Heart attack?

John Bantin · 18th November 2009, 10:00

On reading over reports of casualties that occur during diving, I'm tempted to ask: Why do CCR divers appear to be more predisposed to heart-attacks in the water than those on OC?

Zuercher · 18th November 2009, 10:12

When he breaths higher level of CO2 , I guess...

PhilSiswick · 18th November 2009, 10:13

Hi John,

I'm no expert on this, but have been watching the emerging discussion over the last year or so. It's worth searching on here for posts by Alex Deas on the subject. I think Simon Mitchell has been involved too. That should give you a starting point on the various reasons that people have put forward.

HTH,

mik · 18th November 2009, 10:17

Maybe because they are older, fatter lazier and richer?

Ben Field · 18th November 2009, 10:28

Quote: (Originally Posted by John Bantin)

On reading over reports of casualties that occur during diving, I'm tempted to ask: Why do CCR divers appear to be more predisposed to heart-attacks in the water than those on OC?

Trolling today John?

I suspect Heart attack is sometimes used in "reports" as a coverall for- We don't know much about rebreather diving and SCUBA equipment, we're just coroners!

However the older, fatter, richer, lazier, high CO2, stressed arguments all carry weight too IMO

John Bantin · 18th November 2009, 10:56

Quote: (Originally Posted by Ben Field)

Trolling today John?

Not trolling - unless you confuse food-for-thought with ground-bait!

Mark Chase · 18th November 2009, 11:04

Quote: (Originally Posted by John Bantin)

On reading over reports of casualties that occur during diving, I'm tempted to ask: Why do CCR divers appear to be more predisposed to heart-attacks in the water than those on OC?

I beleive the issue is related to retained co2 more than anything else.

I cut and passte this as referance on the subject:

Exercise needs an amount of oxygen and the cells in turn produce an amount of C02. As cardiovascular rate increases blood flow and lung breathing rate and volume increases. This with the addition of stress and increased excitement this in turn releases stress hormones and adrenalin.

The rebreather all this time with the help of your lung power is pushing the expired C02 laden gas around the breathing tube, through the scrubber and through the loop. Work enough to be called work of breathing WOB. Increased C02 production levels relative to C02 elimination in the scrubber material stimulates the nervous system to increase heart rate, increasing blood volume and blood pressure. The diver is now experiencing the onset of Hypercapnia.

With continued high C02 loadings in the breathing bag then peripheral blood vessel dilation will occur. This will have the effect of increasing heart rate even further culminating in massive myocardial contractions or heart attack.

The second important point is the equipment examination. After a death (in the UK) the equipment (if recovered) is examined by an expert witness. Of most reports I have read, the equipment on examination has show normal operation, the gas analysis (if available) has also been normal within limits. The expert witness would therefore conclude that the equipment was working correctly at the time of death. So as the cause of death is on the coroner to conclude and with a normal autopsy this is routinely shown to be a heart attack. Remember a diver is only a diver while he is alive. At death he is classified as a corpse.

So conclude equipment tested and found to be working OK. Therefore cause of death heart attack. The reason and cause of the heart attack was C02 in the loop. Iain Middlebrook[/QUOTE]

Mark Chase · 18th November 2009, 11:08

Sorry buisy at work and cant find the link:

Also look into lactic acid production C02 and heart failure

ATB

Mark

paulraymaekers · 18th November 2009, 11:18

Quote: (Originally Posted by Mark Chase)

I beleive the issue is related to retained co2 more than anything else.

I cut and passte this as referance on the subject:

Exercise needs an amount of oxygen and the cells in turn produce an amount of C02. As cardiovascular rate increases blood flow and lung breathing rate and volume increases. This with the addition of stress and increased excitement this in turn releases stress hormones and adrenalin.

The rebreather all this time with the help of your lung power is pushing the expired C02 laden gas around the breathing tube, through the scrubber and through the loop. Work enough to be called work of breathing WOB. Increased C02 production levels relative to C02 elimination in the scrubber material stimulates the nervous system to increase heart rate, increasing blood volume and blood pressure. The diver is now experiencing the onset of Hypercapnia.

With continued high C02 loadings in the breathing bag then peripheral blood vessel dilation will occur. This will have the effect of increasing heart rate even further culminating in massive myocardial contractions or heart attack.

