Publications by authors named "Jason Jacobson"

Article Synopsis
  • Metabolic syndrome increases the risk of coronary artery disease and affects heart function, which was studied in female mice fed a Western diet compared to those on regular chow.
  • Mice on the Western diet showed increased body weight and left ventricular mass but maintained systolic and diastolic function, alongside reduced heart rate variability indicating altered cardiac balance.
  • Myocytes from these mice exhibited changes in size and mechanics, with heightened cAMP and PKA activity; interventions affecting this pathway improved their function, suggesting adaptations to maintain heart performance despite diet-induced metabolic issues.
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Diastolic dysfunction and delayed ventricular repolarization are typically observed in the elderly, but whether these defects are intimately associated with the progressive manifestation of the aging myopathy remains to be determined. In this regard, aging in experimental animals is coupled with increased late Na current () in cardiomyocytes, raising the possibility that conditions the modality of electrical recovery and myocardial relaxation of the aged heart. For this purpose, aging male and female wild-type (WT) C57Bl/6 mice were studied together with genetically engineered mice with phosphomimetic (gain of function, GoF) or ablated (loss of function, LoF) mutations of the sodium channel Nav1.

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In this case report, omnipolar mapping, a unique technology, was used to analyze complex atrial arrhythmias in an adult with congenital heart disease. Our patient had surgically corrected tetralogy of Fallot and presented with highly symptomatic atrial arrhythmias. A successful ablation was performed with standard bipolar mapping techniques.

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The analysis of beating rate provides information on the modulatory action of the autonomic nervous system on the heart, which mediates adjustments of cardiac function to meet hemodynamic requirements. In patients with myocardial infarction, alterations of heart rate variability (HRV) have been correlated to the occurrence of arrhythmic events and all-cause mortality. In the current study, we tested whether experimental rodent models of myocardial infarction recapitulate dynamics of heart rate variability observed in humans, and constitute valid platforms for understanding mechanisms linking autonomic function to the development and manifestation of cardiovascular conditions.

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Article Synopsis
  • - Voltage-gated sodium channels (VGSCs) are crucial in heart myocytes for creating sodium currents that impact heart excitability, impulse conduction, and mechanical properties of the heart muscle.
  • - Research on mice with a specific gene deletion related to VGSC β1-subunits revealed increased sodium currents but compromised diastolic function and ventricular compliance, despite preserved systolic function.
  • - The study suggests that VGSC β1/β1B-subunits are important for regulating sodium influx and calcium cycling in heart cells, which influences how well the heart contracts and relaxes, ultimately affecting overall heart function.
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Brugada syndrome (BrS) was initially described in southeast Asians with a structurally normal heart presenting with polymorphic ventricular tachycardia and fibrillation. This condition is marked by J-point elevation ≥ 2 mm with coved-type ST segment elevation followed by negative T wave inversions in at least one precordial lead (V1 or V2) when other etiologies have been excluded. These changes on electrocardiogram (EKG) can either be spontaneous or manifest after sodium channel blockade.

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We introduced a simple technique to eliminate electromagnetic interference between a left ventricular assist device (LVAD) and an implantable cardioverter defibrillator (ICD). A 43-year-old male with heart failure and a reduced ejection fraction who had an ICD presented with decompensated heart failure and received an LVAD as a bridge to transplant. Remote monitoring showed persistent atrial fibrillation causing an inappropriate ICD shock leading to a decision to disable shock therapies.

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Ventricular tachycardia (VT) occurs most commonly in the presence of structural heart disease or myocardial scarring from prior infarction. It is associated with increased mortality, especially when it results in cardiac arrest outside of a hospital. When not due to reversible causes (such as acute ischemia/infarction), placement of an implantable cardioverter-defibrillator for prevention of future sudden death is indicated.

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Heart rate variability (HRV) is a measure of variation in time interval between heartbeats and reflects the influence of autonomic nervous system and circulating/locally released factors on sinoatrial node discharge. Here, we tested whether electrocardiograms (ECGs) obtained in conscious, restrained mice, a condition that affects sympathovagal balance, reveal alterations of heart rhythm dynamics with aging. Moreover, based on emergence of sodium channels as modulators of pacemaker activity, we addressed consequences of altered sodium channels on heart rhythm.

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Esophageal injury leading to esophagopericardial fistula (EPF) or atrioesophageal fistula is a very rare and dreaded complication of catheter ablation for atrial fibrillation that carries a high mortality rate. We present a case of EPF following radiofrequency catheter ablation for atrial fibrillation and an extensive review of the literature regarding catheter ablation-related esophageal injury.

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Arrhythmogenic right ventricular cardiomyopathy, formerly called "arrhythmogenic right ventricular dysplasia," is an under-recognized clinical entity characterized by ventricular arrhythmias and a characteristic ventricular pathology. Diagnosis is often difficult due to the nonspecific nature of the disease and the broad spectrum of phenotypic variations. Therefore, consensus diagnostic criteria have been developed which combine electrocardiographic, echocardiographic, cardiac magnetic resonance imaging and histologic criteria.

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The management of ventricular arrhythmias (VA) has evolved over time to an advanced discipline, incorporating many technologies in the diagnosis and treatment of the myriad types of VA. The first application of imaging is in the assessment for structural heart disease, as this has the greatest impact on prognosis. Advanced imaging has its greatest utility in the planning and execution of ablation for VA.

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Atrial fibrillation (AF) is associated with a substantially higher risk of thromboembolism, particularly stroke events, resulting in significant morbidity and mortality. Oral anticoagulation (OAC), while effective in reducing embolic events in AF patients, is associated with an increased bleeding risk. Thus, not all patients with AF are candidates for OAC and some are only candidates for OAC in the short term.

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Patients with hypertrophic cardiomyopathy may present with a number of arrhythmias. Although not unique, arrhythmias in hypertrophic cardiomyopathy require management approaches that may differ from other populations. Standard permanent pacemaker indications can be seen, but unique applications and implantation considerations pertain to this population.

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Background: Atrioventricular nodal reentrant tachycardia (AVNRT) after orthotropic heart transplant (OHT) is rare, in absence of rejection.

Case: We report a case of a 51-year-old male who underwent simultaneous kidney and heart transplant. Three months after implantation he developed episodes of dyspnea, dizziness, and palpitations.

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The spiny mouse, Acomys cahirinus, is an adult mammal capable of remarkable feats of scar-free tissue regeneration after damage to several organs including the skin and the heart. Here we investigate the regenerative properties of the skeletal muscle of A. cahirinus tibialis anterior in comparison to the lab mouse, Mus musculus.

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Hypertrophic cardiomyopathy (HCM), a disease formerly thought rare in clinical practice, is now believed to affect as many as 1 in 300 individuals, regardless of race or gender. Rising awareness, coupled with advanced imaging and the development of dedicated HCM centers of excellence, has led to more patients coming to clinical presentation. While some are diagnosed at a young age, others are diagnosed in middle age or well into advanced age.

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Notch receptor signaling is active during cardiac development and silenced in myocytes after birth. Conversely, outward K Kv currents progressively appear in postnatal myocytes leading to shortening of the action potential (AP) and acquisition of the mature electrical phenotype. In the present study, we tested the possibility that Notch signaling modulates the electrical behavior of cardiomyocytes by interfering with Kv currents.

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