Liberation of vessel-adherent myeloperoxidase reflects plaque burden in patients with stable coronary artery disease.

OBJECTIVE: Myeloperoxidase (MPO) has emerged as an important pathophysiological determinant of inflammatory vascular artery disease. It is appreciated that vessel immobilized, rather than circulating, MPO is critical for the progression of atherosclerotic lesions. The objective of this study was to investigate whether vessel-immobilized MPO is associated with the extent of coronary plaque burden. METHODS: MPO plasma levels were determined by ELISA before and after heparin-release of vessel-bound MPO, to study the relation between vascular MPO deposition and densitometrically assessed coronary plaque burden in 77 patients with stable coronary artery disease. RESULTS: Patients with a low increase in MPO plasma levels upon heparinization had a significantly smaller total plaque area and volume (12.1[IR:6.2-19.4]mm(2) vs. 19.8[IR:11.3-31.5]mm(2), p < 0.01; 27.8[IR:12.3-44.8]mm(3) vs. 55.2[IR:24.2-87.5]mm(3), p < 0.05). Multivariable linear regression revealed that ΔMPO was independently associated with plaque area, and that ΔMPO increased with the number of affected vessels. Selective sampling confirmed the predominant role of coronary MPO deposition. CONCLUSION: Our data demonstrate that heparin-induced mobilization of vessel-bound MPO is closely linked to coronary plaque burden and thus further corroborate the evidence for the intimate involvement of this enzyme in vascular pathophysiology, as well as the importance of inflammation in atherosclerosis.

Pattern of isthmus conduction recovery using open cooled and solid large-tip catheters for radiofrequency ablation of typical atrial flutter.

INTRODUCTION: Open cooled-tip and solid 8-mm-tip catheters have demonstrated safety and effectiveness for radiofrequency current (RFC) ablation of typical atrial flutter (AFL). However, data from prospective and randomized studies in this setting are lacking. METHODS AND RESULTS: One hundred thirty consecutive patients (104 men; 61 +/- 11 years) with AFL were randomized to undergo RFC catheter ablation either using a solid 8-mm-tip catheter (group A, 65 degrees C, 70 W, 60 s) or an open irrigated-tip catheter (group B, 65 degrees C, 50 W, 60 s, 17 mL/min flow). Endpoint was bidirectional conduction isthmus block. In cases of repeated (two times) transient isthmus block, the catheter was changed (crossed over) to the catheter used in the other randomization arm, but patients remained in the original group following intention-to-treat analysis. The selected endpoint could be achieved in all patients after 12 +/- 6 RFC pulses in group A and 10 +/- 7 RFC pulses in group B (P = 0.11). Procedure times were longer (159 +/- 38 min vs 138 +/- 37 min, P = 0.002) and x-ray exposures higher in group A (fluoroscopy time 25 +/- 17 min vs 21 +/- 10 min, P = 0.08; x-ray dosage 3,133 +/- 2,576 cGy.cm2 vs 2,326 +/- 1,405 cGy.cm2, P = 0.03). Transient isthmus block was observed in 23 group A patients and 12 group B patients (P = 0.03). Onset time of transient isthmus block ranged from 0.5 to 27 minutes. Repeated transient isthmus block occurred in 8 of the 23 patients in group A after 19 +/- 3 RFC applications. After crossover to the cooled-tip catheter, the endpoint was reached another 5 +/- 1 RFC pulses. In group B, all patients could be treated without change of ablation catheter. After a follow-up of 14 +/- 2 months, 2 patients (3%) in group A and 1 patient (1.5%) in group B presented with AFL recurrence. CONCLUSION: Open cooled-tip catheters are more effective than solid large-tip catheters for AFL ablation. The greater effectiveness is evident in cases showing repeated conduction recovery within the cavotricuspid isthmus. Primary use of open irrigated-tip catheters should be considered for AFL ablation.

Catheter ablation of common-type atrial flutter guided by three-dimensional right atrial geometry reconstruction and catheter tracking using cutaneous patches: a randomized prospective study.

INTRODUCTION: EnSite NavX (NavX) is a novel mapping and navigation system that allows visualization of conventional catheters for diagnostic and ablative purposes and uses them to create a three-dimensional (3D) geometry of the heart. NavX is particularly suitable for ablation procedures utilizing an anatomic approach, as in the setting of common-type atrial flutter (AFL). The aim of this study was to compare NavX-guided and conventional ablation procedures for AFL. METHODS AND RESULTS: Forty consecutive patients (32 male, 59 +/- 12 years) with documented AFL were randomized to undergo fluoroscopy-guided (group I, 20 patients) or NavX-guided (group II, 20 patients) ablation, including 3D isthmus reconstruction. The same catheter setup was used in both groups. The endpoint of bidirectional isthmus block was obtained in all patients. Compared to conventional approaches, NavX-guided procedures significantly reduced fluoroscopy time (5.1 +/- 1.4 min vs 20 +/- 11 min, P < 0.01) and total x-ray exposure (5.1 +/- 3.1 Gycm2 vs 24.9 +/- 1.6 Gycm2, P < 0.01). Isthmus geometry reconstruction could be performed in all patients of group II. In 4 patients (20%) of group II, anatomic isthmus variations were detected by NavX. No significant differences in radiofrequency current applications and procedural times were found between the two groups. CONCLUSION: NavX technology allows geometry reconstruction of the cavotricuspid isthmus. NavX-guided ablation of AFL reduces total x-ray exposure compared to the fluoroscopy-guided approach but does not prolong procedure time.