Prolonged repolarization in the early phase of ischemia is associated with ventricular fibrillation development in a porcine model

Background: Repolarization prolongation can be the earliest electrophysiological change in ischemia, but its role in arrhythmogenesis is unclear. The aim of the present study was to evaluate the early ischemic action potential duration (APD) prolongation concerning its causes, expression in ECG and association with early ischemic ventricular fibrillation (phase 1A VF).Methods: Coronary occlusion was induced in 18 anesthetized pigs, and standard 12 lead ECG along with epicardial electrograms were recorded. Local activation time (AT), end of repolarization time (RT), and activation-repolarization interval (ARIc) were determined as dV/dt minimum during QRS-complex, dV/dt maximum during T-wave, and rate-corrected RT–AT differences, respectively. Patch-clamp studies were done in enzymatically isolated porcine cardiomyocytes. IK(ATP) activation and Ito1 inhibition were tested as possible causes of the APD change.Results: During the initial period of ischemia, a total of 11 pigs demonstrated maximal ARIc prolongation >10 ms at 1 and/or 2.5 min of occlusion (8 and 6 cases at 1 and 2.5 min, respectively) followed by typical ischemic ARIc shortening. The maximal ARIc across all leads was associated with VF development (OR 1.024 95% CI 1.003–1.046, p = 0.025) and maximal rate-corrected QT interval (QTc) (B 0.562 95% CI 0.346–0.775, p < 0.001) in logistic and linear regression analyses, respectively. Phase 1A VF incidence was associated with maximal QTc at the 2.5 min of occlusion in ROC curve analysis (AUC 0.867, p = 0.028) with optimal cut-off 456 ms (sensitivity 1.00, specificity 0.778). The pigs having maximal QTc at 2.5 min more and less than 450 ms significantly differed in phase 1A VF incidence in Kaplan-Meier analysis (log-rank p = 0.007). In the patch-clamp experiments, 4-aminopyridine did not produce any effects on the APD; however, pinacidil activated IK(ATP) and caused a biphasic change in the APD with initial prolongation and subsequent shortening.Conclusion: The transiently prolonged repolarization during the initial period of acute ischemia was expressed in the prolongation of the maximal QTc interval in the body surface ECG and was associated with phase 1A VF. IK(ATP) activation in the isolated cardiomyocytes reproduced the biphasic repolarization dynamics observed in vivo, which suggests the probable role of IK(ATP) in early ischemic arrhythmogenesis

Management gaps of traumatic spinal cord injuries in war-torn low and middle-income nations: why has this massive problem garnered little attention? Editorial

Spinal cord injuries (SCIs) are injuries to the spinal cord that can cause changes in sensation, movement, and other functions below the site of the injury1. Traumatic spinal cord injuries (TSCIs), on the other hand, are injuries to the spinal cord caused by external trauma or force that can range in severity from mild to severe2. Spinal shock, pressure ulcers, bladder and bowel dysfunction, respiratory problems, pain, and psychological issues are all common complications of TSCIs2. The location and extent of the damage, the person’s general health, and their age all play a role in determining the specific effects of a TSCI2. TSCIs can have far-reaching consequences for individuals, their families, and society. Physically, TSCIs can cause paralysis, loss of sensation, and difficulty with mobility and daily activities, significantly reducing an individual’s independence and quality of life1. The WHO estimates the yearly incidence of TSCIs to be 40–80 cases per million people3. As a result, the precise prevalence of TSCI in low and middle-income countries (LMICs) is poorly understood; however, the estimated incidence of TSCI in LMICs is 25.5 cases per million people per year4. In many nonconflicted LMICs, the leading causes of TSCIs were motor vehicle accidents and fall injuries, but in war-torn areas, the etiologies were different, with more aggressive complications3,5. This article seeks to highlight the management gaps of TSCIs in LMICs, particularly in war zones, and offers suggested recommendations

Primjena i kompozicija individualiziranih zaštitnih elemenata linijske grafike u projektiranju novčanica

