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Deglutition syncope is a form of situational syncope where patients develop presyncope or syncope during swallowing. This condition has been observed to occur most commonly in patients with prior gastroesophageal conditions. Our patient developed deglutition syncope that started to occur a few weeks after undergoing a total thyroidectomy. The patient was found to have paroxysmal atrioventricular (AV) block, with up to 5.1 seconds of asystole during swallowing, manifested with episodes of dizziness and lightheadedness. A barium swallow test revealed normal peristalsis and no evidence of dysmotility. The patient underwent placement of a dual chamber pacemaker, and the syncopal episodes resolved. Interrogation of the pacemaker showed no recorded abnormal events.

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Atrial high rate episodes (AHRE) confers increased morbidity and mortality amongst patients with permanent pacemaker implantation (PPI). The incidence of AHREs and it's clinical predictors in Indian patients without prior history of atrial fibrillation (AF) are not well understood. A total of 100 dual-chamber PPI patients, who had no prior history of AF, underwent pacemaker interrogation starting from a minimum of 1 month after implantation to detect any AHREs. The incidence of AHREs was 17% at a mean follow up 15.2 ± 7.5 months. Only right ventricular apical lead position was found to have an independent association with AHREs (OR: 3.50, 95% CI: 1.02-12.03; p = 0.04).

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BACKGROUND: Patients with atrial high-rate episode (AHRE) are at higher risk of neurological events. This study aimed to identify the optimal cutoff threshold for AHRE duration in patients with dual chamber permanent pacemakers (PPM) without prior atrial fibrillation. METHODS: We included 355 consecutive patients receiving dual chamber pacemaker implantation. Primary outcome was composite endpoint of subsequent neurological events after various AHRE durations. AHRE was defined as >175 bpm (MEDTRONIC) or > 200 bpm (BIOTRONIK) for longer than 30 s. Cox regression analysis with time-dependent covariates was conducted. RESULTS: The mean age of included patients was 75.6 ± 11.3 years. Among 355 included patients, some had multiple AHREs; 125 patients (35.2%) developed AHRE ≥2 min, 107 (30.1%) had ≥5 min, 55 (15.5%) had ≥6 h, and 37 (10.4%) had ≥24 h. The mean follow-up was 42.1 ± 31.2 months. During follow-up, 19 neurological events occurred. After adjustment for CHA2 DS2 -VASc score and device type, multivariate Cox regression analysis indicated AHRE ≥2 min (HR 13.605, 95% CI 3.010-61.498), and AHRE ≥5 min (HR 5.819, 95% CI 2.056-16.470) were significantly associated with neurological events. Hence, the optimal AHRE cutoff value was 2 min with the highest Youden index (sensitivity, 89.5%; specificity, 67.8%; AUC, 0.823, 95% CI, 0.763-0.884; p < 0.001). CONCLUSIONS: Patients with dual chamber PPM who develop AHRE have increased risk of neurological events. Comprehensive assessment of the risks and benefits of prescribing anticoagulants should be considered in PPM patients with AHRE ≥2 min.

