Programming Antitachycardia Pacing for Primary Prevention in Patients With Implantable Cardioverter Defibrillators: Results From the PROVE Trial

Programming ATP for ICD Patients. Objectives: The PROVE trial was designed to determine if antitachycardia pacing (ATP) is clinically beneficial for primary prevention in patients who have implantable cardioverter defibrillators (ICDs) or cardiac resynchronization therapy defibrillators (CRT‐Ds). Background: Use of ICDs and CRT‐Ds reduces mortality in patients with ventricular dysfunction and mild to moderate heart failure. However, in studies of the primary prevention population, shock‐only ICDs are predominantly used, without ATP programming for less painful termination of ventricular tachycardia (VT). Methods: We conducted a prospective, nonrandomized, multicenter study using market‐released ICDs and CRT‐Ds. Patients received devices programmed to deliver ATP for VT cycle lengths of 270–330 ms. Follow‐up evaluation was performed at 3, 6, and 12 months. The incidence of VT and the rate of successful termination by ATP were analyzed. Results: Of 830 patients in the study population (men, 73%; mean age, 67.3 ± 12 years), 32% received single‐chamber ICDs, 44% dual‐chamber ICDs, and 24% CRT‐Ds. ATP was attempted for 112 VT episodes in 71 patients, and 103 (92%) of the VT episodes were successfully terminated. Three VT episodes were accelerated by ATP and required termination by ICD shock; 6 episodes terminated spontaneously or by ICD shock. Conclusions: VT is common in patients without a history of this arrhythmia who have received ICDs or CRT‐Ds for primary prevention indications. Programming ICDs for ATP therapy at the time of implantation could potentially terminate most VT episodes and reduce the number of painful shocks for these patients. (J Cardiovasc Electrophysiol, Vol. 21, pp. 1349‐1354, December 2010)     

POST-KALA-AZAR DERMAL LEISHMANIASIS IN THE SUDAN: PERIPHERAL NEURAL INVOLVEMENT

Four patients developed post-kala-azar dermal leishmaniasis and neuritis (PKDL) 1 to 6 months following apparently successful treatment of kala-azar. The duration of the lesion varied between 1 month and nearly 5 years. The lesions were macules, papules, or nodules affecting the face, extremities, and trunk. The diagnosis was made by demonstration of the parasite in slit smear and biopsies and by a positive direct agglutination test (DAT). Histologically, the patients were found to have neuritis affecting the cutaneous nerves in the lesion only. The nerves showed a lymphohistiocytic infiltration and occasionally parasites. There was no impairment of sensation. Response to sodium stibogluconate was good. PKDL may simulate leprosy both clinically and pathologically.     

Predictors of Atrial Fibrillation Recurrence After Radiofrequency Catheter Ablation: A Systematic Review

AF Recurrence After RFA: Systematic Review. Introduction: The relationship between success of radiofrequency ablation for atrial fibrillation (AF) and patient characteristics has not been systematically evaluated. Methods and Results: We searched MEDLINE and Cochrane Central Trials Registry databases from 2000 through 2008 for studies reporting preprocedure predictors and AF recurrence after radiofrequency ablation. We extracted multivariable analyses and univariable data on predictors and AF recurrence. Eligible studies were highly heterogeneous, particularly regarding ablation technique and definition of AF recurrence. Among 25 studies with multivariable analyses, two‐thirds to 90% of studies found that AF type, ejection fraction, left atrial diameter, structural heart disease, hypertension, and AF symptom duration did not predict AF recurrence (among patients with ejection fraction above 40% and left atrial diameter below about 55 mm). Studies found that gender and age were not predictors (in patients between 40 and 70 years old). Meta‐analyses of univariable AF recurrence rates by AF type in 31 studies found that studies were statistically heterogeneous, but that nonparoxysmal AF predicted AF recurrence compared to paroxysmal AF (relative risk 1.59; 95% confidence interval 1.38–1.82; P < 0.001); meta‐analyses of persistent or permanent versus paroxysmal AF yielded similar findings. Conclusion: Nonparoxysmal AF may be a clinically useful proxy for a combination of confounded variables, none of which alone is an independent predictor of AF recurrence. Evaluation of predictors was limited by exclusion of patients with severe heart disease or at the age extremes; thus, the evidence may not be as applicable to these populations. (J Cardiovasc Electrophysiol, Vol. 21, pp. 1208‐1216, November 2010)     

