Stenting of Native Right Ventricular Outflow Tract Obstructions in Symptomatic Infants

Objective

To assess feasibility, safety and effectiveness of right ventricular outflow tract (RVOT) stenting in symptomatic young infants.

Methods

Multicentre evaluation of 35 patients intended to undergo RVOT stenting in 11 pediatric cardiac centres from 2009 to August 2011.

Results

Median age and weight at the time of first stent implantation were 8 weeks and 3.3 kg, with 40% of patients <3 kg. A total of 19 patients had suffered from hypoxemic spells, 8 patients were ventilated, 6 on inotropic support and 5 on prostaglandin infusion. Severe concomitant malformations were present in 11 patients, and acute infections in 2. Stenting of the RVOT was successfully performed in 33 patients, improving oxygen saturation from a median of 77 to 90% 2 days after intervention. Besides the 2 patients in whom RVOT stenting was not successful for technical reasons, there were no procedural complications. In 17 of 33 patients, 1–3 reinterventions were performed during follow‐up, less than half of those were reinterventions in the RVOT. A total of 27 patients have undergone successful surgical repair 4–162 (median 19.5) weeks after initial RVOT stent implantation, 2 patients are still waiting. There were no perioperative deaths.

Conclusions

Stenting of the RVOT provides a safe and effective management strategy for initial palliation in symptomatic young infants, including those patients not suitable or at higher risk for surgical therapy. (J Interven Cardiol 2015;28:279–287)

     

Management of Zenker’s diverticulum and postlaryngectomy pseudodiverticulum with the CO2 laser

Dysphagia is a common symptom and can be caused by anterior pharyngeal (pseudodiverticulum after laryngectomy) and posterior pharyngeal (Zenker’s) diverticula. The only treatment is surgical. The experience with an endoscopic treatment, especially with the CO₂ laser, is limited. Between 1984 and 1996, 81 patients with dysphagia were treated endoscopically with the CO₂ laser at the Department of Otorhinolaryngology–Head and Neck Surgery, University of Kiel. In 70 patients the swallowing disorder was caused by a hypopharyngeal diverticulum, and in 11 patients it was caused by a pseudodiverticulum after laryngectomy. In the Zenker’s group, more than 90% of the patients were treated successfully. Eight of 11 patients with pseudodiverticula were without symptoms, and in the remaining 3 patients dysphagia was improved after laser therapy. The excision technique was superior to the incision procedures. The rate of postoperative complications was generally low. The microendoscopic approach with the CO₂ laser is a recommendable method for the treatment of Zenker’s diverticulum and pseudodiverticulum in the postlaryngectomy patient. The surgical technique with the CO₂ laser at low power settings is a less invasive, quick, relatively safe, and effective procedure requiring only short hospitalization. (Otolaryngol Head Neck Surg 1999;121:809-14.)     

DIURNAL SALIVARY CORTISOL PATTERNS DURING PREGNANCY AND AFTER DELIVERY: RELATIONSHIP TO PLASMA CORTICOTROPHIN-RELEASING-HORMONE

The circadian rhythm of salivary cortisol was studied in 10 healthy women every 4 weeks throughout pregnancy. In addition, in 12 women the diurnal patterns of salivary cortisol, serum cortisol, plasma ACTH, plasma CRH and serum progesterone were analysed in late third trimester pregnancy and again 3-5 days after delivery. Salivary cortisol profiles exhibited a clear circadian rhythm during pregnancy with an increase in mean salivary cortisol from the 25th to 28th week onwards reaching concentrations in late pregnancy more than twice as high as in non-pregnant controls, rapidly returning to normal concentrations after delivery. The coefficient of variation of salivary cortisol profiles decreased in third trimester pregnancy due to a parallel upward shift of cortisol concentrations (40.2 +/- 3.4% vs 77.6 +/- 6.6% after delivery, P less than 0.01). A diurnal pattern was also found for plasma ACTH and serum cortisol before and after delivery with lower concentrations post-partum (P less than 0.01). In late pregnancy, progesterone concentrations were significantly higher in the evening (930 +/- 85 nmol/l vs 813 +/- 74 nmol/l at 0900 h, P less than 0.01) but showed no diurnal variation post-partum. Plasma CRH was significantly elevated in late third trimester pregnancy (1.22 +/- 0.23 micrograms/l at 0900 h) but showed no diurnal change (1.30 +/- 0.28 micrograms/l at 1900 h). Moreover, no correlation between the free cortisol increase in late pregnancy and plasma CRH was noted despite a wide range of CRH levels (0.13-3.60 micrograms/l). In contrast, a significant correlation was observed between the serum progesterone increase and the salivary cortisol increase in late pregnancy (r = 0.70, P less than 0.05). These findings demonstrate that placental CRH is not the only regulator of maternal ACTH and cortisol release. Instead, our study suggests that placental CRH has little influence on baseline maternal adrenocortical function in pregnancy. The elevated salivary cortisol levels in pregnancy may be explained by glucocorticoid resistance owing to the antiglucocorticoid action of high progesterone concentrations.     