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BACKGROUND: Patients with atrial high-rate episodes (AHRE) have a high risk of cardiovascular and cerebrovascular events (CCE); however, the optimal cut-off threshold for AHRE duration and the prediction power of AHRE with CHA2DS2-VASc score is unknown. METHODS: We enrolled 355 consecutive patients undergoing dual chamber pacemaker implantations. The primary endpoint was subsequent CCE after AHRE ≥ 30 seconds, 1 minute, 2 minutes, 5 minutes, 6 hours, and 24 hours. AHRE was defined as >175 bpm (Medtronic, Dublin, Ireland) or >200 bpm (Biotronik, Berlin, Germany) lasting ≥30 seconds. Multivariate Cox regression analysis with time-dependent covariates was used to determine the variables associated with higher risks of CCE. RESULTS: The average age of the patients was 75.6 ± 11.3 years, and 162 patients (45.6%) developed AHRE ≥ 30 seconds, 145 (40.8%) ≥1 minute, 125 (35.2%) ≥2 minutes, 107 (30.1%) ≥5 minutes, 55 (15.5%) ≥6 hours, and 37 (10.4%) ≥24 hours. During follow-up (mean 42.1 ± 31.2 months), 145 CCE occurred in 107 patients (incidence rate 11.64/100 patient-years, 95% CI 9.99-13.70). The optimal AHRE cut-off value was 1 minute (sensitivity, 57.9%; specificity, 66.0%; area-under-the-curve, 0.631; 95% CI, 0.563-0.698; p < 0.001). Multivariate Cox regression analysis demonstrated that all categories of AHRE duration were independently associated with CCE. The occurrence of CCE increased with AHRE ≥30 seconds and CHA2DS2-VASc score ≥2 (males) or ≥3 (females). CONCLUSION: Patients with dual chamber pacemakers who develop AHRE ≥ 30 seconds have an increased risk of CCE. The combination of AHRE duration ≥30 seconds and CHA2DS2-VASc score ≥2 (males) or ≥3 (females) is a useful risk-stratification predictor for subsequent CCE.

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PURPOSE: The ultrarapid delayed rectifier current (IKur) carried by Kv1.5 channels, which are solely expressed in the atrium, is a potential target for safer treatment of paroxysmal atrial fibrillation (PAF). XEN-D0103 is a nanomolar ion channel blocker that selectively inhibits potassium ion flux through the Kv1.5 ion channel. The efficacy of XEN-D0103 in reducing AF burden was assessed in patients with DDDRp permanent pacemakers (PPMs) and PAF. METHODS: A double-blind, placebo-controlled, cross-over study was performed in patients with PAF and DDDRp PPMs with advanced atrial and ventricular Holters allowing beat-to-beat arrhythmia follow-up. All anti-arrhythmic drugs were withdrawn before randomised treatment. After baseline assessment, patients were randomly assigned to two treatment periods of placebo then XEN-D0103 50 mg bd, or XEN-D0103 50 mg bd then placebo. RESULTS: Fifty-four patients were screened and 21 patients were eligible and included in the randomised trial. All 21 patients completed both treatment periods. The primary endpoint was change in AF burden assessed by PPM. There was no significant difference in AF burden on treatment with XEN-D0103 versus placebo. There was a reduction in the mean frequency of AF episodes (relative reduction 0.72, 95% CI 0.66 to 0.77; p < 0.0001). XEN-D0103 was safe and well tolerated, and there were no serious adverse events. XEN-D0103 did not have any apparent effect on heart rate compared to placebo. CONCLUSIONS: XEN-D0103 did not reduce AF burden in patients with PAF and dual chamber pacemakers providing beat-to-beat monitoring. XEN-D0103 was well tolerated and did not have any apparent effect on heart rate. Although single-ion channel blockade with XEN-D0103 did not affect AF in this study, there might be a potential for this agent to be used in combination with other atrially specific drugs in the treatment of AF. EUDRACT TRIAL REGISTRATION NUMBER: 2013-004456-38.

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Resumen Objetivos Evaluar la prevalencia de fibrilación auricular (FA) en pacientes portadores de marcapasos bicamerales (MB), las variables asociadas a su aparición y los cambios de conducta clínica que este hallazgo ha generado. Métodos Se incluyó prospectivamente a 500 pacientes ambulatorios portadores de MB. Se realizó interrogatorio sobre el MB. Se contactó a los médicos de cabecera ante la aparición de FA y luego se determinó si esta información resultaba en cambios de conducta terapéutica. Resultados La media de edad de la población fue de 77 años, con un 51% de hombres. Se detectó FA en un 13.2% de los pacientes. Esto generó modificaciones en el tratamiento en un 64.7% de ellos. En el modelo de regresión logística, a través de un análisis multivariado, se asociaron a la aparición de FA las siguientes variables: hipertensión arterial (OR = 2.62; IC 95% 1.01-6.8; p < 0.048), antecedente de FA (OR = 4.30; IC 95% 2.26-8.32; p < 0.001), enfermedad del nodo sinusal como causa de implante (OR = 2.09; IC 95% 1.09-3.97; p < 0.025) y la cantidad de series de extrasístoles supraventriculares detectadas (OR = 1.000033 por cada serie; IC 95% 0.000011-0.000055; p < 0.003). Una cantidad de series de extrasístoles supraventriculares igual o mayor de 77 en un control de marcapasos presenta un área bajo la curva de 0.81 para la detección de FA. Conclusión Se ha detectado una alta prevalencia de FA en pacientes portadores de MB. Este hallazgo condujo a importantes cambios en el tratamiento. Se han detectado 4 variables asociadas independientemente a la detección de FA.

