Flavios Iraklios is lost at the Battle of Yarmouk; consequences?

[Marc]

The supposing is straightforward. Iraklios, or Heraclius, the former the name that he probably formally preferred, is present at that decisive battle and is either killed or captured as his army is routed by one of the greatest generals in history, Ibn al-Walid.

Please, this is not about the premise, but the effect of that alternate event occurring. Granted, in real history the emperor only lived about 5 more years regardless, but without him during those crucial early years when the Byzantines are withdrawing and trying to hold Anatolia, and the troubled condition of the imperial court (quick moral there, don't marry your niece), his loss might cause a significant divergence.
At any rate, I am interested in hearing any thoughts on this - I don't recall this particular possibility coming up in the last few years at least.

 

[trajen777]

Key would be the great move or bad move to fight another campaign in mesp. Vs withdrawing into anatoilia. It is a 50/ 50 deal. The withdrawal meant a safer approach. An attack or fight, if won would have destroyed the Arab aura, reduced its recruits, and devestated it's manpower. A loss might have lost Anatolia.

 

[trajen777]

As a note I think if he would have been their the byz would have won.
1. Theodore would not have withdrawn pre battle with 12,000 troops, giving the byz additional-forces'
2. Her. Would have made better use of cav reserve in day 2 or 3 on key flank attack to provide overwhelming force. For some reason the byz cav was barely used

 

[Marc]

As a note I think if he would have been their the byz would have won.
1. Theodore would not have withdrawn pre battle with 12,000 troops, giving the byz additional-forces'
2. Her. Would have made better use of cav reserve in day 2 or 3 on key flank attack to provide overwhelming force. For some reason the byz cav was barely used

While it's clear that the Byzantines could have fought considerably better (that they didn't, in the face of what they knew was a very dangerous foe, is telling), even with the Emperor Iraklios in command I suspect the stars weren't in their favor on that battlefield that week. A lesser defeat would allow them a more delaying action; they might have held onto Antioch, for a while.
However, my particular interest is what happens if Iraklios dies, or worse, is captured. Structurally, can the Byzantines still manage to fight off the Rashidun army and hold onto Anatolia, or most of it?