are common questions that many new (and waiting) ICD recipients, their
givers, and loved ones ask.
We’ve provided these answers from our experience as ICD
We are not trained medical personnel; as such we don’t offer
advice. Specifics can vary from situation to situation – you should discuss
these questions with the medical personnel providing your care and the
manufacturer of your device. (The
manufacturer will have customer service personnel trained to help you
Through out this document you will find references to Zappers – this is our short hand for ICD owners/recipients. Zappers come in two flavors:
Joeys are Zappers who haven’t received their first shock.
been zapped and bounced back to life – you become a full fledged Electric
Kangaroo! Even those who receive an
inappropriate zap - such as those caused by a programming error -
qualify for the full " Roo" status. We adopted the reference to the Australian
Marsupial because we can do a lot of hopping and we have a little pouch
built in for our EMS crew.
Q. What is an ICD?
A. ICD = Implantable Cardioverter-Defibrillator. Like a pacemaker, it is a device to correct cardiac arrhythmia. This device usually has a pacing function to overcome slow beats. The cardioversion-defibrillation circuitry provides a short burst of high voltage electricity to disrupt the "fluttering" when a heart races as fast as 300+ beats per minute, and restore a normal (sinus rhythm) heart beat.
Q. Is this REALLY medically necessary?
A. YES, if your doctor has performed an electrophysiology study and determined you are likely to suffer potentially fatal arrhythmia. Research posted in the spring of 2002 again verifies the life saving value of these devices: Suggesting it for most people who survive a heart attack that resulted in significant damage to the heart muscle. See below to understand how an ICD improves your chance of survival.
Q. Where is the ICD implanted and why?
A. In the old days, the devices were implanted left of the belly button with a long cable running under the breast, up near the collar bone, and down into the heart. Now that engineers found ways to make the ICD smaller, they are usually implanted in the left upper chest - eliminating some of the persistent pain that goes with the long cable which can move around.
Q. Do I have other options for placement?
A. Previous implants may limit your choices. With a previous pacemaker, your ICD may be implanted on the right side. Depending on your body type, you may have the implant just under the layers of skin. Some prefer to have it deeper - imbedded under muscle tissue: A sub-pectoral implant. Discuss it with your doctor to understand the benefits and disadvantages of each.
Q. How long does it take to recover from surgery and for the wound to heal?
A. It depends on the individual and whether there are other health problems needing attention. Most people leave the hospital the day after their initial implant - or a few hours after a replacement surgery.
The wound should heal in a couple weeks. You can reduce the scarring by using an aloe and vitamin E solution after your wound is sealed.
Q. Why did they tell me not to lift my arm over my shoulder or lift
for six weeks after my implant?
A. Besides inserting the ICD into your body they also had to run 1 or more
(wires) from the device into your heart. They
don’t want them to be pulled out, broken, or disconnected.
During this six week period your body will start to heal over
leads. You can then return to
a normal life.
Q. How much is the ICD going to protrude from my chest and will I look like a freak in a bathing suit?
A. That depends on your body and the type of implant you receive. Most of the new units are very small and appear no larger than a pill bottle lid. It will be easier to see if you are skinny, but it will not make you look like a freak.
Q. Will my husband/wife be afraid to touch me?
A. He or she shouldn't unless your husband/wife was afraid to touch you before your implant. Even if someone is in contact with you when the device zaps you, that person will not be hurt. At most, a bystander may feel a little tingle. One reader wrote to say his spouse actually enjoyed the feeling during an intimate moment.
Q. What's the maintenance on this device?
A. Just make sure you make your regularly scheduled interrogations - usually once every three months. If something needs to be done, the professionals will take care of it. Otherwise, you need to do nothing for it - no oil changes, no air pressure checks, no adding of fluids like antifreeze.
