An elderly Jervell and Lange-Nielsen patient heterozygous compound for two new KCNQ1 mutations.

We present the case of a 66-year-old female with early onset deafness and seizures, who was diagnosed with epilepsy at the age of 2 years. She received antiepileptic drugs and was free of syncope episodes for 32 years. After a syncope at the age of 34, the ECG was characteristic of long-QT syndrome and was treated with antiarrhythmic drugs. Sequencing of the KCNQ1 gene identified two novel KCNQ1 variants interpreted to be pathogenic, and the patient was finally diagnosed with Jervell and Lange-Nielsen syndrome. © 2016 Wiley Periodicals, Inc.

Differences in ventriculoatrial intervals during entrainment and tachycardia: a simpler method for distinguishing paroxysmal supraventricular tachycardia with long ventriculoatrial intervals.

INTRODUCTION: Usefulness of the interval between the last pacing stimulus and the last entrained atrial electrogram (SA) minus the tachycardia ventriculoatrial (VA) interval in the differential diagnosis of supraventricular tachycardias with long (>100 ms) VA intervals has not been prospectively studied in a large series of patients. Our objective was to assess the usefulness of the difference SA-VA in diagnosing the mechanism of those tachycardias in patients without preexcitation. The results were compared with those obtained using the corrected return cycle (postpacing interval-tachycardia cycle length-atrioventricular [AV] nodal delay). METHODS AND RESULTS: We included 314 consecutive patients with inducible sustained supraventricular tachycardias with VA intervals >100 ms undergoing an electrophysiologic study. Atrial tachycardias were excluded. Tachycardia entrainment was attempted through pacing trains from right ventricular apex. The SA-VA difference and the corrected return cycle were calculated for every patient. Electrophysiologic study revealed 82 atypical AV nodal reentrant tachycardias (AVNRT) and 237 AV reentrant tachycardias (AVRT) using septal (n = 91) or free-wall (n = 146) accessory pathways (APs). A SA-VA difference >110 ms identified an atypical AVNRT with sensitivity, specificity, positive and negative predictive values of 99%, 98%, 95%, and 99.5%, respectively. Similarly, these values were 88%, 83%, 77%, and 92% for SA-VA difference <50 ms in identifying AVRT through a septal versus free-wall AP. The SA-VA difference showed higher accuracy in septal AP identification than that obtained using the corrected return cycle. CONCLUSION: The difference SA-VA provides a simpler electrophysiologic maneuver that reliably differentiates atypical AVNRT from AVRT regardless of concealed AP location.

Rate-related changes in QRS morphology in patients with fixed bundle branch block: implications for differential diagnosis of wide QRS complex tachycardia.

AIMS: To analyse QRS morphology in response to rapid atrial pacing (RAP) and supraventricular tachycardia (SVT) in patients with pre-existing bundle branch block (BBB). METHODS AND RESULTS: We prospectively studied 59 patients in sinus rhythm (SR), with QRS > or = 120 ms, and no pre-excitation. Trains of RAP were introduced at increasing rates until atrioventricular block. QRS during SR and last QRS complex of each RAP train were compared on the 12-leads. Previously described criteria for minor and major configuration differences were used to identify QRS changes. During RAP minor QRS changes were seen in 22 (37%) and major changes in 23 (39%) subjects. One patient showed major axis shifts and no one showed a change to the contralateral BBB pattern. QRS changes were significantly and independently related to RAP rate and type of BBB (more frequent if right-BBB). Of 14 subjects (24%) with SVT, 13 displayed the same QRS changes during RAP. CONCLUSION: In patients with organic BBB, important changes in QRS morphology, except for a change in the contralateral BBB, can appear during RAP and SVT. Thus, in these patients, a change in QRS morphology during tachycardia does not necessarily imply that it is ventricular tachycardia.

[Sprint fidelis defibrillation lead: a nine-center experience in Spain]. / Electrodo de desfibrilación Sprint Fidelis: experiencia de nueve centros en España.