The Influence of Specific and Nonspecific Potassium Current Blockade on the Defibrillation Energy Requirement of Biphasic Shock

Block of delayed rectifier potassium current (I_K) is known to decrease defibrillation energy requirements (DERs). We tested the hypothesis that there would be no difference in DER reduction with a nonspecific I_K (I_Kr+ I_KS) blocker, ambasilide, and a specific I_Kr blocker, dofetilide. Methods: An anesthetized canine model (n = 30) of internal transvenous defibrillation with biphasic shocks was used. Ambasilide (n = 9; dose: 4.8 mg/kg, then 9.6 mg/kg/hour), dofetilide (n = 10; dose: 10 (μg/kg, then 3.6 (μg/kg/hour), or matched placebo (n = 11) were administered. DERs (J) were determined in triplicate using an increment-decrement protocol at baseline and during each treatment. ECG intervals were measured at baseline and during each treatment. ANOVA with post-hoc Bonferroni test was used for statistical analysis. Results: Ambasilide resulted in a +23.5 ± 4.06% prolongation of the QTc interval, while dofetilide resulted in a +20.5%± 3.76% prolongation of the QTc interval. Thus, the two drugs resulted in comparable prolongation of the QTc interval (P < 0.05 compared to placebo). Both drugs significantly reduced the DER (-17.7%± 5.33% reduction by ambasilide, and -21.9%± 5.21% reduction by dofetilide, P < 0.05 compared to placebo). There was no difference in the magnitude of DER reduction between the two treatments. Conclusions: Administration of equipotent doses (as indicated by QTc changes) of ambasilide or dofetilide had comparable effects on DERs. Selectivity of I_K blockade has no significant effect on the magnitude of reduction in DERs.     

Color Doppler sonography examination of partially obstructed kidneys associated with ureteropelvic junction stone before and after percutaneous nephrolithotripsy: Preliminary report

AIM: To evaluate resistive index (RI) changes before and after unilateral percutaneous nephrolithotripsy in chronic partially obstructed kidneys due to ureteropelvic junction (UPJ) stones. METHODS: Intrarenal RI of obstructed and contralateral normal kidneys of 18 patients were recorded immediately before the operations and at postoperative days 1, 7 and 30. Postoperative RI measurements were compared with baseline values for all patients without grouping and separately for different groups according to the preoperative RI value of the obstructed kidney. RESULTS: Mean age and symptom duration were 27.5 years and 43.8 weeks, respectively. Preoperatively and at all postoperative controls, kidney diameters and renal parenchyma thicknesses were normal in all patients. Mean RI of obstructed kidneys decreased from 0.68 to 0.63 for all patients (P=0.032), from 0.64 to 0.63 for those with preoperative RI<0.70 (P=0.850) and from 0.73 to 0.62 for those with preoperative RI>or=0.70 (P=0.001). In patients with preoperative RI>or=0.70 in obstructed kidney, significant RI decreases were recorded at postoperative day 7 and RI differences between obstructed and contralateral kidneys disappeared after then. No difference was present pre- and postoperatively between the mean RI of obstructed and contralateral kidneys of the patients with RI<0.70. Mean RI of contralateral kidneys were normal preoperatively and showed no significant change postoperatively. CONCLUSIONS: Preoperative RI levels may indirectly reflect the presence of functionally significant obstruction in chronic obstructed kidneys related to UPJ stones. Patients with RI>or=0.70 may have a good indication for a surgical approach. Normalization of high RI occurs rapidly after percutaneous nephrolithotripsy.