Optimal cardiac rhythm during substrate mapping in scar-related ventricular tachycardia: Significance of wavefront direction on identifying critical sites.

BACKGROUND: A rotational activation pattern (RAP) around the localized line of a conduction block often correlates with sites specific to the critical zones of ventricular tachycardia (VT). The wavefront direction during substrate mapping affects manifestation of the RAP and line of block. OBJECTIVE: The purpose of this study was to investigate the most optimal cardiac rhythm for identifying RAP and line of block in substrate mapping. METHODS: We retrospectively evaluated 71 maps (median 3205 points/map) in 46 patients (65 ± 15 years; 33% with ischemic cardiomyopathy) who underwent high-density substrate mapping and ablation of scar-related VT. Appearance of a RAP during sinus, right ventricular (RV)-paced, left ventricular (LV)-paced, and biventricular-paced rhythms was investigated. RESULTS: RAP was identified in 24 of 71 maps (34%) in the region where wavefronts from a single direction reached but not in the region where wavefronts from multiple directions centripetally collided. The probability of identifying the RAP depended on scar location; that is, anteroseptal and inferoseptal, inferior and apical, and basal lateral RAPs were likely to be identified during sinus/atrial, RV-paced, and LV-paced rhythms, respectively. In 13 patients, the RAP was not evident in the baseline map but became apparent during remapping in the other rhythm, in which the wavefront reached the site earlier within the entire activation time. CONCLUSION: The optimal rhythm for substrate mapping depends on the spatial distribution of the area of interest. A paced rhythm with pacing sites near the scar may facilitate the identification of critical VT zones.

Three-dimensional mapping discovered arrhythmic substrate missed in the initial diagnosis of idiopathic ventricular fibrillation.

During an initial diagnosis of IVF, an arrhythmic substrate may be missed for several reasons such as lack of information; thus, a careful follow-up is important. A three-dimensional mapping may identify a possible missed arrhythmic substrate in IVF.

A case of complete atrioventricular block in secondary hemophagocytic syndrome/hemophagocytic lymphohistiocytosis recovered by plasma exchange and cytokine absorbing therapy with AN69ST continuous hemodiafiltration.

We report a case of incipient systemic lupus erythematosus (SLE) that rapidly progressed to complete atrioventricular block (cAVB). A 20-year-old man was admitted with facial erythema, painless oral aphtha, polyarthritis, and myalgia of each extremity. On admission, he developed first-degree atrioventricular block, pericarditis, pleuritis, renal failure, hemophagocytic lymphohistiocytosis, neurophychiatric SLE (left cerebellar infarction), and Staphylococcus aureus bacteremia. He was subsequently diagnosed with SLE based on several positive findings on immunological tests (including positive for antinuclear antibody). Despite immediate glucocorticoid pulse therapy and plasma exchange (PE) along with antibiotic, he developed cAVB that required temporary pacing on day 2. Because it was thought that hypercytokinemia exacerbated pericarditis, which progressed to myocarditis and cAVB, we decided to PE and cytokine-adsorbing therapy with AN69ST-continuous hemodiafiltration (CHDF). Other than renal failure, his organ dysfunctions improved with the multidisciplinary therapy. CAVB improved and temporary pacing was no longer required on day 11. Even a first-degree atrioventricular block can rapidly progress to cAVB; therefore, strict attention to electrocardiogram is necessary in severe SLE cases. When presenting with organ dysfunctions caused by hypercytokinemia such as severe SLE cases or SLE with severe infection cases, use of the combination of PE and AN69ST-CHDF might be beneficial.