INTRODUCTION AND OBJECTIVES: Sprint Fidelis defibrillation leads are prone to early failure. Most of the reported series come from a single institution. This paper describes the clinical experience in nine Spanish hospitals. METHODS: Clinical, implant, and follow-up data of all patients with a Sprint Fidelis lead were analyzed. All cases of lead failure were identified, medium-term lead survival was calculated, and possible predictors for lead failure were determined. RESULTS: In total, 378 leads in 376 patients were studied. The mean age (male 85.7%) was 64.9 ± 13.6 years. The majority of patients (59.8%) had ischemic heart disease. Mean left ventricular ejection fraction was 33.4% ± 14.5%. Left subclavian vein puncture was used in 74.8%. During a mean follow-up of 30.9 ± 14 months, 16 lead failures have occurred, with a lead survival of 96.1% at 36 months after implantation. Eleven of 16 lead failures were caused by failure of pace/sense conductors, 3 by defects in the high-voltage conductor, and 2 by defects in both types of conductors. A less depressed left ventricular ejection fraction was associated with an increased probability of lead failure (42.4% ± 16% vs. 33% ± 14.3%; P =.011). Three hospitals presented a rate of lead failure higher than 10%; the rate was less than 5% in the remaining 6 hospitals. CONCLUSIONS: In this multicenter series of 378 leads, the 3-year estimated survival was higher than that reported in prior series. Clinical presentation of lead failures was similar to that reported previously. Left ventricular ejection fraction and hospital of implantation were variables associated to lead failure.

Electrodo de desfibrilación Sprint Fidelis: experiencia de nueve centros en España / Sprint Fidelis Defibrillation Lead: a nine-center experience in Spain

Introducción y objetivos. Los electrodos de desfibrilación Sprint Fidelis presentan riesgo de disfunción precoz. La mayor parte de las series en la literatura provienen de un solo centro. Describimos la experiencia clínica en nueve centros españoles. Métodos. Se analizaron los datos clínicos, del implante y el seguimiento de todos los pacientes con un electrodo Sprint Fidelis, describiendo los casos problema, calculando la supervivencia del electrodo a medio plazo e identificando posibles predictores de disfunción. Resultados. Se incluyó un total de 378 electrodos en 376 pacientes (el 85,7% varones), con una media de edad de 64,9±13,6 años. El 59,8% se implantó en pacientes con cardiopatía isquémica. La fracción de eyección ventricular izquierda era 33,4%±14,5%. En el 74,8% de los casos se implantó por punción subclavia izquierda. Tras un seguimiento medio de 30,9±14 meses, 16 pacientes presentaron disfunción del electrodo; la supervivencia a 36 meses fue del 96,1%. En 11 electrodos ocurrió una disfunción aislada del sistema de sensado/estimulación; en 3, del sistema de alta energía, y en 2, de ambos. Una mejor función ventricular se asoció con una mayor probabilidad de fractura del electrodo (el 42,4%±16% frente al 33%±14,3%; p=0,011); tres centros presentaron una tasa de fracturas superior al 10% y los seis restantes, inferior al 5%. Conclusiones. En esta serie multicéntrica de 378 electrodos, la supervivencia estimada a 3 años resultó mayor que en series previas, con un perfil de presentación clínica similar de las disfunciones. La fracción de eyección ventricular izquierda y el centro implantador fueron variables asociadas a la presencia de disfunción (AU)

Introduction and objectives. Sprint Fidelis defibrillation leads are prone to early failure. Most of the reported series come from a single institution. This paper describes the clinical experience in nine Spanish hospitals. Methods. Clinical, implant, and follow-up data of all patients with a Sprint Fidelis lead were analyzed. All cases of lead failure were identified, medium-term lead survival was calculated, and possible predictors for lead failure were determined. Results. In total, 378 leads in 376 patients were studied. The mean age (male 85.7%) was 64.9±13.6years. The majority of patients (59.8%) had ischemic heart disease. Mean left ventricular ejection fraction was 33.4%±14.5%. Left subclavian vein puncture was used in 74.8%. During a mean follow-up of 30.9±14 months, 16 lead failures have occurred, with a lead survival of 96.1% at 36 months after implantation. Eleven of 16 lead failures were caused by failure of pace/sense conductors, 3 by defects in the high-voltage conductor, and 2 by defects in both types of conductors. A less depressed left ventricular ejection fraction was associated with an increased probability of lead failure (42.4%±16% vs. 33%±14.3%; P=.011). Three hospitals presented a rate of lead failure higher than 10%; the rate was less than 5% in the remaining 6 hospitals. Conclusions. In this multicenter series of 378 leads, the 3-year estimated survival was higher than that reported in prior series. Clinical presentation of lead failures was similar to that reported previously. Left ventricular ejection fraction and hospital of implantation were variables associated to lead failure (AU)