9 results on '"Madias, Christopher"'
Search Results
2. Size as an Important Determinant of Chest Blow–induced Commotio Cordis.
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MADIAS, CHRISTOPHER, MARON, BARRY J., ESTES III, NATHAN A. MARK, DAU, NATHAN, BIR, CYNTHIA, and LINK, MARK S.
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HEART physiology , *LEFT heart ventricle , *ANIMAL experimentation , *BLOOD pressure , *BODY size , *BODY weight , *DISEASE susceptibility , *HEART ventricles , *HEART injuries , *SWINE , *VENTRICULAR fibrillation , *MULTIPLE regression analysis , *TEAM sports , *COMMOTIO cordis , *DISEASE complications - Abstract
Purpose: Commotio cordis is sudden cardiac death caused by a relatively innocent blow to the left chest wall. Adolescents account for the majority of the cases; whether this is due to the higher frequency of adolescents playing ball sports or whether there is some maturational reduction of risk is not known. Methods: In a swine model of commotio cordis, the effect of body weight/size (directly related to age) to the susceptibility of chest impact–induced ventricular fibrillation (VF) is examined. Methods: Ball impacts were delivered at escalating velocities from 48.3 to 96.9 km·h−1 (30–60 mph) to 128 swine ranging in weight from 5 to 54 kg. Results: VF occurred in 29% of impacts to the smallest animals compared with 34% in the 14- to 239-kg group, 27% in the 24- to 33.9-kg group, 30% in 34- to 43-kg group, and 15% in the 44- to 54-kg animals. The highest-weight group was associated with a significantly lower incidence of VF compared with other weights (P = 0.002). In a multivariate logistic regression analysis, controlling for repeated measures, four variables predicted VF: body weight (P = 0.0008), velocity (P < 0.0001), distance from the center of the heart, (P < 0.0001), and peak left ventricular pressure induced by the blow (P = 0.0007). Conclusions: In this experimental model, animals weighing <44 kg seem to have a similar susceptibility to commotio cordis, whereas animals weighing ≥44 kg have a lower susceptibility. An increase in size of the individual, rather than reduced play of ball sports, is the likely reason for the decreased commotio cordis incidence in older individuals. [ABSTRACT FROM AUTHOR]
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- 2018
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3. Letter by Madias and Madias Regarding Article, "Efficacy and Safety of Appropriate Shocks and Antitachycardia Pacing in Transvenous and Subcutaneous Implantable Defibrillators: Analysis of All Appropriate Therapy in the PRAETORIAN Trial".
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Madias, Christopher and Madias, John E.
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IMPLANTABLE cardioverter-defibrillators , *VENTRICULAR tachycardia , *SHOCK (Pathology) , *CARDIAC arrest - Abstract
Knops et al[1] reported in I Circulation i the shock efficacy in 426 patients with a subcutaneous implantable cardioverter defibrillator (S-ICD) compared with 423 patients with transvenous implantable cardioverter defibrillator (TV-ICD), using a prespecified secondary ad hoc analysis of the PRAETORIAN trial (A Prospective, Randomized Comparison of Subcutaneous and Transvenous Implantable Cardioverter Defibrillator Therapy), which has shown noninferiority of S-ICD compared with TV-ICD in the rate of inappropriate shocks and complications. The authors did not find any difference in the shock efficacy of S-ICD compared with TV-ICD, with the total number of appropriate shocks not different between the 2 groups. [Extracted from the article]
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- 2022
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4. Role of SREBP-1 in the Development of Parasympathetic Dysfunction in the Hearts of Type 1 Diabetic Akita Mice.
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Ho-Jin Park, Yali Zhang, Chuang Du, Welzig, C. Michael, Madias, Christopher, Aronovitz, Mark J., Georgescu, Serban P., Naggar, Isaac, Bo Wang, Young-Bum Kim, Blaustein, Robert O., Karas, Richard H., Ronglih Liao, Mathews, Clayton E., and Galper, Jonas B.
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STEROLS ,CARRIER proteins ,INSULIN synthesis regulation ,DIABETES ,HEART physiology ,LABORATORY mice - Abstract
The article presents a study that analyzes the mechanism of sterol regulatory element binding protein-1 (SREBP-1) for insulin regulation of cardiac parasympathetic response in Ins2
Akita diabetic mice. It cites the results of Western blot analysis of Akita mice extracts which show that insulin treatment increased GIRK1 expression, SREBP-1, and IKAch activity in atrial myocytes. Moreover, insulin treatment of atrial myocytes induced expression of GIRK1.- Published
- 2009
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5. Long-Term Outcome in High-Risk Patients With Hypertrophic Cardiomyopathy After Primary Prevention Defibrillator Implants.