Abstract Objectives To assess the prevalence of atrial fibrillation (AF) in patients with dual-chamber pacemakers (DP), determine the variables associated with development of AF and evaluate the changes in AF's management by physicians. Methods Five hundred patients with DP were prospectively included and interrogated. When AF was detected physicians in charge of the patient were warned. Changes in AF's management were evaluated. Results Mean age of the study population was 77 years, with 51% of men. AF was detected in 13.2% of patients. These findings led treatment changes in 64.7%. The variables analyzed by logistic regression model which were associated with the occurrence of AF were: arterial hypertension (OR = 2.62; CI 95% 1.01-6.8; P < .048), history of AF (OR = 4.30; CI 95% 2.26-8.32; P < .001), sick sinus syndrome as cause of device implantation (OR = 2.09; CI 95% 1.09-3.97; P < .025) and burden of supraventricular extrasystoles series(OR = 1.000033 per serie; CI 95% 0.000011-0.000055; P < .003.). Conclusion We have detected a high prevalence of AF in patients with DP. The diagnose of AF led to change in treatment. Four clinical variables increase the likelihood of developing this arrhythmia.

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OBJECTIVES: To assess the prevalence of atrial fibrillation (AF) in patients with dual-chamber pacemakers (DP), determine the variables associated with development of AF and evaluate the changes in AF's management by physicians. METHODS: Five hundred patients with DP were prospectively included and interrogated. When AF was detected physicians in charge of the patient were warned. Changes in AF's management were evaluated. RESULTS: Mean age of the study population was 77 years, with 51% of men. AF was detected in 13.2% of patients. These findings led treatment changes in 64.7%. The variables analyzed by logistic regression model which were associated with the occurrence of AF were: arterial hypertension (OR=2.62; CI 95% 1.01-6.8; P<.048), history of AF (OR=4.30; CI 95% 2.26-8.32; P<.001), sick sinus syndrome as cause of device implantation (OR=2.09; CI 95% 1.09-3.97; P<.025) and burden of supraventricular extrasystoles series(OR= 1.000033 per serie; CI 95% 0.000011-0.000055; P<.003.). CONCLUSION: We have detected a high prevalence of AF in patients with DP. The diagnose of AF led to change in treatment. Four clinical variables increase the likelihood of developing this arrhythmia.

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Experimental and clinical studies have shown that right ventricular apical pacing may result in long-term deleterious effects on account of its negative impact on left ventricular remodeling through desynchronization. This risk appears more pronounced in patients with even moderate left ventricular dysfunction and generally occurs after at least 1 year of pacing. As right ventricular apical pacing may be associated with the development of organic mitral insufficiency, other sites that allow for more physiological stimulation, such as right ventricular outflow tract septal pacing, have been developed, with good feasibility and reproducibility. However, the prospective randomized studies and meta-analyses to date have only demonstrated a modest effect on ejection fraction in the medium term, without any significant effect on quality of life and morbimortality. However, the absence of a favorable effect for right ventricular outflow tract septal pacing compared with right ventricular apical pacing in terms of clinical manifestations and patient prognosis appears to be more associated with the designs of these studies, which were not homogeneous with regard to methodology used, judgment criteria, follow-up and, especially, statistical power. Two randomized prospective multicentre studies are currently ongoing in order to evaluate the favorable effect of infundibular septal pacing, when considering the indirect negative effects of right ventricular apical pacing as reported in the literature.

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