Impact of routine right parasternal electrocardiographic screening in assessing eligibility for subcutaneous implantable cardioverter-defibrillator.

INTRODUCTION: Between 7% and 15% of patients with an indication for an implantable cardioverter-defibrillator (ICD) are not eligible for implantation of a subcutaneous implantable cardioverter-defibrillator (S-ICD) on the basis of the result of the conventional left parasternal electrocardiographic screening (LPES). Our objective was to determine the impact of systematically performing right parasternal electrocardiographic screening (RPES) in addition to conventional LPES, in terms of increasing both the total percentage of potentially eligible patients for S-ICD implantation and the number of suitable vectors per patient. METHODS AND RESULTS: Consecutive patients from the outpatient device clinic who already had an implanted ICD, and no requirement for pacing were enrolled. Conventional left parasternal electrode position and right parasternal electrode positions were used. The automatic screening tool was used to analyze the recordings. Screenings were performed in the supine and standing positions. Overall, 209 patients were included. The mean age was 63.4 ± 13 years, 59.8% had ischemic heart disease, mean QRS duration was 100 ± 31 ms, and 69.9% had a primary prevention ICD indication. Based on conventional isolated LPES, 12.9% of patients were not eligible for S-ICD compared with 11.5% based on RPES alone (P = .664). Considering LPES and RPES together, only 7.2% of patients were not eligible for S-ICD (P < .001). Moreover, the number of patients with more than one suitable vector increased from 66.5% with isolated LPES to 82.3% (23.7% absolute increase [P < .001]). CONCLUSION: Adding an automated RPES to the conventional automated LPES increased patient eligibility for the S-ICD significantly. Moreover, combined screening increased the number of suitable vectors per eligible patient.

A regular wide QRS complex tachycardia: What is the mechanism?

A 14-year-old girl with a history of recurrent palpitations and documented wide QRS complex tachycardia was referred for electrophysiologic study and catheter ablation.

A scoring algorithm for the accurate differential diagnosis of regular wide QRS complex tachycardia.

BACKGROUND: The differential diagnosis of regular wide QRS complex tachycardia (RWQRST) remains the subject of numerous publications, all of which aim at diagnosis during the acute phase. Although an accurate diagnosis is necessary to make long-term decisions, it often leads to invasive testing. METHODS: Criteria with high positive predictive values (PPVs) for diagnosis can be obtained by analyzing the electrocardiogram (ECG) data during RWQRST and comparing them with these data at baseline. By assigning points to these criteria, a scoring algorithm to accurately diagnose numerous patients can be obtained. A total of 352 consecutive patients with RWQRST were included. Two electrophysiologists blind to patient condition analyzed the 16 criteria considered as having high PPVs. RESULTS: A total of 149 (42.3%) cases were supraventricular tachycardia (SVT), and 203 (57.7%) cases were ventricular tachycardia (VT). A higher percentage of patients with VT had structural heart disease (86.7% vs 16.1%). Seven of the 16 criteria analyzed had PPVs > 95%, and each criterion was assigned a score. A final score of -1 was indicative of SVT (PPV 98%); a score of 1 was indicative of VT (PPV 98%); and a score of ≥2 was indicative of VT (PPV 100%). A score of ≠0 was obtained for 51.7% of all cases of tachycardia, making it possible to reach a highly accurate diagnosis in approximately half of all cases. No cases of VT scored -1, and no cases of SVT scored ≥2. CONCLUSIONS: The current scoring system stands out for its high PPV (98%) and specificity (98%), enabling an accurate diagnosis for more than half of the patients.

Estimation of the effects of multipoint pacing on battery longevity in routine clinical practice.

Aims: Multipoint pacing (MPP) permits simultaneous multisite pacing of the left ventricle (LV); initial studies suggest haemodynamic and clinical benefits over conventional (single LV site) cardiac resynchronization therapy (CRT). The aim of this study was to estimate the impact of MPP activation on battery longevity in routine clinical practice. Methods and results: Patient (n = 46) and device data were collected from two centres at least 3 months after MPP-CRT device implantation. Multipoint pacing programming was based on the maximal possible anatomical LV1/LV2 separation according to three predefined LV pacing capture threshold (PCT) cut-offs (≤1.5 V; ≤4.0 V; and ≤6.5 V). Estimated battery longevity was calculated using the programmed lower rate limit, lead impedances, outputs, and pacing percentages. Relative to the longevity for conventional CRT using the lowest PCT (8.9 ± 1.2 years), MPP activation significantly shortened battery longevity for all three PCT cut-offs (≤1.5 V, -5.6%; ≤4.0 V, -16.9%; ≤6.5 V, -21.3%; P's <0.001). When compared with conventional CRT based on longest right ventricle-LV delay (8.3 ± 1.3 years), battery longevity was significantly shortened for the MPP ≤ 4.0 V and ≤6.5 V cut-offs (-10.8 and -15.7%, respectively; P's <0.001). Maximal LV1/LV2 spacing was possible in 23.9% (≤1.5 V), 56.5% (≤4.0 V), and 69.6% (≤6.5 V) of patients. Conclusion: Multipoint pacing activation significantly reduces battery longevity compared with that for conventional CRT configuration. When reasonable MPP LV vector PCTs (≤4.0 V) are achieved, the decrease in battery longevity is relatively small which may prompt the clinician to activate MPP.