The second important point is the equipment examination. After a death (in the UK) the equipment (if recovered) is examined by an expert witness. Of most reports I have read, the equipment on examination has show normal operation, the gas analysis (if available) has also been normal within limits. The expert witness would therefore conclude that the equipment was working correctly at the time of death. So as the cause of death is on the coroner to conclude and with a normal autopsy this is routinely shown to be a heart attack. Remember a diver is only a diver while he is alive. At death he is classified as a corpse.

So conclude equipment tested and found to be working OK. Therefore cause of death heart attack. The reason and cause of the heart attack was C02 in the loop. Iain Middlebrook

[/quote]

oh mighty, I think Simon will jump in quickly

paul

from what I understand, at this moment, there is no scientific evidence of correlation between high CO2 (retained or inhaled) and increased risk of heart attack

Ben Field · 18th November 2009, 11:22

Quote: (Originally Posted by John Bantin)

Not trolling - unless you confuse food-for-thought with ground-bait!

I know John, hence the smilie.... (it is however treading a fine line

IMO)

For years the report of "heart attack" has been the fuel for many flame-wars and long drawn out pointless threads as many protagonists feel it is the result of a null-result to any other test looking for COD in rebreather diving accidents.

Its certainly food-for-thought but as far as I'm aware there is no new data on this one, unless you have something?

18th November 2009, 10:00	#1 (permalink)
John Bantin RBW Member Join Date: Feb 2006 Location: Twickenham Posts: 53	Heart attack? On reading over reports of casualties that occur during diving, I'm tempted to ask: Why do CCR divers appear to be more predisposed to heart-attacks in the water than those on OC?
(Offline)

18th November 2009, 10:12	#2 (permalink)
Zuercher RBW Member JJ-CCR Ap Inspiration Classic Join Date: Dec 2007 Location: Switzerland,Thailand Posts: 67	Re: Heart attack? When he breaths higher level of CO2 , I guess...
(Offline)

18th November 2009, 10:13	#3 (permalink)
PhilSiswick Phil Siswick, Tango JJ-CCR APD Inspiration, Evolution Join Date: Apr 2006 Location: Oxford, UK Posts: 1,742	Re: Heart attack? Hi John, I'm no expert on this, but have been watching the emerging discussion over the last year or so. It's worth searching on here for posts by Alex Deas on the subject. I think Simon Mitchell has been involved too. That should give you a starting point on the various reasons that people have put forward. HTH,
(Offline)

18th November 2009, 10:17	#4 (permalink)
mik RBW Member Join Date: Sep 2006 Location: Sydney North Posts: 114	Re: Heart attack? Maybe because they are older, fatter lazier and richer?
(Offline)

18th November 2009, 10:28	#5 (permalink)
Ben Field MCCR+Shearwater Classic KISS Sport KISS Join Date: Aug 2005 Location: Weymouth, England Posts: 2,760	Re: Heart attack? Quote: (Originally Posted by John Bantin) On reading over reports of casualties that occur during diving, I'm tempted to ask: Why do CCR divers appear to be more predisposed to heart-attacks in the water than those on OC? Trolling today John? I suspect Heart attack is sometimes used in "reports" as a coverall for- We don't know much about rebreather diving and SCUBA equipment, we're just coroners! However the older, fatter, richer, lazier, high CO2, stressed arguments all carry weight too IMO
(Online)

18th November 2009, 10:56	#6 (permalink)
John Bantin RBW Member Join Date: Feb 2006 Location: Twickenham Posts: 53	Re: Heart attack? Quote: (Originally Posted by Ben Field) Trolling today John? Not trolling - unless you confuse food-for-thought with ground-bait!
(Offline)

