Sökning: "Depolarization changes"

Visar resultat 1 - 5 av 31 avhandlingar innehållade orden Depolarization changes.

  1. 1. Ventricular Depolarization in Ischemic Heart Disease.Value of Electrocardiography in Assessment of Severity and Extent of Acute Myocardial Ischemia

    Författare :Michael Ringborn; Kardiologi; []
    Nyckelord :MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; Acute myocardial ischemia; Acute myocardial infarction; Severity of ischemia; QRS changes; HF-QRS; QRS slopes; Depolarization changes; Myocardium at risk; Final infarct size; SPECT.;

    Sammanfattning : Background In patients with symptoms compatible with acute myocardial infarction (MI), early triage by ECG in the pre-hospital phase by ST-segment elevation myocardial infarction (STEMI) criteria is important for direct transport of these patients to a regional center for primary percutaneous coronary intervention (pPCI). The time from first medical contact to pPCI should, due to present guidelines, be no longer than two hours. LÄS MER

  2. 2. Conformational Changes during Potassium-Channel Gating

    Författare :Jakob Renhorn; Fredrik Elinder; David Engblom; Stephan Pless; Linköpings universitet; []
    Nyckelord :MEDICAL AND HEALTH SCIENCES; MEDICIN OCH HÄLSOVETENSKAP; MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; ion-channel; electrophysiology; neuron; Jonkanal; neurologi; elektrofysiologi; neuron; aktionspotential;

    Sammanfattning : Voltage-gated ion channels have a paramount importance in many physiological processes such as cell-to-cell communication, action potential-propagation, and cell motility. Voltage-gated ion channels are characterized by their ability to sense membrane voltage and to greatly change channel activity in response to small changes in the voltage. LÄS MER

  3. 3. On spinal mechanisms for reflex control in man : modulation of Ia-afferent excitation with changes in muscle length, activation level and fatigue

    Författare :Maria M. Nordlund; Gymnastik- och idrottshögskolan; Karolinska Institutet; Karolinska Institutet; []
    Nyckelord :Electromyography; eccentric; concentric; presynaptic inhibition; H-reflex; central fatigue; twitch interpolation; muscle spindle; Medicin Teknik; Medicine Technology; MEDICAL AND HEALTH SCIENCES; MEDICIN OCH HÄLSOVETENSKAP; Electromyography; eccentric; concentric; presynaptic inhibition; H-reflex; central fatigue; twitch interpolation; muscle spindle;

    Sammanfattning : To control muscle force, neural activation has to take alterations in muscle mechanics into account. This thesis assesses modulations in excitatory efficacy of Ia-afferents during muscle length changes at different levels of voluntary activation and during fatigue. LÄS MER

  4. 4. Applications of Vectorcardiography for Diagnosis and Risk Stratification in Subpopulations at Risk for Life-Threatening Arrhythmias

    Författare :Daniel Cortez; Kardiologi; []
    Nyckelord :MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; Vectorcardiography; atrial depolarization; ventricular depolarization repolarization;

    Sammanfattning : Introduction: Vectorcardiography, or 3-dimensional electrocardiography is a tool which can be used to identify subtle changes in the electrical forces of the heart, and which can be applied to atrial depolarization, ventricular depolarization and ventricular repolarization for prognostic and diagostic purposes. Methods: Kor’s regression-related and quasi orthogonal methods was used to derive vectorcardiographic parameters from the 12-lead electrocardiogram and applied to a cohort of cryptogenic stroke patients to assess atrial fibrillation, hypertrophic cardiomyopathy patients to assess for ventricular arrhythmias, applied with right-precordial directed quasi orthogonal method to arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVC/D) patients for diagnosis, and applied to ventricular repolarization only to patients with genotype-positive/phenotype-negative Long QT2 syndrome (KNCH2 mutation) to assess for cardiac events. LÄS MER

  5. 5. Stimulation of insulin secretion independently from changes in cytosolic free Ca²+-concentration : studies with imidazolines and inositol polyphosphates

    Författare :Alexander Efanov; Karolinska Institutet; Karolinska Institutet; []
    Nyckelord :MEDICAL AND HEALTH SCIENCES; MEDICIN OCH HÄLSOVETENSKAP; insulin secretion; pancreatic ß-cell; imidazolines; inositol polyphosphates;

    Sammanfattning : Insulin secretion from the islets of Langerhans is regulated by changes in glucose concentration. Glucose stimulates secretion by two mechanisms. First, it increases cytosolic free Ca2+ concentration ([Ca2+]i) by inhibition of ATP-dependent K+-channels (KATP) and induction of membrane depolarization. LÄS MER