Pulmonary vein total occlusion following catheter ablation for atrial fibrillation: clinical implications after long-term follow-up.

OBJECTIVES: We present the clinical course and management outcomes of patients with total pulmonary vein occlusion (PVO). BACKGROUND: Pulmonary vein occlusion is a rare complication that can develop after radiofrequency catheter ablation (RFA) of atrial fibrillation (AF). The long term follow-up data of patients diagnosed with PVO are minimal. METHODS: Data from 18 patients with complete occlusion of at least one pulmonary vein (PV) were prospectively collected. All patients underwent RFA for AF using different strategies between September 1999 and May 2004. Pulmonary vein occlusion was diagnosed using computed tomography (CT) and later confirmed by angiography when intervention was warranted. Lung perfusion scans were performed on all patients before and after intervention. The percent stenoses of the veins draining each independent lung were added together to yield an average cumulative stenosis of the vascular cross-sectional area draining the affected lung (cumulative stenosis index [CSI]). RESULTS: The patients' symptoms had a positive correlation with the CSI (r = 0.843, p < 0.05) and a negative one with the lung perfusion (r = -0.667, p < 0.05). A CSI > or =75% correlated well with low lung perfusion (<25%; r = -0.854, p < 0.01). Patients with a CSI > or =75% appeared to improve mostly when early (r = -0.497) and repeat dilation/stenting (r = 0.0765) were performed. CONCLUSIONS: Patients with single PVO are mostly asymptomatic and should undergo routine imaging. On the other hand, patients with concomitant ipsilateral PV stenosis/PVO and a CSI > or =75% require early and, when necessary, repeated pulmonary interventions for restoration of pulmonary flow and prevention of associated lung disease.     

Stent implantation activates RhoA in human arteries: inhibitory effect of rapamycin

In-stent restenosis is a novel pathobiologic process resulting from vascular smooth muscle cell (VSMC) proliferation, migration and excessive matrix production. The present study was designed to assess the activity of RhoA, a major regulator of VSMC proliferation and migration, after stenting and to determine its role in the neointimal formation. Analysis of RhoA activity in an ex vivo organ culture model of human internal mammary arteries demonstrates that stenting induced a time-dependent increase in RhoA activity (4.9 +/- 0.4 vs. 1.2 +/- 0.2 in control at 28 days, n = 4, p < 0.0001) associated with a concomitant decrease in p27 expression. Treatment of stented arteries with the permeant RhoA inhibitor TAT-C3 (10 microg/ml) or Rho-kinase inhibitors (Y-27632, 10 micromol/l; fasudil, 10 micromol/l) inhibited both neointimal formation and decrease in p27 expression. Rapamycin (1 and 10 nmol/l) also inhibited neointimal formation, and induced a loss of RhoA expression. The inhibitory effect of rapamycin on neointimal thickening is prevented by the dominant active form of RhoA. Our study shows that stent implantation induces maintained RhoA activation and demonstrates that the inhibitory action of rapamycin on RhoA expression plays a key role in its antirestenotic effect.     

Coronary sinus focus acting as a trigger for atrial fibrillation in a patient with orthotopic heart transplantation

Coronary Sinus Focus Acting as a Trigger for Atrial Fibrillation. We report the case of a 46-year-old man who presented for evaluation and ablation of paroxysmal atrial fibrillation, which he developed one year prior to presentation and that was refractory to antiarrhythmic drugs. His past medical and surgical history was significant for orthotopic heart transplantation (OHTX) and idiopathic nonfamilial dilated cardiomyopathy. We present the first case of post OHTX where the coronary sinus was acting as a trigger and driver for atrial fibrillation. This illustrates an unusual role of nonpulmonary vein foci in the etiology of atrial fibrillation in patients status post OHTX.