Q. Will an ICD change my quality of life?
A. Only if YOU let it become an excuse for not doing things you want to do. The condition you have that requires the implant of the ICD may have a profound impact on your life. But the device itself should be nothing more than a small annoyance when you swing a golf club or tennis racket and demands no attention beyond the routine interrogations. After the surgical wound heals, you can nearly forget about it and go about living life the way you choose.
Q. How much does an ICD cost?
A. Like a car, it depends on the model implanted. Some people need lots of the new whistles and bells for specialized treatments such as CHF - others are fine with the basic monitor and therapy functions. Generally, the basic hardware costs $35,000 and the surgical costs for doing the implant run about $35,000. Much of that is covered by most insurance companies, including Medicare.
Q. How long does an ICD last and why does a pacemaker last longer?
A. Current models can last up to eight years. That can be reduced by the number of times you need "therapy" and will be shorter if you need frequent pacing. A pacemaker lasts longer because its battery demands are much lower - its purpose is simpler requiring much less energy and demanding less power for monitoring and analysis.
Q. I feel scared, depressed, etc. Is this normal?
A. This is very common among all readers of The ZAPPER - ICD recipients and their loved ones. In fact, if you do not experience this, you are the exception. Because it's a pretty normal reaction to needing a piece of electronic hardware inside you to stay alive, it is imperative you find ways to deal with it. For extreme cases, your doctor may prescribe psychotropic drugs such as paxil or xanax.
As time passes, you may be able to stop taking drugs as you find other ways to deal with the fear and depression. Many of us find just "talking about it" is every bit as effective as drugs. Local ICD support groups are great for providing this kind of outlet. See ZAP• Groups
Our online, real-time support groups (see ZAP• Chats) have given relief to hundreds of people over the years - as ICD recipients can share thoughts with others who have experienced the same things. Our internet messaging service (see ZAP• Folks) provides a way to exchange thoughts with others at any time of the day or night. Others prefer posting messages on the ZAPPER• BBS or ZAP• List... then come later to read responses to their posting (or via email for the list service.)
Scientific research and personal experience have shown the emotional impact is actually greater on our loved ones than us - the implant recipients. Because of that, we make all of our programs available to spouses, significant others, parents, children, and others. Be sure to let your friends and family knows: They are welcome here, too.
Q. Can I still have a heart attack even though I have the ICD or do I become immune?
A. Yes, you can still have a heart attack. An ICD does not prevent a myocardial infarction, which is a blocked artery causing heart muscle tissue to die. Things like exercise, improved diet, reduced stress, and other lifestyle changes suggested in a cardiac rehab program will reduce chances for a heart attack.
ICD implant will save your life 99% of the time if you have a
episode of arrhythmia. (According to current statistics.) Currently,
available medications prevent fatal arrhythmias about 85% of the time. So you can see, the ICD does increase your survival odds significantly.
So you can see, the ICD does increase your survival odds significantly.
Since arrhythmia is often experienced by people after an MI, your device may act as an early warning system - to announce you have a problem needing prompt attention for situations such as a heart attack, congestive heart failure, or an electrolyte imbalance - all of which can be life threatening.
Q. I feel flutters at times. Are missing heartbeats normal?
A. Actually, most of the time it's not a "missing" heart beat... but an extra one that we experience in the form of a PVC - pre-ventricular contraction. While discomforting they are not uncommon and only become a problem when there is a long sustained run of them. Many of us take medications to decrease these events - and the ICD is inside us to take care of those which may lead to a dangerous situation.
Suggestion: Don't stare at your EKG monitor in the ambulance, ER, or CICU looking for these things. If they happen, they happen. Learn to trust your device and your caregivers to respond if necessary. You should NOT worry as that will only make the situation worse - perhaps much worse.
What does a shock (aka: "zap" by us and "therapy" by
doctors) feel like?
That’s a tough one. Like a sneeze,
everyone’s reaction is different. Some
people describe it like being kicked by a mule, others hit by a two by
still others describe the rush of electricity through their body to
people black out and may collapse before “therapy” is administered.
