| Type | MGI:General | Description | mutants have a severe contraction defect both left ventricular end-diastolic dimensions and end-systolic dimensions are markedly increased 5 to 6 weeks after birth the percent fractional shortening and mean velocity of circumferential fiber shortening (indicators of systolic cardiac function) are severely reduced in isolated cardiomyocytes resting intracellular and diastolic Ca2+ is normal however, with increasing pacing frequencies a significant decrease in both Ca2+ transients and cell contraction are detected defects in Ca2+ relaxation kinetics and reduced Ca2+ transients would weaken the excitation-contraction coupling in response to increasing workload |
