Successful prediction of left bundle branch block-induced cardiomyopathy and treatment effect by artificial intelligence-enabled electrocardiogram.

BACKGROUND: Left bundle branch block (LBBB) induced cardiomyopathy is an increasingly recognized disease entity.  However, no clinical testing has been shown to be able to predict such an occurrence. CASE REPORT: A 70-year-old male with a prior history of LBBB with preserved ejection fraction (EF) and no other known cardiovascular conditions presented with presyncope, high-grade AV block, and heart failure with reduced EF (36%). His coronary angiogram was negative for any obstructive disease. No other known etiologies for cardiomyopathy were identified. Artificial intelligence-enabled ECGs performed 6 years prior to clinical presentation consistently predicted a high probability (up to 91%) of low EF. The patient successfully underwent left bundle branch area (LBBA) pacing with correction of the underlying LBBB. Subsequent AI ECGs showed a large drop in the probability of low EF immediately after LBBA pacing to 47% and then to 3% 2 months post procedure. His heart failure symptoms markedly improved and EF normalized to 54% at the same time. CONCLUSIONS: Artificial intelligence-enabled ECGS may help identify patients who are at risk of developing LBBB-induced cardiomyopathy and predict the response to LBBA pacing.

Predictors of myocardial recovery in arrhythmia-induced cardiomyopathy: A multicenter study.

BACKGROUND: Arrhythmia-induced cardiomyopathy (AIC) is characterized by improvement in left ventricular ejection fraction (LVEF) following arrhythmia treatment. Predictors of recovery in LVEF are not well understood. OBJECTIVE: We evaluated predictors of AIC recovery in a large multicenter cohort. METHODS: In total, 243 patients (age 65 ± 11, 73% male) with AIC caused by atrial fibrillation (49%), atrial tachycardia (20%), and premature ventricular contractions (PVCs; 31%) were treated and included. LVEF was assessed before and after treatment. Patients were stratified by arrhythmia duration (known [KN, n = 132] vs. unknown [UKN, n = 111]), arrhythmia type, LVEF, and presence of structural heart disease (SHD). RESULTS: Arrhythmia treatment was rhythm control in 95%. Median arrhythmia duration in the KN group was 47 months (25-75th percentile, 24-80 months). Post treatment LVEF was higher in KN group (55.9 ± 7 vs. 46.2 ± 12%; p < .0001) but the degree of LVEF improvement was similar (21.2 ± 9 vs. 19.4 ± 11; p = .16). Comparing highest quartile (longest arrhythmia duration) versus the rest of the KN group, the extent of LVEF improvement was similar (21.5 ± 8 vs. 21 ± 9%; p = .1). Patients in lowest index LVEF quartile (n = 74) had more PVC-induced AIC, greater EF improvement after treatment (24 ± 17 vs. 19 ± 7%; p < .0001) but lower post treatment EF (45 ± 14 vs. 54 ± 8%; p < .0001) versus other patients. Patients with SHD had lower index EF (28 ± 8 vs. 34 ± 8%; p < .0001) and lower final EF (47 ± 12 vs. 56 ± 7; p ≪ .0001). In multivariate regression, low index LVEF predicted myocardial recovery (odds ratio, 11.4; p < .005). CONCLUSIONS: In this AIC cohort, LVEF improved regardless of arrhythmia duration or type but those with PVCs had lower index LVEF and had less recovery. Low index LVEF predicted LVEF recovery following arrhythmia treatment.

Biochemical and genetic requirements for function of the immune response regulator BOTRYTIS-INDUCED KINASE1 in plant growth, ethylene signaling, and PAMP-triggered immunity in Arabidopsis.