Proces stvaranja novčanica je dugotrajan i složen, što rezultira kompleksnim rješenjima koja predstavljaju pravo remek djelo grafike. Novčanice su prožete brojnim detaljima i prenose različite informacije koje se analiziraju u teorijskom dijelu rada. Prvotno se postavljaju kriteriji po kojima se izrađuje detaljna analiza velikog broja zaštitnih i konceptualnih elemenata na primjerima novčanica. Time je prikazan okvirni povijesni pregled razvoja novčanica i utjecaji kojima je bio izložen. Analizira se međuovisnost dizajna o sigurnosnim značajkama, te se ispituje razina informiranosti javnosti o zaštitama na novčanicama. Zaključuje se koje metode zaštite su najučinkovitije, te kako šira javnost najčešće provjerava autentičnost novčanica. U eksperimentalnom dijelu rada se na temelju donesenih zaključaka iz teorijskog dijela izrađuje prototip novčanice koja je u najvećoj mjeri prožeta individualiziranim PostScript programskim rješenjima elemenata linijske grafike (rozete, mikrotekst, zaštitne linije, brojevi apoena), a od ostalih zaštita modeliran je individualizirani raster transformacijom matematičkog izraza u PostScript programski kod. Sve ostale zaštite tipične za novčanice simulirane su alatima za rastersku i vektorsku grafiku. U radu se ispituje utjecaj kompozicije zaštitnih elemenata na prepoznavanje autentičnosti novčanica, te efikasnost samih individualiziranih programskih rješenja

Development and Evaluation of Clinical Efficacy of Intraocular Lens Fixation after Cataract Phacoemulsification, Complicated by Capsular Lenticular Disruption

Рurpose. Evaluation of the clinical efficacy of the original procedure for fixing the posterior chamber intraocular lens (IOL) after phacoemulsification of cataracts (FEC), complicated by the violation of capsular lens support.Patients and Methods. 194 patients were examined after FEC,  complicated by a capsular lenticular impairment. They were divided  into 3 groups. In the main group (OG, 64 eyes) the IOL was sutured  with an original technique, fundamentally different method, there  nodes formed at the ends of the filaments were fixed in the layers of the cornea. In 2 controls groups, there the traditional IOL under  the scleral flap (K1, 68 eyes) was performed and the IOL was  attached to the iris (K2, 62 eyes). A comprehensive examination of  the patients’ vision state included an evaluation of clinical, functional and subjective indicators.Results. The lowest total probability of postoperative complications development was noted in OG (6.4%) compared to K2 and K1  (16.0–17.7%). The overall probability of changing the positions of  the IOL in the exhaust gas is 6.4%, which is significantly lower than  in the K2 (9.6%) and K1 (14.6%) groups. The developed method in  comparison with the traditional methods of fixation provides a higher level of patient’s quality of life (by 10.2–11.7%, p < 0.05)  and functional indicators associated with the brightness and contrast sensitivity of the eye.The conclusion. The developed technique provides, in comparison with the traditional, a higher level of safety and functionality of IOL fixation

Interconnection at the level of uric acid and apolipoprotein e in the blood of persons with normal and hyper lipidemia

To investigate the levels of uric acid and apoE in patients with normo- and hyperlipidemia. The serum lipids, apolipoproteins and uric acid levels were measured with Chronolab (Switzerland) kits in 78 patients: 53 patients with normolipidemia and 25 patients with hyperlipidemia of type IIa and IIb. Significantly higher levels of apo-E were registered in patients with hyperlipidemia than in patients with normolipidemia, but there were no differences in content of uric acid. A comparative correlation analysis detected a significant correlation between uric acid and apoE levels in both groups but in normolipidemic patients the correlation was positive while in hyperlipidemic patients it was negative. Hyperlipidemia provokes inversion of correlation between the levels of uric acid, apoE and apoC3. A rise of apoC3 may serve an adaptive mechanism of inhibition of apo-E induced hyperlipidemia

