Optimizing sowing window, cultivar choice, and plant density to boost maize yield under RCP8.5 climate scenario of CMIP5.

The impacts of climate change and possible adaptations to food security are a global concern and need greater focus in arid and semi-arid regions. It includes scenario of Coupled Model Intercomparison Phase 5 (CMIP-RCP8.5). For this purpose, two DSSAT maize models (CSM-CERES and CSM-IXIM) were calibrated and tested with two different maize cultivars namely Single Cross 10 (SC10) and Three Way Cross 324 (TW24) using a dataset of three growing seasons in Nile Delta. SC10 is a long-growing cultivar that is resistant to abiotic stresses, whereas TW24 is short and sensitive to such harsh conditions. The calibrated models were then employed to predict maize yield in baseline (1981-2010) and under future time slices (2030s, 2050s, and 2080s) using three Global Climate Models (GCMs) under CMIP5-RCP8.5 scenario. In addition, the use of various adaptation options as shifting planting date, increasing sowing density, and genotypes was included in crop models. Simulation analysis showed that, averaged over three GCMs and two crop models, the yield of late maturity cultivar (SC10) decreased by 4.1, 17.2, and 55.9% for the three time slices of 2030s, 2050s, and 2080s, respectively, compared to baseline yield (1981-2010). Such reduction increased with early maturity cultivar (TW24), recording 12.4, 40.6, and 71.3% for near (2030s), mid (2050s), and late century (2080s) respectively relative to baseline yield. The most suitable adaptation options included choosing a stress-resistant genotype, changing the planting date to plus or minus 30 days from baseline planting date, and raising the sowing density to 9 m-2 plants. These insights could minimize the potential reduction of climate change-induced yields by 39% by late century.

Unmasking pulmonary hypertension following tricuspid valve replacement.

In this Viewpoint, we highlight a possible hemodynamic problem arising following tricuspid valve replacement (TVR) in patients with severe chronic tricuspid regurgitation, represented by "unmasking" of pulmonary hypertension (PH) following the surgery. We share an observation that should alert cardiologists to the fact that this increasingly utilized surgery is not risk free, and careful assessment of the right ventricular function and pulmonary circulation preoperatively is extremely important, especially in patients with preexisting risk factors for PH, since TVR may lead to a sudden increase in right ventricular afterload.

Spigelian-cryptorchidism syndrome in an adult male complaining of primary infertility: Case report.

History of cryptorchidism is present in about 10% of infertile patients seeking medical help, whereas 20% of them are azoospermic. Most of the patients with bilateral cryptorchidism have a low testicular volume and high serum FSH level. Ectopic testes are present only in 5% of the patients with cryptorchidism. The anterior abdominal wall is a rare site for ectopic testis where Spigelian hernia is usually accompanied. We present a case of bilateral ectopic anterior abdominal wall testes associated with Spigelian hernia on the left side.

Use of Direct Oral Anticoagulants in the Treatment of Left Ventricular Thrombus: Systematic Review of Current Literature.

BACKGROUND: Left ventricular thrombus (LVT) is an important complication in the setting of systolic dysfunction, particularly after acute myocardial infarction. Current guidelines recommend the vitamin-K antagonist, warfarin, for the treatment of LVT. AREA OF UNCERTAINTY AND STUDY QUESTION: The direct oral anticoagulants (DOACs) are being increasingly used for the management of this entity, despite lack of randomized trials in support of it or knowledge about their efficacy. We aimed to assess the frequency of use and the efficacy of DOACs in the treatment of LVT. DATA SOURCES: We searched published articles in Google Scholar, PubMed, MEDLINE, and Embase from the introduction of DOACs in any therapy until April 2018. Reports describing patients diagnosed with LVT and who were treated with a DOAC were examined. Patient characteristics, comorbidities, pharmacologic treatments, and outcomes were collected. The primary end points of this study were thrombus resolution and time to resolution. Other end points were bleeding and thromboembolic events. RESULTS: Thirty articles describing 41 patients were analyzed. The most common risk factors for LVT formation were male gender, ischemic heart disease, and low ejection fraction. Most patients were treated with rivaroxaban (51.2%), followed by apixaban (26.8%) and dabigatran (22%). Patients were treated with DOAC alone (46.3%), DOAC and aspirin (12.2%), DOAC and clopidogrel (2.4%), and triple therapy (39%). Thrombus resolution success rate was 81%, 100%, and 88.9% for rivaroxaban, apixaban, and dabigatran, respectively. The median time of thrombus resolution was 40 days, 36 days, and 24 days for rivaroxaban, apixaban, and dabigatran, respectively. One nonfatal bleeding event and one stroke event were reported while on a DOAC. CONCLUSIONS: The use of DOACs is a reasonable alternative to vitamin-K antagonists in the management of LVT.

