| Type | MGI:General | Description | 2-3 month old males exhibit erratic heart rate patterns, with sudden pauses in the regular rhythm of the heart rate and bradycardic events 2 month old males present with a variety of spontaneous cardiac arrhythmias ranging from sinus pauses and atrioventricular block to aberrant ventricular contractions treatment with atropine results in a drop in the frequency of arrhythmias treatment with isoproterenol decreases the rate of sinus pauses treatment with propranolol or carbachol does not reduce the rate of sinus pauses treatment with both atropine and propranolol decreases the rate of sinus pauses but has little effect on the overall heart rate treatment with propranolol does not decrease heart rate but increases sinus pauses |
