All Phenotypes Tg(Myh6-ADRB1)4Mjlo MGI Mouse

premature death ( J:55719 )

• several mice die before 14 months of age of heart failure

abnormal heart morphology ( J:55719 )

• hearts contain large pleomorphic nuclei not seen in wild-type hearts

increased myocardial fiber size ( J:55719 )

• myocyte hypertrophy

increased heart weight ( J:55719 )

• overall weight of hearts is increased by 10%

cardiac hypertrophy ( J:55719 )

• progressive myocyte hypertrophy that is not present at birth but develops after a few weeks

cardiac fibrosis ( J:55719 )

decreased cardiac muscle contractility ( J:55719 )

• cardiac contractility decreases after 16 weeks of age, going to below 50% of wild-type level at 35 weeks

• propranolol causes a greater drop in contractility than in wild-type mice, indicating impaired systolic function

decreased heart left ventricle muscle contractility ( J:55719 )

• mice exhibit an ejection fraction of only 21% and left ventricular maximal contractility (dp/dt) decreasing from 16 weeks of age indicating a severe reduction of left ventricular function

increased cardiac muscle contractility ( J:55719 )

• mice show increased cardiac contractility at a young age but the difference is lost at 16 weeks of age

• right atria from 8-12 week old mice in organ bath show slightly elevated frequencies of beats per minute

• atria show higher sensitivity to isoproterenol induced increases in frequency of contraction compared to wild-type atria

• mice exhibit increased sensitivity of contractile responses to dobutamine

increased heart rate ( J:55719 )

• spontaneous cardiac frequency is elevated at all age

• treatment with propranolol reduces the elevated cardiac frequency

congestive heart failure ( J:55719 )

• several mice show signs of heart failure such as ascites and death before 14 months

ascites ( J:55719 )

• seen in mice with heart failure

increased physiological sensitivity to xenobiotic ( J:55719 )

• hearts show increased sensitivity to catecholamines