Hello,
Thank you for your query at doctorspring.com.
An ECG done at that time would have really helped. But going by the description and the recommendations of your doctors it seems your father is likely suffering from tachybrady syndrome or AF with intermittent slow and fast rates. So the doctor must have prescribed your father a pacemaker for low heart rate and amiodarone for high heart rate.
Also the irregular rhythm of Atrial fibrillation or AF will require blood thinning agent like aspirin and warfarin so as to reduce the risk of clot formation and strokes. The fact that during the low heart rate episodes your father has bp of 80/50 indicates that the low heart rate results in hemodynamic instability and reduced blood supply to brain resulting in the symptoms like body shaking and up rolling of eye balls. These are most likely seizures following syncopal attacks. Such a symptomatic bradycardia or low heart rate requires pacemaker without much delay.
Amiodarone may be necessary if the heart rate increases beyond 100. This is my analysis from the description given by you.
Hope it helps. Please feel free to discuss further.
Regards
Dr Vivek Mahajan