Battery replacement pacemaker changeout

I live 9,000 miles from my rythem specialaist, and cardiologist. Once I am ready for a battery change, I will travel back to the US. I also have a leaking Mitral valve that is knocking the shxx out of me, causing oxygen deprivation. I will have both attended to upon my return. I cannot afford the thousands of dollars to go back & forth. I go to Makati Medical Ctr in Manila once every 6 months, and have been trackingt my battery charge closely. I was told originally that the batteries would last 5 - 10 years when my St.Jude pacemaker was embedded in my chest 6 years ago. 2 years ago I had 1.5 years of charge remaining, 6 months later I had 1.4, 6 months later 1.5 again: ?, 6 months later 1.4, 6 months later 1.3..................... ? When it was 1.5 we went through the agonizing process of getting a visa for my Filipina wife, only to find out, I still had over a year to go. My point is the inconsistency of battery life testing, and the inability to estimate remaining charge based on past performance.  I am paced at 93%, and have had 2 episodes where the defib. fired. I share this with you all because I am sure you have questions on battery longevity, just like I do. By the way when I went into an episode, I didnt feel much, but passed out, and woke up as my defib. was firing. I have died twice now, and am grateful for every day I am alive.