Is the Atrial High Rate Episode Diagnostic Feature Reliahle in Detecting Paroxysmal Episodes of Atrial Tachyarrhythmias?

The atrial high rate episode diagnostic in The Thera® pacemaker reports frequency, duration, and date/time of atrial tachyarrbytbmias according to programmed criteria. The aim of The study was to validate The atrial high rate episode diagnostic feature. Episodes of atrial fibrillation recorded by Holter monitoring were compared to episodes detected by the pacemaker. Eorty five ambulatory (Holter) recordings were used for evaluation. Thirty of 45 ambulatory (Holter) recordings showed sinus rhythm. On 4 of these 30 ambulatory (Holter) recordings, The Thera® detected 12 episodes of atrial tachyarrbythmias as false-positives (sinus rhythm was detected as atrial tacbyarrbytbmia). The main reason was far-field R and T wave oversensing. On 15 of 45 ambulatory (Holter) recordings, 125 episodes of atrial tachyarrhytbmias were recorded. Ninety-three of these events also were detected by the pacemaker, while for 32 events the Thera® reported sinus rhythm. The main reason was that the episodes were of too short duration. Therefore, the Thera® (programmed with detection rate 160 beats/min, detection beats 40, termination beats 10) was unable to detect atrial tachycardias. Software simulation of The diagnostic algorithm under several programming settings using the digitized Holter files demonstrated highly reliable detection of atrial tachyarrhythmias (sensitivity 98%, specificity 100%) when programmed as follows: detection rate 220 beats/min, detection beats 10, termination beats 20. It can be concluded that Thera®'s high rate episode monitor is a reliable tool for detection of a trial tachyarrhythmias, if programmed as recommended.     

Effect of elevated PEEP on dynamic variables of fluid responsiveness in a pediatric animal model

Background: Previous studies have demonstrated that stroke volume variation (SVV), pulse pressure variation (PPV) and global end‐diastolic volume (GEDV) can be used to predict the response to fluid administration. Currently, little information is available whether application of different levels of positive end‐expiratory pressure (PEEP), especially in infants and neonates, affects their ability to predict fluid responsiveness. The aim of our study was to assess the effect of increasing PEEP levels on the predictive value of SVV, PPV and GEDV with respect to fluid responsiveness. Methods: Stroke volume variation and PPV were monitored continously in 22 anesthetized piglets during changing PEEP levels (5 and 10 cmH₂O) both before and after fluid loading (FL). GEDV was measured by transpulmonary thermodilution; cardiac output and stroke volume (SV) were measured by pulmonary artery thermodilution. A positive response to FL was defined as ≥15% increase in SV. Results: Fluid loading induced significant changes in all hemodynamic variables except of heart rate and systemic vascular resistance. At PEEP 5 cmH₂O, SVV, PPV and GEDV significantly correlated with volume induced percentage change in SV, whereas at PEEP 10 cmH₂O, this correlation was abolished for PPV. As assessed by receiver operating characteristic curve analysis, SVV and GEDV, independent of PEEP level applied, were the best predictors of a positive response to FL [area under the curve: SVV = 0.88; GEDV = 0.80]. Conclusions: In this pediatric animal model, SVV and GEDV were sensitive and specific predictors of fluid responsiveness during increasing PEEP levels.     

