Intracardiac echocardiography guided anatomical ablation of the arcuate ridge for drug refractory inappropriate sinus tachycardia.

INTRODUCTION: Inappropriate sinus tachycardia (IST) is a common condition with frequently not tolerated beta-blockers or ivabradine and a high rate of complication in ablation strategy; we describe an alternative anatomical approach of sinus node (SN) modulation. METHODS: This retrospective study describes a case series of 6 patients from two centers diagnosed with symptomatic IST undergoing SN ablation. RESULTS: The mean age was 40.6 ± 13.9 years; five of the six patients were female, 100% of patients reported heart palpitations, and 66% reported dizziness, the average heart rate (HR) on a 24-h Holter was 93.2 ± 7.9 bpm. HR during the first stage of a stress test using a standard Bruce protocol was 150 ± 70 bpm, The average HR on 24-h Holter postablation was 75 ± 5.6 bpm, the sinus rate HR during stage 1 of a Bruce protocol exercise stress test was 120 ± 10 bpm. CONCLUSION: This is the first case series reporting the acute and long-term results of a novel anatomical approach for SN modulation to treat IST targeting the arcuate ridge (AR) under intracardiac echography (ICE) guidance. The novel anatomic ICE-guided catheter ablation approach aimed to identify the earliest activation at the AR with an extension of RF lesions toward its septal region seems effective and safe to modulate the SN in symptomatic patients with IST refractory to medical treatment.

Loss of LaMATE impairs isoflavonoid release from cluster roots of phosphorus-deficient white lupin.

White lupin (Lupinus albus L.) forms brush-like root structures called cluster roots under phosphorus-deficient conditions. Clusters secrete citrate and other organic compounds to mobilize sparingly soluble soil phosphates. In the context of aluminum toxicity tolerance mechanisms in other species, citrate is released via a subgroup of MATE/DTX proteins (multidrug and toxic compound extrusion/detoxification). White lupin contains 56 MATE/DTX genes. Many of these are closely related to gene orthologs with known substrates in other species. LaMATE is a marker gene for functional, mature clusters and is, together with its close homolog LaMATE3, a candidate for the citrate release. Both were highest expressed in mature clusters and when expressed in oocytes, induced inward-rectifying currents that were likely carried by endogenous channels. No citrate efflux was associated with LaMATE and LaMATE3 expression in oocytes. Furthermore, citrate secretion was largely unaffected in P-deficient composite mutant plants with genome-edited or RNAi-silenced LaMATE in roots. Moderately lower concentrations of citrate and malate in the root tissue and consequently less organic acid anion secretion and lower malate in the xylem sap were identified. Interestingly, however, less genistein was consistently found in mutant exudates, opening the possibility that LaMATE is involved in isoflavonoid release.

A Rare Case of Botulism in an Adult Patient / Un caso raro de botulismo en una paciente adulta

Presentation of botulism in adults is extremely rare and symptoms can be easily confused for symptoms of acute stroke, Guillain-Barre, or myasthenia gravis. The purpose of this clinical case report is to ensure adult botulism will be included in the differential diagnoses for a patient with this presentation so swift and accurate care can be provided to ensure optimal patient outcome. A 41-year-old-female presented with complaints of sudden onset of difficulty speaking. The patient reports a history of intravenous polysubstance abuse and symptoms progressed to bilateral facial weakness, ptosis, and external ophthalmoplegia. With no notable findings from a non-contrast computed tomography and magnetic resonance imaging and given the symptoms, a diagnosis of wound botulism from intravenous drug use was made. Botulism antitoxin was given and the patient was admitted into the intensive care unit for supportive follow-up care. A colony of Clostridium species was discovered in this patient’s arm and the patient showed significant improvement after a few days of care. (AU)