18th November 2009, 11:04	#7 (permalink)
Mark Chase So many CCR So little etc JJ Hybrid Inspo, Hammer Head, KISS rEvo Join Date: Jan 2005 Location: Kent Posts: 4,533	Re: Heart attack? Quote: (Originally Posted by John Bantin) On reading over reports of casualties that occur during diving, I'm tempted to ask: Why do CCR divers appear to be more predisposed to heart-attacks in the water than those on OC? I beleive the issue is related to retained co2 more than anything else. I cut and passte this as referance on the subject: Exercise needs an amount of oxygen and the cells in turn produce an amount of C02. As cardiovascular rate increases blood flow and lung breathing rate and volume increases. This with the addition of stress and increased excitement this in turn releases stress hormones and adrenalin. The rebreather all this time with the help of your lung power is pushing the expired C02 laden gas around the breathing tube, through the scrubber and through the loop. Work enough to be called work of breathing WOB. Increased C02 production levels relative to C02 elimination in the scrubber material stimulates the nervous system to increase heart rate, increasing blood volume and blood pressure. The diver is now experiencing the onset of Hypercapnia. With continued high C02 loadings in the breathing bag then peripheral blood vessel dilation will occur. This will have the effect of increasing heart rate even further culminating in massive myocardial contractions or heart attack. The second important point is the equipment examination. After a death (in the UK) the equipment (if recovered) is examined by an expert witness. Of most reports I have read, the equipment on examination has show normal operation, the gas analysis (if available) has also been normal within limits. The expert witness would therefore conclude that the equipment was working correctly at the time of death. So as the cause of death is on the coroner to conclude and with a normal autopsy this is routinely shown to be a heart attack. Remember a diver is only a diver while he is alive. At death he is classified as a corpse. So conclude equipment tested and found to be working OK. Therefore cause of death heart attack. The reason and cause of the heart attack was C02 in the loop. Iain Middlebrook[/QUOTE]
(Offline)

18th November 2009, 11:08	#8 (permalink)
Mark Chase So many CCR So little etc JJ Hybrid Inspo, Hammer Head, KISS rEvo Join Date: Jan 2005 Location: Kent Posts: 4,533	Re: Heart attack? Sorry buisy at work and cant find the link: Also look into lactic acid production C02 and heart failure ATB Mark
(Offline)

18th November 2009, 11:18	#9 (permalink)
paulraymaekers rEvo's daddy rEvo Join Date: May 2005 Location: belgium Posts: 3,639	Re: Heart attack? Quote: (Originally Posted by Mark Chase) I beleive the issue is related to retained co2 more than anything else. I cut and passte this as referance on the subject: Exercise needs an amount of oxygen and the cells in turn produce an amount of C02. As cardiovascular rate increases blood flow and lung breathing rate and volume increases. This with the addition of stress and increased excitement this in turn releases stress hormones and adrenalin. The rebreather all this time with the help of your lung power is pushing the expired C02 laden gas around the breathing tube, through the scrubber and through the loop. Work enough to be called work of breathing WOB. Increased C02 production levels relative to C02 elimination in the scrubber material stimulates the nervous system to increase heart rate, increasing blood volume and blood pressure. The diver is now experiencing the onset of Hypercapnia. With continued high C02 loadings in the breathing bag then peripheral blood vessel dilation will occur. This will have the effect of increasing heart rate even further culminating in massive myocardial contractions or heart attack. The second important point is the equipment examination. After a death (in the UK) the equipment (if recovered) is examined by an expert witness. Of most reports I have read, the equipment on examination has show normal operation, the gas analysis (if available) has also been normal within limits. The expert witness would therefore conclude that the equipment was working correctly at the time of death. So as the cause of death is on the coroner to conclude and with a normal autopsy this is routinely shown to be a heart attack. Remember a diver is only a diver while he is alive. At death he is classified as a corpse. So conclude equipment tested and found to be working OK. Therefore cause of death heart attack. The reason and cause of the heart attack was C02 in the loop. Iain Middlebrook [/quote] oh mighty, I think Simon will jump in quickly paul from what I understand, at this moment, there is no scientific evidence of correlation between high CO2 (retained or inhaled) and increased risk of heart attack __________________ www.rEvo-rebreathers.com ...."Yes you have to pre-breathe to activate the scrubber sorb, anyone who says different doesn't know what they are talking about!"... .... to get more accurate CO2 injection in the breathing machine we put 2 mass flow controllers in series ... .... radial scrubbers give longer dwell time than axials... .... the earth is flat and ...
(Online)

18th November 2009, 11:22	#10 (permalink)
Ben Field MCCR+Shearwater Classic KISS Sport KISS Join Date: Aug 2005 Location: Weymouth, England Posts: 2,760	Re: Heart attack? Quote: (Originally Posted by John Bantin) Not trolling - unless you confuse food-for-thought with ground-bait! I know John, hence the smilie.... (it is however treading a fine line IMO) For years the report of "heart attack" has been the fuel for many flame-wars and long drawn out pointless threads as many protagonists feel it is the result of a null-result to any other test looking for COD in rebreather diving accidents. Its certainly food-for-thought but as far as I'm aware there is no new data on this one, unless you have something?
(Online)

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