Arabidopsis thaliana BOTRYTIS-INDUCED KINASE1 (BIK1) regulates immune responses to a distinct class of pathogens. Here, mechanisms underlying BIK1 function and its interactions with other immune response regulators were determined. We describe BIK1 function as a component of ethylene (ET) signaling and PAMP-triggered immunity (PTI) to fungal pathogens. BIK1 in vivo kinase activity increases in response to flagellin peptide (flg22) and the ET precursor 1-aminocyclopropane-1-carboxylic acid (ACC) but is blocked by inhibition of ET perception. BIK1 induction by flg22, ACC, and pathogens is strictly dependent on EIN3, and the bik1 mutation results in altered expression of ET-regulated genes. BIK1 site-directed mutants were used to determine residues essential for phosphorylation and biological functions in planta, including PTI, ET signaling, and plant growth. Genetic analysis revealed flg22-induced PTI to Botrytis cinerea requires BIK1, EIN2, and HUB1 but not genes involved in salicylate (SA) functions. BIK1-mediated PTI to Pseudomonas syringae is modulated by SA, ET, and jasmonate signaling. The coi1 mutation suppressed several bik1 phenotypes, suggesting that COI1 may act as a repressor of BIK1 function. Thus, common and distinct mechanisms underlying BIK1 function in mediating responses to distinct pathogens are uncovered. In sum, the critical role of BIK1 in plant immune responses hinges upon phosphorylation, its function in ET signaling, and complex interactions with other immune response regulators.

Echocardiographic changes and heart failure hospitalizations following rhythm control for arrhythmia-induced cardiomyopathy: results from a multicenter, retrospective study.

BACKGROUND: The incidence and prevalence of arrhythmia-induced cardiomyopathy (AIC) are unclear but likely underrecognized. LV dysfunction is common among patients with atrial fibrillation (AF), atrial flutter (AFL), and frequent premature ventricular contractions (PVC). The hallmark of AIC is the improvement of left ventricular ejection fraction (LVEF) following arrhythmia treatment. Changes in echocardiographic parameters and their effect on outcomes after rhythm control for AIC are not well understood. We aimed to study echocardiographic parameters and outcomes following rhythm control for AIC. METHODS: A multicenter, retrospective study was conducted at 4 different medical centers involving patients with AIC. Clinical, echocardiographic, and outcome (mortality and heart failure hospitalizations [HFH]) parameters were extracted from the medical record. RESULTS: Two hundred fifty-five patients (age 66 ± 11 years, 73% male) with AIC caused by AF (51%), atrial tachycardia/AFL (20%), and PVCs (29%) were included and followed for a median period of 6 months after successful rhythm control. Significant improvements in left ventricular (LV) ejection fraction (P < 0.0001), LV end-systolic volume (ml) (90 ± 48 to 58 ± 30; P < 0.0001), LV internal diameter end diastole (cm) (5.5 ± 0.78 to 5.3 ± 0.64; P = 0.0001) and end systole (4.7 ± 0.95 to 4.3 ± 1.02; P < 0.0001), right atrial pressure (mmHg) (11.3 ± 5.0 to 7.4 ± 3.2; P = 0.0001), and right ventricular function (n (%)) (42 (44) to 9 (11); P < 0.0001) were noted following arrhythmia treatment. No deaths occurred during follow-up. HFH occurred in 7 patients. Arrhythmia recurrence rate was 50.5%. Neither echocardiographic parameters nor recurrence of arrhythmia correlated with HFH. CONCLUSION: Arrhythmia treatment significantly improved echocardiographic LV dimensions, LVEF, and RAP in this multicenter AIC cohort, underscoring the need for early recognition and aggressive rhythm control in suspected AIC patients. The event rate was too low to assess for outcome predictors.

Case Report: ST-Elevation Myocardial Infarction Secondary to Acute Atherothrombotic Occlusion Treated With No Stent Strategy.