Others are conscious for the whole thing. The lucky ones feel a little tingle. Suffice it to say, it’s not the most pleasant experience that you will encounter during
life. However, it sure beats the
times a single shock is enough to restore your heart back to a normal
other times you make be shocked multiple times.
This is often referred to as an "electrical Storm."
This is often referred to as an "electrical Storm."
What should I do after a shock?
Sit down, if you’re not already sitting or lying down! If the first
doesn’t correct the problem you may receive another.
You want to avoid further injury as you may fall onto something.
Your doctor should have given you instructions on how to proceed. Generally, if you have received multiple shocks they will want to see you immediately. If you have a single shock and you feel fine, you should still give your EP office a call. They may set up a time in the next couple of days to interrogate your device.
Q. Will I be able to drive?
A. Driving restrictions vary from state to state - many prohibit driving
period of 3 or 6 months from the date of implant.
Others only restrict driving if you've blacked out during the
several months. Your doctor, local
DMV, or State Police should
be able to advise you about whether you may drive.
if you are permitted to drive you may want to consider letting someone
drive if that is possible. This is
especially true if you faint or blackout due to your
condition. Before driving you
should be comfortable with the potential consequences if you were to
shock while at the wheel. A recent
study did conclude that Zappers were safer drivers (involved in fewer
than the general public.
Remember: Having an ICD does not restrict your driving privilege. The reason you have an ICD is what determines whether you can drive.
Q. Will my car's seatbelt interfere with my device?
A. A seat belt may feel uncomfortable, especially the first few weeks after implant. Some people find that a padded seat belt protector reduces the discomfort. (You can also just wrap the seat belt with a towel.)
Q. I am going on a trip. What do I do about airport security? Will the scanners interfere with my ICD?
A. Make sure that in addition to your passport or other identification
also have your ICD owner's card with you when you travel.
Generally, you can pass through the scanner, but you may likely
the alarm. NEVER let the
security guard scan you with the handheld
wand; it can interfere with your device and change the programming!
Have your ICD card handy to show security.
Tell them that you have an ICD / pacemaker and you need to
searched. Some people are more
comfortable requesting a hand search from the start.
Airport security guards are pretty good about this, but most deputies at court houses have yet to receive the training necessary to understand the danger to us. If you run into a uniformed officer determined to use the wand: Demand they call their supervisor to the scene!
Q. What about store security systems?
A. Generally, they do not interfere with your device.
Walk thru them. Do not linger
between them. In those rare cases where you set off the detector, just
them your ICD implant card and you can continue on your way. If
you hear a
beeping noise - it may be your ICD telling you to move away from the
Q. My ICD is making a beeping noise, what should I do?
A. Some ICD’s make audible
tones for a variety of situations.
Some are programmed to do a “self check” every day at a specific
time. If there is a problem, broken
lead, low battery, etc. it will make a noise.
If there is a more immediate problem the device may emit a
If your device starts making a tone contact the doctor/hospital
monitors your device. They will
advise you what to do next.
addition some ICD’s will emit a tone if you are too close to a powerful
magnetic field. This is often
reported by concert fans that stand too close to the huge loud
speakers. Move back away from
the potential source. If you are clear of the field the noise will
your next interrogation ask and they should be able to demonstrate the
your ICD can make and explain their meanings.
Q. How do they change the ICD batteries?
they cannot change the batteries.
The ICD is an intact sealed case. When
the batteries run low your implant will be replaced.
This is not bad because each generation of ICD is
more sophisticated that the generation before, allowing you to get upgraded hardware.
the replacement is done on an out-patient basis.
If the leads are still good, they will open you up, remove the
and install the new one. Your
recovery time will be faster. You
will not have the same restrictions about raising you arm and lifting
during the initial implant.
