This study examined the effects of short-term high-intensity interval training (HIT) and continuous moderate-intensity training (CMT) on left ventricular (LV) function in young, healthy men. Sixteen untrained men were randomly assigned to HIT (8-12 X 60:75 seconds cycling at 95-100%:10% V˙O2peak) and CMT (90-120 minutes cycling at 65% V˙O2peak) and assessed before and after six sessions of training. LV function was determined at rest and during submaximal exercise using two-dimensional and Doppler echocardiography. HIT and CMT improved V˙O2peak and induced plasma volume expansion to a similar magnitude. Although resting LV function did not change, increased exercise stroke volume and cardiac output was observed, secondary to increases in end-diastolic volume. Numerous ECHO-derived indices of diastolic performance were similarly enhanced during exercise in both groups. Short-term HIT and CMT elicit rapid increases in V˙O2peak and LV filling without global changes in systolic performance or cardiac morphology at rest.

Rationale: In the breast cancer setting, anti-cancer therapies, including Doxorubicin (DOX) and Trastuzumab (TRZ), are associated with an increased risk of cardiotoxicity. There is a need to develop prophylactic cardioprotective agents to mitigate the cardiotoxic side effects of these common anti-cancer drugs. Objective: To investigate whether the anti-oxidant, N-acetylcysteine amide (NACA), can attenuate the drug-induced heart failure caused by DOX+TRZ in a murine model. Methods: A total of 100 female mice received one of the following drug regimens: i) saline; ii) NACA; iii) DOX; iv) TRZ; v) DOX+TRZ; vi) NACA+DOX; vii) NACA+TRZ; and viii) NACA+DOX+TRZ. Serial echocardiography was performed over a 10-day study period, after which the mice were euthanized for histological and biochemical analyses. Results: In mice receiving DOX, left ventricular ejection fraction (LVEF) decreased from 73±4% to 43±2% at day 10. In mice receiving DOX+TRZ, LVEF decreased from 72±3% to 32±2% at day 10. Prophylactic administration of NACA to mice receiving DOX or DOX+TRZ was cardio-protective with an LVEF of 62±3% and 55±3% at day 10, respectively. Histological and biochemical analyses demonstrated loss of cellular integrity, increased oxidative stress (OS), and increased cardiac apoptosis in mice treated with DOX+TRZ which was attenuated by the prophylactic administration of NACA. Conclusion: NACA attenuates the cardiotoxic side effects of DOX+TRZ in a murine model of chemotherapy induced cardiac dysfunction by decreasing OS and apoptosis. / October 2015

Timely coronary artery reperfusion is essential to prevent myocyte death following myocardial infarction. The act of restoring blood flow however, paradoxically reduces the beneficial effects of reperfusion. This phenomenon, termed myocardial reperfusion injury, refers to the injury of cardiac myocytes that were viable immediately before reperfusion. Recent studies have shown that the timing and hemodynamic sequence of events which govern reperfusion can help to minimize the severity of reperfusion injury. The term postconditioning describes a modified form of reperfusion that involves a series of flow interruptions which confer significant cardioprotection to the heart. This thesis investigates ischemic postconditioning and endothelial nitric oxide synthase (eNOS) phosphorylation as cardioprotective therapies against reperfusion injury. In the first half of this thesis, we test the hypothesis that phosphorylation of eNOS serves as a cardioprotection nodal point for ischemic postconditioning. We show that phosphorylation of eNOS increases enzyme activity and that its product, nitric oxide, plays a critical role in cardioprotection. A number of cardiac dysfunctions arise after reperfusion and we address the effects of postconditioning on infarct size and myocardial blood flow. The second half of this thesis introduces the use of magnetic relaxometry sensors to detect cardiac biomarkers. The ability to non-invasively measure infarct size in small animals would be helpful in studying models of myocardial ischemia-reperfusion injury. We investigate the use of implantable biosensors in vivo and show that the cumulative detection of cardiac biomarkers correlates with infarct severity. / Engineering and Applied Sciences

published_or_final_version / Medical Sciences / Master / Master of Medical Sciences

Key-words: echocardiography, cardiac hypertrophy, aerobic capacity. Subject of the study. Endurance athletes' left ventricular morphofunction. Background. Whether left ventricular structure and function depend on the mode of the regularly performed endurance exercise is not conclusive. If it depended indeed, specialists in sports medicine, exercise physiologist, as well as athletic coaches would have a great possibility to design the architecture and predict the function of athletes' and possibly certain type of patients myocardium in response to aerobic exercise of different kind. Aim. To determine the peculiarities of the left ventricular structure and function between athletes of different endurance sports. Objectives: 1. To compare endurance athletes' left ventricular structure and function with that of healthy sedentaries. 2. To compare left ventricular structure between athletes of different endurance sports. 3. To compare left ventricular function between athletes of different endurance sports. Hypothesis. Distance-running- and swimming-induced haemodynamic overload triggers more substantial eccentric left ventricular remodelling when compared with canoe-kayak- and road-cycling-training. Regular paddling induces concentric left ventricular hypertrophic adaptation to similar extent as road cyclists' performed loads. Either mode of endurance exercise training has negative effect upon myocardial function. Conclusions. Myocardial mass is significantly greater in endurance... [to full text]

