A novel method of standardized myocardial infarction in aged rabbits.

The incidence of both myocardial infarction (MI) and sudden cardiac death increases with age. Here, we describe the development of a minimally invasive large animal model of MI that can be applied to young or aged animals. We demonstrate that rabbit coronary anatomy is highly variable, more so than described in previous literature. In this work, we categorize the coronary pattern of 37 young rabbits and 64 aged rabbits. Aged rabbits had a higher degree of branching from the left main coronary artery. Standardizing the model across age cohorts required a new approach, targeting an area of myocardium rather than a specific vessel. Here, we present a method for achieving a reproducible infarct size, one that yielded a consistent scar encompassing ~30% of the apical left ventricular free wall. The model's consistency allowed for more valid comparisons of MI sequelae between age cohorts.NEW & NOTEWORTHY This study describes the coronary angiographic imaging of young and aged rabbits. We developed and improved a novel minimally invasive approach for coil embolization that targets a specific area of myocardium and yielded a consistent scar encompassing ~30% of the left ventricular free wall of young and aged rabbit hearts.

Impact of Racial and Gender Variations in Patients With Out-of-hospital Cardiac Arrest: A Nation-Wide Study.

The overall incidence of Out-of-hospital Cardiac Arrest (OHCA) is decreasing worldwide due to emergency responses, but there are gender and racial differences in the incidence of OHCA, which remain under investigation. Our aim was to identify the incidence, gender, and racial disparities in patients admitted with OHCA. The National Inpatient Sample Database is one of the largest all-payer inpatient database. It was queried to identify patients 18 years or older who were hospitalized with the principal diagnosis of OHCA. There was a total of 85,988 patients who were discharged with a diagnosis classified as OHCA using the ICD-9 code for a period of 2 years. The mean age of the patients who had presented to the hospital with OHCA was 64.3 (±18.5 years). Overall, a greater number of males suffered from OHCA were compared with female population of (48,635 vs 37,366; P < 0.0001). The incidence of OHCA was higher among Caucasians as compared with African Americans (54,812, 63.8% vs 13,787, 16%; P < 0.0001). In-hospital deaths after OHCA were 43,024 (50%). But African Americans had higher mortality than Caucasians after hospitalization for OHCA (adjusted odds ratio, 1.23; 95% confidence interval, 1.18-1.26; P < 0.01). We observed significant differences in gender and racial factors in the patients who were admitted to the hospital with a diagnosis of OHCA based on an analysis of the national inpatient database.

Takotsubo Cardiomyopathy and LV Outflow Tract Obstruction after Initiation of Novel Oral Chemotherapy.

BACKGROUND: Japanese authors first reported a reversible cardiomyopathy due to emotional stress known as Takotsubo cardiomyopathy or stress-induced cardiomyopathy or apical ballooning syndrome. In this case report, we describe Takotsubo cardiomyopathy associated with use of a chemotherapy drug, Regorafenib (Stivarga). CASE HISTORY: A 72-year-old female with history of metastatic colon cancer, with liver metastasis status post-resection and a recent diagnosis of primary non-small cell lung cancer on chemotherapy presented with shortness of breath exacerbated on exertion for 3 days. Patient was treated with Regorafenib for 10 days. EKG done showed 2mm ST elevation in V2-V4 leads and troponin was elevated to 6.8 ng/ml. The patient was taken for emergency cardiac catheterization which revealed normal coronaries but left ventriculogram showed low ejection fraction of 30% with apical akinesis and basal hyperkinesis with typical Takotsubo pattern. DISCUSSION: Regorafenib is a multi-kinase inhibitor, approved by the FDA for metastatic colon carcinoma, hepatic carcinoma and advanced gastrointestinal stromal tumors. The stress of cancer diagnosis and chemotherapeutic agents can cause significant cardiac mortality including Takotsubo cardiomyopathy. Cardiogenic shock and thromboembolic complications are an important cause of mortality. CONCLUSION: This is a rare presentation of Takotsubo cardiomyopathy associated with use of Regorafenib along with dynamic LVOT obstruction and systolic anterior motion of the mitral valve.

Atrial Fibrillation in Hypertrophic Cardiomyopathy: Evidence-based Review About Mechanism, Complications and Management.

