Comparison of p-wave patterns derived from correct and incorrect placement of V1-V2 electrodes

P-wave indices as predictors of atrial fibrillation

Background

P‐wave duration (P_DURATION) and P‐wave area (P_AREA) have been linked to risk of atrial fibrillation (AF), but they do not improve the efficacy of Framingham AF risk score. We suggest the incorporation of both variables in one index, the P‐wave area/P‐wave duration (P_{AREA/DURATION}) index, which may be considered an expression of the average amplitude of the P wave that reflects aspects of P‐wave morphology.

Objective

To assess the prognostic value of P‐wave area/P‐wave duration index (P_{AREA/DURATION} index) in lead II together with other P‐wave indices (PWIs) in incidence of AF in the Copenhagen Holter Study.

Methods

The study included 632 men and women, between 55 and 75 years with no apparent heart disease or AF. Baseline standard 12‐lead Electrocardiography (ECGs) were analyzed manually.

Results

The median follow‐up time was 14.7 (14.5;14.9) years. A total of 68 cases of AF and 233 cases of death were recorded. The restricted cubic spline method showed a U‐shaped association between P_{AREA/DURATION} and rate of AF. The lowest quintile of P_{AREA/DURATION} index in lead II was associated with increased rate of AF, HR 2.80 (1.64–4.79). The addition of the new index to the Framingham model for AF improved the model in this population. The P_AREA in lead II in its lowest quintile was also associated with increased rate of AF, HR 2.16 (1.25–3.75), but did not improve the Framingham model. P_DURATION and P‐wave terminal force (PTF) were not significantly associated with AF.

Conclusion

A flat P wave as expressed by a small P_{AREA/DURATION} index in lead II is associated with increased rate of incident AF beyond known AF risk factors.

Significance of a negative sinus P wave in lead V2 of the clinical electrocardiogram

BACKGROUND

A negative sinus P wave in lead V₂ (NPV₂ ) of the electrocardiogram (ECG) is rare when leads are positioned correctly. This study was undertaken to clarify the significance of an unusually high incidence of this anomaly found in ECGs at my institution.

METHODS

One thousand four hundred thirty-five ECGs were randomly selected to determine the incidence and gender frequency in tracings showing positive (PPV₂ ), and biphasic (BPV₂ ) P waves in V₂ , as well as NPV₂ . To those cases with NPV₂ , 84 cases with that anomaly from earlier archived ECGs were added to give a larger group for analysis. Medical records were reviewed for clinical details and other archived ECGs.

RESULTS

PPV₂ , BPV₂ , and NPV₂ were found in 1,216 (84.5%), 150 (10.5%), and 69 cases (4.8%), respectively. Cases with NPV₂ were more likely to be female (46 of 69 or 67.7%) than were those with either PPV₂ (500 of 1,216 or 41.1%; p < .001), or BPV₂ (71 of 150 or 47.3%; p < .01). NPV₂ was commonly associated with ECG findings of left atrial abnormality (LAA), septal myocardial infarction, or a ventricular repolarization abnormality, but when multiple ECGs were available in these cases, such abnormalities were usually absent when there was either PPV₂ or BPV₂ .

CONCLUSIONS

With correct precordial lead placement, NPV₂ is rare and BPV₂ is also uncommon, and their presence should alert one to the probability of high placement of V₁ and V₂ , which can produce ECGs that mimic LAA, septal infarction, and ventricular repolarization abnormality.

Precordial electrode placement accuracy by nurses in a large midwestern tertiary care hospital

A quality improvement project to increase the knowledge of nurses and the accuracy of electrocardiogram precordial lead placement among intensive care unit and progressive care unit staff was conducted using a single-group, pretest-posttest preexperimental design. Educational interventions based on the theory of planned behavior were developed from focus group data. A tip card, poster, and video were sequentially presented to more than 1,600 nurses. This resulted in statistically significant gains in both knowledge and accuracy (p < 0.02). This project supports the use of focus groups and the theory of planned behavior to guide education related to quality improvement.

