Cardiologists once hailed it as a miracle worker: a gadget the size of a matchbox which, when inserted under the collarbone, can jump-start a dodgy heart.
The implantable cardioverter-defibrillator (ICD), as it is called, is able to detect a dangerously abnormal heartbeat (arrhythmia) and, by giving the heart an electric shock, jolt it back into normal rhythm.
Since their introduction in the Eighties, ICDs have been fitted in some 30,000 patients and have extended countless lives. According to the charity Arrhythmia Alliance, they cut the risk of sudden death in patients suffering from arrhythmia by 70 per cent.
Yet specialists are concerned that, though they can save lives, evidence is emerging of major drawbacks. According to Dr Mark Sopher, a consultant cardiologist at the Royal Bournemouth Hospital, one third of the shocks given by ICDs are triggered by variations in heartbeat that pose no immediate danger to the patient.
He says the powerful electric shocks they deliver can have “devastating” psychological consequences. “Saving lives comes at a cost, certainly in terms of the psychological results of shock therapy,” Dr Sopher recently told a conference of European cardiologists in Paris.
“We’ve all experienced patients whose quality of life has been greatly impaired by repeated shock therapy from ICDs, even if their quantity of life has been increased. And many of us will be familiar with patients for whom the fear of more shocks disrupts their normal life.”
ICDs are given to patients with heart tremors, called ventricular fibrillation (VF) or ventricular tachycardia (VT). In VF, the muscles in the two lower heart chambers (called ventricles) contract randomly, rather than in rhythm. In VT, the ventricles beat too rapidly. Both VF and VT can stop the heart pumping blood normally, which can be fatal. About eight in 10 sudden cardiac deaths are caused by these conditions.
An ICD is a battery-powered device implanted below the left shoulder that monitors the heart rhythm via electrode leads passed through a vein into the heart. If it detects a dangerously abnormal rhythm, it can deliver a shock, restoring the heart to a normal rhythm. ICDs can also send out “pacing” pulses to correct less serious rhythm abnormalities.
While many patients may be unconscious when they receive the shock – which causes chest muscles to contract – a significant number are awake. For these patients, says Dr Sopher, the impact and pain of an ICD shock should not be underestimated.
“Imagine a horse kicking you in the chest – from the inside out,” he says. “There’s no question that having a shock out of the blue, when you are otherwise feeling fine, is an awful experience.”
Roger Birchall, 79, from Oxford, received multiple shocks from an ICD while conscious. The retired teacher was diagnosed with VT after he collapsed at home while washing the car and he was implanted with an ICD at the city’s John Radcliffe Hospital last July. On one occasion, while still in hospital, he received 11 shocks from his ICD in half an hour; eventually doctors had to turn it off with a special magnet. He was also given a drug used to stop dangerous heart rhythms.
Roger died in hospital a month later, following a cardiac arrest. His son Hamish, 54, a jazz musician and teacher, believes that the multiple shocks his father received, and the fear of a repeat event, led to acute anxiety and a mental collapse. “It was very, very sad to see a once very strong man reduced in his last days to nightmares and panic attacks,” he recalls.
Hamish claims his father was inadequately informed of the psychological risks of having an ICD fitted, and says: “If he had known, he may well have chosen quality of life rather than quantity.” Mr Birchall wants hospitals to explain fully all the benefits and risks of ICDs, saying his father only had a brief discussion before the operation. “The serious psychological effects of defibrillation shocks are not only understated by cardiologists, they are not adequately discussed with patients, and crucially not entered on the implantation consent form.”
An independent report, requested by Roger Birchall’s family, later concluded that the 11 shocks were “appropriate therapy” because he had been suffering from repeated arrhythmias (called a “VT storm”). The ICD, however, failed to stop them: the report concluded that the arrhythmias either ceased spontaneously or in response to drug treatment.
Roger’s widow, Ann, 85, says: “We were given very little information about the ICD. There was nothing on the patient consent form about the mental disturbances it could cause. When I heard that he’d had 11 shocks, I was simply appalled. How dreadful for him to have to put up with that on top of everything else.
“He was a stiff-upper-lip, old-fashioned type and didn’t want to complain. But when he got those awful horrors at night [following the shock] he could not sleep.”
Dr Sopher said cardiologists must discuss with patients and their families the possibility of “technical failure” of ICDs and “inappropriate” shocks.
“I also tell them that there are occasionally patients who, for a period of time, regret having them implanted,” he said. “That’s a conversation I would expect any consultant to have.”
But he said ICDs were under-used in Britain and doctors needed to make them work better.
Dr Sopher is involved in an international, multi-centre project involving 3,000 patients worldwide, to reprogram ICD software and cut the risk of unnecessary or inappropriate shocks. For example, ICDs should be able to distinguish between dangerous disturbances in the ventricles and less serious ones in the upper chambers. ICDs, he says, could be programmed to react to arrhythmias more slowly, since some arrhythmias stop of their own accord. And some could be dealt with painlessly, by an ICD delivering low-energy pulses that the patient would not notice. Computer simulation suggests these tweaks could reduce the number of patients getting “inappropriate” shocks by three quarters.
A spokesman for the John Radcliffe Hospital said: “As a result of our discussions with Mr Birchall’s family, we have strengthened the Trust’s consent process, and made sure that the doctor or specialist nurse consenting patients for ICDs discusses the risk of psychological impacts – particularly making the point that an ICD shock can be administered when a patient is still conscious.”
Dr Kim Rajappan, a consultant cardiologist at the John Radcliffe, added: “I don’t think there will be a cardiologist in the country who would not support raising awareness of this issue – and the need for resources to be available to provide psychological support to ICD patients.”
What is an ICD?
ICDs are small, battery-powered devices suggested for patients who are at severe risk of cardiac death from ventricular arrhythmia. The ICD contains a battery, pulse generator and computer. Two wires with electrodes at the ends lead from it, through a vein, into the patient’s heart, where they transmit electrical signals back to the ICD.
ICDs can be implanted under the skin of the pectoral region, outside the ribcage, in a local-anaesthetic operation usually lasting a few hours.
A healthy heart controls the rhythm of its own beat by sending internal electrical signals that cause it to contract and pump blood at a regular speed. If a problem develops with this system, the heart produces irregular beats called arrhythmias. Most of these are harmless, but arrhythmias can sometimes lead to a fatal sudden cardiac arrest (SCA) when the heart stops beating.
An ICD controls arrhythmia by monitoring the regularity of the heart’s rhythm and restoring any abnormalities by emitting low-energy electrical pulses which are carried to the heart down the wires. If the ICD detects a serious arrhythmia, it will act as a defibrillator and deliver a higher-energy pulse to shock the heart.