Hypertrophic cardiomyopathy (HCM) is 1 of the most frequent genetic cardiovascular diseases affecting 1 out of every 500 individuals in general population. Atrial Fibrillation incidences were 3.8% per 100 patients per year and overall prevalence among HCM patients are 27.09%. Higher risk of death noted in HCM patients with atrial fibrillation. Stroke and other thrombo embolic risks are increased in such patients. Medical management using mainly betablockers or amiodarone produced variable results and high rate of recurrence. Catheter ablation reduced symptom burden and complications despite moderate recurrence. Patients with multiple repeated procedures found to have better success rate and outcomes. The complications are not high leading to increased feasibility of the procedure. More research using latest techniques in catheter ablation need to be studied.

Evaluation of Anticoagulation Practice With New-Onset Atrial Fibrillation in Patients with Sepsis and Septic Shock in Medical Intensive Care Unit: A Retrospective Observational Cohort Study.

Objective To investigate the anticoagulation practice in patients presenting with new-onset atrial fibrillation (NOAF) during sepsis and septic shock with one-year follow-up since discharge and to evaluate factors associated with the development of NOAF. Methods A retrospective observational cohort study was conducted using chart review in patients diagnosed with sepsis and septic shock.  Results There was a total of 1132 patients diagnosed with sepsis and septic shock over a one-year period. Thirty-two patients were found to have NOAF in the setting of sepsis. Of this, eight (25%) patients were anticoagulated with warfarin and 14 (44%) patients were not anticoagulated during discharge. At one-year follow-up post-discharge, nine (29%) patients continued on warfarin and 16 (52%) patients remained not anticoagulated. Conclusion We found that the majority of patients who developed NOAF did not get anticoagulated at the time of discharge. A similar trend followed after one year of follow-up. Since proper treatment guidelines are not in place, these patients are at high risk for recurrent atrial fibrillation, stroke, transient ischemic attack, and death.

Late INa Blocker GS967 Supresses Polymorphic Ventricular Tachycardia in a Transgenic Rabbit Model of Long QT Type 2.

BACKGROUND: Long QT syndrome has been associated with sudden cardiac death likely caused by early afterdepolarizations (EADs) and polymorphic ventricular tachycardias (PVTs). Suppressing the late sodium current (INaL) may counterbalance the reduced repolarization reserve in long QT syndrome and prevent EADs and PVTs. METHODS: We tested the effects of the selective INaL blocker GS967 on PVT induction in a transgenic rabbit model of long QT syndrome type 2 using intact heart optical mapping, cellular electrophysiology and confocal Ca2+ imaging, and computer modeling. RESULTS: GS967 reduced ventricular fibrillation induction under a rapid pacing protocol (n=7/14 hearts in control versus 1/14 hearts at 100 nmol/L) without altering action potential duration or restitution and dispersion. GS967 suppressed PVT incidences by reducing Ca2+-mediated EADs and focal activity during isoproterenol perfusion (at 30 nmol/L, n=7/12 and 100 nmol/L n=8/12 hearts without EADs and PVTs). Confocal Ca2+ imaging of long QT syndrome type 2 myocytes revealed that GS967 shortened Ca2+ transient duration via accelerating Na+/Ca2+ exchanger (INCX)-mediated Ca2+ efflux from cytosol, thereby reducing EADs. Computer modeling revealed that INaL potentiates EADs in the long QT syndrome type 2 setting through (1) providing additional depolarizing currents during action potential plateau phase, (2) increasing intracellular Na+ (Nai) that decreases the depolarizing INCX thereby suppressing the action potential plateau and delaying the activation of slowly activating delayed rectifier K+ channels (IKs), suggesting important roles of INaL in regulating Nai. CONCLUSIONS: Selective INaL blockade by GS967 prevents EADs and abolishes PVT in long QT syndrome type 2 rabbits by counterbalancing the reduced repolarization reserve and normalizing Nai. Graphic Abstract: A graphic abstract is available for this article.

Impact of Drug Induced Long QT Syndrome: A Systematic Review.

