Two consecutive cases are presented of patients with ICDs in whom the use of commercial units for muscle stimulation for abdominal training caused interference with the device, mimicked cardiac signals, and resulted in inappropriate treatment shock delivery.
Patients with orthotopic heart transplantation may have a variety of arrhythmias. There are reports of successful radiofrequency catheter ablation of some of them. Two months after orthotopic cardiac transplantation by bicaval anastomosis, a 49-year-old man developed episodes of tachycardia. The patient developed with dyspnoea and hypotension during typical atrioventricular nodal reentrant tachycardia (AVNRT) revealed by electrocardiogram. During programmed atrial stimulation with progressively increasing prematurity, dual auriculoventricular nodal physiology was observed and AVNRT was induced. This tachycardia was successfully eliminated without complications by radiofrequency catheter ablation of the slow pathway. The patient remained asymptomatic at 4-month follow-up.
Hipertensión arterial en población pediátrica, sus efectos en la dispersión de la onda P y el área auricular izquierda. Resumen:Antecedentes: Entre los factores descritos para desarrollar fibrilación auricular se encuentra el mayor tamaño de la aurícula izquierda; esto lleva a cambios en sus propiedades eléctricas y a mayores valores de dispersión de la onda P del electrocardiograma.Objetivo: Determinar la dispersión de la onda P con relación al área de la aurícula izquierda en niños entre 8 a 11 años.Métodos: Se estudiaron 400 niños aparentemente sanos de ese rango de edad. Se les realizó electrocardiograma de superficie de 12 derivaciones para medir los valores de P máxima, P mínima y se calculó la dispersión de la onda P; se les midió 4 veces la presión arterial. Se realizó además, ecocardiograma para medición del área auricular izquierda.Resultados: Los valores de media de dispersión de la onda P aumentan desde normotensos a hipertensos (32.5 a 38.5 ms, respectivamente), existiendo diferencias significativas intergrupos, encontrando la mayor significación al comparar los normotensos con el grupo de prehipertensos (p=0.001). Un estudio de regresión demostró la dependencia de la dispersión de la onda P del electrocardiograma en el grupo de normotensos y prehipertensos con r=0,22 y p<0.05. Una regresión lineal para la muestra de niños hipertensos muestra una correlación positiva para la dependencia de la onda P con el área auricular izquierda.Conclusiones: Existe dependencia de la dispersión de la onda P del electrocardiograma con el área auricular izquierda, así como diferencias significativas entre valores medios de dispersión de la onda P en los subgrupos de niños normotensos, prehipertensos e hipertensos. Background: left atrial size is a recognized factor increasing the risk of atrial fibrillation. Left atrial electrical properties are modified, with a greater dispersion of the P wave on the electrocardiogram. Aim: to determine the relation between left atrial area and P wave dispersion in children. Methods: 400 healthy children from 8 to 11 years of age had a 12 lead ECG. Maximum and minimum voltages of the P wave and P wave dispersion were measured. Blood pressure was recorded in 4 separate measurements. Echocardiography was used to determine left atrial area. Results: Compared to normotensive children, mean dispersion of the P wave was higher in hypertensives (38.5 vs 32.5 ms, respectively). The most significant difference was observed between normotensives and pre-hypertensive children (regression analysis, p=0.001). Linear regression analysis showed a positive correlation of P wave dispersion and left atrial area Conclusion: P wave dispersion and left atrial area are positively correlated in groups of normal, prehypertensive and hypertensive children. The corresponding mean values of dispersion follow the same tendency. Key Words: P wave, children, arterial hypertension.Hypertension in pediatric patients: effects upon P wave dispersion and left atrial area Introducción:En los últimos años se ha descr...
Purpose To analyze the evolution post-cardiac resynchronization therapy (CRT) in left ventricular non-compaction (LVNC) cardiomyopathy (CM) patients compared to other types of CM, according to clinical and functional variables, by using gated-SPECT myocardial perfusion imaging (MPI). Methods Ninety-three patients (60 ± 11 years, 28% women) referred for pre-CRT assessment were studied and divided into three groups: 1 (non-ischemic CM with LVNC, 11 patients), 2 (ischemic CM, 28 patients), and 3 (non-ischemic CM, 53 patients). All were studied by a 99mTc-MIBI gated-SPECT MPI at rest pre-CRT implantation and 6 ± 1 months after, including intraventricular dyssynchrony assessment by phase analysis. Quality of life was measured by the Minnesota Living with Heart Failure Questionnaire (MLHFQ). Results No differences in sex, atherosclerotic risk factors other than smoking habit, and MLHFQ results were found among groups. LVNC CM patients were younger, with greater QRS width and lower left ventricular ejection fraction (LVEF) at baseline, but the differences were not significant. No significant differences were found at baseline regarding ventricular function, although end-systolic volume was slightly higher in LVNC CM patients. Mean SRS was significantly higher (p < 0.0001) in ischemic patients (14.9) versus non-ischemic ones (8.7 in group 1 and 9 in group 2). At baseline, LVNC CM patients were significantly more dyssynchronous: Their phase standard deviation (PSD) was higher (89.5° ± 14.2°) versus groups 2 (65.2° ± 23.3°) and 3 (69.7° ± 21.7°), p = 0.007. Although the quality of life significantly improved in all groups, non-ischemic patients (with or without LVNC) showed a higher LVEF increase and volumes reduction at 6 months post-CRT. Dyssynchrony reduced post-CRT in all groups. Nevertheless, those more dyssynchronous at baseline (LVNC CM) exhibited the most significant intraventricular synchronism improvement: PSD was reduced from 89.5° ± 14.2° at baseline to 63.7° ± 20.5° post-CRT (p = 0.028). Six months post-CRT, 89% of patients were responders: 11 (100%) of those with LVNC CM, 25 (86%) of those with ischemic CM, and 47 (89%) of patients with non-ischemic CM. No patient with LVNC CM had adverse events during the follow-up. Conclusion CRT contributes to a marked improvement in non-ischemic CM patients with non-compaction myocardium. Phase analysis in gated-SPECT MPI is a valuable tool to assess the response to CRT.
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