Advanced interatrial block may be a useful parameter for determining a clinically relevant subgroup of heart failure patients with preserved ejection fraction - a pilot study

    Authors

    Abstract

    **Background**: An advanced interatrial block (aIAB) is seen on the ECG as the combination of a P wave duration >120 ms and biphasic P wave morphology in the inferior leads. It is considered a marker of an electromechanically dysfunctional left atrium (LA) and hence a risk factor for supraventricular arrhythmias and heart failure (HF). (1) The aim of our pilot study is to explore aIAB as a potential marker for determining a clinically relevant subgroup of HF patients. **Patients and Methods**: An echocardiogram and a surface ECG were performed on a total of 51 HF patients in sinus rhythm (31 (61%) with HF with preserved ejection fraction (HFpEF), 20 (39%) with HF with reduced ejection fraction (HFrEF)) diagnosed per the current guidelines, and 20 sex-matched healthy controls. Echocardiographic parameters of LA structure and function were measured. ECG measurements were performed digitally with an electronic calliper. **Results**: Prevalence of aIAB was 11% (n=8) in the studied group, significantly greater in HFpEF patients, compared to HFrEF patients and healthy controls (88% vs. 0% vs. 12%, p=0.025, **Figure 1**). The HFpEF patients formed an aIAB HFpEF subgroup (n=7) that was compared to two control groups, both without P wave duration >120 ms or biphasic P wave morphology in the inferior leads: age- and sex- matched HFpEF patients (n=7) and sex-matched healthy controls (n=12). Based on this subanalysis, the aIAB patients had a significantly higher occurrence of paroxysmal atrial fibrillation (healthy controls vs. HFpEF controls vs. aIAB: 0% vs. 43% vs. 86%, p 120 ms | Biphasic P wave in inferior leads and P wave > 120 ms | Biphasic P wave in inferior leads and P wave > 120 ms | P values | P values | P values | | --- | --- | --- | --- | --- | --- | --- | | | Yes | No | | aIAB | aIAB | HFpEF controls | | | aIAB | HFpEF controls | Healthy controls | vs | vs | vs | | | (n=7) | (n=7) | (n=12) | HFpEF controls | Healthy controls | Healthy controls | | **Male sex – no. (%)** | 1 (14) | 1 (14) | 4 (33) | 1 | 0.603 | 0.603 | | **Age (IQR) –years** | 74 (71-81) | 75 (67-82) | 54 (51-55) | 1 | 2** | 46.4 (41.4-50.6) | 37.6 (32.7-54.1) | 26.6 (18.7-29.6) | 0.318 | 2** | 26.8 (23.9-32.0) | 21.6 (21.0-25.5) | 18.2 (15.0-20.3) | 0.073 | <0.0001 | 0.007 | | **LAEF (IQR) - %** | 34.6 (31.8-44.6) | 39.7 (31.0-41.3) | 57.8 (46.4-66.7) | 0.902 | 0.013 | 0.005 | | **V max (IQR) - ml** | 85.0 (81.0-109.0) | 71.0 (61.0-92.0) | 51.5 (35.5-59.5) | 0.259 | <0.0001 | 0.005 | | **V min (IQR) - ml** | 53.0 (35.0-75.0) | 42.0 (38.0-51.0) | 20.5 (12.3-28.8) | 0.456 | 0.001 | 0.0001 | | **preA volume (IQR) - ml** | 64.0 (52.0-86.0) | 59.0 (46.0-65.0) | 38.0 (22.2-28.8) | 0.456 | <0.0001 | 0.010 | [†] aIAB – advanced interatrial block; HFpEF – heart failure with preserved ejection fraction; IQR – interquartile range, AF – atrial fibrillation; LVEF – left ventricular ejection fraction; LAVI – left atrial volume index; LAA – left atrial area; LAEF – left atrial ejection fraction; V max – maximal volume of the left atrium; V min – minimal volume of the left atrium; preA volume – volume of the left atrium at start of P wave on ECG. Variables in the table are described with a percentage or with the median and interquartile range. **Conclusion**: This pilot study relates aIAB to the HFpEF part of the HF spectrum. Significant differences in LA structural and functional characteristics suggest that aIAB may be a useful parameter for determining a clinically relevant subgroup of HFpEF patients, however an analysis of a larger patient cohort would be required to further establish these findings.

    Keywords

    advanced interatrial block, heart failure, heart failure with preserved ejection fraction, P wave morphology, surface electrocardiogram

    DOI

    https://doi.org/10.15836/ccar2017.357

    Literature

    1. Bayés de Luna A, Platonov P, Cosio FG, Cygankiewicz I, Pastore C, Baranowski R, et al. Interatrial blocks. A separate entity from left atrial enlargement: a consensus report. J Electrocardiol. 2012 Sep;45(5):445–51. https://doi.org/10.1016/j.jelectrocard.2012.06.029
    Cardiologia Croatica
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    Advanced interatrial block may be a useful parameter for determining a clinically relevant subgroup of heart failure patients with preserved ejection fraction - a pilot study

    Extended Abstract
    Issue9-10
    Published
    Pages357-358
    PDF via DOIhttps://doi.org/10.15836/ccar2017.357
    advanced interatrial block
    heart failure
    heart failure with preserved ejection fraction
    P wave morphology
    surface electrocardiogram

