The sinoatrial (SA) node is the natural pacemaker of the heart and thereby is an essential part of the cardiac conduction system. A sinoatrial node measures 13.5 millimeters in length in an average adult and is innervated by the sympathetic and vagus nerves.
The sinoatrial nodal artery, which supplies blood to the sinoatrial node, arises from the right coronary artery in 60% of cases and the left circumflex coronary artery in 40% of cases.
Sinus bradycardia is a heart rhythm that produces less than 60 beats per minute (bpm) with the appropriate cardiac muscle depolarization starting at the sinus node. A visualization of an electrocardiogram showing a normal sinus rhythm at a rate lower than 60 bpm confirms the diagnosis of sinus bradycardia.
Signs and Symptoms of Bradycardia
If an individual’s heart rate is below normal (i.e., below 60 bpm), the body’s organs and tissues may not be receiving enough oxygen-rich blood.
The efficiency by which the body performs its typical processes and functions may be affected by this. A number of patients with bradycardia are usually asymptomatic. However, when symptoms do exist, they may include:
- fatigue
- chest pain
- weakness
- dyspnea
- episodes of light-headedness or dizziness
- fainting or nearly fainting
- exercise intolerance
- confusion or memory problems
The signs and symptoms of bradycardia can be brought on by a variety of factors. It is crucial to have prompt and accurate diagnosis and treatment.
If the signs and symptoms of bradycardia are worrisome, it is recommended to consult a medical professional. If one experiences chest pain that lasts more than a few minutes, trouble breathing, or fainting, call 911 or emergency medical assistance.
Types of Bradycardia
Different types of slow heart rates exist (bradycardias or bradyarrhythmia). Each type entails a certain risk of consequences and a range of available treatments. These types and their characteristics are further discussed below.
- Sinus bradycardia. Sinus bradycardia is characterized by a heart rate that is lower than 60 beats per minute. This slow heartbeat could be normal and is frequently observed in fit, healthy individuals. Unless the heart rate is extremely slow (less than 40 beats per minute), problems from this type are unlikely. If there is no easily treatable cause, a pacemaker may then be installed.
- Sinus pause. The heart may skip one or more beats during a sinus pause because its internal pacemaker fails to activate the conduction system throughout the rest of the heart. A person may occasionally experience symptoms and require a pacemaker if this happens frequently or over an extended length of time. If a cause is found, it may be addressed first if it is a condition.
- Sick sinus syndrome. Sick sinus syndrome develops when the sinus node, the heart’s natural pacemaker, malfunctions. Arrhythmias of many types, or combinations of arrhythmias, can occur. Slow arrhythmias or a mix of fast and slow arrhythmias can occur in people with this disease.
- Tachy-brady syndrome. The term “tachy-brady syndrome” refers to a condition in which the heart occasionally beats too fast and occasionally too slowly (brady). People with an atrial fibrillation diagnosis frequently have this irregular heart rhythm issue. When the heart’s natural pacemaker is damaged, it can happen. A pacemaker may be used as part of the treatment to keep the heart from beating too slowly. It is possible to use medications to stop the heart from beating too quickly. Medications that thin the blood may be used to lessen the risk of a stroke.
- Heart block. Heart block describes an irregularity in how electricity travels along the heart’s normal conduction pathways. A slower heart beat is typically the result because the anomaly “blocks” the electrical impulse from traveling through the regular pathways.
Cause of Bradycardia
Bradycardia could develop as a result of cardiac muscle injury. This can cause disruptions in the electrical transmission that regulates an individual’s heartbeat. Bradycardia can be caused by cardiac and non-cardiac etiologies which are listed below.
- Cardiac etiologies. These are underlying causes of bradycardia which arise directly from the heart.
- Acute and chronic coronary artery disease
- Acute myocardial infarction
- Congenital heart conditions
- Previous cardiac surgery
- Myocarditis
- Pericarditis
- Rheumatic fever
- Damage to the cardiac electrical system from prior infection or inflammation
- Ischemic heart disease
- Chest trauma
- Sick sinus syndrome
- Non-cardiac etiologies. These are underlying causes of bradycardia that originate from other parts of the body other than the heart.
