Avoiding unnecessary ventricular pacing is associated with reduced incidence of heart failure hospitalizations and persistent atrial fibrillation in pacemaker patients.

AIMS: In bradycardia patients treated with dual-chamber pacing, we aimed to evaluate whether pacing with atrioventricular (AV) delay management [AV hysteresis (AVH)], compared with standard pacing with fixed AV delays, reduces unnecessary ventricular pacing percentage (VPP) and is associated with better clinical outcomes. Main study endpoints were the incidence of heart failure hospitalizations (HFH), persistent atrial fibrillation (AF), and cardiac death. METHODS AND RESULTS: Data from two identical prospective observational studies, BRADYCARE I in the USA and BRADYCARE II in Europe, Africa, and Asia, were pooled. Overall, 2592 patients (75 ± 10 years, 45.1% female, 50% with AVH) had complete clinical and device data at 1-year follow-up and were analysed. Primary pacing indication was sinus node disease (SND) in 1177 (45.4%), AV block (AVB) in 974 (37.6%), and other indications in 441 (17.0%) patients. Pacing with AVH, compared with standard pacing, was associated with a lower 1-year incidence of HFH [1.3% vs. 3.1%, relative risk reduction (RRR) 57.5%, P = 0.002] and of persistent AF (5.3% vs. 7.7%, RRR = 31.1%, P = 0.028). Cardiac mortality was not different between groups (1.0% vs. 1.4%, RRR = 27.8%, P = 0.366). Pacing with AVH, compared with standard pacing, was associated with a lower (P < 0.001) median VPP in all patients (7% vs. 75%), in SND (3% vs. 44%), in AVB (25% vs. 98%), and in patients with other pacing indications (3% vs. 47%). CONCLUSION: Cardiac pacing with AV delay management via AVH is associated with reduced 1-year incidence of HFH and persistent AF, most likely due to a reduction in VPP compared to standard pacing.

Antidromic Atrioventricular Reentry Tachycardia with Wolff Parkinson White Syndrome: A Rare Beast.

Orthodromic atrioventricular reentrant tachycardia (AVRT) is the second-most-common form of supraventricular tachycardia (SVT) and is inducible in approximately 55% of individuals with Wolff Parkinson White (WPW) syndrome. Antidromic AVRT, where the accessory atrioventricular connection is used as the antegrade limb and the atrioventricular node serves as the retrograde limb of the circuit, has been clinically documented in less than 5% of patients with WPW syndrome and may be induced in less than 10% of these WPW cases in the electrophysiology laboratory. Left lateral pathways are considered more frequent and septal locations are less common when associated with antidromic AVRT. We report a case of 21-year-old male with a history of WPW syndrome who had undergone a prior electrophysiology study in 2010 at an outlying facility, documenting an anteroseptal accessory pathway near the His bundle along with an unsuccessful attempt at radiofrequency ablation at that time. No supraventricular tachycardia was induced at that previous study. The surface electrocardiogram (ECG), at this time, was consistent with the anteroseptal WPW pattern. The patient now presented with a complaint of intermittent palpitations with no definitive trigger. He also described a recent syncopal episode while walking inside his home. His physical exam and all lab work were within normal limits for his age. He underwent a repeat electrophysiology (EP) study where the baseline PR interval was 62 milliseconds and the QRS duration was 172 milliseconds in a pre-excited pattern. There was found to be an antegrade-only conducting accessory pathway at the anteroseptal region near the His bundle. Antegrade AVRT was induced with a single ventricular extra stimulus while on 2 mcg/min isoproterenol. Cryoablation was performed in a position slightly posterior to the His bundle, which successfully resolved the accessory pathway conduction. First-degree atrioventricular (AV) block was noted in the sinus rhythm with a PR interval of 226 milliseconds post-cryoablation. There was no recurrence of accessory pathway conduction on follow-up ECG 24 hours post-cryoablation. Antidromic AVRT is a very rare finding in WPW syndrome during an EP study. Catheter ablation is the treatment of choice for patients who have symptomatic WPW syndrome. Catheter ablation can be especially challenging when the accessory pathway is in close proximity to the normal conduction pathways. The prognostic significance of inducible antidromic AVRT is controversial in asymptomatic patients and limited data indicate it may be a poor prognostic sign in children. In adults, the prognostic significance is not well-established. Cryoablation is an option for the ablation of accessory pathways that are close to the normal conduction pathways. "Cryomapping" is designed to have precise ablation and to reassure the absence of complications.

Long-term follow-up of a pediatric cohort with short QT syndrome.