La presentación del botulismo en adultos es extremadamente rara y los síntomas pueden confundirse fácilmente con los síntomas de accidente cerebrovascular agudo, Guillain-Barré o miastenia gravis. El propósito de este informe de caso clínico es garantizar que el botulismo del adulto se incluya en los diagnósticos diferenciales de un paciente con esta presentación, de modo que se pueda brindar una atención rápida y precisa para garantizar un resultado óptimo del paciente. Una mujer de 41 años presentó quejas de aparición repentina de dificultad para hablar. El paciente refiere antecedentes de abuso de múltiples sustancias por vía intravenosa y los síntomas progresaron a debilidad facial bilateral, ptosis y oftalmoplejía externa. Sin hallazgos destacables de la tomografía computarizada sin contraste y la resonancia magnética y ante la sintomatología, se realizó el diagnóstico de botulismo de la herida por uso de drogas intravenosas. Se le administró antitoxina de botulismo y la paciente fue ingresada en la unidad de cuidados intensivos para cuidados de seguimiento de apoyo. Se descubrió una colonia de especies de Clostridium en el brazo de esta paciente, mostrando una mejoría significativa después de unos días de atención. (AU)

Ventricular Tachycardia in the Setting of Chagasic Cardiomyopathy: Use of Voltage Mapping to Characterize Endoepicardial Nonischemic Scar Distribution.

BACKGROUND: Chagasic cardiomyopathy (CC) is the most frequent nonischemic substrate causing left ventricular (LV) tachycardia in Latin America. Systematic characterization of the LV epicardial/endocardial scar distribution and density in CC has not been performed. Additionally, the usefulness of unipolar endocardial electroanatomic mapping to identify epicardial scar has not been assessed in this setting. METHODS AND RESULTS: Nineteen patients with CC undergoing detailed epicardial and endocardial LV tachycardia mapping and ablation were included. A total of 8494 epicardial and 6331 endocardial voltage signals and 314 epicardial/endocardial matched pairs of points were analyzed. Basal lateral LV scar involvement was observed in 18 of 19 patients. Bipolar voltage mapping demonstrated larger epicardial than endocardial scar and core-dense (≤0.5 mV) scar areas (28 [20-36] versus 19 [15-26] and 21 [2-49] versus 4 [0-7] cm2; P=0.049 and P=0.004, respectively). Bipolar epicardial and endocardial voltages within scar were low (0.4 [0.2-0.55] and 0.54 [0.33-0.87] mV, respectively) and confluent, indicating a dense/transmural scarring process in CC. The endocardial unipolar voltage value (with a newly proposed ≤4-mV cutoff) predicted the presence and extent of epicardial bipolar scar (P<0.001). CONCLUSIONS: CC causes a unique ventricular tachycardia substrate concentrated to the basal lateral LV, with marked epicardial predominance. The scar pattern is particularly dense and transmural as compared with the more erratic/patchy scar patterns seen in other nonischemic cardiomyopathies. Endocardial unipolar voltage mapping serves to characterize epicardial scar in this setting.

Cardiac sympathetic denervation for intractable ventricular arrhythmias in Chagas disease.

BACKGROUND: Autonomic modulation is a valuable therapeutic option for the management of ventricular arrhythmias. Bilateral cardiac sympathetic denervation (BCSD) has shown promising results in the acute, intermediate, and long-term management of polymorphic and monomorphic ventricular tachycardia (VT) in patients with structural heart disease. Cardiomyopathy (CM) due to Chagas disease (CD), and associated VT, is thought to be in part due to autonomic neuronal destruction and dysfunction. OBJECTIVE: The purpose of this study was to assess whether BCSD is a safe and effective treatment modality in patients with CD and VT storm or refractory VT. METHODS: A retrospective analysis of data from patients with chagasic CM who underwent BCSD between 2009 and 2015 at 2 international centers was performed. RESULTS: Of 75 patients who underwent BCSD for VT storm or refractory VT in the setting of CM, 7 (9.3%) patients had CD as the etiology of CM. All patients had monomorphic VT. Median follow-up was 7 months (range 1-46 months). All patients either underwent previous unsuccessful catheter ablation or were not candidates for ablation. The median number of implantable cardioverter-defibrillator (ICD) shocks 1 month before BCSD was 4 (range 2-30) and decreased to 0 (range 0-2) during available follow-up after BCSD. When antitachycardia pacing therapies were included in the analysis, the median number of ICD therapies (shocks + antitachycardia pacing) still decreased to 1 (range 0-3). CONCLUSION: In patients with chagasic CM presenting with refractory monomorphic VT, early evidence suggests that BCSD reduces appropriate ICD therapy and may represent a valuable treatment option.