Background: Intravascular imaging plays a vital role in the pathophysiology-based diagnosis and treatment of patients with ST-elevation myocardial infarction (STEMI). We present a case of STEMI due to plaque erosion, which was managed with a no stent approach. Case Summary: A 43-year-old female with a history of tobacco abuse presented with an anterior STEMI. Coronary angiography revealed acute thrombotic occlusion of the left anterior descending artery with spontaneous recanalization. Intravascular imaging with optical coherence tomography (OCT) demonstrated plaque erosion as the underlying etiology for the acute thrombotic occlusion. A no stent strategy with aspiration thrombectomy and dual antiplatelet therapy was used to manage the patient given that there was no evidence of plaque rupture. Repeat coronary imaging was done at 2 months to assess the status of the lesion. Conclusion: A 43-year-old female with STEMI due to plaque erosion was successfully managed only by thrombus aspiration and not by angioplasty and stent placement. Individualized treatment approaches in patients with acute coronary syndromes, can not only achieve optimal management goals but also avoid unnecessary complications associated with interventions. This case illustrates how intracoronary imaging and pathophysiology-guided treatment can dramatically change management. In this young patient, STEMI was managed purely by thrombus aspiration. Intravascular imaging obviated the need for stent placement possibly preventing stent-related complications including restenosis and thrombosis.

Use of Mutant-Assisted Gene Identification and Characterization (MAGIC) to identify novel genetic loci that modify the maize hypersensitive response.

The partially dominant, autoactive maize disease resistance gene Rp1-D21 causes hypersensitive response (HR) lesions to form spontaneously on leaves and stems in the absence of pathogen recognition. The maize nested association mapping (NAM) population consists of 25 200-line subpopulations each derived from a cross between the maize line B73 and one of 25 diverse inbred lines. By crossing a line carrying the Rp1-D21 gene with lines from three of these subpopulations and assessing the F(1) progeny, we were able to map several novel loci that modify the maize HR, using both single-population quantitative trait locus (QTL) and joint analysis of all three populations. Joint analysis detected QTL in greater number and with greater confidence and precision than did single population analysis. In particular, QTL were detected in bins 1.02, 4.04, 9.03, and 10.03. We have previously termed this technique, in which a mutant phenotype is used as a "reporter" for a trait of interest, Mutant-Assisted Gene Identification and Characterization (MAGIC).

Two Limitations of Subcutaneous Implantable Cardioverter Defibrillator in the Same Patient Warranting Its Explant.

BACKGROUND A subcutaneous implantable cardioverter defibrillator (S-ICD) is preferred over a transvenous implantable cardioverter defibrillator (TV-ICD) in selected cases owing to a lower rate of lead-related complications such as infections and venous thrombosis. However, the S-ICD has its own limitations, including inappropriate shocks due to oversensed events, and the inability to treat ventricular tachycardia (VT) below a heart rate of 170 beats per minutes (bpm). We present a patient case which showed manifestations of both of these limitations, warranting explant of the device. CASE REPORT A 50-year-old man with a history of nonischemic cardiomyopathy and VT had a S-ICD placed at an outside facility. However, he continued to have VT despite on anti-arrhythmic drugs and required recurrent S-ICD shocks. Device interrogation showed that he was intermittently receiving appropriate shocks for slower VT (with a heart rate ranging from 150 bpm to 160 bpm) due to oversensing of T waves. However, treatment was delayed for other VT episodes owing to appropriate sensing and the patient's heart rate being below the lowest detection zone for S-ICD. Due to slower VT cycle length and frequent oversensed events, the S-ICD was ultimately replaced by a TV-ICD system. CONCLUSIONS This case report emphasizes the importance of S-ICD pre-implant vector screening and the need for paying attention to VT cycle length to prevent inappropriate device shocks and/or delayed therapies.

Myocardial infarction secondary to coronary embolus in a patient with left ventricular non-compaction cardiomyopathy: a case report.