OBJECTIVES: The purpose of this study was to define the clinical characteristics and long-term follow-up of pediatric patients with short QT syndrome (SQTS). BACKGROUND: SQTS is associated with sudden cardiac death. The clinical characteristics and long-term prognosis in young patients have not been reported. METHODS: This was an international case series involving 15 centers. Patients were analyzed for electrocardiography characteristics, genotype, clinical events, Gollob score, and efficacy of medical or defibrillator (implantable cardioverter-defibrillator [ICD]) therapy. To assess the possible prognostic value of the Gollob score, we devised a modified Gollob score that excluded clinical events from the original score. RESULTS: Twenty-five patients 21 years of age or younger (84% males, median age: 15 years, interquartile range: 9 to 18 years) were followed up for 5.9 years (interquartile range: 4 to 7.1 years). Median corrected QT interval for heart rate was 312 ms (range: 194 to 355 ms). Symptoms occurred in 14 (56%) of 25 patients and included aborted sudden cardiac death in 6 patients (24%) and syncope in 4 patients (16%). Arrhythmias were common and included atrial fibrillation (n = 4), ventricular fibrillation (n = 6), supraventricular tachycardia (n = 1), and polymorphic ventricular tachycardia (n = 1). Sixteen patients (84%) had a familial or personal history of cardiac arrest. A gene mutation associated with SQTS was identified in 5 (24%) of 21 probands. Symptomatic patients had a higher median modified Gollob score (excluding points for clinical events) compared with asymptomatic patients (5 vs. 4, p = 0.044). Ten patients received medical treatment, mainly with quinidine. Eleven of 25 index cases underwent ICD implantation. Two patients had appropriate ICD shocks. Inappropriate ICD shocks were observed in 64% of patients. CONCLUSIONS: SQTS is associated with aborted sudden cardiac death among the pediatric population. Asymptomatic patients with a Gollob score of <5 remained event free, except for an isolated episode of supraventricular tachycardia, over an average 6-year follow-up. A higher modified Gollob score of 5 or more was associated with the likelihood of clinical events. Young SQTS patients have a high rate of inappropriate ICD shocks.

Time-dependent risk of Fidelis lead failure.

The Medtronic Sprint Fidelis leads (models 6930, 6931, 6948, 6949) are 6.6-F bipolar high-voltage implantable cardioverter-defibrillator electrodes that were first introduced in September 2004. In October 2007, Fidelis leads were removed from the market. We sought to determine the time-dependent hazard of the Fidelis failure rate to date. A retrospective chart review was conducted in all patients who underwent implantation of a Sprint Fidelis lead (426 leads) at our center. We primarily implanted models 6931 and 6949. With 1,056 years of combined follow-up (average 2.3 +/- 1), 38 of 426 (8.92%) Sprint Fidelis leads failed (3.6%/year). The hazard of fracture increased exponentially over time by a power of 2.13 (95% confidence interval [CI] 1.98 to 2.27, p <0.001) and the 3-year survival was 90.8% (95% CI 87.4 to 94.3). If a Fidelis lead was functioning normally at 1 year, the chance it would survive another year was 97.4% (95% CI 95.7 to 99.1); if functioning at 2 years, the chance of surviving another year was 94.7% (95% CI 91.8 to 97.7); and if functioning at 3 years, the chance of surviving 1 more year was 86.7% (95% CI 78.8 to 95.5). Other commonly used implantable cardioverter-defibrillator leads showed no evidence of increased failure rates. In conclusion, to date, the hazard of Fidelis lead fracture is increasing exponentially with time and, based on our data, occurring at a higher rate than the latest manufacturer's performance update. Further accumulative data are needed because it remains unknown if the fracture rate will level off or continue to increase.

Clinical outcomes following IVUS-guided stent deployment in a community hospital.

OBJECTIVES: A discrepancy exists in the medical literature as to what effect intravascular ultrasound (IVUS)-guided stent deployment has on target vessel revascularization (TVR) at 6 months. The major endpoints of this study are the need for TVR, defined as clinically driven repeat interventional or surgical therapy of the index vessel at 6 months and major adverse cardiac events. METHODS: One hundred interventional stent cases (50 IVUS-guided, 50 non-IVUS guided) were randomly selected in a 6-month period (January to June 2001) for review by measurement of minimal luminal diameter (MLD) pre- and post-intervention. Seventy males and 30 females were distributed among the 2 groups. There were a total of 135 lesions (70 IVUS-guided, 65 non-IVUS guided) in the 2 groups. A 6-month follow-up chart review was performed following the initial stenting. RESULTS: At 6-month follow-up, there were 2 deaths in the IVUS-guided group and 3 deaths in the non-IVUS guided group (p=NS). All deaths were cardiovascular in nature. Post-procedure MLD was 3.58+/-0.08 mm for the IVUS-guided group and 2.88+/-0.09 mm for the non-IVUS guided group [t=5.7 (df, 133); p<0.001]. Ten of 70 IVUS-guided lesions (14.3%) and 3 of 65 non-IVUS guided lesions (4.2%) underwent TVR within the 6-month study period (Chi square=3.62; p=0.057). CONCLUSION: In this population, IVUS-guided stent deployment does not appear to reduce either the need for TVR or overall cardiovascular mortality at 6 months. The added expense of IVUS does not appear to be warranted.

Persistent candiduria complicating intraureteral stenting: a case report and review of literature.

Over the past 20 years, there has been a significant increase in the number of nosocomial infections. Nosocomial infections by fungal organisms, in particular Candida species, have shown the highest increase in incidence, currently being the leading pathogen in urinary tract infections and the fourth most common blood-born pathogen within hospitalized patients. This case report describes a patient with acute pancreatitis, complicated by acute renal failure, who developed nosocomial fungiuria and fungemia following bilateral ureteral stenting, and whose fungiuria persisted despite adequate antifungal treatment. Conditions resolved with removal of the intraureteral stents, which we believe, served as the nidus for her persistent fungiuria.

Successful treatment of iatrogenic renal artery perforation with an autologous vein-covered stent.

A 72-year-old woman developed severe flank pain associated with hemodynamic compromise immediately after a J-curve guidewire was inadvertently advanced into the right renal artery during cardiac catheterization. Contrast extravasation consistent with perforation of the main renal artery was seen on abdominal angiography. The perforation was successfully sealed using a premounted coronary stent that was covered with an autologous antecubital vein. Wide stent patency without aneurismal dilatation was confirmed on a 2-year follow-up renal angiogram.