Electrocardiographic left atrial abnormality and risk of heart failure

INTRODUCTION

The association and the racial differences of the electrocardiographic markers of left atrial abnormality (ECG-LAA) with heart failure (HF) are unclear.

METHODS

We examined the cross-sectional association of ECG-LAA, defined as deep terminal negativity of P wave in V1 (DTNPV1) with HF in 8460 participants (51.5% women, 60.3 ± 13.5 age and 49.8% Whites) from the US Third National Health and Nutrition Examination Survey. We excluded participants without P-wave in their ECG or with ECG findings that interfere with measurements of P-wave. DTNPV1 was automatically measured from ECGs processed at a central lab. Values of DTNPV1 ≥ 100 μV were considered abnormal. Past medical history of HF was identified through health interviews. Multivariable logistic regression analysis was used to examine the associations of DTNPV1 with HF.

RESULTS

Abnormal DTNPV1 was detected in 3.2% (n = 271) of the participants. HF was significantly more common in individuals with abnormal, compared to those with normal, DTNPV1 (14.7% vs. 4.8%, respectively; p-value <0.001). In a model adjusted for socio-demographics and cardiovascular risk factors, ECG-LAA was associated with 98% increased odds of HF (OR (95% CI): 1.98 (1.30-3.01), p < 0.001). This association was stronger in non-White (vs. White) participants (OR (95% CI): 3.14 (1.82-5.43) vs. 1.01 (0.51-1.97), respectively; interaction p-value =0.01), but consistent in subgroups stratified by age and sex.

CONCLUSIONS

ECG-LAA, defined as abnormal DTNPV1, is associated with an increased risk of HF, underscoring the role of atrial disease in developing HF. Racial differences in this association exist, possibly suggesting considering ECG-LAA in personalized assessments of HF risk.

Influence of the earliest right atrial activation site and its proximity to interatrial connections on P-wave morphology

AIMS

P-wave morphology correlates with the risk for atrial fibrillation (AF). Left atrial (LA) enlargement could explain both the higher risk for AF and higher P-wave terminal force (PTF) in lead V₁. However, PTF-V₁ has been shown to correlate poorly with LA size. We hypothesize that PTF-V₁ is also affected by the earliest activated site (EAS) in the right atrium and its proximity to inter-atrial connections (IAC), which both show tremendous variability.

METHODS AND RESULTS

Atrial excitation was triggered from seven different EAS in a cohort of eight anatomically personalized computational models. The posterior IACs were non-conductive in a second set of simulations. Body surface ECGs were computed and separated by left and right atrial contributions. Mid-septal EAS yielded the highest PTF-V₁. More anterior/superior and more inferior EAS yielded lower absolute PTF-V₁ values deviating by a factor of up to 2.0 for adjacent EAS. Earliest right-to-left activation was conducted via Bachmann's Bundle (BB) for anterior/superior EAS and shifted towards posterior IACs for more inferior EAS. Non-conducting posterior IACs increased PTF-V₁ by up to 150% compared to intact posterior IACs for inferior EAS. LA contribution to the P-wave integral was 24% on average.

CONCLUSION

The electrical contributor's site of earliest activation and intactness of posterior IACs affect PTF-V₁ significantly by changing LA breakthrough sites independent from LA size. This should be considered for interpretation of electrocardiographical signs of LA abnormality and LA enlargement.