BACKGROUND: Drug induced long QT syndrome is quite common in daily clinical practice but its impact is unknown. METHODS: PubMed and EMBASE databases (until May 2, 2017) were searched to identify studies reporting drug induced long QT syndrome and followed the PRISMA guidelines. The main outcomes measured in these studies were QTc prolongation, ventricular arrhythmias, torsade de pointes (TdP) and death. RESULTS: Out of 176 non-duplicate reports, 36 studies satisfied inclusion criteria and provided data on patients exposed to drugs that can potentially cause long QT. Totally, 14,756 patients were exposed and 930 patients (6.3%) were found to have QTc prolongation. The number of males was 6,400 and females were 5,723 patients. The mean age of the patients was 43.8 ± 9.36 years. Ventricular arrhythmias were found in 379 patients (2.6%), 26 patients were found to have premature atrial contractions (PACs) and premature ventricular contractions (PVCs). TdP was found in 49 patients (0.33 %), sudden cardiac death (SCD) was found in five patients and 586 patients were found to have all-cause mortality. CONCLUSIONS: Around 6% of patients have risk of QT prolongation when exposed but only 0.3% developed TdP and 2.6% developed ventricular arrhythmias. Risk of developing arrhythmias is higher with concomitant use of multiple QT prolonging drugs.

PVCs, PVC-Induced Cardiomyopathy, and the Role of Catheter Ablation.

Premature ventricular contractions (PVCs) are common arrhythmias noticed in the clinical setting because of premature depolarization of the ventricular myocytes. Although often thought to be reflective of underlying disease rather than intrinsically harmful, PVCs have recently been linked with worse outcomes in patients without significant cardiac disease. Long-term exposure to a high PVC burden can lead to the development of PVC-induced cardiomyopathy. The pathogenesis of this condition is poorly understood at the current time. Many studies have suggested that catheter ablation of these PVCs may result in reversal of the PVC-induced cardiomyopathy. This article will go over the natural history of PVCs and PVC-induced cardiomyopathy, as well as review the current literature on the role of catheter ablation in treating PVC-induced cardiomyopathy.

Bloodstream infections due to extended-spectrum ß-lactamase-producing Enterobacteriaceae among patients with malignancy: a systematic review and meta-analysis.

Extended-spectrum ß-lactamase-producing Enterobacteriaceae (ESBL-PE) are an increasing cause of resistant infections among patients with malignancy. This study sought to estimate the prevalence of bloodstream infections (BSIs) caused by ESBL-PE in this population and to examine regional and temporal differences. The PubMed and EMBASE databases (to 30 April 2016) were searched to identify studies reporting ESBL-PE BSI rates among patients with malignancies. Of 593 non-duplicate reports, 22 studies providing data on 5650 BSI cases satisfied the inclusion criteria. Among all BSIs the pooled prevalence of ESBL-PE was 11% (95% CI 8-15%) and among Gram-negative BSIs it was 21% (95% CI 16-27%). Among patients with haematological malignancies, the pooled ESBL-PE prevalence was 11% (95% CI 8-15%), whereas no studies providing specific data on patients with solid tumours were identified. Stratifying per geographic region, the pooled prevalence was 7% each in Europe (95% CI 5-11%), the Eastern Mediterranean region (95% CI 4-11%) and South America (95% CI 2-14%), 10% in the Western Pacific region (95% CI 4-19%) and 30% in Southeast Asia (95% CI 18-44%). Importantly, there was a 7.1% annual increase in the ESBL-PE incidence (P = 0.004). Overall, ca. 1 in 10 BSIs in patients with malignancy is caused by ESBL-PE and in some areas this rate can be as high as 1 in 3 cases. Additionally, the incidence of these resistant infections is rising. These findings should be considered when selecting empirical antimicrobial therapy and should prompt strict adherence to antimicrobial stewardship.

Atypical presentation of infective endocarditis.

The HACEK group of organisms are one of the infrequent causes of infective endocarditis. Infective endocarditis should be recognized and treated promptly to prevent excessive morbidity and mortality associated with the disease. Sometimes the diagnosis is delayed due to vague and subtle presentation. Through this case report, risk factors of Cardiobacterium hominis endocarditis and its atypical presentation is illustrated to increase the recognition of infective endocarditis as one of the differential diagnosis. [Full article available at http://rimed.org/rimedicaljournal-2016-07.asp, free with no login].

Refractory sciatica could be a sign of malignancy: A unique case presentation.

t Renal cell carcinoma is one of the highly aggressive tumors and notorious for late presentations. It is associated with high morbidity and mortality. Renal cell carcinoma is known for rare metastatic sites. In clinical practice, it is often important not to anchor to a particular diagnosis but rather revisit and revaluate entire history and clinical examination. We describe a case of metastatic renal cell carcinoma that was initially treated as sciatica and later found to have advanced debilitating malignancy. Internal medicine physicians should be able to recognize one of the rare metastatic sites of renal cell carcinoma and understand the importance of imaging studies if patient has persisting sciatica symptoms without improvement.