Toward a Quasi-dynamic Pulsed Field Electroporation Numerical Model for Cardiac Ablation: Predicting Tissue Conductance Changes and Ablation Lesion Patterns.

Pulsed field ablation (PFA) has the potential to evolve into an efficient alternative to traditional RF ablation for atrial fibrillation treatment. However, achieving irreversible tissue electroporation is critical to suppressing arrhythmic pathways, raising the need for accurate lesion characterization. To understand the physics behind the tissue response PFA, we propose a quasi-dynamic model that quantifies tissue conductance at end-electroporation and identifies regions that have undergone fully irreversible electroporation (IRE). The model uses several parameters and numerically solves the electrical field diffusion into the tissue by iteratively updating the tissue conductance until equilibrium at end-electroporation. The model yields a steady-state tissue conductance map used to identify the irreversible lesion. We conducted numerical experiments mimicking a lasso catheter featuring nine 3-mm electrodes spaced circumferentially at 3.75 mm and fired sequentially using a 1500 V and 3000 V pulse amplitude. The IRE lesion region has a surface area and volume of 780 mm2 and 1411 mm3, respectively, at 1500 V, and 1178 mm2 and 2760 mm3, respectively, at 3000 V. Lesion discontinuity was observed at 5.0 mm depth with 1500 V, and 7.2 mm depth with 3000 V. This quasi-dynamic model yields tissue conductance maps, predicts irreversible lesion and lesion penumbra at end-electroporation, and confirms larger lesions with higher pulse amplitudes.

Meta-Analysis of New-Onset Atrial Fibrillation Versus No History of Atrial Fibrillation in Patients With Noncardiac Critical Care Illness.

The incidence of new-onset secondary atrial fibrillation (NOSAF) is as high as 44% in noncardiac critical illness. A systematic review and meta-analysis were performed to evaluate the impact of NOSAF, compared with history of prior atrial fibrillation (AF) and no history of AF in noncardiac critically ill patients. Patients undergoing cardiothoracic surgery were excluded. NOSAF incidence, intensive care unit (ICU)/hospital length of stay (LOS), and mortality outcomes were analyzed. Of 2,360 studies reviewed, 19 studies met inclusion criteria (n = 306,805 patients). NOSAF compared with no history of AF was associated with increased in-hospital mortality (risk ratio [RR] 2.06, 95% confidence interval [CI] 1.76 to 2.41, p <0.001), longer ICU LOS (standardized difference in means [SMD] 0.66, 95% CI 0.41 to 0.91, p <0.001), longer hospital LOS (SMD 0.31, 95% CI 0.07 to 0.56, p = 0.001) and increased risk of long-term (>1 year) mortality (RR 1.76, 95% CI 1.29 to 2.40, p <0.001). NOSAF compared with previous AF was also associated with higher in-hospital mortality (RR 1.29, 95% CI 1.12 to 1.49, p <0.001), longer ICU LOS (SMD 0.37, 95% CI 0.03 to 0.70, p = 0.03) but no difference in-hospital LOS (SMD -0.18, 95% CI -0.66 to 0.31, p = 0.47). In conclusion, NOSAF, in the setting of noncardiac critical illness is associated with increased in-hospital mortality compared with no history of AF and previous AF. NOSAF (vs no history of AF) is also associated with increased long-term mortality.

Delayed cerebellar ataxia: A rare self limiting complication of plasmodium falciparum malaria.

The classic presentation of malaria with paroxysms of fever is seen only in 50-70% of the patients. The development of immunity, the increasing resistance to anti-malarial drugs, and the indiscriminate use of anti-malarial drugs have led to malaria with the presentation of unusual features. Cerebellar ataxia, extrapyramidal rigidity and various psychiatric symptoms have been described either as early manifestations of cerebral malaria or as a part of post malaria neurological syndrome. In this case report, we will discuss one such patient of falciparum malaria infection who developed midline cerebellar signs, and responded to anti-malarial treatment.

Lutembacher's syndrome.

The definition of Lutembacher's syndrome has undergone many changes. It refers to combination of congenital Atrial Septal Defect with acquired mitral stenosis. Lutembacher's syndrome is a very rare disease and in the past, it has been either overdiagnosed or misdiagnosed. Here, we will discuss a case of a pregnant lady who developed breathlessness during her third trimester of pregnancy and on detailed examination and investigation, she was found to be having Lutembacher's syndrome.

Ichthyosis vulgaris and pycnodysostosis: an unusual occurrence.

Pycnodysostosis is a rare autosomal recessive disorder whose gene responsible for this phenotype (CTSK), mapped to human chromosome 1q21, code for the enzyme cathepsin K, a lysosomal cysteine protease; with an estimated incidence of 1.7 per 1 million births. This clinical entity includes micromelic dwarfism, increased radiological bone density, dysplasia of the skull, acro-osteolysis, straightening of the mandibular angle and in some cases, dysplasia of the acromial end of the clavicle. Oral and maxillo-facial manifestations of this disease are very clear. Herein we reported a case of pycnodysostosis, showing short stature with widening of the sutures, unfused anterior and posterior fontanelles, crowding of teeth with dental caries and typical radiological features associated with ichthyosis vulgaris and palmoplantar keratoderma.

Diastolic dysfunction in asymptomatic type 2 diabetes mellitus with normal systolic function.

BACKGROUND: The incidence of heart failure in diabetic subjects is high even in the absence of hypertension and coronary artery disease. AIMS: The purpose of this study was to study the incidence of diastolic dysfunction in diabetic subjects and its relation to age, duration of diabetes mellitus (DM), Glycosylated hemoglobin (HbA1c) levels, obesity indices and diabetic microangiopathies. SETTINGS AND DESIGN: This was a case control prospective study conducted at the teaching hospital during a one year period. MATERIALS AND METHODS: A total of 127 subjects (case) with type 2 diabetes of more than five years duration were studied. Total 100 healthy subjects were included as the control group. Echocardiography was performed to assess left ventricular diastolic function. RESULTS: Out of the total 127 subjects, 69 (54.33%) from the case group had diastolic dysfunction, and 11% amongst 100 in the control group population showed the diastolic dysfunction (P < 0.001). Patients with a longer duration of DM (of 11 to 15 years) had a higher prevalence of diastolic dysfunction (P < 0.02). Subjects with high waist circumference and high waist to hip ratio had statistically significant diastolic dysfunction with 'P' =0.001 and 'P' = < 0.02 respectively. Subjects with HbA1c > 7.5% had a higher prevalence of diastolic dysfunction than subjects with HbA1c < 7.5% (P < 0.02). Diastolic dysfunction was present in majority of the subjects with autonomic neuropathy and retinopathy. CONCLUSIONS: Present study reveals high incidence of diastolic dysfunction in asymptomatic diabetic; subjects and, this finding was correlated with the duration of diabetes, HbA1c levels, obesity indices and diabetic microangiopathies. We conclude that early diagnosis and institution of treatment will reduce morbidity and improve the outcomes, and prevent future heart failure.