РЕПОЛЯРИЗАЦИЯ ЭПИКАРДИАЛЬНОЙ ПОВЕРХНОСТИ ЖЕЛУДОЧКОВ СЕРДЦА КРОЛИКА ПРИ ЭКСПЕРИМЕНТАЛЬНОМ САХАРНОМ ДИАБЕТЕ

The purpose of the study was to find out the spatial pattern of ventricular repolarization in diabetes mellitus in heart of rabbits in vivo.Цель работы: исследование реполяризации эпикарда желудочков сердца кролика с индуцированным аллоксаном сахарным диабетом in vivo

Prolongation of The Activation Time in Ischemic Myocardium is Associated with J-wave Generation in ECG and Ventricular Fibrillation

J-wave pattern has been recognized as an arrhythmic risk marker, particularly in myocardial infarction patients. Mechanisms underlying J-wave development in ischemia remain unknown. In myocardial infarction model, we evaluated activation time delay as a prerequisite of J-wave appearance and predictor of ventricular fibrillation. Body surface ECGs and myocardial unipolar electrograms were recorded in 14 anesthetized pigs. 48 intramural leads were positioned across ventricular free walls and interventricular septum. Myocardial ischemia was induced by ligation of the left anterior descending coronary artery and the recordings were done during 40-minute coronary occlusion. The local activation times were determined as instants of dV/dt minimum during QRS complex in unipolar electrograms. During occlusion, ventricular local activation time prolonged in the middle portion of the left ventricular free wall, and basal and middle portions of septum, while J-waves appeared in precordial leads in 11 animals. In logistic regression and ROC curve analyses, activation time delay at a given time-point was associated with J-wave development, and a longer activation time was associated with ventricular fibrillation appearance. In experimental coronary occlusion, activation delay in ischemic myocardium was associated with generation of the J waves in the body surface ECG and predicted ventricular fibrillation

Prolonged repolarization in the early phase of ischemia is associated with ventricular fibrillation development in a porcine model

Background: Repolarization prolongation can be the earliest electrophysiological change in ischemia, but its role in arrhythmogenesis is unclear. The aim of the present study was to evaluate the early ischemic action potential duration (APD) prolongation concerning its causes, expression in ECG and association with early ischemic ventricular fibrillation (phase 1A VF). Methods: Coronary occlusion was induced in 18 anesthetized pigs, and standard 12 lead ECG along with epicardial electrograms were recorded. Local activation time (AT), end of repolarization time (RT), and activation-repolarization interval (ARIc) were determined as dV/dt minimum during QRS-complex, dV/dt maximum during T-wave, and rate-corrected RT–AT differences, respectively. Patch-clamp studies were done in enzymatically isolated porcine cardiomyocytes. IK(ATP) activation and Ito1 inhibition were tested as possible causes of the APD change. Results: During the initial period of ischemia, a total of 11 pigs demonstrated maximal ARIc prolongation >10 ms at 1 and/or 2.5 min of occlusion (8 and 6 cases at 1 and 2.5 min, respectively) followed by typical ischemic ARIc shortening. The maximal ARIc across all leads was associated with VF development (OR 1.024 95% CI 1.003–1.046, p = 0.025) and maximal rate-corrected QT interval (QTc) (B 0.562 95% CI 0.346–0.775, p < 0.001) in logistic and linear regression analyses, respectively. Phase 1A VF incidence was associated with maximal QTc at the 2.5 min of occlusion in ROC curve analysis (AUC 0.867, p = 0.028) with optimal cut-off 456 ms (sensitivity 1.00, specificity 0.778). The pigs having maximal QTc at 2.5 min more and less than 450 ms significantly differed in phase 1A VF incidence in Kaplan-Meier analysis (log-rank p = 0.007). In the patch-clamp experiments, 4-aminopyridine did not produce any effects on the APD; however, pinacidil activated IK(ATP) and caused a biphasic change in the APD with initial prolongation and subsequent shortening. Conclusion: The transiently prolonged repolarization during the initial period of acute ischemia was expressed in the prolongation of the maximal QTc interval in the body surface ECG and was associated with phase 1A VF. IK(ATP) activation in the isolated cardiomyocytes reproduced the biphasic repolarization dynamics observed in vivo, which suggests the probable role of IK(ATP) in early ischemic arrhythmogenesis