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Rowin, Ethan J., Burrows, Austin, Madias, Christopher, Estes III, N.A. Mark, Link, Mark S., Maron, Martin S., Maron, Barry J., and Estes, N A Mark 3rd
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VENTRICULAR fibrillation treatment ,CARDIAC hypertrophy ,TIME ,IMPLANTABLE cardioverter-defibrillators ,RETROSPECTIVE studies ,VENTRICULAR tachycardia ,PREVENTIVE health services ,RISK assessment ,TREATMENT effectiveness ,CARDIAC arrest ,ELECTRIC countershock ,VENTRICULAR fibrillation ,DISEASE complications - Abstract
Background: The implantable cardioverter-defibrillator (ICD) is effective for preventing sudden death in patients with hypertrophic cardiomyopathy. However, data on performance and complications of implanted ICDs over particularly long time periods to inform clinical practice is presently incomplete.Methods: The study cohort comprises 217 consecutive hypertrophic cardiomyopathy patients with primary prevention ICDs implanted before 2008 and followed for ≥10 years (mean 12±4; range to 31).Results: Patients were 38±17 years at implant and 45 (21%) experienced appropriate interventions terminating ventricular tachycardia/ventricular fibrillation. The majority of ICD discharges occurred ≥5 years after implant (29 patients; 64%), including ≥10 years in 16 patients (36%). Initial device therapy increased in frequency from 2.3% of patients at <1 year to 8.5% of patients at ≥10-years after implant (P=0.005). Inappropriate ICD shocks in 39 patients occurred most commonly <5 years after implant (54%) and decreased in frequency with increasing time from implant (from 9.7% of patients at <5 years to 3.8% at ≥10 years, P=0.02). Other major device complications including infection and lead fractures and dislodgement occurred in 27 patients (12%) but did not increase in frequency over follow-up after implant (P=0.47). There were no arrhythmic sudden death events among the 217 patients with ICD.Conclusions: In hypertrophic cardiomyopathy, after a primary prevention implant, ICD therapy often followed prolonged periods of device dormancy and increased progressively in frequency over time, including one-third of patients with initial therapy after 5 to 9 years, and an additional one-third of patients at ≥10 years. Frequency of inappropriate shocks decreased over follow-up, likely reflecting standard changes in device programming, while occurrence of device complications, such as lead fractures/infection, did not increase during follow-up. [ABSTRACT FROM AUTHOR]- Published
- 2020
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6. Duloxetine-Induced Tako-Tsubo Cardiomyopathy: Implications for Preventing a Broken Heart.
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Trohman, Richard G. and Madias, Christopher
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CARDIOMYOPATHIES , *DULOXETINE , *DRUG side effects , *NORADRENALINE , *MEDICAL history taking , *CARDIOVASCULAR diseases risk factors - Abstract
The authors reflect on the drugs that can precipitate tako-tsubo cardiomayopathy and its prevention. They feature the case study by F. Rotondi and colleagues which examines the adverse effects of duloxetine administration such as increase circulating norepinephrine. They suggest cautious serotonin norepinephrine reuptake inhibitors (SNRIs) prescription, careful history assessment, and gender considerations.
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- 2011
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7. SREBP1 Repairs the Parasympathetic Dysfunction in Atrial Myocytes From Diabetic Hearts.
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Park, Ho-Jin, Zhang, Yali, Du, Chuang, Aronovitz, Mark, Georgescu, Serban P, Naggar, Isaac, Madias, Christopher, Welzig, Charles M, Mathews, Clayton E, Wang, Bo, Liao, Ronglih, Blaustein, Robert O, Karas, Richard H, and Galper, Jonas B
