ICD Problems

[bouillion532]

My husband is 39 and has HCM. His ICD fired 74 times on 8/22/04. He wasn't in any way physically exerting himself and he was not under and stress. His EP can not figure out why, and we are at a loss. He said that his bpm was at 176 but the ICD wasn't set to fire until it was at 182 (it is now reprogrammed to 194). I've been researching ICD misfires and have found something of particular interest termed "Ventricular Double Counting".

Any ideas on why inappropriate shocks occur or VDC? Thanks!

[CCF-M.D.-MJM]

I am sorry to hear about 8/22/04--what a tough day.

VDC applies to patients with biventricular pacemakers. With BiV pacemakers, there is a lead that stimulate the right ventricle and a seperate lead that stimulates the left ventricle.  The ICD picks up both stimuli and counts them as seperate beats.  Therefore at a rate of 90, the ICD is seeing a rate of 180.  There is no indication for BiV pacing for HOCM alone, so I don't think this applies to your husband.

Without seeing the ICD rhythm print out, it is difficult to say why it shocked him.  It usually records the rhythm at the time of shock so you can see if there is interference of artifact.  I don't think I can help as much with your second question with out seeing the strips.

Good luck and I hope he is feeling better.

[Konopka1955]

Hi bouillion532  Sorry to hear about your husband misfires. It happens unfortunately..  I'm surprised his EP didn't call the manufacturer to see if they could shed some light on that..  

www.zaplife.org  is a great site for ICD patients to support one another and share experiences and sometimes suggestions.  

I think there was one girl who lived overseas and she got shocked the first time and I think it was for VDC - but her EP fixed it and it hasn't ever happened again..  I've heard of people getting shocked repeatedly.  I think he can request a manual on his device and I believe they have to give him one..  but he may have to go through his doc to get it.  I got a manual on my device.  

I know sometimes patients forget to take their meds and sometimes they get shocked..    

Best Wishes
Marilyn (runner)

[bouillion532]

Thanks to you both for you replies. He had taken his meds that morning and was feeling fine. We have found the zapped website a couple of weeks ago, but thanks for the suggestion! I tried to call the Medtronics and they said that they did not have to release case study findings to me because it was proprietary infomation!!! We just want to know how to prevent this in the future...

[bouillion532]

Also, the doctor said that it shocked when it read a v-tach and it should only shock him when it records a high sinus tach?? Does that sound right or do I have my tach's confused??? :-)

[Konopka1955]

Hi,  I believe you can get shocked for either 'tach' - but the VT tach is the one they generally consider dangerous if you have heart disease..  But I believe an ICD can be programmed to try and 'pace' you out of v-tach first and then shock therapy.  I would get a ICD manual and study it..  Surely, he went to the hospital and was put on meds?  That should help to prevent further shocks..

I would also expect my EP to tell me 'why' I was shocked 74 times..  and if he couldn't then I would ask him to find someone who can..  

Good Luck
Marilyn  (runner)

[bouillion532]

Yes. We live in Houston and were about 150 miles from home when it happened. They life flighted him out of Jasper, TX to Beaumont, then grounded us because of the weather. 5 hours later he was life flighted to his doctor at the Methodist hospital in Houston.

His EP insists that he must have been doing something strenous and he wasn't. He was filling a deer feeder with feed. The bag of feed only weighed 10 pounds.

He goes back to the doctor again in 2 weeks.

His first ICD which was implanted 12/2003 was replaced this past June because he had developed an infection.

We are thinking of going to the Heart Institute of Texas and having them evaluate him.

Thanks for all of your help!