Left superior vena cava isolation in patients undergoing pulmonary vein antrum isolation: impact on atrial fibrillation recurrence.

BACKGROUND: A persistent left superior vena cava (SVC) can be an arrhythmogenic source in patients with atrial fibrillation (AF) through connections from the coronary sinus (CS) and the left atrium (LA). The left SVC can be electrically isolated. However, little clinical data about the impact of left SVC disconnection on AF outcome are available. We report on six patients with left SVC and recurrent AF. OBJECTIVES: The purpose of this study was to assess the impact of left SVC isolation on AF recurrence. METHODS: Six patients (4 men and 2 women; age 50 +/- 6.4 years) with symptomatic drug-refractory AF and persistent left SVC presented to our laboratory for treatment. Four of the patients had left SVC isolation only because there was no conduction recovery in the pulmonary veins (PVs) after several previous procedures. RESULTS: Conduction between the left SVC and the CS and LA was documented, as was spontaneous ectopies in three patients that degenerated into AF in one patient. Isolation of the left SVC was successful in all patients. Isolation was relatively easy to perform (10.25 +/- 1.6 minutes), with no complications. After follow-up of 13 +/- 7.4 months, all patients were in sinus rhythm and free from AF without antiarrhythmic drugs. CONCLUSION: This study stresses the importance of looking for unusual sources of AF in patients presenting for repeat procedures or in those in whom the PVs have been ruled out as a source triggering AF. We present clinical evidence that in patients with AF and left SVC, isolation of the PVs only may not be sufficient to suppress AF. Thus, diagnosis and isolation of the left SVC appears critical to preventing AF recurrence in patients with AF when ablation is considered.     

Safety and efficacy of radiofrequency energy catheter ablation of atrial fibrillation in patients with pacemakers and implantable cardiac defibrillators

BACKGROUND: Catheter ablation has significantly transformed the clinical management of atrial fibrillation (AF). The safety and efficacy of this procedure are not well understood in patients with pacemakers and defibrillators. OBJECTIVES: The purpose of this study was to study the impact of radiofrequency catheter ablation of AF in patients with pacemakers and implantable cardiac defibrillators. METHODS: We studied 86 patients with pacemakers and defibrillators (group I) and a similar number of age- and gender-matched controls (group II) who underwent AF ablation between 1999 and 2004. Clinical and procedural variables were compared between the two groups. In group I, various generator and lead parameters were compared before and after the procedure. Resurgence of clinical AF after 2 months was considered recurrence. RESULTS: Both groups were similar with regard to age, gender, body mass index, and type of AF. Group I had a higher incidence of diabetes (17% vs 6%, P = .03), coronary artery disease (25% vs 13%, P = .05), less prolonged AF (31 +/- 21 vs 45 +/- 30 months, P <.001), lower left ventricular ejection fraction (49 +/- 13% vs 52 +/- 9%, P = .03), and left ventricular end-diastolic dimensions (4.97 +/- 0.81 vs 4.72 +/- 0.67, P = .03). No changes in the sensing and pacing thresholds, impedance of atrial and ventricular leads, or defibrillator coil impedance after AF ablation were observed in group I. Atrial lead dislodgment was seen in two patients. Transient abnormal but "expected" pulse generator behavior was seen in 25% of patients without permanent malfunction. Stroke (1% vs 1%, P = 1.000), pulmonary vein stenosis (2% vs 1%, P = .77), and AF recurrence rates at 12 months were similar between groups I and II, respectively (19% vs 21%, P = .73). CONCLUSION: AF ablation is safe and efficacious in patients with pacemakers and defibrillators.     