BACKGROUND: Coronary embolism is a rare cause of myocardial infarction (MI). We present a case report which emphasizes the importance of intracoronary imaging in these cases to identify the pathophysiological mechanism of MI. CASE SUMMARY: A 53-year-old male with no past medical history presented to the hospital with typical angina. Electrocardiogram and serum troponin I level trend confirmed non-ST-elevation myocardial infarction. Coronary angiography showed no evidence of any obstructive coronary artery disease, but two small thrombi were noted in the distal first obtuse marginal branch. Optical coherence tomography imaging confirmed this finding in absence of any underlying atherosclerotic plaque rupture or erosion. Cardiac magnetic resonance imaging revealed the diagnosis of non-compaction cardiomyopathy with severely depressed left ventricular function. Transmural MI was revealed by late gadolinium enhancement in the mid-lateral wall. Based on the pathophysiology of the MI confirmed by intracoronary imaging, antiplatelet medications were discontinued, and the patient was discharged on warfarin. Medical therapy was initiated for his cardiomyopathy. The patient recovered well and was asymptomatic at 1-year follow-up visit. DISCUSSION: Intracoronary imaging plays an important role to supplement coronary angiography to confirm the pathophysiology of MI in coronary embolism cases. This is important as it alters management in these patients.

A 37-Year-Old Woman with Hypertrophic Cardiomyopathy with a Dual-Chamber Implantable Cardioverter-Defibrillator Requiring Percutaneous Transvenous Lead Extraction and Multidisciplinary Management.

BACKGROUND Percutaneous transvenous lead extraction (TLE) of cardiac implantable electronic devices can be performed with a high success rate. However, TLE has its limitations and challenges. Recognizing the challenges at an early stage during the procedure is vital for appropriate patient management. We present a challenging case of implantable cardioverter-defibrillator (ICD) lead extraction in which we aborted TLE in favor of elective surgical extraction (SE). This potentially prevented a major catastrophic complication of vascular tear, which would have required an emergent thoracotomy. CASE REPORT A 37-year-old woman with history of hypertrophic cardiomyopathy had a primary prevention dual-chamber ICD implant in 2001 and underwent right ventricular ICD lead revision in 2009 due to lead fracture. In 2019, she was again found to have right ventricular ICD lead malfunction. TLE was attempted, but no meaningful progression could be made despite using multiple extraction tools. Therefore, TLE was aborted in favor of SE. During elective SE, significant adhesions were noted, and the innominate vein was completely avulsed during removal of the leads, requiring venous reconstruction by the vascular surgery team. After SE and vascular reconstruction, an epicardial ICD system was placed, and the patient had an uneventful postoperative recovery. CONCLUSIONS This case report highlights the limitations of TLE and the importance of recognizing them in a timely manner. In all challenging cases, conversion to elective SE should be considered to avoid potential injuries warranting emergent surgical repair.

Meta-Analysis of Transradial vs Transfemoral Access for Percutaneous Coronary Intervention in Patients With ST Elevation Myocardial Infarction.

Transradial access (TRA) has emerged as an alternative to transfemoral access (TFA) for percutaneous coronary intervention (PCI) in ST elevation myocardial infarction (STEMI) patients. However, the rate of TRA adoption has been much slower in the acute coronary syndrome (ACS) patient population. This meta-analysis was conducted to assess clinical outcomes of TRA compared with TFA in STEMI patients undergoing PCI. A manual search of PubMed, EMBASE, Cochrane library database, Cumulative Index to Nursing and Allied Health Literature (CINAHL), ClinicalTrials.gov, and recent major scientific conference sessions from inception to October 15th, 2019 was performed. Primary outcomes in our analysis were all-cause mortality and trial-defined major bleeding. Secondary outcomes included vascular complications, myocardial infarction, stroke, procedure, and fluoroscopy time. 17 randomized controlled trials (RCTs) (N = 12,018) met inclusion criteria. TRA was associated with lower all-cause mortality (risk ratio [RR]: 0.71, 95% confidence interval [CI]: 0.57 to 0.88), major bleeding (RR: 0.59, 95%CI: 0.45 to 0.77), and vascular complications (RR: 0.42, 95%CI: 0.32 to 0.56) compared with TFA. There was no difference in the incidence of myocardial infarction (MI), stroke, or procedure duration between the 2 groups. The difference in all-cause mortality between TRA and TFA was statistically nonsignificant when major bleeding was held constant. In conclusion, TRA was associated with lower risk of all-cause mortality, major bleeding, and vascular complications compared with TFA in STEMI patients undergoing PCI.