- Electrolyte imbalances (e.g., hyperkalemia, hypomagnesemia, or hypocalcemia)
- Hypothyroidism
- Sleep apnea
- Amyloidosis
- Lyme disease
- Collagen vascular disease
- X-linked muscular dystrophy
- Neuromuscular disorder
- Familial disorder
- Inherited channelopathy
- Medications (i.e., beta-blockers, certain calcium channel blockers, opioids, some types of antiarrhythmic drugs)
Risk Factors to Bradycardia
Bradycardia is frequently associated with cardiac disease of some kind that has damaged the heart tissue. Any risk factor associated with cardiac problems also increases the risk of developing bradycardia. Contributory factors that may increase the risk of developing cardiac disease include:
- Hypertension
- Older age
- Smoking
- Stress and anxiety
- Excessive consumption of caffeine and alcohol
- Recreational drug use
Medical intervention or healthy lifestyle modifications may help reduce the risk of heart disease.
Complications of Bradycardia
Bradycardia can occasionally occur without any symptoms or negative effects. Complications that could arise if bradycardia is severe enough to manifest as symptoms include:
- Syncope (frequent fainting). Fainting and injuries from falls can happen if the heart doesn’t pump enough oxygen-rich blood to the brain.
- Heart failure (heart’s inability to pump enough blood). Different physiological systems are affected by symptoms when the heart is unable to adequately pump oxygen-rich blood to the rest of the body.
- Sudden cardiac arrest or abrupt death. The heart may cease pumping due to inadequate blood flow, which can result in unconsciousness or cessation of breathing. This is a rare complication that frequently occurs in severe situations.
Diagnosis of Bradycardia
Diagnostic tests for bradycardia should usually include:
- Comprehensive history taking and physical examination. The history and physical examination are the most important parts of evaluating a patient who manifests signs and symptoms of bradycardia. Vital signs (heart rate, blood pressure, temperature, and respiration rate) as well as an electrocardiogram should be included. It should be determined during the assessment whether the patient is hemodynamically unstable; indicators of this include high blood pressure, a change in mental status, or trouble breathing. No additional medical treatment is necessary if the patient is active, healthy, and free of symptoms. In contrast, sinus bradycardia in older individuals may indicate an unhealthy sinus node. Sinus bradycardia is a common symptom of congestive heart failure patients. The patient’s medication history should be examined for any potential bradycardia-causing medications, and those medications should ideally be stopped while management decisions for a patient with sinus bradycardia are determined.
- Laboratory studies. Laboratory studies that should be ordered to evaluate the presence of bradycardia include troponin level, glucose level, serum electrolytes, calcium and magnesium levels, toxicological drug screen, and thyroid function test.
- Electrocardiogram (ECG or EKG). The main test used to identify bradycardia is a 12-lead electrocardiogram (ECG or EKG) which measures the electrical activity of the heart. It identifies whether the heart is beating too slowly, too quickly, or not at all.
- 24-hour Holter recording. It is recommended for patients to wear portable ECG equipment because an ECG cannot detect bradycardia unless a slow heartbeat occurs during the exam. A Holter monitor is a portable machine that records ECG signals over 24 hours.
- Tilt table test. This test can help identify how bradycardia contributes to the occurrence of fainting spells in a patient. Initially, the patient is positioned flat on a special table and is subsequently tilted as if the patient is standing up. A tilt test is done to identify if fainting is caused by a change in position.
- Stress exercise test. In exercise stress rest, the heart activity is monitored while the patient is riding a stationary bike or walking on a treadmill. During these activities, the patient’s ECG is monitored. If the patient cannot perform the exercise, a drug may be administered to stimulate the heart and mimic its activity during exercise.
Treatment for Bradycardia
Treatment for bradycardia should usually include the following:
- Medications. Hemodynamic instability should be assessed in a patient with sinus bradycardia. If determined to be hemodynamically unstable, the patient may be given 0.5 mg of atropine pushed intravenously (IV) every 3 to 5 minutes, up to a maximum dose of 3 mg.
