When is a defibrillator necessary?

I am 43 years old and in relatively good shape.  Last spring I went to the doctor to determine whether or not I should be worried about ongoing heart palpitations and fatigue. I wore a Holter monitor which showed multiple PVCs. I then had a stress test which was abnormal, which led to a Cardiac Catheterization. During this procedure, they determined that I had Anomalous Left Coronary Artery from the Pulmonary Artery. I have since had open heart surgery and my left coronary artery was transplanted to the correct location.  

While in the hospital, recovering, I had multiple events of ventricular tachycardia. One event was 23 beats long, though I am unsure how fast my heart rate was. I was put on Amioderone, Altenolol, aspirin, and Coumadin; however, my blood pressure and heart rate decreased too much on this regimen, and I am now only on 25 mg of Altenolol, low dose aspirin, and 5mg of Coumadin.

I also had a cardiac MRI which showed that my right coronary artery is 11mm in diameter. It also showed the following: probable myocardial infarction, papillary muscle infarction, minimal mitral regurgitation, borderline reduced left ventricular systolic function, mild biatrial and left ventricular dilation, possible bicuspid aortic valve, and a lesion on the right hepatic lobe (possible hepatic hemangioma).

Over the last 3 months, the palpitations have continued.  I have had episodes of shortness of breath/breathlessness/starving for air. These occur at random times, but first happened while I was falling asleep. I have had an episode of my vision blacking out upon standing, though I did not lose consciousness.  I have had multiple episodes of the edges of my vision graying out. I have also had an increase of twinges (chest discomfort more than pain, accompanied by a feeling tightness, heaviness, or fullness). And, lastly, I am very fatigued.  

My local electrophysiologist has referred me to a doctor 3.5 hours away to determine whether or not I will need a defibrillator. I have read multiple articles about these and cannot determine when they are needed. How do the doctors determine whether to treat tachycardia with medicine, ablation, or ICDs?  How can I best educate myself and prepare for this doctor's visit?

[itdood]

I found a list of when an ICD is medically indicated

At least one episode of ventricular tachycardia (VT) or ventricular fibrillation (Vfib)
Previous cardiac arrest or abnormal heart rhythm that has caused you to pass out
A fast heart rhythm that keeps returning and could cause death
A fast heart rhythm that cannot be cured by surgery
A fast heart rhythm that cannot be controlled with medications
Severe side effects from medications

I'm wondering if the uptick in arrhythmia is due to your left ventricle now getting the correct blood supply?  After all, you lived quite some time with the defect, amazingly so.  perhaps it will settle down with time?

[Jo0731]

I am hoping that it will just settle down on its own. I had trained myself to ignore the abnormal rhythms before, but now they are harder to ignore. Thanks for your help.