Q. What are interrogations?
A. An interrogation is a periodic visit where the medical personnel with
your ICD to a computer. They place
a device on the skin above your ICD that is about the size of a
Using the computer they can download information about events
detected, therapy administered, make adjustments in the programming,
test leads and
the device, and verify battery settings. More and more device makers are offering advanced systems that allow the remote monitoring of an ICD over phone lines, cell phones, internet connections, even satellites!
should bring a list of medications that you are currently taking.
In addition, if you have any notes about dates/times when you
well, you may want to bring them too.
results of the interrogation will be printed out and added to your file.
You may want to request a copy of your device settings to keep
especially if you travel.
is not painful. You are able to
talk and ask questions during the interrogation.
If they exercise some of the pacing functionality you may experience some
discomfort or facial "flushing" as the technician increases the pace of your heartbeat.
What’s pacing and why do I have it?
A. Almost all implantable cardioverter-defibrillators have built in circuitry to pace the heart, in addition to familiar "zapping" function to correct V-Tach or V-Fib, when the heart beats too fast. The pacing function starts if the heart beats too slowly. That happens to many of us, especially when we sleep, because some of the anti-arrhythmic medicines we take do slow down the heart beat. Newer ICD models will actually try to pace you out of a dangerous arrhythmia, before giving you a full powered therapy.
Q. What is a NIPS test?
A. NIPS stands for Non-Programmed Stimulation test.
So clinics periodically (every year or two - if you have not
received a therapy) perform this procedure, others never do this after
you are initially
implanted. This test is done on an
outpatient basis. Under anesthesia,
your heart is placed in arrhythmia, and your ICD shocks you back into
rhythm. If for some reason the
device does not work correctly they would restore a normal rhythm with
external defibrillator. The purpose
of the test is to verify that all the components are connected and
What’s inappropriate therapy?
A. Though the programming in the ICD's is very sophisticated there are
where physicians may misdiagnose your situation resulting in improper ICD programming, and you get a shock/zap/therapy that is not needed.
This is called an inappropriate therapy.
Many inappropriate therapy situations can be addressed by
your ICD. Others may be avoided by
medication. Finally, the ICD
manufacturers are always trying to improve their devices to avoid these
situations. The vast majority of
shocks received are appropriate and life saving therapy.
If you do receive an “inappropriate therapy,” don’t be surprised if you wish that your doctor, nurse, etc would receive a little “inappropriate therapy” themselves. Especially, if they caused the problem by the settings.
Q. What are phantom zaps?
A. Our publisher, Jon Duffey is credited with first joining the words to form the name "Phantom Zap," having authored the term for an article he wrote in early 1995.
This, like the depression and anxiety is pretty common. Many Zapper readers report being zapped (usually as they are going to sleep or waking up) but their subsequent ICD interrogation shows nothing happened. OK, there was no 700 volt dose of therapy. But it sure felt like the real thing. Your doctor may tell you it was just your imagination, but that doesn't mean it is not a real problem that needs to be addressed. Some report relief by going to a hypnotist.
One important thing to help stop these annoying episodes is to understand what is happening. Like the term " Phantom Zap," Duffey is responsible for this idea. It's only a theory but thinking about it this way has helped many accept them and gradually make them go away:
When your device was implanted, you were asleep.
After the device is implanted, doctors test the device to make sure it works on you. (See NIPS above)
Even though you were unconscious, the event was burned into your memory - but a section of memory that is not easily accessed when you are awake.
However, in that brief period between being wake and going to sleep - or during that period when you awaken from a nap or sleep - THOSE memories are accessed.
In that limbo state, what you experience is every bit as real as an actual dose of therapy.
Ultimately, when you accept them as a flashback of a reality from your past (the testing after implantation) they seem to lose their reason for being (raison d'être) and fade away.
