| Type | MGI:General | Description | in vivo telemetric long-term ECG in freely moving mutants and echocardiographic analysis indicates a sinus bradycardia characterized by lower mean heart rates by 16% compared to wild-type and more frequent episodes of low heart rate bradycardia is not due to an increase in resting phases because mutants exhibit the same activity and resting behavior as wild-type mice beta-adrenergic stimulation with isoproterenol results in the same relative increase in heart rate as in wild-type mice, however the maximum heart rate is lower in mutants intact sinoatrial node preparations show a reduced firing rate of spontaneous pacemaker potentials by 29% compared with wild-type isolated perfused hearts exhibit a reduction in beating rate by 20.2% isolated sinoatrial pacemaker cells show a shifted resting membrane potential to more hyperpolarized potentials, and a reduced firing rate (by 13%), indicating reduced beating frequency |