Trends in the Incidence of In-Hospital Mortality, Cardiogenic Shock, and Utilization of Mechanical Circulatory Support Devices in Myocarditis (Analysis of National Inpatient Sample Data, 2005-2014).

BACKGROUND: Myocarditis may be associated with hemodynamic instability and portends a poor prognosis when associated with cardiogenic shock (CS). There are limited data available on the incidence of in-hospital mortality, CS, and utilization of mechanical circulatory support (MCS) devices in these patients. METHODS: We queried the 2005-2014 National Inpatient Sample databases to identify all patients aged >18 years with myocarditis in the United States. RESULTS: The number of reported cases of myocarditis per 1 million gradually increased from 95 in 2005 to 144 in 2014 (Pfor trend <.01). The trend and incidence of endomyocardial biopsy remained the same despite the increase in clinical diagnosis. Overall, in-hospital mortality was 4.43% of total admissions without a change in overall trend over the study period. We also observed a significant increase in the incidence of CS from 6.94% in 2005 to 11.99% in 2014 (Pfor trend <.01). There was a parallel increase in the utilization of advanced MCS devices during the same time period such as extracorporeal membrane oxygenation or percutaneous cardiopulmonary support (0.32% in 2005 to 2.1% in 2014; P< .01) and percutaneous ventricular assist devices such as Impella/tandem heart (0.176% in 2005 to 1.75% in 2014; P< .01). CONCLUSION: Although the incidence of myocarditis has increased in the last decade, the in-hospital mortality has remained the same despite increases in the incidence of CS, possibly reflecting the benefits of increased usage of advanced MCS devices. We noted that increasing age, presence of multiple comorbidities and CS were associated with an increase in in-patient mortality.

In-hospital outcomes of transcatheter mitral valve repair with Mitraclip in patients with pulmonary hypertension: Insights from the National Inpatient Sample.

BACKGROUND: Periprocedural outcomes of transcatheter mitral valve repair (TMVR) with Mitraclip in patients with pulmonary hypertension (PH) are not well studied. METHODS: Patients who underwent TMVR with Mitraclip between 2011 and 2015 were identified using the National Inpatient Sample (NIS). All missing variables were excluded from the analysis and therefore, complete case analysis was performed. RESULTS: A total of 1,037 patients underwent TMVR with Mitraclip between 2011 and 2015. The prevalence of PH in these patients was 32.6%. In-hospital outcomes were compared between PH group and non-PH group. Inpatient mortality after TMVR was similar between the two groups (3.2% vs. 2.1%, OR 1.57, P = 0.335). There was no statistical significance between the two groups in the rates of hemorrhage requiring transfusion (8.5% vs. 7.2%, OR 1.17, P = 0.587), cardiogenic shock (4.4% vs. 4.5%, OR 0.98, P = 0.951), acute respiratory failure (15.2% vs. 13.1%, OR 1.23, P = 0.460), postoperative sepsis (2.75% vs. 3.9%, OR 0.66, P = 0.340), postoperative deep vein thrombosis or pulmonary embolism (2.7% vs. 3.9%, OR 1.98, P = 0.348). In addition, non-routine home discharge, median hospital cost and length of stay were similar between the two groups. CONCLUSION: Pre-existing PH in patients undergoing TMVR with Mitraclip does not adversely affect in-hospital outcomes in this cohort of patients. Therefore, PH does not carry a prohibitive risk in selecting patients for Mitraclip procedure.

