Posts by Nat Jenkins:
If I had my way, all schools should be equipped with a defibrillator. Although sudden death in young people is rare, it does occur and when it does occur, it destroys lives and costs many, many life years. The terminal heart rhythm disturbance in individuals who die is ventricular fibrillation. There is only one treatment for ventricular fibrillation and that is prompt defibrillation. So it makes sense that if a school has a defibrillator, there is a chance that a life may be saved.
However, there are logistical problems. There are several questions, for example – who is going to learn how to use the defibrillator, where will the defibrillator be kept, how do we contact the individual that can use the defibrillator, who will service the defibrillator? Once we have got all of this in order or some sort of protocol that allows schools to tick all the right boxes, then I do feel it’s important that every school does have a defibrillator, in fact I’m pushing for our children’s school to have a defibrillator of their own.
An ICD stands for an internal cardioverter defibrillator. This is a device that is implanted into the body under local anaesthetic . The patient usually comes in as a day case to have the procedure done and the device lives just under the left collar bone. We make a 5cm incision under the left collar bone and we make a pocket under which this device – which is about this big – lives. The device is connected to two leads and these leads are inserted into the heart by making a puncture under the collar bone and accessing the veins that take us to the heart. The leads are then secured into the heart and the wound is sewn up and the patient is ready to leave. The big question mark is who gets an ICD and what it does.
The job of an ICD is to watch the heart day and night – that is, to watch the heart specifically for fatal rhythm disorders. If this lead identifies a fatal rhythm disorder, it will try its level best to pace the heart back into a normal rhythm. If after about 20 beats it fails to do so, it will deliver a small shock of 20 joules that will restore the heart back into a normal rhythm. So it’s a life saving device. The sort of people that get ICDs are those who have already survived a sudden cardiac death. If someone’s been fortuitous enough to survive a sudden cardiac death, we will not let that happen again. That sort of individual will have an ICD without any questions. Other people that get ICDs are those individuals with hypertrophic cardiomyopathy, arrhythmogenic right ventricular cardiomyopathy, Brugada syndrome and long QT syndrome who are deemed to be at high risk of sudden death and we have various investigation protocols that can identify high risk individuals versus low risk individuals.
It’s also important that many acquired conditions can also predispose to sudden death. For example there may be some individuals who have suffered a bout of myocarditis that has rendered them with a very poor ventricle that is prone to very nasty rhythm disturbances. That group of people may also require an internal cardioverter defibrillator.
Most people that play sport are evaluated with a simple ECG and a health questionnaire. However, the very elite athletes normally undergo an ECG and an echocardiogram. To be quite honest, ECG alone is inferior to an ECG and a cardiac ultrasound. The ECG alone will exclude important electrical faults of the heart but will miss minor anatomical or structural abnormalities of the heart. Missing these abnormalities may not be so important in recreational athletes or those individuals that don’t do enough sport. But if you consider that some of our elite athletes are putting their hearts under a lot of strain, it’s possible that some of these minor structural abnormalities may become more severe with time so it’s important to pick up even the most minor problems in our most elite athletes and therefore I believe that elite athletes should have an ECG and an echocardiogram.
There is a financial argument here as well, in that most individuals that exercise in this country are not elite and if they are part of a more junior or amateur sporting organisation, the organisation may not have the funds to do an ECG – and an echocardiogram is substantially more expensive than an ECG. However, many elite organisations are funded or are financially well endowed and can afford both investigations in all their athletes.
The ECG is very good at picking up electrical faults of the heart but the echocardiogram is a much more detailed investigation that looks at structural abnormalities of the heart. So, minor holes in the heart, minor valve problems will be missed by an ECG but will be picked up with an echocardiogram. In my experience, about 1% of people we screen have such minor abnormalities that are only picked up on a cardiac ultrasound.