Meta-analysis Comparing Transradial Versus Transfemoral Secondary Access in Transcatheter Aortic Valve Implantation.

Up to a quarter of vascular complications during transcatheter aortic valve implantation (TAVI) result from secondary access via the femoral artery (FA). The radial artery (RA) is increasingly used as an alternative to the FA for secondary access in TAVI. Limited data exist on the outcomes of RA secondary access versus FA secondary access. We therefore conducted a systematic review and meta-analysis comparing secondary access sites. PubMed, EMBASE, Scopus, Cochrane library and CINAHL were searched systematically for studies comparing RA and FA as secondary access sites for TAVI. Primary outcomes of interest were vascular complications and major bleeding. Secondary outcomes included all-cause mortality, stroke and myocardial infarction (MI). Risk ratio (RR), standardized mean difference and corresponding 95% confidence intervals (CI) were calculated using a random effects model. Six observational studies comprising 6,373 patients (RA: 1,514, FA: 4,859) met inclusion criteria. Secondary access was utilized for aortography during valve deployment and to manage primary access site complications. Procedural characteristics were similar in both groups. RA was associated with a lower risk of major bleeding (RR: 0.51, 95% CI: 0.40 to 0.64, p <0.00001). No statistically significant difference was observed in the incidence of overall vascular complications, however, the risk of major vascular complications was lower with RA (RR: 0.45, 95% CI: 0.32 to 0.63, p <0.00001). The incidence of stroke and all-cause mortality was lower in RA, whereas no difference was observed in the risk of MI. In conclusion, our meta-analysis suggests that RA secondary access is associated with better outcomes for TAVI than FA.

Continued versus Suspended Cardiac Resynchronization Therapy after Left Ventricular Assist Device Implantation.

Cardiac resynchronization therapy (CRT) improves outcomes in heart failure patients with wide QRS complex. However, CRT management following continuous flow Left Ventricular Assist Device (LVAD) implant vary: some centers continue CRT while others turn off the left ventricular (LV) lead at LVAD implant. We sought to study the effect of continued CRT versus turning off CRT pacing following continuous flow LVAD implantation. A comprehensive retrospective multicenter cohort of 295 patients with LVAD and pre-existing CRT was studied. CRT was programmed off after LVAD implant in 44 patients. We compared their outcomes to the rest of the cohort using univariate and multivariate models. Mean age was 60 ± 12 years, 83% were males, 52% had ischemic cardiomyopathy and 54% were destination therapy. Mean follow-up was 2.4 ± 2.0 years, and mean LVAD support time was 1.7 ± 1.4 years. Patients with CRT OFF had a higher Interagency Registry for Mechanically Assisted Circulatory Support (INTERMACS) mean profile (3.9 vs 3.3, p = 0.01), more secondary prevention indication for a defibrillator (64.9% vs 44.5%, p = 0.023), and more pre-LVAD ventricular arrhythmias (VA) (77% vs 60%, p = 0.048). There were no differences between the CRT OFF and CRT ON groups in overall mortality (Log rank p = 0.32, adjusted HR = 1.14 [0.54-2.22], p = 0.71), heart transplantation, cardiac and noncardiac mortality, all cause hospitalizations, hospitalizations for ICD shocks, and number and frequency of ICD shocks or anti-tachycardia pacing therapy. There were no differences in post LVAD atrial arrhythmias (AA) (Adjusted OR = 0.45 [0.18-1.06], p = 0.31) and ventricular arrhythmias (OR = 0.65 [0.41-1.78], p = 0.41). There was no difference in change in LVEF, LV end diastolic and end systolic diameters between the 2 groups. Our study suggests that turning off CRT pacing after LVAD implantation in patients with previous CRT pacing did not affect mortality, heart transplantation, device therapies or arrhythmia burden. A prospective study is needed to confirm these findings.

Questionable utility of digoxin in left-ventricular assist device recipients: A multicenter, retrospective analysis.

