What is a heart shock?
A heart shock, also known as a defibrillation shock, is an electrical shock that is delivered to the heart in an attempt to restore a normal heart rhythm. It is used to treat life-threatening heart rhythm abnormalities known as ventricular fibrillation and pulseless ventricular tachycardia. In these conditions, the heart beats in a rapid, chaotic way and is unable to pump blood effectively. As a result, the person quickly loses consciousness and will die within minutes without treatment.
A defibrillator device delivers an electric shock to the heart through pads or paddles placed on the chest. This shock briefly stops all electrical activity in the heart. The hope is that when the heart restarts, it will resume beating in a normal, organized rhythm and be able to pump blood properly again. Defibrillation is an essential life-saving treatment for cardiac arrest.
What does a defibrillation shock feel like?
Patients who survive cardiac arrest and recover consciousness often report little memory of the experience of being shocked. However, some individuals are awake and alert at the time the shock is delivered.
For those patients, receiving a defibrillation shock has been described in many different ways:
– A forceful punch or kick to the chest
– A painful jolt, electric buzzing, or burning feeling
– A feeling of all the muscles in the body contracting at once
– A sense of heat or tingling sensations spreading through the body
– A brief but very painful experience
The shock causes muscles to strongly contract and may produce a sudden tightening of the chest and difficulty breathing for a few seconds. Some people lose consciousness when shocked, while others remain awake but feel dazed and confused.
The pain from the shock itself usually lasts just a few seconds. However, the chest may remain sore for hours or days afterwards. This is because defibrillation shocks require high amounts of electricity delivered all at once, which can damage muscle tissue in the chest wall.
The intensity of discomfort depends on the strength of shock given. Modern defibrillators determine the optimal shock dose for each patient to minimize pain and side effects. Higher energy shocks are required to treat some types of arrhythmias, while lower doses may be effective for others. But any defibrillation is likely to cause at least moderate pain due to the large amount of electricity delivered through the chest.
What factors affect the pain experience?
Several factors influence the degree of discomfort felt from a defibrillation shock:
– **Shock strength** – Shock doses given by an automated external defibrillator (AED) are typically in the range of 120 to 200 Joules. Manual defibrillators used by medical professionals allow shocks of up to 360 Joules when needed. Stronger shocks increase the force and pain experienced.
– **Paddle size** – Larger paddle/pad size spreads the shock over more skin area and may reduce pain slightly.
– **Medications** – Sedatives, anesthetics, paralytics, and other emergency medications given during resuscitation alter pain perception. Patients may be less aware of shock discomfort if under the influence of these drugs.
– **Chest wall impedance** – Lean patients with less muscle and fat over the chest experience more shock pain since electricity passes through tissue more easily. Obese patients have higher chest impedance which may reduce shock pain slightly.
– **Skin preparation** – Disruption of the outer skin layers with abrasion or burns can increase shock discomfort due to irritation of exposed nerves. Proper skin preparation should be done to avoid this.
– **Psychological factors** – Anxiety, fear, and tension prior to defibrillation can amplify the perceived pain. Calm and reassurance from medical staff can minimize these effects. Some individuals may also have little memory of the shock afterward due to the stressful, chaotic situation involved.
Does the shock cause any tissue damage?
Defibrillation shocks require very high levels of electricity to be effective. As a result, some degree of tissue damage is expected, although major injuries are uncommon when shocks are delivered properly.
Potential adverse effects include:
– **Burns** – First and second-degree burns can develop under the paddle sites after defibrillation, caused by electrical heating of the skin and deeper tissues. Blistering may occur in more severe cases. This can be minimized by proper paddle pressure and gel use.
– **Muscle damage** – The forceful muscle contraction induced by the shock can cause muscle fiber tears and inflammation (rhabdomyolysis) in the chest wall, arms, back or abdominal muscles. This can lead to lingering soreness.
– **Bone fractures** – Rib fractures are an infrequent complication, occurring in about 3% of adult shock cases. The compressive and contracting forces on the ribcage can lead to fractures, usually under the paddle sites.