Diagnosing conditions causing sudden cardiac death can result in utilisation of several diagnostic modalities. These can range from something as simple as an ECG to something as complex as an electrophysiological study. The more tests that are performed, the higher the yield of picking up something that causes sudden cardiac death. Let’s just look at the common causes of sudden death, these are the cardiomyopathies and ion channel diseases. The ion channel diseases certainly can be identified using an ECG, the possibility of underlying cardiomyopathy can be identified with an ECG alone. So at CRY we try to adopt a very pragmatic model which is cost effective and we normally recommend health questionnaire and ECG on the understanding that an abnormality on any of these investigations will result in further tests which CRY will fund.
We do offer echocardiography, obviously that’s a second test in addition to the ECG and that will have a better diagnostic yield. An echocardiogram will pick up things that an ECG won’t, for example anomalous coronary arteries, a small hole in the heart, a minor valvular problem. These things may be more important for the very elite athletes as opposed to someone who is just doing recreational sport. So we give that choice and the choice of people doing ECG and ECHO is usually taken up by pretty elite or financially endowed sporting organisations. I personally don’t believe it’s mandatory to do both.
Please note: since this video was filmed, CRY’s screening activities at King’s College Hospital and the Olympic Medical Institute have been relocated to the new CRY Centre for Inherited Cardiovascular Conditions and Sports Cardiology, based at St George’s Hospital in Tooting.
CPR stands for cardio pulmonary resuscitation and there are two forms of CPR. There’s the basic CPR and there’s the advanced CPR. Basic CPR involves cardiac massage and providing artificial breaths to someone whose heart has stopped. I believe that every British citizen should be trained in basic CPR – basic CPR can save lives. Basic CPR can prevent an individual who has survived from being in a permanent vegetative state.
In the event that someone collapses, I believe that most individuals in this country should be in a position to ascertain that there is no pulse and the individual is not breathing and should be able to initiate basic cardiopulmonary resuscitation until the paramedics arrive. The paramedics are all trained in advanced life support and will be in a position to institute drugs and even to defibrillate the heart, if required. But CPR is crucial and goes a long way in saving lives and reducing the risk of brain damage in people that have suffered a cardiac arrest.
The exercise stress test could be regarded as an important part of screening for cardiac abnormalities. My personal opinion – in young people in whom the commonest cause of sudden death is from the cardiomyopathies or the ion channel diseases, is that an ECG and an echocardiogram alone is enough. However, there are lots of people out there that play sport that are aged over 35 years of age. In that group, the commonest cause of sudden death are blocked arteries and in that group, the most important investigation would be an exercise stress test. So an exercise test for people over 35; in people below 35, an ECG and echocardiogram will suffice.
There is certainly a connection between certain sport deaths and long QT syndrome. The most common sporting discipline that is associated with sudden death in long QT syndrome is swimming. The thought process is that the dive into the water at the beginning of a swimming contest incites an adrenergic surge – that is a rapid rise in adrenalin levels – probably because the face and the body hits cold water suddenly. This surge in adrenalin causes the heart to go into an abnormal rhythm – so most deaths in long QT syndrome appear to occur in swimmers.
Unfortunately, many people don’t recognise that this death may be due to an abnormal cardiac problem and these deaths are falsely attributed to drowning. There are many situations where there is an excellent swimmer who went out to swim in a lake and drowned suddenly and people feel that they may have run into trouble or it’s an unusual cause of death, unusual drowning. But such drowning should be investigated and family members of such individuals must be screened for long QT syndrome. It’s usually the females that die during swimming more so than males.
There are certain people who are gene carriers for some of the conditions such as hypertrophic cardiomyopathy or long QT syndrome but these individuals do not manifest any of the clinical features, ECG features or echocardiographic features of the condition. These types of individuals are known as obligate carriers. They can, however, pass the gene on to their children who may have the full blown version of the condition that they have passed on. When it comes to exercise, expert opinions vary, our own opinion is that if someone is a gene carrier but does not show any features of the condition on clinical testing, we do not prevent them from exercise and that seems to be the stance that the Americans have taken as well.