chapter 26

Pacemakers

  • Overview of Cardiac Pacemakers

    • Cardiac pacemaker is necessary when the heart is not beating adequately for life.

    • Complete heart block example with a rate of 20 to 30 beats per minute is insufficient for survival.

    • Temporary pacemakers are utilized in emergencies to prevent cardiac arrest.

  • Functionality in Emergency Situations

    • Temporary pacemaker setup includes a standard defibrillation machine modified to function as a pacemaker.

    • Uses pads typically employed for defibrillation and cardioversion, requiring adjustment of gain.

  • Gain Adjustment

    • Gain refers to the intensity of electrical impulses sent through the pads to stimulate heart contractions.

    • Target pacing rate is approximately 60 to 80 beats per minute.

  • Permanent Pacemakers

    • Administered when temporary pacing is established, especially in cases of symptomatic bradycardia and third-degree heart block.

    • Waiting for the operating room for permanent pacemaker implantation is crucial, as the temporary pacemaker prevents cardiac arrest.

  • Use of Defibrillators in Pacemakers

    • Some pacemakers also integrate defibrillators, used based on the type of cardiac event experienced by the patient.

  • Procedural Details for Implantation

    • Permanent pacemakers are placed under fluoroscopy, using radiographic equipment to guide implantation.

    • The pacemaker is embedded subcutaneously, while leads (wires) attach to the heart chambers (atrium and ventricle).

  • Identifying Pacemaker Functionality

    • Pacemaker presence may not be noticeable during assessments; however, dark highlighted lines on a rhythm strip indicate pacing activity.

    • Rhythm strips show specific locations of pacing (e.g., atrial vs. ventricular).

  • Pacemaker Longevity and Maintenance

    • Pacemakers generally have a lifespan of 8 to 12 years, requiring battery replacement through outpatient surgery.

    • Interrogation may be necessary to assess device function and lead status.

  • Possible Pacemaker Complications

    • Issues include failure to sense intrinsic heart beats, pulse generator malfunctions, and lack of electrical capture by the heart.

    • Temporary measures include turning the patient onto their left side or using a magnet to deactivate the device in emergencies.

Nursing Care for Patients with Pacemakers

  • Care Requirements

    • One-on-one nursing care may be necessary for unstable patients with recently implanted temporary pacemakers.

    • Recognition of potential failure in pacing efforts, leading to initiation of CPR if necessary.

  • Post-implantation Nursing Considerations

    • Patients may need sedation to cope with external electrical currents used in temporary pacing.

    • After permanent pacemaker implantation, patient education is critical regarding wound care, activity restrictions, signs of infection, and avoiding electromagnetic interference.

Defibrillation and Cardioversion

  • Defibrillation Procedures

    • Utilized for patients with ventricular tachycardia (V-tach) or ventricular fibrillation (V-fib) who lack pulse.

    • CPR is conducted until pads are applied from a defibrillator, with careful positioning to avoid accidental shocks to caregivers.

  • Safety Measures in Cardiac Events

    • Key role of designated personnel to deliver defibrillation shocks, ensuring no one else is touching the patient or equipment to prevent shared electrical discharge.

  • Cardioversion Protocols

    • Cardioversion synchronizes shock timing to the R wave of the QRS complex to restore normal rhythm without inducing cardiac arrest.

    • Requires precise timing and the delivery of a synchronized electrical current between 25 and 50 joules.

  • Recognizing Electrical Intervention Outcomes

    • Successful cardioversion aims to re-establish sinus rhythm and improve symptoms like low blood pressure, dyspnea, and chest pain.

Heart Failure

  • Definition and Diagnosis

    • Heart failure (HF) refers to the heart's inability to pump effectively, leading to decreased perfusion and fluid overload.

  • Symptoms of Heart Failure

    • Cardinal signs include dyspnea, fatigue, and fluid volume overload. Chronic heart failure impacts the patient's quality of life over time.

  • Etiology of Heart Failure

    • Contributing conditions include coronary artery disease, myocardial infarction, cardiomyopathy, and uncontrolled hypertension.

  • Classifications of Heart Failure

    • Systolic failure relates to problems in contraction, while diastolic failure involves issues with relaxation.

    • Identifiable as left-sided, right-sided, or biventricular failure.

Left-sided Heart Failure

  • Most common and typically the first to weaken due to eminent workload involving resistance from the aorta.

  • Backward fluid overload leads to pulmonary congestion, presenting symptoms like shortness of breath and orthopnea.

  • Acute pulmonary edema is a severe manifestation requiring aggressive intervention.

Right-sided Heart Failure

  • Often follows left-sided failure, resulting in systemic venous congestion and symptoms such as jugular venous distension (JVD), peripheral edema, and abdominal discomfort.

    • Compensatory Mechanisms and Pathophysiology

  • Sympathetic nervous system activation attempts to maintain cardiac output through heart rate increase, but perpetuates heart failure over time.

Complications of Heart Failure

  • Progressive Symptoms and Diagnostics

    • Diagnostic tools include blood gas analyses, chest X-rays, EKGs, CBCs, and renal function tests to assess changes in cardiac function and fluid overload.

  • Therapeutic Measures for Heart Failure

    • Patients may require oxygen therapy, diuretics, vasodilators, and inotropic agents to manage symptoms acutely.

  • Long-term Treatment Considerations

    • Diet modifications (sodium restriction), monitoring of vital signs, heart rate, daily weights, and ongoing education around managing their condition to prevent exacerbations.

Advanced Treatments for Heart Failure

  • Mechanical Support Devices

    • Devices such as ECMO and LVADs may be necessary in severe cases.

    • Intra-aortic balloon pumps help alleviate heart strain during recovery.

Heart Transplantation

  • Indications for Transplant

    • Patients with congenital, acquired, or degenerative heart conditions may qualify based on severity and overall health criteria.

  • Post-operative Management

    • Close monitoring following transplant for signs of rejection or infection is critical; immunosuppressive therapy is indefinite following surgery.

  • Patient Education and Risk Management

    • Patients educated on potential complications, lifestyle modifications, and importance of follow-up care.