- Surgical implantation of a temporary pacemaker. The patient is a candidate for a temporary pacemaker if their heart rate and symptoms do not get better with medications. Pacemakers only function when necessary. It causes the heart to beat more quickly when it beats too slowly through electrical stimulation. A surgical operation is necessary to implant a pacemaker. With the guidance of radiographic imaging, one or more cables are placed into a significant vein under or close to the clavicle. Each cable has one end fixed to the proper location in the heart, and the other end connected to a pulse generator implanted under the skin just below the clavicle.
- Surgical implantation of a permanent pacemaker. A patient may qualify for a permanent pacemaker if he or she has comorbidities that make it necessary for him or her to take specific medications that may be the cause of the bradycardia. Withdrawal of the medication can be made in cases where it can be withdrawn as per the physician’s advice. The patient may be assessed for a permanent pacemaker if symptoms and heart rate don’t improve.
Nursing Diagnosis for Bradycardia
Nursing Care Plan for Bradycardia 1
Risk for Decreased Cardiac Output
Nursing Diagnosis: Risk for Decreased Cardiac Output related to bradycardia secondary to congenital heart disease
Desired Outcome: The patient will demonstrate adequate cardiac output as evidenced by blood pressure, pulse rate and rhythm within the normal limits for the patient, strong palpable peripheral pulses, and an activity tolerance without symptoms of chest pain, dyspnea, or syncope.
Nursing Care Plan for Bradycardia 2
Nursing Diagnosis: Impaired Gas Exchange related to bradycardia secondary to apnea as evidenced by hypercapnia, preterm birth, hypoxia, and pallor.
Desired Outcomes:
- The patient will demonstrate improved gas exchange.
- The patient will maintain arterial blood gas levels within age-specific normal ranges.
| Intervention | Rationale |
| Evaluate the patient’s depth, ease, and rate of breathing, as well as any apneic episodes. | This reveals respiratory effort, rate, and depth (deviation from baseline), all of which have an impact on how much air enters the alveoli for the purpose of ventilation and oxygen diffusion (external respiration). |
| Evaluate the patient’s perfusion and skin tone. | Apnea can result in tissue hypoxia and inadequate tissue perfusion, which can affect the hue of the skin. |
| Check for alterations in consciousness, agitation, and somnolence. | This reveals a state of hypoxia as the blood’s oxygen content drops and the brain’s ability to receive oxygen is compromised. |
| Monitor the patient’s arterial blood gases levels and oxygen saturation. | Checks for variations in the partial pressure of oxygen and carbon dioxide brought on by an aberrant ventilatory drive in hypoxia and altered respiratory function. |
| Monitor the patient’s chest X-ray results for further evaluation and analysis. | This may reveal the presence of a respiratory infection which may impair gas exchange. |
Nursing Care Plan for Bradycardia 3
Nursing Diagnosis: Ineffective Tissue Perfusion related to bradycardia secondary to heart failure as evidenced by generalized weakness, chest pain, generalized pallor, dyspnea, abnormal pulse rate and rhythm, altered blood pressure readings, bipedal pitting edema, and pitting edema on both forearms and hands.
Desired Outcomes:
- The patient will perform health-seeking behaviors to enhance circulation.
- The patient will demonstrate vital signs within acceptable limits, absence of or controlled dysrhythmias, and no symptoms of heart failure.
| Nursing Interventions Bradycardia | Rationale |
| Identify the patient’s pain intensity, location, quality, onset, duration. Evaluate also the precipitating and palliative factors. | To aid in correct diagnosis, identify intensity, triggering circumstances, and location. |
| Monitor the patient’s vital signs, especially the pulse and blood pressure, every 5 minutes until the pain ceases. | Typical symptoms of angina include tachycardia and high blood pressure, which are compensatory reactions to sympathetic nervous system activity. |
| Assess the patient’s cardiac and circulatory status. | This evaluation establishes a baseline and looks for variations that might point to an alteration in cardiac output or perfusion. |
| Monitor the patient’s heart rhythms and 12 lead ECG results. | This identifies irregular tracings that might point to ischemia. |
| Evaluate the patient’s response to medications every 5 minutes. | The effectiveness of treatment and the need for additional therapies are determined by evaluating the patient’s response to medication. |
Nursing Care Plan for Bradycardia 4
Nursing Diagnosis: Activity Intolerance related to bradycardia secondary to syncope as evidenced by fatigue, feeling weak, abnormal blood pressure or heart rate in response to activity, ECG changes reflecting arrhythmias or ischemia, and exertional dyspnea.