Q. What’s an ejection fraction?
A. With each beat, a healthy heart will pump out 55% to 60% of the blood in it. After a heart attack or other ailment that damages the heart muscle, that number (the ejection fraction) is reduced. The government standard for disability approval is usually anything under 30%. Heart patients, not excluded for a heart transplant for reasons of age or other health problems, become "candidates" for transplant when their EF drops below 19%.
science is making significant progress finding ways to boost heart
EF. Among those are a variety of medicines such as coreg
(carvedilol.) Others are finding relief - with an increase in EF
- from a
relatively new therapy in the United States called EECP which was developed in China. Unfortunately, not every drug
procedure works for everyone. Each of us needs to explore the
My doctor won’t talk with me or answer my questions.
What should I do?
A. Remind your doctor, that you are the patient. You've got the condition. You deserve the right to understand your treatment and have your questions answered. If your doctor doesn't correct that behavior immediately, then FIRE him or her ASAP - and find someone you can trust! A lack of confidence in your caregiver can lead to other problems and not all of them are emotional. You (or your insurance) pays them. They work for you. If you are not getting what you want, need, and deserve - you are throwing money... and your health... away. You should consider this action even if the doctor is great, but an incompetent staff prevents you from getting the appropriate care.
When you fire a doctor, make sure your medical records are transferred to the new physician - completely and immediately. Without those, your new care givers will have an incomplete picture of what makes you a unique patient.
Q. What's the difference between an EP and cardiologist?
A. Think of it this way.
1. Consider your cardiologist as your heart's plumber. His specialty is your pipes.
2. Consider your electrophysiologist (EP) as your heart's electrician. His specialty is your wiring.
Q. Can I still work with an ICD?
A. That all depends on your condition and your line of work.
Many ICD owners still work without a problem.
For others the condition that caused the need for the
ICD is significant enough that they qualify for social security
Some people need to find a different type of work – for example
no longer be qualified to be a front line police officer, or a steel worker
balancing on a girder hundreds of feet above the ground, if you have the potential of getting a 700 volt zap .
Q. Can I still have sex? What will
happen to my partner if I receive a shock?
A. Many zappers can attest to having happy and fulfilling sex lives. Sex does elevate your heart rate, similar to exercise. If you were to receive a shock during sex, they say your partner would feel a slight tingling and the electrical energy dissipates.
of us with an ICD do experience trouble in this area, but it is NOT the
implanted device causing problems - beyond the mental issues.
Many of the
medications we take have a profound impact on love making equipment.
does NOT mean you should stop taking your pills! Work with your
find alternatives and solutions to this situation.
Q. Can I still golf? Ride a bike? Run? Swim? Play football? Dance? Play
A. You will be able to do many of the activities that you were able to do
the implant. You should always talk
with your doctor before resuming any of these activities.
Some activities like contact sports that could damage your
device or cable may be
prohibited. Others like swimming
may be discouraged, or allowed with certain restrictions.
(After all what’s the advantage of saving your life, if you
a few ZAP• Folks have run marathons and triathlons, climbed
mountains (such as
Machu Pichu,) 100 mile bike races, or played 36 holes of
golf a day for 3-4 days. While these are extremes many others do
varying levels of physical activity. Mowing a lawn can be an achievement! Your
doctor may suggest that you participate in cardiac rehab where you
under controlled circumstances, under close supervision to learn the
levels and types of exercise for your situation.
ICD owners are also on medication to lower their heart rate.
As a result, they may find it difficult getting the heart rate
into the “target zone” for exercise. Your
physician may suggest that you still exercise, but do not attempt to
your heart rate significantly.
ICD monitors your heart rate and when it exceeds a certain threshold it
delivers a shock. If you are an
active exerciser, your doctor may have to adjust your settings to
ensure that an
elevated heart rate during exercise does not result in an
Q. Can I ride amusement park rides?
A. You better talk this over with your doctor. Your specific condition may, or may not make it an unsafe adventure. The publisher has had no problem on wild roller coasters, but did get zapped watching his college team play basketball. Different kinds of excitement affects each of us differently.
Those of us with an abdominal implant site may not be able to handle rapid direction changes, which may damage the leads. Some rides also use powerful electromagnets, and the radiation field could affect device programming. That could be catastrophic! Park administrators can tell you which rides pose this kind of problem.
