I'm gonna even go a step further. There's no way the heart could literally explode. Your valves would blow open long before any cardiac tissue ruptured. I was thinking about that this morning and I have no idea why.
+1 with everyone who said something to the effect of "rupture, but not explode"
Stat doc is probably the best to answer these questions. But it sounds interesting so let's come up with a doomsday scenario and see what he can do.
So let's pretend for a bit and see if there's absolutely no way you could blow a hole in the wall of the left ventricle in a severly hypertensive patient (for shits and giggles lets say 260/210) with Dilated Hypertrophic Cardiomyopathy and Coronary Artery Disease, who's ventricle is plunkin away at, say 400 beats/sec. To make it fun, let's say he's already had some inferior wall damage from earlier ischemic events. Let's say he has pericarditis too from a little ischemia he had this weekend while playing with his grandkids. That'll make that sack nice and fragile too.
Well, it would explode in a sense, IMO. Not C4 McGyver explosions, but it wouldnt simply rupture and seep out. You'd get a helluva flood.
1) A patient with CAD cant handle a ventricular rate >150 without damage. A rate of 500 would lead to necrosis in seconds. That would soften up that already soft wall (previous MI). Oh, but I want his nodal artery to be nice and strong, so he cant have any CAD in the proximal Right Coronary Artery or its first branch, the nodal artery. That will keep the electrical activity of the heart strong. Well, atleast making sure the ventricles dont "lose signal" early in the event.
2) Since he's got dilated hypertrophy from having high blood pressure for so long, his aorta and valves have adapted and toughened over time. The muscle in the heart doesnt cope so well though. It dilates, and stretches out making the wall of the heart even thinner than a normal heart, even though the heart looks bigger than it should be.
3) Wicked high bp
So.....
soft deadish wall + thin wall + thickened calficied valves and main vessels + grim reaper bp + walmart bag for a pericardial sac + V Fib = the Hoover Dam giving way inside your chest.
Of course, theres not that much space in the mediastinum but at those pressures it'll flow for a bit and probably give you a bilateral hemothorax......