Effect of Girth Supersizing on Patient Satisfaction After Semi-Rigid Penile Implant Insertion: A Prospective Case-Control Study.

BACKGROUND: Penile length and girth have long been sources of anxiety for men. OBJECTIVES: The authors sought to measure satisfaction with intercourse and erectile function 3 and 6 months after girth augmentation in patients with semi-rigid penile implants who received autologous fat injections. METHODS: Thirty married participants in Egypt were recruited and divided into 2 groups between January 2016 and August 2017. Fifteen patients who underwent semi-rigid penile implant insertion and 15 controls all received autologous fat injections and were followed-up for 3 and 6 months. RESULTS: Median penile girth increased significantly in both groups, although fat loss was noted after 6 months. There was a positive correlation between the amount of fat injected and the change in penile girth measured 6 months after the procedure in the controls. CONCLUSIONS: Autologous fat transfer is a simple and safe procedure that can be used to augment penile girth in patients whose girth is less than 11.5 cm after penile prosthesis insertion.

Multivariate analysis and GIS approaches for modeling and mapping soil quality and land suitability in arid zones.

Assessing soil quality marks the initial step in precision farming and agricultural management. Developing countries like Egypt face numerous hurdles in ensuring food security due to increasing populations and limited agricultural resources. A geographic information system (GIS) and multivariate analysis were utilized in the current work to evaluate and map a soil quality index (SQI). Moreover, the land suitability of the land for two plantations of the tree's oak (Quercus robur), and pine (Pinus silvestris), respectively was assessed using a parametric approach. A total of 82 soil profiles were selected to fulfill the objectives of the study. Based on the samples' PC scores, and agglomerative hierarchical clustering (AHC, the data was divided into two clusters: Cluster I and Cluster II, which collectively account for approximately 57% and 43% of the total data, respectively.. . The findings indicated that land suitability for planting Q. robur planted identified 2.14% of the research area as highly suitable (S1), 37.98% as moderately suitable (S2), and 59.89% as not suitable (N). Furthermore, the assessment of suitability for P. silvestris indicated that 50.88% of the investigated area was classified into: S1, 48.73% as S2, and 0.39% as N, which means it is not suitable for conservation activities. The research identified that soil depth beside excessive salinity and calcium carbonate as the primary soil constraints in the area in both clusters. The average soil depth, ECd and CaCO3 were 113.62 ± 12.41, 17.27 ± 10.23, 16.83 ± 6.57 in Cluster 1 and 45.43 ± 15.21, 22.42 ± 12.43, 21.55 ± 5.63 in Cluster II. The study demonstrates that integrating multivariate analysis with GIS enables a precise and streamlined assessment of the Soil Quality Index (SQI). Soil suitability modelling underscores the importance of implementing efficient management practices to attain agricultural sustainability in arid regions, particularly amidst intensive land utilization pressures.

Serum ACE2 and S19P gene polymorphism in Egyptian patients with COVID-19 infection: correlation with disease severity.