Q. What are all those alphabetical codes/abbreviations my doctors and nurses use?
A. There are a bunch of them. This list of cardio codes was compiled by Eileen Yeisley, RN:
A-A Interval: Interval between two paced atrial contractions.
When there is an atrial contraction for each ventricular beat, the A-A
Interval is the same as beats per minute or heart rate. A-A Interval is
usually measured in milliseconds (ms); one ms is 1/1000 of a second. A
normal A_A Interval is between 600 and 1000 milliseconds or 60 to 100
beats per minute.
AICD: Automatic Implantable Cardioverter Defibrillator. AICD is a Guidant trademark.
ADL: Activities of Daily Living. Includes activities like feeding oneself, bathing, brushing one’s teeth, etc.
AF: Atrial Fibrillation. Although not usually a life threatening arrhythmia, atrial fibrillation can cause a loss of ‘atrial kick’; responsible for about 25% of cardiac output. It is a condition where the muscle cells of the atria do not contract at the same time but each cell at its own rate. This results in a ‘quivering’ of the atria instead of a contraction that would push the blood into the ventricles.
AP: Atrial Pace; when a pacemaker or ICD paces the atria (stimulates it to contract).
AS: Atrial Sense; when a pacemaker or ICD senses depolarization of the atria when the heart depolarizes on it’s own. The muscle must depolarize to initiate a contraction.
AV: Atrioventricular; meaning of the atrias and the ventricles.
BBB: Bundle Branch Block; a block in conduction of electrical activity in one of the three bundle branches.
BOL: Beginning of Life; a term used to describe the battery condition of a new pacemaker or ICD.
BPM: Beats Per Minute; the number of beats the heartbeats in one minute; normal is between 60 and 100. Also known as your pulse (i.e. a pulse of 80 means a heart rate of 80 bpm). bpm = 60,000 divided by milliseconds
CO: Cardiac Output; the amount of blood the heart ejects in one minute. It is the stroke volume (amount of blood ejected in a single heartbeat) times beats per minute; usually measured in liters per minute.
CPR: Cardiopulmonary Resuscitation
EGM: Electrogram; an "EKG" measured from within the heart instead of from patches placed over the chest. Because it is less likely to pick up other electrical stimuli from other muscles it tends to be more accurate.
EMI: Electromagnetic Interference; interference that can upset the workings of pacemakers and ICD's; caused by high-energy forces; MRI's, arc welders, transformers, can all cause interference with pacemakers/ ICD's.
EOL: End of Life; a term used to describe the battery condition of a used up pacemaker or ICD. When and ICD or pacemaker is approaching EOL your cardiologist will schedule surgery for a replacement.
EP: Electrophysiologist; a cardiologist who specializes in electrical problems or arrhythmias of the heart.
EPS: Electrophysiology Study; there are two main workings of the heart: 1. the plumbing and 2. the electrical circuits. A cardiac catheterization studies disease in the ‘plumbing of the heart’ (blockages in the arteries of the heart) and electrophysiology studies disease in the electrical circuits of the heart).
ICD: Implantable Cardioverter Defibrillator
IPG: Implantable Pulse Generator; pacemaker.
mA: Milliampere; 1/1000 of an ampere; used to describe current flow of a pacemaker or ICD.
