OBJECTIVETo investigate the relationship between abnormal ECG and pathologic changes in the cardiac conduction system (CCS).

METHODPathological changes of the CCS in 12 cases with abnormal ECG out of 16 pre-death ECG were observed.

RESULTS(1) Among 7 cases of sudden cardiac death, ECG monitoring recorded bradyarrhythmia in 6 cases, tachyarrhythmia 6 cases, bradycardia-tachycardia syndrome 2 cases, conduction block 6 cases, atrial premature beats 6 cases, ventricular premature beats 6 cases, and ST-T changes 4 cases. (2) The histopathological findings in the CCS were noted in all cases. Of these 12 cases, three had signs of fatty infiltration, and/or fibrous 4 cases, three of amyloidosis, one of chronic inflammatory changes, two of acute inflammatory changes, two of developmental anomalies, two of hemorrhages and one of LAD stenosis. (3) Acute inflammation changes in the CCS corresponded to tachyarrhythmia and multiple ventricular premature beats, whereas chronic inflammation and degenerative changes in the CCS were often related to bradyarrhythmia, bradycardia-tachycardia syndrome and conduction block. (4) The CCS changes alone could lead to ST-T changes in ECG.

CONCLUSIONThe pathological changes in the CCS are related to ECG changes, and attributed to the pathological bases of arrhythmia.