The expression of ACE2 is linked to disease severity in COVID-19 patients. The ACE2 receptor gene polymorphisms are considered determinants for SARS-CoV-2 infection and its outcome. In our study, serum ACE2 and its genetic variant S19P rs73635825 polymorphism were investigated in 114 SARS-CoV-2 patients. The results were compared with 120 control subjects. ELISA technique and allele discrimination assay were used for measuring serum ACE2 and genotype analysis of ACE2 rs73635825. Our results revealed that serum ACE2 was significantly lower in SARS-CoV-2 patients (p = 0.0001), particularly in cases with hypertension or diabetes mellitus. There was a significant difference in the genotype distributions of ACE2 rs73635825 A > G between COVID-19 patients and controls (p-value = 0.001). A higher frequency of the heterozygous AG genotype (65.8%) was reported in COVID-19 patients. The G allele was significantly more common in COVID-19 patients (p < 0.0001). The AG and GG genotypes were associated with COVID-19 severity as they were correlated with abnormal laboratory findings, GGO, CXR, and total severity scores with p < 0.05. Our results revealed that the ACE2 S19P gene variant is correlated with the incidence of infection and its severity, suggesting the usefulness of this work in identifying the susceptible population groups for better disease control.

Enhancing Maize Yield and Soil Health through the Residual Impact of Nanomaterials in Contaminated Soils to Sustain Food.

Studying the impact of residual soil nanomaterials is a promising challenge for sustainable agricultural development to improve soil health and crop productivity. The objective of this study is to assess the long-term impacts of 50, 100, and 250 mg kg-1 soil of nanobiochar (nB) and nano-water treatment residues (nWTR) on the fertility, biological activity, and yield of maize (Zea mays L.) growing in heavy metal-contaminated soils. The results showed that when nB and nWTR were added in larger quantities, the concentrations of lead (Pb), nickel (Ni), cadmium (Cd), and cobalt (Co) extracted with DTPA decreased. With the addition of nB or nWTR, it also showed a significant increase in exchangeable cations, cation exchange capacity (CEC), soil fertility, soil organic matter (OM), microbial biomass carbon (MBC), and a decrease in soil salinity and sodicity. Catalase and dehydrogenase activities rose as nB addition increased, while they decreased when nWTR addition increased. In comparison to the control, the addition of nB and nWTR greatly boosted maize yield by 54.5-61.4% and 61.9-71.4%, respectively. These findings suggest that the researched nanomaterials' residual effect provides an eco-friendly farming method to enhance the qualities of damaged soils and boost maize production. Our research suggested that adding recycling waste in the form of nanoparticles could immobilize heavy metals, improve soil characteristics, and increase the soil's capacity for productivity.

Development of an AI-Driven QT Correction Algorithm for Patients in Atrial Fibrillation.

BACKGROUND: Prolongation of the QTc interval is associated with the risk of torsades de pointes. Determination of the QTc interval is therefore of critical importance. There is no reliable method for measuring or correcting the QT interval in atrial fibrillation (AF). OBJECTIVES: The authors sought to evaluate the use of a convolutional neural network (CNN) applied to AF electrocardiograms (ECGs) for accurately estimating the QTc interval and ruling out prolongation of the QTc interval. METHODS: The authors identified patients with a 12-lead ECG in AF within 10 days of a sinus ECG, with similar (±10 ms) QRS durations, between October 23, 2001, and November 5, 2021. A multilayered deep CNN was implemented in TensorFlow 2.5 (Google) to predict the MUSE (GE Healthcare) software-generated sinus QTc value from an AF ECG waveform, demographic characteristics, and software-generated features. RESULTS: The study identified 6,432 patients (44% female) with an average age of 71 years. The CNN predicted sinus QTc values with a mean absolute error of 22.2 ms and root mean squared error of 30.6 ms, similar to the intrinsic variability of the sinus QTc interval. Approximately 84% and 97% of the model's predictions were contained within 1 SD (±30.6 ms) and 2 SD (±61.2 ms) from the sinus QTc interval. The model outperformed the AFQTc method, exhibiting narrower error ranges (mean absolute error comparison P < 0.0001). The model performed best for ruling out QTc prolongation (negative predictive value 0.82 male, 0.92 female; specificity 0.92 male, 0.97 female). CONCLUSIONS: A CNN model applied to AF ECGs accurately predicted the sinus QTc interval, outperforming current alternatives and exhibiting a high negative predictive value.