– **Heart injury** – Animal studies show that repeated high-energy shocks may damage cardiac muscle and blood vessels inside the heart. However, heart damage from single defibrillation shocks in medical use is extremely rare.
What is felt if awake when shocked?
Patients who are awake at the time of defibrillation most often describe an extremely painful, forced muscle contraction in the chest wall. A sense of burning or electricity permeating through the body is also commonly reported.
The intensity of discomfort is usually moderate to severe for a few seconds and then dissipates quickly once the shock ends. However, a residual sore, bruised feeling in the chest may last for some time afterwards.
Those who lose consciousness with the shock often report no memory of the experience at all. In other cases, there may be fragments of memory such as a loud noise, bright flash, or electrical buzzing sensation before blacking out.
The heart will often restart into a normal organized rhythm almost immediately after successful defibrillation. Blood flow to the brain rapidly improves once the heart resumes effective pumping action. Return of consciousness usually occurs within seconds to minutes if defibrillation reverses the cardiac arrest.
Can pain be lessened during defibrillation?
Since defibrillation is an urgently needed and lifesaving treatment for cardiac arrest, steps to reduce pain are limited during the procedure itself. However, some strategies may help decrease discomfort both during and after shock delivery:
– Use of anesthesia or sedative medications when feasible
– Allowing a few seconds for gel to soak in before shocking
– Proper paddle pressure and placement
– Cooler temperature gel
– Verbal reassurance and relaxation coaching
– Administering pain medications promptly afterwards
– Application of ice packs over the paddle sites to reduce soreness
– Gentle chest wall stretching exercises
More research is needed to determine optimal ways to minimize defibrillation pain without interfering with treatment effectiveness. But ultimately some amount of discomfort is unavoidable given the high electrical currents needed to halt life-threatening arrhythmias.
How is shock pain assessed?
Since many patients are unconscious or have impaired memory after defibrillation, assessing the degree of pain caused by a shock can be challenging. For responsive patients, self-reported pain scales can be helpful by having individuals rate their discomfort on a scale of 0 to 10. Descriptors of the type and location of pain are also useful.
Monitoring vital signs for spikes in blood pressure or heart rate immediately after a shock may provide indirect clues to the stress response. Observation of facial expressions and body language can also indicate pain reactions in some cases.
Recording patient experiences when able to communicate can inform development of better techniques to mitigate pain and improve the patient experience in the future. Further research correlating discomfort levels with defibrillation parameters andPADDLE CONSIDERATIONS
Since shock pain is influenced by paddle factors, optimal pad or paddle characteristics should be considered.
Paddle Size
Larger pad size spreads the shock over greater chest wall area and may reduce pain slightly. Adult pads should have a surface area >100 cm2. Pediatric pads are smaller but still typically >50 cm2.
Paddle Composition
Solid metal paddles may concentrate current density and increase pain. Flexible pads or paddles coated in conductive gel improve skin contact and current distribution.
Paddle Pressure
15-25 lbs of firm pressure is recommended during shock delivery to avoid arcing or sparks which can burn skin. However, excessive force increases current density and pain.
Conductive Gel
Gel enhances electrical contact with skin and allows current to flow freely through tissue. Letting gel soak in for 10-15 seconds before shocking may slightly lessen pain.
Skin Preparation
Avoid placing pads over broken, burned or excessively hairy skin which can increase discomfort. Removing debris and gently wiping skin improves conduction.
| Paddle Factor | Influence on Pain |
|---|---|
| Larger pad size | May reduce pain somewhat due to greater current spread |
| Flexible pads vs. rigid paddles | More even current distribution and less pain |
| Proper paddle pressure | Avoids arcing injury which increases pain |
| Conductive gel use | Allows current to flow through tissue more evenly |
| Intact clean skin | Avoids irritation of exposed nerves |
What happens after successful defibrillation?
After delivery of a successful shock that restores organized electric activity in the heart, several outcomes may be observed:
– **Regaining pulse and consciousness** – Return of spontaneous circulation and awakening can occur within seconds if defibrillation reverses ventricular fibrillation effectively on the first shock.