ms: Millisecond; used in EP studies to measure beats per minute and the different waveforms of electrical activity of the heart. 1/1000 of a second. To convert beats per minute to milliseconds: ms = 60,000 divided by bpm
NGB: Generic Pacemaker code; code used to describe pacemaker functions. Usually 3 or four letters. DDDR is a common code for pacemakers and ICD's. The first letter signifies the chamber paced. V means Ventricle, A is Atrium, D is both or Dual, O is none and occasionally S is used by some manufacturers to mean Single. The second letter indicates the chamber that is sensed (the ICD/ pacemakers detection of electrical activity). The third letter indicates the pacers response to sensing; T means it will trigger pacing, I means it will inhibit pacing D means it will do both inhibiting and triggering, and O means none. The fourth letter is for programmability functions—Rate responsiveness. P is simple Programmable; M is Multiprogrammable; C is Communicating functions (telemetry); and R is Rate Responsive. If a fourth letter is present it is usually rate responsive. Therefore, a pacemaker or ICD that is DDDR means the pacemaker is pacing electrical activity in both the atrium and the ventricle and it is sensing activity in both the atrium and the ventricle. When it senses an event it will either trigger a response or inhibit pacing and the rate is responsive (the pacing rate will change in response to sensors that detect changes in metabolic needs to increase the cardiac output).
NSR: Normal Sinus Rhythm. The a normal EKG waveform.
PAC: Premature Atrial Complex. If the atria conduct a beat before it should they will not fill properly before contracting. If this occurs in the ventricle it is called a PVC or premature ventricular contraction. Both can lead to ventricular tachycardia although it is more common with PVCs.
PMT: Pacemaker Mediated Tachycardia. As the name implies, an induced tachycardia in persons who have either an ICD or pacemaker. This is a fairly rare tachycardia since the development of features in newer pacemakers. Anytime a pacemaker or ICD feels they have a racing heart rate it should be checked out by their EP.
PSVT: Paroxysmal Supraventricular Tachycardia; Paroxysmal means abrupt onset and termination. SVT is an abbreviation for Supraventricular Tachycardia. This is a tachycardia that originates above the ventricles. It is often difficult to distinguish the difference between SVT and ventricular tachycardia by looking at the EKG signals.
PVC: Premature Ventricular Contraction; occurs when the electrical signal that causes the muscle to contract comes too soon. The ventricle does not have enough time to fill before contracting. When PVC’s occur several times in a row and too close together, there is a danger of developing ventricular tachycardia or ventricular fibrillation. Although everyone has PVC’s, persons with damaged heart muscle have many more.
SCD: Sudden Cardiac Death; a condition in which the heart develops a lethal arrhythmia and is unable to pump enough blood to sustain life. If untreated, the person with these lethal arrhythmias will die in minutes. The most lethal arrhythmia is ventricular fibrillation. It is different from a heart attack; a heart attack is a condition where blood vessels that supply blood to the heart are blocked and cause the heart muscle to die (that is the plumbing of the heart is defective). In sudden cardiac death, the electrical system of the heart is defective.
SSS: Sick Sinus Syndrome; also called sick sinus node dysfunction. A condition where the natural pacemaker of the heart (the sinus node or SA node) initiates slow or irregular heart beats. Persons with this syndrome, if symptomatic, are surgically implanted with a pacemaker.
SV: Stroke Volume; the amount of blood ejected by the ventricle in one contraction. The stroke volume times the beats per minute is the cardiac output.
SVT: Supraventricular Tachycardia; a tachycardia that is initiated above the ventricles. It includes atrial tachycardia, atrial flutter and reentrant tachycardia that are not ventricular. It tends to be a catch all phrase of those arrhythmias that are not easily distinguishable from each other with an EKG.
VF: Ventricular Fibrillation; a lethal arrhythmia in which the muscle cells of the ventricles contract at a different rate resulting in a ‘quivering’ of the ventricles. There is little or no cardiac output. A person in VF will live only 4-6 minutes before brain death occurs. A person with VF is said to be experiencing sudden cardiac death. VF can occur without warning. It is also the hardest arrhythmia to defibrillate back into a normal sinus rhythm. Electrophysiologists usually test ICD's by putting the patient into VF and defibrillating the patient to see how many joules it will take to get the patient out of VF.
VP: Ventricular Pace; when a pacemaker or ICD paces the ventricles (stimulates it to contract).
VS: Ventricular Sense; when a pacemaker or ICD senses depolarization of the ventricles when the heart depolarizes on it’s own. The muscle must depolarize to initiate a contraction.
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