The Impact of Bacteriospermia on Semen Parameters Among Infertile Egyptian Men: A Case-Control Study.

This study aimed to detect the impact of bacteriospermia on semen parameters and sperm DNA fragmentation. This prospective case-control study was conducted over a period of 9 months. Samples were collected from andrology outpatient clinic attendants of Cairo University Hospitals. We enrolled 68 semen samples divided into two groups: a study group (34 semen samples with bacteriospermia) and a control group (34 semen samples without bacteriospermia). The characteristics of the semen, including morphology, motility, count, liquefaction, viscosity, pH, volume, and appearance, were evaluated according to the standard protocols. Patients with and without bacteriospermia had a comparable liquefaction time (p = .343), semen appearance and color (p = 1.00), semen pH (p = 1.00), velocity (p = .163), and total sperm count (p = .451). Patients with bacteriospermia were associated with lower progressive motility (p = .001), nonprogressive motility (p = .032), total motility (p = .001), and normal forms (p = .001). The prevalence of abnormal semen analysis was 64.71% in the study group compared with 35.29% in the control group. Staphylococcus aureus (67.6%) and Escherichia coli (14.7%) were the most commonly detected organisms. Samples from which Methicilin-resistant Staphylococcus aureus was isolated showed significant abnormalities in both progressive motility and normal morphology of sperm. Bacteriospermia has deteriorative effects on sperm quality parameters, such as semen volume, sperm motility, and sperm normal morphology.

Impact of chronic kidney disease on in-hospital mortality and clinical outcomes of catheter ablation of ventricular tachycardia: Insights from the national readmission database.

BACKGROUND: Catheter ablation is an effective treatment for ventricular tachycardia (VT), albeit the decision to undergo this procedure is often influenced by underlying comorbidities. The present study aims at evaluating the effects of chronic kidney disease (CKD) on clinical outcomes of VT ablation. METHODS: We identified 7212 patients who presented between 2016 and 2018 and underwent catheter ablation for VT. Their clinical data were retrospectively accrued from the national readmission database (NRD) using the corresponding diagnosis codes. We compared clinical outcomes between patients with chronic kidney disease (CKD group) and patients without. Odds ratios (OR) for the primary and secondary outcomes were calculated, and multivariable regression analysis was utilized to adjust for confounding variables. RESULTS: Compared with patients without CKD, patients in CKD group were older (mean age 67.9 vs. 60.5 years, P < 0.01), had a longer mean length of stay (8.73 vs. 5.69 days, P < 0.01), and higher in-hospital mortality 113 (6.7%) vs. 119 (2.2%) (OR 2.24, 95% confidence interval (CI) (1.29-3.88), P < 0.01). CKD group patients had increased risk of developing acute kidney injury 726 (43%) vs. 623 (11.3%) (3.69 95% CI (2.87-4.74), P < 0.01). CONCLUSION: In patients with CKD, VT ablation is associated with worse clinical outcomes in-hospital mortality, acute kidney injury, mean length of stay, and total hospital charge. This significantly influences the decision-making prior to performing this procedure.

Sex differences in outcomes of transvenous lead extraction: insights from National Readmission Database.