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- 2006
8. Marked variability in susceptibility to ventricular fibrillation in an experimental commotio cordis model.
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Alsheikh-Ali AA, Madias C, Supran S, and Link MS
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- Animals, Commotio Cordis complications, Commotio Cordis genetics, Disease Susceptibility, Male, Retrospective Studies, Swine, Ventricular Fibrillation etiology, Ventricular Fibrillation genetics, Commotio Cordis physiopathology, Disease Models, Animal, Ventricular Fibrillation physiopathology
- Abstract
Background: Precordial blows in sports and daily activities can trigger ventricular fibrillation (VF) (commotio cordis). Whereas chest wall blows are common, commotio cordis is rare. Although factors such as timing, location, orientation, and energy of impact are critically important, we also hypothesize that there is individual susceptibility to commotio cordis. Using our model of commotio cordis, we evaluated individual animal susceptibility to VF induction and assessed animal characteristics that might be involved., Methods and Results: This retrospective analysis included 139 juvenile swine (weight, 8 to 54 kg) that were anesthetized and placed prone in a sling to receive chest wall strikes with a ball propelled at 30 to 40 mph. Each animal received a minimum of 4 impacts directly over the cardiac silhouette, all timed to a narrow vulnerable window during cardiac repolarization. Of 1274 total impacts, 360 impacts (28%) resulted in VF. There was wide variability in individual animal susceptibility to VF. In 38 animals, none of the impacts resulted in VF (range, 4 to 18 impacts per animal). The majority of animals (91; 65%) were induced into VF with <30% of the strikes. In fact, only 19 animals (14%) had >50% occurrence of VF with chest wall impacts, and only 7 (5%) had >80% occurrence of chest impacts that induced VF. In the animal-based analysis, individual correlates of VF included animal weight, mean impact velocity, mean left ventricular pressure generated by the blow, mean QRS duration, mean QTc, and QTc variability. In multivariable analysis, mean left ventricular pressure generated by the blow, mean QRS duration, and QTc variability remained significant correlates of risk, and number of impacts gained statistical significance such that animals with more impacts were less susceptible to VF., Conclusions: Swine display a wide range of individual vulnerability to VF triggered by chest wall impact, with a distinct minority being uniquely susceptible. Mild abnormalities in cardiac depolarization and repolarization might underlie this susceptibility. Such individual susceptibility may also be present in humans and contribute to the rarity of commotio cordis.
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- 2010
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9. Role of SREBP-1 in the development of parasympathetic dysfunction in the hearts of type 1 diabetic Akita mice.
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Park HJ, Zhang Y, Du C, Welzig CM, Madias C, Aronovitz MJ, Georgescu SP, Naggar I, Wang B, Kim YB, Blaustein RO, Karas RH, Liao R, Mathews CE, and Galper JB
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- Animals, Carbachol pharmacology, Cells, Cultured, Chick Embryo, Cholinergic Agents pharmacology, Diabetes Mellitus, Type 1 pathology, Diabetic Neuropathies pathology, Disease Models, Animal, G Protein-Coupled Inwardly-Rectifying Potassium Channels genetics, G Protein-Coupled Inwardly-Rectifying Potassium Channels metabolism, Heart Atria metabolism, Heart Atria pathology, Heart Ventricles metabolism, Heart Ventricles pathology, Insulin metabolism, Insulin pharmacology, Male, Mice, Mice, Mutant Strains, Myocardium metabolism, Myocardium pathology, Myocytes, Cardiac drug effects, Myocytes, Cardiac metabolism, Myocytes, Cardiac pathology, Parasympathetic Nervous System drug effects, Parasympathetic Nervous System metabolism, Patch-Clamp Techniques, Proinsulin metabolism, Sterol Regulatory Element Binding Protein 1 genetics, Diabetes Mellitus, Type 1 metabolism, Diabetic Neuropathies metabolism, Heart innervation, Parasympathetic Nervous System physiopathology, Sterol Regulatory Element Binding Protein 1 metabolism
- Abstract
Rationale: Diabetic autonomic neuropathy (DAN), a major complication of diabetes mellitus, is characterized, in part, by impaired cardiac parasympathetic responsiveness. Parasympathetic stimulation of the heart involves activation of an acetylcholine-gated K+ current, I(KAch), via a (GIRK1)2/(GIRK4)2 K+ channel. Sterol regulatory element binding protein-1 (SREBP-1) is a lipid-sensitive transcription factor., Objective: We describe a unique SREBP-1-dependent mechanism for insulin regulation of cardiac parasympathetic response in a mouse model for DAN., Methods and Results: Using implantable EKG transmitters, we demonstrated that compared with wild-type, Ins2(Akita) type I diabetic mice demonstrated a decrease in the negative chronotropic response to carbamylcholine characterized by a 2.4-fold decrease in the duration of bradycardia, a 52+/-8% decrease in atrial expression of GIRK1 (P<0.01), and a 31.3+/-2.1% decrease in SREBP-1 (P<0.05). Whole-cell patch-clamp studies of atrial myocytes from Akita mice exhibited a markedly decreased carbamylcholine stimulation of I(KAch) with a peak value of -181+/-31 pA/pF compared with -451+/-62 pA/pF (P<0.01) in cells from wild-type mice. Western blot analysis of extracts of Akita mice demonstrated that insulin treatment increased the expression of GIRK1, SREBP-1, and I(KAch) activity in atrial myocytes from these mice to levels in wild-type mice. Insulin treatment of cultured atrial myocytes stimulated GIRK1 expression 2.68+/-0.12-fold (P<0.01), which was reversed by overexpression of dominant negative SREBP-1. Finally, adenoviral expression of SREBP-1 in Akita atrial myocytes reversed the impaired I(KAch) to levels in cells from wild-type mice., Conclusions: These results support a unique molecular mechanism for insulin regulation of GIRK1 expression and parasympathetic response via SREBP-1, which might play a role in the pathogenesis of DAN in response to insulin deficiency in the diabetic heart.
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- 2009
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