Abstract 16636: Correlation Between Interatrial Block Detected by High-Resolution Electrocardiography and Echocardiographic Markers of Left Atrial Cardiomyopathy

Introduction: Left atrial cardiomyopathy (LACM) involves electromechanical changes in the left atrium (LA) and is linked to atrial fibrillation (AF) and embolic stroke. Several diagnostic ECG and transthoracic echocardiogram (TTE) parameters have been suggested, but information about their interrelationship is limited.

Hypothesis: To evaluate if partial or advanced interatrial block (IAB) using high-resolution 12-lead ECG (HR-ECG) is related to TTE indicators of LACM.

Methods: A retrospective analysis of consecutive patients aged over 18 was performed. The evaluation included HR-ECG (signal-averaging technique, ≥ 200 cycles, QRS-triggered, 0.25-262 Hz bandwidth, 1000 samples/sec) and TTE. Exclusion criteria: AF, pacemaker/ICD carriers, heart surgery history, poor ultrasound window, or significant ECG noise. Inferior leads (DII, DIII, aVF) classified patients into three groups: no IAB, partial IAB (P wave ≥ 120 ms), and advanced IAB (typical/atypical patterns with negative aVF terminal component). TTE parameters of LACM considered were LA volume indexed to body surface area (LAVI), PA-TDI (surface ECG onset P wave to A' peak of LA lateral wall on Tissue-Doppler Imaging), and PALS (peak atrial longitudinal strain) during reservoir phase.

Results: Of 851 patients, 533 met the inclusion criteria. Both IAB groups had a higher prevalence of TTE indicators of LACM (Table 1), and a statistically significant correlation was found between P wave duration (PWD) and TTE markers of LACM (Figure 1).

Conclusions: Patients with partial or advanced IAB (assessed by HR-ECG) show a higher prevalence of TTE markers of LACM and a significant correlation between PWD, LAVI, PA-TDI, and PALS.