Background: Ventricular pacing is detrimental to cardiac function, with more deleterious effects when it is apical, widening the QRS complex, so the best cardiac pacing site is still being sought. Objective: To compare, by electrocardiographic measurements, the duration of QRS complexes at different cardiac stimulation sites, from the medical records of patients with pacemakers, who attended the external cardiac stimulation consultation at Monte Sinai Hospital in Cuenca-Ecuador. Methods: A total of 323 patients were retrospectively analyzed from January 2011 to November 2018, classifying them by electrocardiographic morphology as apical, low septal, middle septal and right ventricular outflow tract (RVOT) stimulation. The duration of stimulated QRS complexes was quantified using digital software that allows such measurement and stores all records. Subsequently, the comparison of the means of the different stimulation sites was performed using ANOVA. Results: The average age was 73.6 years; 56.03% corresponded to males; 49.84% had apical stimulation, 21.67% middle septal, 15.78% RVOT, 12.69% low septal. At the end of the QRS complex measurements, an average on apex of 179.94 ms, on low septum of 172.56 ms, an average on middle septum of 153.89 ms and on RVOT 171.66 ms were obtained. When comparing these values with the average ANOVA, the duration of the QRS stimulated in the middle septum was shorter than the other sites, being statistically significant (p < 0.001). Conclusion: Cardiac pacing in the middle septum is a viable alternative, which results in shorter QRS complex duration, therefore, better synchronization of myocardial contraction, also avoiding the deleterious effects of apical stimulation.

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Background: Ventricular pacing is detrimental to cardiac function, with more deleterious effects when it is apical, widening the QRS complex, so the best cardiac pacing site is still being sought. Objective: To compare, by electrocardiographic measurements, the duration of QRS complexes at different cardiac stimulation sites, from the medical records of patients with pacemakers, who attended the external cardiac stimulation consultation at Monte Sinai Hospital in Cuenca-Ecuador. Methods: A total of 323 patients were retrospectively analyzed from January 2011 to November 2018, classifying them by electrocardiographic morphology as apical, low septal, middle septal and right ventricular outflow tract (RVOT) stimulation. The duration of stimulated QRS complexes was quantified using digital software that allows such measurement and stores all records. Subsequently, the comparison of the means of the different stimulation sites was performed using ANOVA. Results: The average age was 73.6 years; 56.03% corresponded to males; 49.84% had apical stimulation, 21.67% middle septal, 15.78% RVOT, 12.69% low septal. At the end of the QRS complex measurements, an average on apex of 179.94 ms, on low septum of 172.56 ms, an average on middle septum of 153.89 ms and on RVOT 171.66 ms were obtained. When comparing these values with the average ANOVA, the duration of the QRS stimulated in the middle septum was shorter than the other sites, being statistically significant (p < 0.001). Conclusion: Cardiac pacing in the middle septum is a viable alternative, which results in shorter QRS complex duration, therefore, better synchronization of myocardial contraction, also avoiding the deleterious effects of apical stimulation.

BACKGROUND: Supraventricular tachycardia is commonly diagnosed in clinical practice, despite having a good prognosis, it can significantly affect the patient’s life quality. Pharmacological treatment does not result in the total absence of the arrhythmia, which is why ablation therapy has become the treatment of choice, due to its high success rate, and for offering a definitive solution. The aim of this study was to determine the frequency of each supraventricular tachycardia type, according to age and sex, the rate of success of percutaneous ablation and its related factors, and the frequency of complications due to the procedure. METHODS: A cross-sectional, descriptive, correlational study was conducted, including 156 patients diagnosed with supraventricular tachycardia and ablated, from five hospitals where the procedure was performed, based on their clinical records. RESULTS: From the 156 patients in this study, 51.9% were women and 48.1% men, the age ranged between 10 and 80 years. The most commonly reported arrhythmias were nodal reentrant tachycardia, atrioventricular reentrant tachycardia and atrial flutter, being the atrioventricular reentrant tachycardia the most frequent of all. The global success rate was 93.5%, no complications were reported, and none of the studied factors had significant statistical association with the success rate. CONCLUSION: Ablation treatment had a high success rate, with cero complications in this study, demonstrating the efficacy and safety of the procedure.

RESUMEN INTRODUCCIÓN:La Endocarditis Bacteriana es una enfermedad grave de difícil diagnós-tico, debido al cuadro clínico inespecífico. Se caracteriza por la formación de vegetaciones infectadas por microorganismos en las válvulas y cámaras cardiacas o en el endotelio de los grandes vasos. Las valvulopatías congénitas y las enfermedades reumáticas son los principales factores de riesgo asociados con el padecimiento en válvulas nativas. Desde hace un siglo, la cavidad bucal ha sido reconocida como una fuente potencial de bacteriemia.CASO CLÍNICO: Paciente masculino de 40 años de edad, presentó disnea de inicio súbito, debilidad muscular, pérdida del estado de conciencia, posteriormente afasia y hemiplejia derecha. Se realizó una tomografía simple de cráneo evidenciando una zona isquémica, presentó alza térmica ≥ 38ºC. En el ecocardiograma con presencia de imagen sugestiva de vegetación adherida a la válvula aórtica y protrusión hacia tracto de salida del ventrículo izquierdo.EVOLUCIÓN: Se realizó cirugía de cambio valvular aórtico mecánico, con tratamiento antibiótico presentado evolución favorable y recuperando la fuerza muscular en hemicuerpo derecho. En hospitalización se instauró anticoagulación oral durante el cual luego varios días presentó cuadro convulsivo, se evidencia en la tomografía zona hemorrágica y se remplazó medicación por heparina de bajo peso molecular. CONCLUSIÓN:La endocarditis bacteriana se sospecha en todo paciente que presenta clí-nica de fiebre y criterios de DUKE positivos. Siendo la piedra angular del diagnóstico el ecocardiograma y el hemocultivo positivo, para establecer su etiología requiriendo un manejo adecuado, precoz para brindar una terapéutica oportuna. *DESCRIPTORES DeCS