Abstract 12551: Manifestation of J Waves in the General Population is Associated With Excessive Trabeculation Localized in the Left Ventricular Apex

Introduction: The presence of J wave in inferior and lateral ECG leads is a common finding in the general population, but the electrophysiological mechanism underlying the manifestation of the J wave remains unclear. Left ventricular (LV) trabeculation is frequently observed in healthy individuals, but its extent is highly variable among individuals. Hypothesis: Excessive LV trabeculation (ELVT) may be a cause of J wave in the general population. Methods: Of outpatients in our hospital for last 5 years who underwent 12-lead ECG and transthoracic echocardiography (TTE) simultaneously, we identified 148 patients who satisfied the following criteria: (1) no abnormalities on 12-lead ECG, (2) fair visualization of TTE especially in a short-axial view at the papillary muscle and an apical level, respectively, and in a long-axial apical view, and (3) no previous history of nor no echocardiographic evidence of heart diseases. We searched for ELVT, semi-quantitatively defined as the presence of noncompaction greater compaction. The study population was divided into 56 patients with J waves (56±17 year-old, 44 men. J-wave group), characterized by ≥0.1 mV notches or slurs of the terminal portion of the QRS complex, and 92 patients without (59±15 year-old, 39 men, control). Results: There was no significant difference in ECG parameters including RR, PQ, QRS width, QT and QTc between the two groups. In J-wave group, J wave with 0.2±0.1 mV, ranging between 0.1 and 0.5, was observed in the inferior leads in 51 patients, left precordial in 30 and high lateral in 10, and its morphology was slur in 36, notch in 11 and both in 9. ELVT was observed more frequently in J-wave group than control (28 patients (50%) versus 15 (16%), p<0.01), but was distributed mainly in inferolateral wall of LV apex in both groups (inferior in 15 patients, lateral in 24, 1 in anterior and 1 in septal versus inferior in 1 and lateral in 15, p=0.04). No ELVT was detected at the papillary muscle level in both groups. Conclusions: These observations support our hypothesis that ELVT localized in the LV apex, probably carrying the Purkinje system deeper into the midmyocardium, might alter a propagation process in the terminal portion of QRS complexes, thus resulting in the manifestation of J waves in the general population.