BACKGROUND: While clinical experience with left ventricular assist devices (LVAD) continues to grow and evolve, little is known regarding the ongoing use of certain medications in this population. We sought to evaluate the utility of digoxin in LVAD recipients and its association with outcomes. METHODS: A total of 505 patients who underwent continuous-flow LVAD implantation at 5 centers from 2007-2015 were included. Patients were divided into 4 groups: not on digoxin at any time (ND; n = 257), received digoxin pre implant (PreD; n = 144), received digoxin pre and post implant (ContD; n = 55), and received digoxin only post implant (PostD; n = 49). Survival and all-cause readmission were compared between the 4 groups. RESULTS: There was no difference in survival at 1 year nor at 3 years between groups (ND = 88%, 66%, respectively; PreD = 85%, 66%; ContD = 86%, 57%; PostD = 90%, 51%; p = 0.7). Readmission per 100 days also was not different between groups (ND = 0.5, PreD = 0.6, ContD = 0.5, PostD = 0.7; p = 0.1). CONCLUSIONS: In this large, multicenter cohort, use of digoxin was not associated with any significant benefit in regard to mortality or hospitalization in patients supported with a continuous-flow LVAD. Importantly, its discontinuation post implant did not worsen all-cause hospitalization or survival.

Cardiac Resynchronization Therapy and Clinical Outcomes in Continuous Flow Left Ventricular Assist Device Recipients.

BACKGROUND: Many patients with heart failure continue cardiac resynchronization therapy (CRT) after continuous flow left ventricular assist device (CF-LVAD) implant. We report the first multicenter study to assess the impact of CRT on clinical outcomes in CF-LVAD patients. METHODS AND RESULTS: Analysis was performed on 488 patients (58±13 years, 81% male) with an implantable cardioverter defibrillator (ICD) (n=223) or CRT-D (n=265) who underwent CF-LVAD implantation at 5 centers from 2007 to 2015. Effects of CRT on mortality, hospitalizations, and ventricular arrhythmia incidence were compared against CF-LVAD patients with an ICD alone. Baseline differences were noted between the 2 groups in age (60±12 versus 55±14, P<0.001) and QRS duration (159±29 versus 126±34, P=0.001). Median biventricular pacing in the CRT group was 96%. During a median follow-up of 478 days, Kaplan-Meier analysis showed no difference in survival between groups (log rank P=0.28). Multivariate Cox regression demonstrated no survival benefit with type of device (ICD versus CRT-D; P=0.16), whereas use of amiodarone was associated with increased mortality (hazard ratio 1.77, 95% confidence interval 1.1-2.8, P=0.01). No differences were noted between CRT and ICD groups in all-cause (P=0.06) and heart failure (P=0.9) hospitalizations, ventricular arrhythmia incidence (43% versus 39%, P=0.3), or ICD shocks (35% versus 29%, P=0.2). During follow-up, 69 (26%) patients underwent pulse generator replacement in the CRT-D group compared with 36 (15.5%) in the ICD group (P=0.003). CONCLUSIONS: In this large, multicenter CF-LVAD cohort, continued CRT was not associated with improved survival, hospitalizations, incidence of ventricular arrhythmia and ICD therapies, and was related to a significantly higher number of pulse generator changes.

Arrhythmia-Induced Cardiomyopathy: Prevalent, Under-recognized, Reversible.

Arrhythmia-induced cardiomyopathy (AIC) is a clinical condition in which a persistent tachyarrhythmia or frequent ectopy contribute to ventricular dysfunction leading to systolic heart failure. AIC can be partially or completely corrected with adequate treatment of the culprit arrhythmia. Several molecular and cellular alterations by which tachyarrhythmias lead to cardiomyopathy have been identified. AIC can affect children and adults, can be clinically silent in the form of asymptomatic tachycardia with cardiomyopathy, or can present with manifest heart failure. A high index of suspicion for AIC and aggressive treatment of the culprit arrhythmia can result in resolution of heart failure symptoms and improvement in cardiac function. Recurrent arrhythmia, following recovery from the index episode, can hasten the left ventricular dysfunction and result in HF, suggesting persistent adverse remodeling despite recovery of left ventricular function. Several aspects of AIC, such as predisposing factors, early diagnosis, preventive measures to avoid adverse remodeling, and long-term prognosis, remain unclear, and need further research.