– **Brief unconsciousness** – It is common to lose consciousness briefly after defibrillation. Normal heart rhythm may resume promptly but the patient may remain unconscious for a few minutes.
– **Confusion** – Some individuals are awake but exhibit confusion, delirium or agitation initially after a shock until blood flow to the brain improves. Memory of the event is often impaired.
– **Gradual recovery** – On occasion, the heart rhythm may revert but recovery of consciousness occurs more slowly over hours as other medical issues are addressed.
– **Continued cardiac arrest** – If the initial defibrillation shock is unsuccessful, CPR will be resumed and repeated shocks or other interventions may be needed to achieve return of sustained circulation.
– **Recurrence** – Even after initial revival, recurrent arrhythmias requiring additional shocks can develop in some patients in the hours after resuscitation.
The outlook depends significantly on how rapidly defibrillation was achieved after the onset of cardiac arrest. The sooner shock delivery occurs, the better the chances for survival and intact neurological recovery.
Does defibrillation in a hospital feel different?
Defibrillation shocks given in a hospital or clinic setting are comparable in terms of pain or discomfort to those delivered with an AED in the out-of-hospital setting. However, there are a few differences that may impact perception:
– **Sedation use** – Medications for analgesia, amnesia or anesthesia may be given in a hospital and offset some of the shock pain.
– **Shock dose** – Hospital defibrillators allow selection of customized energy levels, which may enable delivery of lower initial doses less likely to cause injury.
– **Paddles** – Hand-held paddles are more commonly used rather than adhesive pads in hospitals. This may concentrate shock density somewhat.
– **Patient condition** – Those with cardiac arrest in a hospital are more likely to have serious comorbidities that could dampen awareness of shock pain.
– **Psychological factors** – The unfamiliar, frantic out-of-hospital environment likely provokes more anxiety and perception of pain.
Overall, the electrical shock sensation itself is similar whether in or out of hospital. But the experience may be modified to some degree based on medications given, the patient’s underlying state, and contextual factors.
What can be done to reduce ongoing chest soreness?
A painful, sore chest is common after defibrillation due to muscle and tissue trauma from the strong muscle contraction and electrical currents. These strategies may help minimize post-shock chest discomfort:
– **Pain medication** – Oral over-the-counter medicines or prescription analgesics can help reduce soreness as the chest wall recovers.
– **Cold packs** – Applying ice packs intermittently over the paddle sites for the first 24-48 hours can alleviate pain and inflammation.
– **Gentle stretches** – Light chest wall stretching focusing on intercostal muscles between the ribs can aid recovery.
– **Rest** – Avoiding strenuous exertion limits further injury to the affected muscles.
– **Monitor for complications** – Watch for signs of more severe muscle damage, burns or fractures and follow-up promptly if these develop.
– **Local wound care** – Use topical emollients and keep paddle sites clean while skin repairs itself after burns.
– **Supportive gear** – Wrapping the chest or using an elastic compression garment may provide comfort by stabilizing the injured structures.
The soreness should gradually diminish over the course of several days as the bruised chest wall muscles heal after defibrillation. Report any increasing pain or symptoms to a provider.
Summary: Key Points
– Defibrillation is a necessary lifesaving treatment for cardiac arrest that requires a high-energy electrical shock to the heart.
– The shock can be very painful, causing intense muscle contraction and discomfort. But tissue injury is usually minimal with appropriate delivery.
– Discomfort duration is just for a few seconds but residual chest soreness is common.
– Multiple factors influence perceived pain, including shock strength, paddle issues, medications, and psychological state.
– Strategies like sedation, verbal support, topical cooling, and post-shock analgesics can help reduce pain.
– Brief unconsciousness after the shock is typical, but return of awareness usually follows soon after for successful defibrillations.
– Ongoing research aims to find ways to limit defibrillation pain without impacting treatment effectiveness. But some amount of discomfort remains unavoidable currently to reverse life-threatening arrhythmias.