BACKGROUND Patients with dilated cardiomyopathy (DCM) who are undergoing catheter ablation of ventricular arrhythmias (VAs) are at risk of rapidly progressive heart failure (HF). Endocardial... Show moreBACKGROUND Patients with dilated cardiomyopathy (DCM) who are undergoing catheter ablation of ventricular arrhythmias (VAs) are at risk of rapidly progressive heart failure (HF). Endocardial voltages decrease with loss of viable myocardium. Global left ventricular (LV) voltage as a surrogate for the amount of remaining viable myocardium may predict prognosis.OBJECTIVES This study evaluated whether the newly proposed parameter volume-weighted (vw) unipolar voltage (UV) can predict HF-related adverse outcomes (HFOs), including death, heart transplantation, or ventricular assist device implantation, in DCM. METHODS In consecutive patients with DCM referred for VA ablation, vwUV was calculated by mathematically integrating UV over the left ventricle, divided by the endocardial LV surface area and wall thickness. Patients were followed for HFOs.RESULTS A total of 103 patients (57 +/- 14 years of age; left ventricular ejection fraction [LVEF], 39% +/- 13%) were included. Median vwUV was 9.75 (IQR: 7.27-12.29). During a median follow-up of 24 months (IQR: 8-47 months), 25 patients (24%) died, and 16 had HFOs 7 months (IQR: 1-18 months) after ablation. Patients with HFOs had significantly lower LVEF (29% +/- 10% vs 41% +/- 12%), vw bipolar voltage (BV) (3.00 [IQR: 2.47-3.53] vs 5.00 [IQR: 4.12-5.73]), and vwUV (5.94 [IQR: 5.28-6.55] vs 10.37 [IQR: 8.82-12.81]; all P < 0.001), than patients without HFOs. In Cox regression analysis and goodness-of-fit tests, vwUV was the strongest and independent predictor for HFOs (HR: 3.68; CI: 2.09-6.45; likelihood ratio chi-square, 33.05; P < 0.001).CONCLUSIONS The novel parameter vwUV, as a surrogate for the amount of viable myocardium, identifies patients with DCM with VA who are at high risk for HF progression and mortality. Show less
OBJECTIVES This study sought to assess the relative effect of catheter, tissue, and catheter-tissue parameters, on the ability to determine the amount of viable myocardium in vivo.BACKGROUND... Show moreOBJECTIVES This study sought to assess the relative effect of catheter, tissue, and catheter-tissue parameters, on the ability to determine the amount of viable myocardium in vivo.BACKGROUND Although multiple variables impact bipolar voltages (BVs), electrode size, interelectrode spacing, and directional dependency are of particular interest with the development of catheters incorporating mini and microelectrodes.METHODS Nine swine with early reperfusion myocardial infarctions were mapped using the QDot catheter and then remapped using a Pentaray catheter. All QDot points were matched with Pentaray points within 5 mm. The swine were sacrificed, and mapping data projected onto the heart. Transmural biopsies corresponding to mapping points were obtained, allowing a comparison of electrograms recorded by mini, micro-, and conventional electrodes with histology.RESULTS The conventional BV of 2,322 QDot points was 1.9 +/- 1.3 mV. The largest of the 3 microelectrode BVs (BV mu Max) average 4.8 +/- 3.1 mV. The difference between the largest (BV mu Max) and smallest (BV mu Min) at a given location was 53.7 +/- 18.1%. The relationships between both BV mu Max and BV mu Min and between the conventional BV and BV mu Max were positively related but with a significant spread in data, which was more pronounced for the latter. Pentaray points positively related to the BV mu Max with poor fit. On histology, increasing viable myocardium increased voltage, but both the slope coefficient and fit were best for BV mu Max.CONCLUSIONS Using histology, we could demonstrate that BV mu Max is superior to identify viable myocardium compared with BVC and BV using the Pentaray catheter. The ability to simultaneously record 3 BV(mu)s with different orientations, for the same beat, with controllable contact and selecting BV mu Max for local BV may partially compensate for wave front direction. (C) 2021 by the American College of Cardiology Foundation. Show less
