Electrical therapy plays a critical role in managing life-threatening cardiac arrhythmias. The human heart relies on an intrinsic electrical conduction system to maintain a coordinated heartbeat. When this system fails, dangerous rhythms like ventricular fibrillation can occur, stopping effective blood flow. Applying an external electrical current can depolarize the heart muscle all at once, effectively resetting the chaotic electrical activity and allowing the natural pacemaker to resume normal control.
Defibrillation delivers a therapeutic dose of electrical energy to the heart. The two main types of waveform energy used in modern practice are monophasic and biphasic.
Energy delivery is measured in joules. Proper pad placement is vital to ensure the current passes directly through the heart mass between the apex and the sternum.
Emergency defibrillation is indicated strictly for shockable cardiac arrest rhythms. These specific rhythms are ventricular fibrillation (VF) and pulseless ventricular tachycardia (VT). Non-shockable rhythms, such as asystole and pulseless electrical activity (PEA), must not be shocked; instead, management focuses on high-quality cardiopulmonary resuscitation and epinephrine administration.
When treating a patient in VF or pulseless VT, the healthcare team must minimize interruptions in chest compressions, clear the area to ensure safety before discharging the device, and immediately resume compressions right after the shock is delivered.
A cardiac pacemaker is a small medical device designed to artificially stimulate the heart muscle when the intrinsic conduction system fails to generate a reliable rate. The device consists of a pulse generator containing a battery and computer circuitry, along with one or more insulated leads that connect directly to the heart wall. Pacemakers monitor the heart's electrical activity and deliver tiny electrical impulses only when the natural heart rate drops below a pre-set limit.
Pacemakers are categorized based on how long they are needed.
Careful monitoring is essential for patients with cardiac devices. For patients with pacemakers, healthcare providers must observe the cardiac monitor for pacing spikes—vertical lines indicating the device has fired—followed by a captured heartbeat. Nurses should regularly assess the insertion site for signs of hematoma, infection, or bleeding. Patient education is also vital; individuals with permanent pacemakers must learn to avoid strong magnetic fields, monitor their pulse daily, and report symptoms like dizziness or shortness of breath immediately.
Device malfunctions can occur in both pacemakers and defibrillators. Common pacemaker issues include failure to capture, where pacing spikes appear without a resulting heart contraction, and failure to sense, where the device fires inappropriately because it does not recognize the heart's own natural beats. Lead displacement and battery depletion are other mechanical concerns. Midwives and nurses caring for obstetric or general patients with these devices must recognize sudden changes in vital signs, report anomalies promptly, and ensure emergency resuscitation equipment remains immediately available at the bedside.