BACKGROUND: With the growing use of implantable cardiac devices, the need for transvenous lead extraction has increased, which translates to increased procedural volumes. Sex differences in lead extraction outcomes are not well studied. OBJECTIVE: The present study aims at evaluating the impact of sex on outcomes of lead extraction. METHODS: We identified 71,754 patients who presented between 2016 and 2019 and underwent transvenous lead extraction. Their clinical data were retrospectively accrued from the National Readmission Database (NRD) using the corresponding diagnosis codes. We compared clinical outcomes between male and female patients. Odds ratios (ORs) for the primary and secondary outcomes were calculated, and multivariable regression analysis was utilized to adjust for confounding variables. RESULTS: Compared to male patients, female patients had higher in-hospital complications including pneumothorax (OR 1.26, 95% CI (1.07-1.4), P < 0.01), hemopericardium (OR 1.39, 95% CI (1.02-1.88), P = 0.036), injury to superior vena cava and innominate vein requiring repair (OR 1.88, 95% CI (1.14-3.1), P = 0.014; OR 3.4, 95% CI (1.8-6.5), P < 0.01), need for blood transfusion (OR 1.28, 95% CI (1.18-1.38), P < 0.01), and pericardiocentesis (OR 1.6, 95% CI (1.3-2), P < 0.01). Thirty-day readmission was also significantly higher in female patients (OR 1.09, 95% CI (1.02-1.17), P < 0.01). There was no significant difference regarding in-hospital mortality (OR 0.99, 95% CI (0.87-1.14), P = 0.95). CONCLUSION: In female patients, lead extraction is associated with worse clinical outcomes and higher 30-day readmission rate.

Daily intake of 30 mg duloxetine is effective in decreasing premature ejaculation severity: a prospective randomized placebo-controlled cross over clinical trial.

BACKGROUND: Premature ejaculation (PE) is considered to be the most common male sexual disorder affecting 20% to 66% of sexually active men. Most of the patients had already tried on demand dapoxitine with no improvement. We aimed in the current study to assert the efficacy and safety profile of daily intake of 30 mg duloxetine in treating patients with lifelong premature ejaculation (LPE) as well as patients with acquired premature ejaculation (APE). RESULTS: The current study showed significant improvement in intravaginal ejaculatory latency time (IELT) after intake of duloxetine. All participants had a median Arabic index of premature ejaculation (AIPE) of 26, median IELT of 180 s, median male sexual quality of life (SQOL) of 43 after being treated with duloxetine (p value < 0.001 for all). While median AIPE after placebo was 19, median IELT after placebo was 60 s and median male SQOL after placebo was 21. Paired comparison of AIPE, IELT (Secs), inter quartile range (IQR) and male SQOL in group (A) patients at baseline and after duloxetine intake showed statistically significant improvement among treated patients (p values < 0.001 for all). Paired comparison of AIPE, IELT (Secs), IQR and male SQOL in group (A) patients at baseline and after placebo treatment showed no significant improvement of male SQOL. Furthermore, AIPE and IELT returned to baseline scores after discontinuation of duloxetine (p values 0.729; 0.892, respectively). Paired comparison of AIPE, IELT (Secs), IQR and male SQOL in group (B) patients at baseline and after placebo treatment showed almost same scores of patients in group (A) who received placebo for 2 months after a 2 month washout period (p values 1.000 for all). Paired comparison of AIPE, IELT (Secs), IQR and male SQOL in group (B) patients at baseline and after duloxetine treatment showed statistically significant improvement among all treated patients (p values < 0.001 for all). CONCLUSION: Duloxetine is an effective drug for treatment of LPE and APE patients. Further, larger studies are needed to compare duloxetine to different known therapeutic modalities for PE to assert it's efficacy and superiority.