Paradoxical preexcitation during cryoablation of a concealed parahisian accessory pathway.

A 16-year-old male presented with an orthodromic atrioventricular reentrant tachycardia over a concealed parahisian accessory pathway (AP). Cryoablation of the AP resulted in transient manifestation of a fully preexcited sinus rhythm of parahisian AP morphology. Potential causes for the paradoxical preexcitation include inadvertent atrioventricular nodal block, sourse-sink mismatch, as well as the activation of a dormant AP capable of anterograde conduction.

Isolated palpitations and ventricular pre-excitation.

A 27-year-old male was referred for further assessment after being evaluated by his general practitioner for isolated palpitations. A twelve-lead electrocardiogram was performed in which sinus rhythm with ventricular pre-excitation were observed. Electrophysiologic study demonstrated the presence of a fasciculoventricular accessory pathway.

A regular wide QRS complex tachycardia with fusion beats?

A case of wide complex tachycardia with isolated QRS complexes of different amplitude suggesting that this was ventricular tachycardia.

Quantification of acute parasympathetic denervation during cryoballoon ablation by using extracardiac vagal stimulation.

AIMS: The purpose of this study was to systematically quantify the level of acute parasympathetic denervation in a stepwise fashion by means of extracardiac vagal stimulation (ECVS) by positioning a quadripolar catheter in the internal jugular vein, in a cohort of patients undergoing second-generation cryoballoon ablation for paroxysmal atrial fibrillation. METHODS: Fifty patients with symptomatic paroxysmal atrial fibrillation, having undergone extracardiac vagal stimulation before and after ablation by means of second-generation cryoballoon second-generation cryoballoon ablation, were included. RESULTS: The extracardiac vagal stimulation performed preablation provoked cardioinhibitory responses in all patients with mean pause duration of 10130.6 ± 3280.0 ms. At the end of the procedure, the VRs were significantly diminished with mean pause of 1687.5 ms ± 2183.7 ms (P = 0.00 compared with the pause before the procedure). CONCLUSION: The ECVS proved to be a reproducible, feasible and reliable method to quantify the degree of parasympathetic denervation during CB-A. In all patients, significant cardiac parasympathetic denervation could be observed at the end of the procedure. Responses to ECVS were more specific to quantify the vagal denervation than the increase in the heart rate. However larger studies are needed to confirm this observation.

Snakebite poisoning in Spain. / Envenenamiento por mordedura de serpiente en España.

OBJECTIVES: Emergencies due to snakebites, although unusual in Spain, are potentially serious. Of the 13 species native to the Iberian peninsula, only 5 are poisonous: 2 belong to the Colubridae family and 3 to the Viperidae family. Bites from these venemous snakes can be life-threatening, but the venomous species can be easily identified by attending to certain physical traits. Signs denoting poisoning from vipers, and the appropriate treatment to follow, have changed in recent years.

OBJETIVO: Las urgencias por mordeduras de serpientes ibéricas en España son poco frecuentes pero potencialmente graves. De las trece especies autóctonas, sólo cinco son venenosas (2 especies de colúbridos y las 3 especies de vipéridos) y pueden suponer un riesgo para la vida del paciente. La identificación de las especies puede ser sencilla teniendo en cuenta una serie de rasgos del ofidio. Las manifestaciones clínicas debidas al envenenamiento de las víboras, así como su tratamiento, han experimentado modificaciones en los últimos años.

Acute and Long-term Results After Contemporary Subcutaneous Implantable Cardioverter-defibrillator Implantation: A Single-center Experience.

INTRODUCTION AND OBJECTIVES: The subcutaneous implantable cardioverter-defibrillator (S-ICD) has emerged as an alternative to the transvenous defibrillator. The incidence of complications is similar, with inappropriate shocks (IS) being more frequent than those occurring with contemporary programming of transvenous defibrillators. Several improvements have been implemented after the S-ICD was approved for use in Europe in 2009. This study reports the results of S-ICD use in a single center, whose experience began late, at the end of 2013. METHODS: Prospective observational study including consecutive patients with defibrillator indication and no indication for either permanent pacing or cardiac resynchronization who underwent S-ICD implantation. Implant data and long-term follow-up were analyzed. RESULTS: An S-ICD was implanted in 50 patients who were deemed suitable after electrocardiographic screening. The mean age was 46.9±15 (range, 15-78) years and 72% were male. Thirty eight percent had left ventricular ejection fraction ≤ 35%. The most frequent heart disease was ischemic heart disease (34%), followed by hypertrophic cardiomyopathy (18%). The intermuscular technique was used, with 3 incisions in 10% and 2 incisions in the remaining 90%. Ventricular fibrillation was induced in 49 patients, with 100% effectiveness in their conversion. After a mean follow-up of 18.1 (range, 2.3-44.8) months, there were no late complications requiring surgical revision, the rate of IS was 0%, and 1 patient (2%) experienced appropriate shocks. CONCLUSIONS: Improvements in technology, implant technique and device programming, along with appropriate patient selection, have led to outstanding acute and long-term results, especially regarding the absence of both IS and complications requiring surgical revision.