Reguliarios aerobinės treniruotės sąlygoja saikingą ištvermę lavinančių sportininkų kairiojo širdies skilvelio hipertrofiją. Vyrauja nuomonė, kad sportuojančių moterų struktūrinė – miokardo adaptacija yra mažesnė nei vyrų. Nėra tiksliai žinoma, ar ištvermę lavinančiųjų sportininkių miokardo hipertrofija yra kitokia nei sportuojančiųjų vyrų. Mūsų tyrimo tikslas buvo nustatyti ilgųjų nuotolių bėgikų ir bėgikių bei trumpųjų nuotolių bėgikių širdies struktūros ir funkcijos ypatumus. Tyrimo metodai: echokardiografija; anketavimas; antropometrija; matematinė statistika. Tyrimo kontingentą sudarė 10 sprinterių ir 10 ilgųjų nuotolių bėgikės, kurios pagal amžių (amžiaus vidurkis – apie 25 metus), treniravimo stažą ir meistriškumo lygį nesiskyrė, buvo pasiekusios šalies arba tarptautinį pripažinimą. Ilgųjų nuotolių bėgikės (n = 10) specializavosi bėgimuose nuo 3000 m iki maratono; sprinterių grupę sudarė trumpųjų nuotolių (nuo 100 m iki 400 m, n = 8) ir barjerinio bėgimo (100 m b/b, n = 2) bėgikės. Jos mažiausiai penkerius metus reguliariai startavo savo rungtyse, intensyviai treniravosi keturis – septynis kartus per savaitę. Tyrimo kontrolinę grupę sudarė sveikos tokio pat amžiaus nesportuojančios moterys, kurios sportavo ne ilgiau kaip 1 valandą per savaitę. Tyrime taip pat dalyvavo 67 ilgųjų nuotolių bėgikai, kurių amžiaus vidurkis buvo 24,0 ± 6,7 metai. Rezultatai. Reikšmingi echokardiografiniai rodiklių skirtumai tarp sprinterių ir nesportuojančių moterų nenustatėme (p>0,05)... [toliau žr. visą tekstą] / Regular participation in certain competitive endurance sports such as cycling, rowing, paddling, and running causes moderate left ventricular (LV) hypertrophy in males. Female athletes, however, are considered to possess less pronounced structural cardiac adaptation, and the type of cardiac hypertrophy in female (endurance) athletes remains vaguely understood. The aim of this study was to shed more light on the topic of gender influence on the extent and type of cardiac hypertrophic response to two different types athletic conditioning.   Raktiniai žodžiai   Methods. Standard transthoracic two-dimensional M-mode and Doppler echocardiography was performed at rest in Caucasian female sprinters (n = 10) and long?distance runners (n = 10) of similar age (average 25 years, range 16 to 34 years), training experience (5 to 18 years), and competitive level, as well as in age-matched healthy female sedentary controls (n = 10), and also compared with Caucasian male endurance runners (n = 67) of similar age, training experience, and competitive level. Runners were considered endurance athletes if their favorite event was 3000 m or longer, and sprinters, if they preferred to compete in distances of 400 m or shorter (two of our sprinters were 100 m hurdlers). Results. No significant echocardiographic differences between female sprinters and sedentary controls were detected (p>0,05). Interventricular septum and LV wall (p<0,05) were thicker, and LV mass was greater (p<0,01) in female... [to full text]

Background: Although Bevacizumab (BVZ) and Sunitinib (SNT) prolong survival in cancer patients, an unanticipated side-effect is cardiotoxicity. Early indices of left ventricular (LV) systolic dysfunction would be useful to address the cardiac safety of anti-cancer drugs. Objective: Whether cardiac biomarkers, tissue velocity imaging (TVI), and/or strain rate (SR) can detect early cardiac dysfunction. Methods: A total of 95 C57Bl/6 mice received one of the following drug regimens: i) 0.9% saline; ii) BVZ; or iii) SNT and followed for 14 days. Serial blood pressure, high sensitivity troponin I (hsTnI), and echocardiography were performed. Results: BVZ- and SNT-treated mice demonstrated an increase in mean arterial blood pressure, hsTnI, cardiac apoptosis, and loss of cell integrity. TVI and SR values confirmed early LV systolic dysfunction at day 8, compared to conventional LVEF at day 13. Conclusions: Novel imaging techniques can detect early LV systolic dysfunction in a model of drug-mediated cardiomyopathy.

Diss. (sammanfattning) Stockholm : Kungliga Tekniska högskolan, 2007. / Härtill 5 uppsatser.

Thesis (Ph. D.)--Ohio State University, 2008. / Title from first page of PDF file. Includes bibliographical references (p. 102-122).

Thesis (Ph. D.)--Ohio State University, 2005. / Available online via OhioLINK's ETD Center; full text release delayed at author's request until 2006 Aug 15.