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Impact of early postnatal period on pro-arrhytmogenic substrate development caused by pressure overload in rat heart
Zábrodská, Eva ; Olejníčková, Veronika (advisor) ; Kolesová, Hana (referee)
In adult heart, pressure overload leads to cardiac hypertrophy. Higher propensity of hypertrophied myocardium to life-threatening arrhythmia is attributed to structural, mechanical and electrical remodeling. Pro-arrhythmogenic remodeling comprise several factors depending on an experimental model and a stage of heart failure. This thesis aims to characterize the impact of these factors in our unique model of pressure overloaded neonatal rat heart. The constriction of abdominal aorta was performed at postnatal day 2 in male Wistar rats. Decreased body weight, significant since week 6, was observed during development of cardiomegaly. At 12 weeks, the heart to body weight ratio was increased by 45 % and by 109 % in group with compensated (AC I) and decompensated (AC II) heart failure, respectively. At this age, the ECG was recorded and histological and immunohistochemical measurements were performed to analyze the pro-arrhythmogenic remodeling of working myocardium and cardiac conduction system. The markers of pro-arrhytmogenic remodeling such as significant prolongation of QT and QTc intervals were observed in the ECG recordings of AC II animals. However, spontaneously occurring arrhythmias was not detected. Further analysis of working myocardium showed decrease in Cx43 expression and its...
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The effect of pressure overload on developing heart.
Zábrodská, Eva ; Olejníčková, Veronika (advisor) ; Hrdlička, Jaroslav (referee)
The early postnatal period plays important role in heart and cardiovascular system development. The substantial increase of hemodynamic load after birth results in rapid growth and differentiation of cardiac tissue. Therefore, neonatal myocardium is characterized by specific reaction to the pathological stimuli. In adult heart, the pressure overload results to cardiac hypertrophy development. However, for the short period after the birth, the cardiac tissue possesses higher proliferative activity which could be further increased as reaction to the pressure overload. The project aims to outline current knowledge about the effect of pressure overload on developing myocardium and focused to the specific changes of heart and cardiovascular system. Key words: Neonatal myocardium, Fibrosis, Heart remodeling, Hypertrophic myocardium, Gap junction
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