Journal: American Journal of Physiology. Heart and Circulatory Physiology

Abbreviation

Am J Physiol Heart Circ Physiol

Publisher

American Physiological Society

Journal Volumes

ISSN

0363-6135
1522-1539

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Publications 1 - 10 of 13
  • The impact of capillary dilation on the distribution of red blood cells in artificial networks
    Item type: Journal Article
    Schmid, Franca; Reichold, Johannes; Weber, Bruno; et al. (2015)
    American Journal of Physiology. Heart and Circulatory Physiology
  • Magnetic resonance stress tagging in ischemic heart disease
    Item type: Journal Article
    Paetsch, Ingo; Föll, Daniela; Kaluza, Adam; et al. (2005)
    American Journal of Physiology. Heart and Circulatory Physiology
  • Structural and functional adaptations of human cardiomyocytes in metabolic disease and heart failure
    Item type: Journal Article
    Huettemeister, Judith; Bögner, Markus; Eggert-Doktor, Dirk; et al. (2025)
    American Journal of Physiology. Heart and Circulatory Physiology
    Heart failure (HF), obesity, and diabetes are associated with structural and functional changes that affect the heart at both the organ and cellular levels. Studying isolated adult single cardiomyocytes provides valuable mechanistic insights. However, isolating single cardiomyocytes from human tissue is particularly challenging. This study presents an optimized multiple-step digestion protocol to isolate viable cardiomyocytes from atrial and ventricular human tissue obtained perioperatively or through myocardial biopsies. Using this method and resource, we analyzed calcium-signaling during excitation-contraction coupling and structural features such as t-tubules and mitochondria using confocal microscopy in patients with or without HF, obesity, or diabetes. In a subset of patients undergoing open heart surgery, tissue samples and serum from the great cardiac vein were obtained either under control conditions or upon cardiac volume challenge (VC). We isolated viable cells and observed distinct structural differences between atrial and ventricular cardiomyocytes, including variations in t-tubular and cell size. In atrial cardiomyocytes, when comparing control with patients with HF, the t-tubular networks were unchanged. However, patients with obesity exhibited significantly more t-tubules associated with larger cell sizes. Furthermore, mitochondrial density appeared higher in patients with overweight and diabetes, suggesting that the metabolic status influences cardiomyocyte structure. Finally, when exposing isolated cardiomyocytes with VC serum from the respective patients, excitation-contraction coupling was markedly enhanced, indicating a distention-related alteration of the cardiac secretome with immediate effects on cardiomyocytes. In summary, an optimized protocol for isolating human cardiomyocytes confirmed structural features, identified disease-related changes, and allowed studying the dynamic impact of cardiac distention on secretome-related cardiomyocyte function.
  • Intracoronary ECG ST-segment shift remission time during reactive myocardial hyperemia: a new method to assess hemodynamic coronary stenosis severity
    Item type: Journal Article
    Bigler, Marius Reto; Kieninger-Gräfitsch, Andrea; Rohla, Miklos; et al. (2024)
    American Journal of Physiology. Heart and Circulatory Physiology
    Fractional flow reserve (FFR) measurements are recommended for assessing hemodynamic coronary stenosis severity. Intracoronary ECG (icECG) is easily obtainable and highly sensitive in detecting myocardial ischemia due to its close vicinity to the myocardium. We hypothesized that the remission time of myocardial ischemia on icECG after a controlled coronary occlusion accurately detects hemodynamically relevant coronary stenosis. This retrospective, observational study included patients with chronic coronary syndrome undergoing hemodynamic coronary stenosis assessment immediately following a strictly 1-min proximal coronary artery balloon occlusion with simultaneous icECG recording. icECG was used for a beat-to-beat analysis of the ST-segment shift during reactive hyperemia immediately following balloon deflation. The time from coronary