    Authors

    Filip Lončarić*ORCIDUniversity Hospital Centre Zagreb, Zagreb, Croatia
    Dora FabijanovićORCIDUniversity Hospital Centre Zagreb, Zagreb, Croatia
    Vedran VelagićORCIDUniversity Hospital Centre Zagreb, Zagreb, Croatia
    Nina JakušORCIDUniversity Hospital Centre Zagreb, Zagreb, Croatia
    Marijan PašalićORCIDUniversity Hospital Centre Zagreb, Zagreb, Croatia
    Ivo PlanincORCIDUniversity Hospital Centre Zagreb, Zagreb, Croatia
    Davor MiličićORCIDUniversity Hospital Centre Zagreb, Zagreb, Croatia
    Maja ČikešORCIDUniversity Hospital Centre Zagreb, Zagreb, Croatia

    *Correspondence email: loncaric.filip@gmail.com

    Abstract

    **Background**: An advanced interatrial block (aIAB) is seen on the ECG as the combination of a P wave duration >120 ms and biphasic P wave morphology in the inferior leads. It is considered a marker of an electromechanically dysfunctional left atrium (LA) and hence a risk factor for supraventricular arrhythmias and heart failure (HF). (1) The aim of our pilot study is to explore aIAB as a potential marker for determining a clinically relevant subgroup of HF patients. **Patients and Methods**: An echocardiogram and a surface ECG were performed on a total of 51 HF patients in sinus rhythm (31 (61%) with HF with preserved ejection fraction (HFpEF), 20 (39%) with HF with reduced ejection fraction (HFrEF)) diagnosed per the current guidelines, and 20 sex-matched healthy controls. Echocardiographic parameters of LA structure and function were measured. ECG measurements were performed digitally with an electronic calliper. **Results**: Prevalence of aIAB was 11% (n=8) in the studied group, significantly greater in HFpEF patients, compared to HFrEF patients and healthy controls (88% vs. 0% vs. 12%, p=0.025, **Figure 1**). The HFpEF patients formed an aIAB HFpEF subgroup (n=7) that was compared to two control groups, both without P wave duration >120 ms or biphasic P wave morphology in the inferior leads: age- and sex- matched HFpEF patients (n=7) and sex-matched healthy controls (n=12). Based on this subanalysis, the aIAB patients had a significantly higher occurrence of paroxysmal atrial fibrillation (healthy controls vs. HFpEF controls vs. aIAB: 0% vs. 43% vs. 86%, p 120 ms | Biphasic P wave in inferior leads and P wave > 120 ms | Biphasic P wave in inferior leads and P wave > 120 ms | P values | P values | P values | | --- | --- | --- | --- | --- | --- | --- | | | Yes | No | | aIAB | aIAB | HFpEF controls | | | aIAB | HFpEF controls | Healthy controls | vs | vs | vs | | | (n=7) | (n=7) | (n=12) | HFpEF controls | Healthy controls | Healthy controls | | **Male sex – no. (%)** | 1 (14) | 1 (14) | 4 (33) | 1 | 0.603 | 0.603 | | **Age (IQR) –years** | 74 (71-81) | 75 (67-82) | 54 (51-55) | 1 | 2** | 46.4 (41.4-50.6) | 37.6 (32.7-54.1) | 26.6 (18.7-29.6) | 0.318 | 2** | 26.8 (23.9-32.0) | 21.6 (21.0-25.5) | 18.2 (15.0-20.3) | 0.073 | <0.0001 | 0.007 | | **LAEF (IQR) - %** | 34.6 (31.8-44.6) | 39.7 (31.0-41.3) | 57.8 (46.4-66.7) | 0.902 | 0.013 | 0.005 | | **V max (IQR) - ml** | 85.0 (81.0-109.0) | 71.0 (61.0-92.0) | 51.5 (35.5-59.5) | 0.259 | <0.0001 | 0.005 | | **V min (IQR) - ml** | 53.0 (35.0-75.0) | 42.0 (38.0-51.0) | 20.5 (12.3-28.8) | 0.456 | 0.001 | 0.0001 | | **preA volume (IQR) - ml** | 64.0 (52.0-86.0) | 59.0 (46.0-65.0) | 38.0 (22.2-28.8) | 0.456 | <0.0001 | 0.010 | [†] aIAB – advanced interatrial block; HFpEF – heart failure with preserved ejection fraction; IQR – interquartile range, AF – atrial fibrillation; LVEF – left ventricular ejection fraction; LAVI – left atrial volume index; LAA – left atrial area; LAEF – left atrial ejection fraction; V max – maximal volume of the left atrium; V min – minimal volume of the left atrium; preA volume – volume of the left atrium at start of P wave on ECG. Variables in the table are described with a percentage or with the median and interquartile range. **Conclusion**: This pilot study relates aIAB to the HFpEF part of the HF spectrum. Significant differences in LA structural and functional characteristics suggest that aIAB may be a useful parameter for determining a clinically relevant subgroup of HFpEF patients, however an analysis of a larger patient cohort would be required to further establish these findings.

    Literature

    1. 1.
      Bayés de Luna A, Platonov P, Cosio FG, Cygankiewicz I, Pastore C, Baranowski R, et al. Interatrial blocks. A separate entity from left atrial enlargement: a consensus report. J Electrocardiol. 2012 Sep;45(5):445–51.DOI