RéSUMé: CONTEXTE: L'éjaculation précoce (EP) est considérée comme le trouble sexuel masculin le plus courant, touchant 20% à 66% des hommes sexuellement actifs. La plupart des patients avaient déjà essayé la dapoxitine à la demande sans amélioration. Dans la présente étude, nous avons cherché à déterminer l'efficacité et l'innocuité de l'apport quotidien de 30 mg de duloxétine comme traitement de patients atteints d'éjaculation précoce de longue durée et de patients atteints d'éjaculation précoce acquise. RéSULTATS: La présente étude a montré une amélioration significative du temps de latence éjaculatoire intravaginal (IELT) après la prise de duloxétine. Tous les participants avaient un indice médian de l'éjaculation précoce (AIPE) de 26, un IELT médian de 180 secondes, et une médiane de la qualité de vie sexuelle masculine (SQOL) de 43 après avoir été traités par la duloxétine (p < 0,001 pour tous). Après placebo, l'AIPE médian était de 19, l'IELT médian de 60 secondes et la médiane de la SQOL masculine de 21. La comparaison appariée de l'AIPE, de l'IELT, de l'intervalle interquartile (IQR) et de la SQOL masculine chez les patients du groupe (A) au départ et après la prise de duloxétine a montré une amélioration statistiquement significative chez les patients traités (p < 0,001 pour tous). La comparaison appariée de l'AIPE, de l'IELT, de l'IQR et de la SQOL masculine chez les patients du groupe (A) au départ et après traitement par placebo n'a montré aucune amélioration significative de la SQOL masculine. De plus, l'AIPE et l'IELT sont revenus aux scores de base après l'arrêt de la duloxétine (respectivement p 0,729; 0,892). La comparaison appariée de l'AIPE, de l'IELT, de l'IQR et de la SQOL masculine chez les patients du groupe (B) au départ et après traitement par placebo a montré presque les mêmes scores que les patients du groupe (A) qui ont reçu un placebo pendant 2 mois après une période de sevrage thérapeutique de 2 mois (p 1,000 pour tous). La comparaison appariée de l'AIPE, de l'IELT, de l'IQR et de la SQOL masculine chez les patients du groupe (B) au départ et après le traitement par la duloxétine a montré une amélioration statistiquement significative chez tous les patients traités (p < 0,001 pour tous). CONCLUSIONS: La duloxétine est un médicament efficace pour traiter des patients atteints d'éjaculation précoce de longue durée, et ceux atteints d'éjaculation précoce acquise. D'autres études de plus grande envergure sont nécessaires pour comparer la duloxétine aux différentes modalités thérapeutiques connues de l'éjaculation précoce, afin de déterminer son efficacité et sa supériorité. MOTS-CLéS: Ejaculation précoce de longue Durée; Ejaculation précoce acquise; Duloxétine; Qualité de Vie sexuelle masculine.

Comparison of combined substrate-based mapping techniques to identify critical sites for ventricular tachycardia ablation.

BACKGROUND: Established electroanatomic mapping techniques for substrate mapping for ventricular tachycardia (VT) ablation includes voltage mapping, isochronal late activation mapping (ILAM), and fractionation mapping. Omnipolar mapping (Abbott Medical, Inc.) is a novel optimized bipolar electrogram creation technique with integrated local conduction velocity annotation. The relative utilities of these mapping techniques are unknown. OBJECTIVE: The purpose of this study was to evaluate the relative utility of various substrate mapping techniques for the identification of critical sites for VT ablation. METHODS: Electroanatomic substrate maps were created and retrospectively analyzed in 27 patients in whom 33 VT critical sites were identified. RESULTS: Both abnormal bipolar voltage and omnipolar voltage encompassed all critical sites and were observed over a median of 66 cm2 (interquartile range [IQR] 41.3-86 cm2) and 52 cm2 (IQR 37.7-65.5 cm2), respectively. ILAM deceleration zones were observed over a median of 9 cm2 (IQR 5.0-11.1 cm2) and encompassed 22 critical sites (67%), while abnormal omnipolar conduction velocity (CV <1 mm/ms) was observed over 10 cm2 (IQR 5.3-16.6 cm2) and identified 22 critical sites (67%), and fractionation mapping was observed over a median of 4 cm2 (IQR 1.5-7.6 cm2) and encompassed 20 critical sites (61%). The mapping yield was the highest for fractionation + CV (2.1 critical sites/cm2) and least for bipolar voltage mapping (0.5 critical sites/cm2). CV identified 100% of critical sites in areas with a local point density of >50 points/cm2. CONCLUSION: ILAM, fractionation, and CV mapping each identified distinct critical sites and provided a smaller area of interest than did voltage mapping alone. The sensitivity of novel mapping modalities improved with greater local point density.