In cross sections, VEGFR-1 TK−/− mice exhibited significantly larger cardiomyocyte area (Figure 4A), that was confirmed by cell area quantification (21% increase compared to the controls) and echocardiographic measurement of LV mass (15% increase compared to the controls) revealing more robust cardiac hypertrophy in VEGFR-1 TK−/− mice compared to the control mice (Figure 4B,C). This evidence concerns the gene FLT1 and cardiac hypertrophy.