optimal Electrocardiograms)-1 study enrolled patients with stable cardiovascular disease and a clinical indication for an ECG. Each participant underwent both a standard (S) 12-lead ECG and a patch (P) ECG (EKG-Patch™) during one routine ambulatory clinic visit. The P-ECG has an all-in-one design with built-in lead wires attached to pre-positioned electrodes. An experienced clinical research coordinator performed all ECGs. Each was interpreted by an experienced cardiologist blinded to the method of ECG. A total of 200 participants (67.4 ± 14.9 years; range: 21-95 years) (women 44%) had P- and S-ECGs. Common clinical indications included coronary artery disease (40.5%), essential hypertension (14.0%), heart failure (10.5%), atrial fibrillation (10.0%) and valvular heart disease (6.5%). Many participants had more than one indication. The P-ECG provided a tracing in 1.4 ± 0.5 min compared to 2.4 ± 0.5 min with the S-ECG (p < 0.001). Most participants either preferred the P-ECG (47%) or did not have a preference (52%). Baseline artifacts that impacted interpretability were detected in 13 (6.5%) P-ECGs and 30 (15.0%) S-ECGs (p = 0.006). Heart rhythm, rate, conduction, axis, intervals (PR, QRS, QT, and QTc) and ST-T wave findings did not differ between P-and S-ECGs. In conclusion, the P-ECG was preferred among participants, had fewer baseline artifacts than the S-ECG, and provided a rapid and reproducible ECG in patients with stable cardiovascular disease in an ambulatory clinic setting.

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.

Main artifacts in electrocardiography

Electrocardiographic artifacts are defined as electrocardiographic alterations, not related to cardiac electrical activity. As a result of artifacts, the components of the electrocardiogram (ECG) such as the baseline and waves can be distorted. Motion artifacts are due to shaking with rhythmic movement. Examples of motion artifacts include tremors with no evident cause, Parkinson's disease, cerebellar or intention tremor, anxiety, hyperthyroidism, multiple sclerosis, and drugs such as amphetamines, xanthines, lithium, benzodiazepines, or shivering (due to hypothermia, fever (rigor due to shaking), cardiopulmonary resuscitation by chest compression (oscillations of great amplitude) and patients who move their limbs during the test, causing sudden irregularities in the ECG baseline that may resemble premature contractions or interfere with ECG wave shapes, or other supraventricular and ventricular arrhythmias. When the skeletal muscles experience shaking, the ECG is "bombarded" by apparently random electrical activity.

A Perplexing ECG

An unusual appearing electrocardiogram (ECG) is sent to the medical director's department for interpretation prior to receiving the actual life insurance application. As a result, no background details are available to provide a clinical context. Preliminary perusal of the ECG suggests several diagnostic possibilities.

Unusual QRS Pattern in the Early Precordial Leads

An asymptomatic, middle-aged man is found to have a QR pattern in lead V1 and a qR pattern in lead V2 of his ECG obtained during routine life insurance applicant screening. The risk assessment implication of this ECG finding is reviewed.