Effects of norepinephrine on dynamic variables of fluid responsiveness during hemorrhage and after resuscitation in a pediatric porcine model

Background:  The effect of vasopressors on pulse pressure variation (PPV), stroke volume variation (SVV) and on the volumetric variable global end-diastolic volume (GEDV) during changing loading conditions is currently under debate. The aim of our study was to investigate the effect of norepinephrine (NE) on PPV, SVV and GEDV in a pediatric animal model of hemorrhage and resuscitation.
Methods:  Eight anesthetized piglets were studied at normovolemia, after stepwise blood withdrawal (25 ml·kg⁻¹), after infusion of NE to restore mean arterial pressure (MAP), after NE titration was stopped and shed blood was retransfused and finally again after NE titration. Stroke volume (SV) was measured using a thermodilution pulmonary artery catheter. GEDV was measured by transpulmonary thermodilution. PPV and SVV were monitored continuously by pulse contour analysis. In response to NE administration during hemorrhage, MAP significantly increased ( P  < 0.01), PPV significantly decreased ( P  = 0.02), whereas SVV, SV and GEDV remained unchanged. After retransfusion, SVV and GEDV significantly correlated with volume induced percentage change in SV. This significant correlation was reversed after NE administration for SVV and persisted for GEDV. In conclusion, NE administration significantly affected PPV and SVV, whereas the volumetric variable GEDV remained unchanged.     

Geographic Differences in Implantable Cardioverter Defibrillator Usage

Geographic Differences in ICD Usage. Despite the demonstrated efficacy of implantable cardioverter defibrillators (ICDs) in reducing sudden and total mortality in selected patients, their implantation rates vary greatly among countries. In the United States, the implantation rate is 185 implants per million inhabitants compared with only 31 implants per million in western Europe. The differences in ICD use may be explained by the following factors: manner in which sudden cardiac death is perceived by politicians and physicians (sudden cardiac death is perceived as a “nice way of dying”); differences in indications; physicians' information; prevalence of coronary artery disease; sudden cardiac death survival rates; perceived reliability of alternative treatment (namely, antiarrhythmics including amiodarone); economic backgrounds; and health care politics. Furthermore, the cost of this treatment strategy must be considered. This issue has been raised because generalization of ICD use in patients matching clinical characteristics of patients enrolled in the primary prevention trials may represent a significant economic burden to be added to the already overloaded health care system. This low acceptance may not be entirely related to budget constraint but also to the perceived efficacy of ICDs by physicians and health authorities.     

Noncontact Mapping of Ectopic Atrial Tachycardias:

SEIDL, K., et al. : Noncontact Mapping of Ectopic Atrial Tachycardias: Different Characteristics of Isopotential Maps and Unipolar Electrogram. The success rate for catheter ablation of ectopic atrial tachycardia (AT) has been limited by the inherent difficulty in localizing the site of origin within the complex three-dimensional structures of the atria. The objective of the study was to determine the usefulness of a noncontact mapping system for catheter ablation of AT. Radiofrequency ablation of 25 ATs was performed using a noncontact mapping system. Three different characteristics of isopotential maps and unipolar electrogram morphologies were observed: Group 1: Isopotential maps displayed a narrow, sharp ring of colors around a white, center spot. Unipolar electrograms revealed a Q-S morphology with a rapid dV/dt. Group 2: Isopotential maps displayed a broad ring of colors with little or no white spot in the center. Unipolar electrograms revealed a low amplitude, broad and smooth Q-S morphology in front of a second component with a rapid dV/dt. Group 3: Isopotential maps displayed a broad ring of colors. Unipolar electrogams revealed a low amplitude and fractionated waveform followed by endocardial breakthrough with a gradual dV/dt. Radiofrequency catheter ablation was successful in all ATs of groups 1 and 2, and failed in two of three ATs in group 3. The overall success rate was 92%. No severe complications were observed. Noncontact isopotential mapping is helpful to identify and characterize the origin of ectopic AT. Ablation success is associated with the characteristics of isopotential maps and unipolar electrogram morphologies. The overall success rate was 92%. (PACE 2003; 26[Pt. I]:16–25)