Proposed bedside maneuver to facilitate accurate anatomic orientation for correct positioning of ECG precordial leads V1 and V2: a pilot study

BACKGROUND

Misplacement of right precordial electrocardiogram (ECG) electrodes superiorly is a prevalent procedural error that may lead to false findings of T-wave inversion or QS complexes in V2-possibly triggering wasteful utilization of health care resources. Standard technique for proper placement of V1-V2 entails initial palpation for the sternal angle, pointing to the second intercostal space (ICS), followed by lead fixation at the fourth ICS.

STUDY OBJECTIVE

Because adherence to this approach may be limited by lack of a visual landmark for the second ICS, we assessed an alternative technique.

METHODS

The evaluated technique involved placement of the patient's hand up against the base of his/her neck (H→N maneuver) to help demarcate visually a specific point "X" on the chest.

RESULTS

Of 112 patients studied, "X" landed on the first rib in 2.7%, first ICS in 7.1%, second rib in 56.3%, second ICS in 33.0%, and third rib in 0.9%. Thus, in 89.3% (95% confidence interval 83.6-95.0%) of cases (93.3% of men, 84.6% of women; p=0.13), the second ICS could be identified by H→N via the following simple rule: Utilize "X" if it overlies an ICS; or the immediately subjacent ICS if "X" overlies a rib.

CONCLUSION

The H→N maneuver provides a primarily visual approach to identifying the second ICS and, thereby, the fourth ICS for affixing V1-V2. If the present initial experience is confirmed, H→N might merit consideration as an educational tool to promote anatomically correct placement of these precordial leads, a prerequisite to diminishing the incidence of ECG procedure-related "septal ischemia/infarction."

Importance of recognizing pseudo-septal infarction due to electrocardiographic lead misplacement

Awareness of the problem of false electrocardiographic diagnosis of septal infarction due to cranially misplaced precordial leads V1 and V2, a common technical error, is important because this pseudo-pathologic finding can trigger unnecessary medical procedures and have other adverse sequelae. The non-trivial nature of this problem is emphasized by the case of a patient in whom the misdiagnosis caused loss of an employment opportunity. We demonstrate how P wave morphology in lead V2 can aid the clinician in suspecting erroneous right precordial lead placement in cases of apparent septal infarction. Ultimately, improved education of health care personnel regarding accurate precordial lead positioning technique is needed to minimize the occurrence of this electrocardiographic misdiagnosis.

Prevalence and prognostic value of poor R-wave progression in standard resting electrocardiogram in a general adult population. The Health 2000 Survey

AIMS

We examined the prevalence and prognostic impact of poor R-wave progression (PRWP) in a standard electrocardiogram (ECG) in a general population.

METHODS

Data and standard resting ECG recording were collected from a large nationally representative (random sample) health examination survey conducted in Finland in 2000-2001. The final study population consisted of 5613 individuals.

RESULTS

The prevalence of PRWP (defined as RV3 < or = 3 mm and RV2 < or = RV3) was 7.0% in women and 2.7% in men (P< or = 0.001 for difference). During follow-up of 70 +/- 9 months (mean +/- SD), 317 patients died (5.6%). Both all-cause and cardiovascular mortality was higher in the group with PRWP than in those without PRWP in both women and men. In Cox regression analysis after adjustment for age, hypertension, diabetes, previous myocardial infarction, and coronary heart disease, the relative risk for all-cause mortality for PRWP was 1.69 (95% CI 0.89-3.22, P=0.112) for men and 2.00 (95% CI 1.28-3.13, P=0.002) for women. For cardiovascular mortality the relative risk for individuals with PRWP was 1.85 (0.74-4.65, P=0.19) for men and 3.02 (1.54-5.93, P=0.001) for women.

CONCLUSIONS

PRWP is a common ECG finding and predicts risk for total and cardiovascular mortality in women in a general population.

Technical mistakes during the acquisition of the electrocardiogram

In addition to knowledge of normal and pathological patterns, the correct interpretation of electrocardiographic (ECG) recordings requires the use of acquisition procedures according to approved standards. Most manuals on standard electrocardiography devote little attention to inadequate ECG recordings. In this article, we present the most frequent ECG patterns resulting from errors in limb and precordial lead placement, artifacts in 12-lead ECG as well as inadequate filter application; we also review alternative systems to the standard ECG, which may help minimize errors.