Assessment of aldehyde dehydrogenase in viable cells

Cytosolic aldehyde dehydrogenase (ALDH), an enzyme responsible for oxidizing intracellular aldehydes, has an important role in ethanol, vitamin A, and cyclophosphamide metabolism. High expression of this enzyme in primitive stem cells from multiple tissues, including bone marrow and intestine, appears to be an important mechanism by which these cells are resistant to cyclophosphamide. However, although hematopoietic stem cells (HSC) express high levels of cytosolic ALDH, isolating viable HSC by their ALDH expression has not been possible because ALDH is an intracellular protein. We found that a fluorescent aldehyde, dansyl aminoacetaldehyde (DAAA), could be used in flow cytometry experiments to isolate viable mouse and human cells based on their ALDH content. The level of dansyl fluorescence exhibited by cells after incubation with DAAA paralleled cytosolic ALDH levels determined by Western blotting and the sensitivity of the cells to cyclophosphamide. Moreover, DAAA appeared to be a more sensitive means of assessing cytosolic ALDH levels than Western blotting. Bone marrow progenitors treated with DAAA proliferated normally. Furthermore, marrow cells expressing high levels of dansyl fluorescence after incubation with DAAA were enriched for hematopoietic progenitors. The ability to isolate viable cells that express high levels of cytosolic ALDH could be an important component of methodology for identifying and purifying HSC and for studying cyclophosphamide-resistant tumor cell populations.     

Synergistic effect of aqueous extract of Telfaria occidentalis on the biological activities of artesunate in Plasmodium berghei infected mice

Background

Resistance to most antimalarial drugs has encouraged the use of herbal preparations along with prescribed orthodox drugs.

Objective

To investigate effect of co-administration of aqueous extract of T. occidentalis leaves; commonly used as antimalarial and haematinic agent in Nigeria and artesunate using P. berghei animal model.

Methods

In vivo curative antiplasmodial effect of T. occidentalis (200mg/kg) alone and combination with artesunate (2mg/kg) were evaluated using albino mice infected with 10⁶ parasitized erythrocytes of P. berghei intraperitoneally. The haematological parameters: haemoglobin level, red blood cells and white blood cells and packed cell volume were monitored using standard methods.

Results

Aqueous extract of T. occidentalis, artesunate and the combination gave 72.17±4.07%, 70.43± 4.27% and 85.43±3.65% reduction in parasitaemia after 48hours respectively. A significant enhancement of the PCV was obtained with the coadministration of artesunate and aqueous extract (p< 0.01). Similar trends were also observed with heamatological parameters at 72hours of administration.

Conclusion

This study revealed a synergistic effect of the co-administration on parasite clearance rate of P. berghei infection in mice, with a significant enhancement of haematological parameters within 48 hours of administration. This indicates a rapid rate of recovery from plasmodial infections with the co-administration.     

Worldwide Experience with the Robotic Navigation System in Catheter Ablation of Atrial Fibrillation: Methodology, Efficacy and Safety

Worldwide Survey on Robotic AF Ablation . Introduction: The Hansen Robotic system has been utilized in ablation procedures for atrial fibrillation (AF). However, because of the lack of tactile feedback and the rigidity of the robotic sheath, this approach could result in higher risk of complications. This worldwide survey reports a multicenter experience on the methodology, efficacy, and safety of the Hansen system in AF ablations. Methods and Results: A questionnaire addressing questions on patient's demographics, procedural parameters, ablation success rate and safety information was sent to all centers where more than 50 robotic AF ablation cases have been performed. From June 2007 to December 2009, 1,728 procedures were performed at 12 centers utilizing the Hansen robotic navigation technology. The overall complication rate was 4.7% and the success rate was 67.1% after 18 ± 4 months of follow‐up. In 5 low volume centers there appeared to be a learning curve of about 50 cases (complication rate 11.2% for the first 50 cases vs 3.7% for the 51–100 cases; P = 0.044) and a trend showing a decrease of complication rate with increasing case volume. However, in the remaining 7 centers no learning curve was present and the complication rate was stable over time (3.7% for the first 50 cases vs 3.6% for the 51st case thereafter; P = 0.942). Conclusion: The Hansen robotic system can be used for AF ablation safely. In low volume centers, there appeared to be a learning curve of the first 50 cases after which the complication rate decreased. With a higher case volume, the success rate increased. (J Cardiovasc Electrophysiol, Vol. 23, pp. 820‐826, August 2012)