The experience of receiving a defibrillator shock from an ICD is one that many survivors describe in vivid terms, yet it is rarely discussed openly before device implantation. Understanding what a shock feels like, and how to manage the psychological and practical aftermath, is an important part of living with an ICD.
What a shock feels like
The sensation varies between individuals but is most commonly described as a sudden, forceful blow or thump to the chest, a sensation of being kicked, or an intense jolt. Most people describe it as startling and briefly painful rather than prolonged. The shock lasts a fraction of a second. Some people lose consciousness immediately before the shock and do not feel it; others are fully conscious at the moment of delivery.
Appropriate versus inappropriate shocks
An appropriate shock is one delivered in response to a genuine life-threatening arrhythmia (VF or fast VT). An inappropriate shock is delivered when the device has misidentified a non-dangerous rhythm (such as fast AF or electrical noise from a broken lead). Both feel the same to the patient, which is why a shock is always distressing and should always be reported to the device clinic so the stored electrogram can be reviewed.
When to call for help
If multiple shocks occur (two or more in quick succession), call 999. This can indicate an electrical storm (repeated ventricular arrhythmias) requiring emergency treatment.
Psychological impact
Even a single shock can cause significant psychological distress, including anxiety, hypervigilance, fear of another shock, and in some cases PTSD. These responses are normal and should be discussed with the cardiac team. Psychological support, including CBT, is effective in reducing shock-related anxiety and improving quality of life in ICD recipients.
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