balloon deflation until the ST-segment shift reached 37% of its maximum level, i.e., icECG ST-segment shift remission time (τ-icECG in seconds), was obtained by an automatic algorithm. τ-icECG was tested against the simultaneously obtained reactive hyperemia FFR at a threshold of 0.80 as a reference parameter. From 120 patients, 139 icECGs (age, 68 ± 10 yr old) were analyzed. Receiver operating characteristic (ROC) analysis of τ-icECG for the detection of hemodynamically relevant coronary stenosis at an FFR of ≤0.80 was performed. The area under the ROC curve was equal to 0.621 (P = 0.0363) at an optimal τ-icECG threshold of 8 s (sensitivity, 61%; specificity, 67%). τ-icECG correlated inversely and linearly with FFR (P = 0.0327). This first proof-of-concept study demonstrates that τ-icECG, a measure of icECG ST segment-shift remission after a 1-min coronary artery balloon occlusion accurately detects hemodynamically relevant coronary artery stenosis according to FFR at a threshold of ≥8 s.
  • A dynamic model of oxygen transport from capillaries to tissue with moving red blood cells
    Item type: Journal Article
    Lücker, Adrien; Weber, Bruno; Jenny, Patrick (2015)
    American Journal of Physiology. Heart and Circulatory Physiology
  • Patient-specific three-dimensional simulation of LDL accumulation in a human left coronary artery in its healthy and atherosclerotic states
    Item type: Journal Article
    Olgac, Ufuk; Poulikakos, Dimos; Saur, Stefan C.; et al. (2009)
    American Journal of Physiology. Heart and Circulatory Physiology
  • Age, aerobic fitness, and cerebral perfusion during exercise
    Item type: Journal Article
    Flück, D.; Braz, I.D.; Keiser, S.; et al. (2014)
    American Journal of Physiology. Heart and Circulatory Physiology
  • Heat training increases exercise capacity in hot but not in temperate conditions: a mechanistic counter-balanced cross-over study
    Item type: Journal Article
    Keiser, Stefanie; Flück, Daniela; Hüppin, Fabienne; et al. (2015)
    American Journal of Physiology. Heart and Circulatory Physiology
  • Effects of Thoratec pulsatile ventricular assist device (PVAD) timing on the abdominal aortic wave intensity pattern
    Item type: Journal Article
    Ekroll Jahren, Silje; Amacher, Raffael; Weber, Alberto; et al. (2014)
    American Journal of Physiology. Heart and Circulatory Physiology
  • Wall stress of the cervical carotid artery in patients with carotid dissection: a case-control study
    Item type: Journal Article
    Callaghan, Fraser M.; Luechinger, Roger; Kurtcuoglu, Vartan; et al. (2011)
    American Journal of Physiology. Heart and Circulatory Physiology
    Spontaneous internal carotid artery (ICA) dissection (sICAD) results from an intimal tear located around the distal carotid sinus. The mechanisms causing the tear are unknown. This case-control study tested the hypotheses that head movements increase the wall stress in the cervical ICA and that the stress increase is greater in patients with sICAD than in controls. Five patients with unilateral, recanalized, left sICAD and five matched controls were investigated before and after maximal head rotation to the left and neck hyperextension after 45° head rotation to the left. The anatomy of the extracranial carotid arteries was assessed by magnetic resonance imaging and used to create finite element models of the right ICA. Wall stress increased after head movements. Increases above the 80th and 90th percentile were located at the intimal side of the artery wall from 7.4 mm below to 10 mm above the cranial edge of the carotid sinus, i.e., at the same location as histologically confirmed tears in patients with sICAD. Wall stress increase did not differ between patients and controls. The present findings suggest that wall stress increases at the intimal side of the artery wall surrounding the distal edge of the carotid bulb after head movements may be important for the development of carotid dissection. The lack of wall stress difference between the two groups indicates that the carotid arteries of patients with carotid dissection have either distinct functional or anatomical properties or endured unusually heavy wall stresses to initiate dissection.
Publications 1 - 10 of 13