Importance of hospital entry: walk-in STEMI and primary percutaneous coronary intervention.

INTRODUCTION: Patients with ST elevation myocardial infarction (STEMI) require rapid identification and triage to initiate reperfusion therapy. Walk-in STEMI patients have longer treatment times compared to emergency medical service (EMS) transported patients. While effective triage of large numbers of critically ill patients in the emergency department is often cited as the reason for treatment delays, additional factors have not been explored. The purpose of this study was to evaluate baseline demographic and clinical differences between walk-in and EMS-transported STEMI patients and identify factors associated with prolonged door to balloon (D2B) time in walk-in STEMI patients. METHODS: We performed a retrospective review of 136 STEMI patients presenting to an urban academic teaching center from January 2009 through December 2010. Baseline demographics, mode of hospital entry (walk-in versus EMS transport), treatment times, angiographic findings, procedures performed and in-hospital clinical events were collected. We compared walk-in and EMS-transported STEMI patients and identified independent factors of prolonged D2B time for walk-in patients using stepwise logistic regression analysis. RESULTS: Walk-in patients (n=51) were more likely to be Latino and presented with a higher heart rate, higher systolic blood pressure, prior history of diabetes mellitus and were more likely to have an elevated initial troponin value, compared to EMS-transported patients. EMS-transported patients (n=64) were more likely to be white and had a higher prevalence of left main coronary artery disease, compared to walk-in patients. Door to electrocardiogram (ECG), ECG to catheterization laboratory (CL) activation and D2B times were significantly longer for walk-in patients. Walk-in patients were more likely to have D2B time >90 minutes, compared to EMS- transported patients; odds ratio 3.53 (95% CI 1.03, 12.07), p=0.04. Stepwise logistic regression identified hospital entry mode as the only independent predictor for prolonged D2B time. CONCLUSION: Baseline differences exist between walk-in and EMS-transported STEMI patients undergoing primary percutaneous coronary intervention (PCI). Hospital entry mode was the most important predictor for prolonged treatment times for primary PCI, independent of age, Latino ethnicity, heart rate, systolic blood pressure and initial troponin value. Prolonged door to ECG and ECG to CL activation times are modifiable factors associated with prolonged treatment times in walk-in STEMI patients. In addition to promoting the use of EMS transport, efforts are needed to rapidly identify and expedite the triage of walk-in STEMI patients.

A connected set of genes associated with programmed cell death implicated in controlling the hypersensitive response in maize.

Rp1-D21 is a maize auto-active resistance gene conferring a spontaneous hypersensitive response (HR) of variable severity depending on genetic background. We report an association mapping strategy based on the Mutant Assisted Gene Identification and Characterization approach to identify naturally occurring allelic variants associated with phenotypic variation in HR. Each member of a collection of 231 diverse inbred lines of maize constituting a high-resolution association mapping panel were crossed to a parental stock heterozygous for Rp1-D21, and the segregating F(1) generation testcrosses were evaluated for phenotypes associated with lesion severity for 2 years at two locations. A genome-wide scan for associations with HR was conducted with 47,445 SNPs using a linear mixed model that controlled for spurious associations due to population structure. Since the ability to identify candidate genes and the resolution of association mapping are highly influenced by linkage disequilibrium (LD), we examined the extent of genome-wide LD. On average, marker pairs separated by >10 kbp had an r(2) value of <0.1. Genomic regions surrounding SNPs significantly associated with HR traits were locally saturated with additional SNP markers to establish local LD structure and precisely identify candidate genes. Six significantly associated SNPs at five loci were detected. At each locus, the associated SNP was located within or immediately adjacent to candidate causative genes predicted to play significant roles in the control of programmed cell death and especially in ubiquitin pathway-related processes.