Desired Outcomes:
- The patient will participate in desired and compulsory activities.
- The patient will demonstrate fewer physiological signs of activity intolerance.
- The patient will demonstrate a measurable rise in activity tolerance.
| Nursing Interventions Bradycardia | Rationale |
| Examine how the patient perceives the causes of activity intolerance. | Causative variables might be physical or psychological, as well as transient or ongoing. Knowing the cause will serve as a guide in formulating the nursing intervention. |
| Assess and monitor the patient’s sleeping habits and the amount of sleep they’ve gotten lately. | Before good activity progression can be achieved, sleep deprivation and sleep difficulties must be addressed as they can impair the patient’s level of activity. |
| Before beginning any activity, check the patient’s baseline cardiopulmonary condition (such as heart rate and orthostatic blood pressure). | When engaging in ordinary activities, an adult’s normal heart rate should not rise by more than 20 to 30 beats per minute. The risk of orthostatic declines in blood pressure with posture changes is increased in the older population. |
| Identify the patient’s daily activities and over-the-counter medications. | The patient’s capacity to carry out necessary tasks may be hampered by fatigue. It could also be an adverse side effect of the medication. Keep an eye on the patient’s consumption of beta-blockers, calcium channel blockers, sedatives, alcohol, and sedatives as well as tranquilizers, antihistamines, and relaxants. |
| Active range-of-motion exercises in bed should be gradually increased to sitting and finally standing. | Overexertion is avoided when the activity is progressed gradually. |
Nursing Care Plan for Bradycardia 5
Nursing Diagnosis: Deficient Knowledge related to bradycardia secondary to cardiovascular disease as evidenced by inaccurate follow-through of instructions.
Desired Outcomes:
- The patient will verbalize an understanding of the condition, individual risk factors, potential complications, and function of a pacemaker (if utilized).
- The patient will relate signs of pacemaker failure.
- The patient will verbalize an understanding of the therapeutic regimen.
- The patient will list desired action and potential adverse effects of medications.
- The patient will accurately perform necessary procedures and explain the rationale for these procedures.
- The patient will keep follow-up appointments.
| Nursing Interventions Bradycardia | Rationale |
| Assess the level of knowledge of the patient and his or her significant other. | This is necessary for creating an individualized instruction plan and reinforces that the process will be a learning experience. |
| Evaluate signs of avoidance, such as deviating from the subject matter, and extremes of behavior such as euphoria or withdrawal. | These are natural defense mechanisms and can block learning. These behaviors can also affect the patient’s response and ability to absorb information. Transitioning to a less structured style may be more effective until the patient and significant other are ready to deal with the situation. |
| Reinforce the explanations of risk factors and symptoms requiring immediate medical attention and the importance of dietary and activity restrictions and medications. | This provides an opportunity for the patient to retain information, assume control over the situation, and participate in a rehabilitation program. |
| Encourage the patient to identify and reduce individual risk factors such as obesity, smoking, and excessive alcohol consumption. | These behaviors and chemicals may impair cardiovascular function and in turn, may increase the risk of complications and impede recovery. |
| Explain to the patient the rationale behind the recommended dietary regimen (i.e., a diet low in sodium, saturated fats, and cholesterol) | Excessive consumption of cholesterol, saturated fats, and sodium increases the blood pressure and the risk of developing for cardiovascular disease. Atherosclerosis (plaque buildup in arteries) is caused by the accumulation of cholesterol in the walls of arteries. |
Nursing References
Ackley, B. J., Ladwig, G. B., Makic, M. B., Martinez-Kratz, M. R., & Zanotti, M. (2020). Nursing diagnoses handbook: An evidence-based guide to planning care. St. Louis, MO: Elsevier. Buy on Amazon
Gulanick, M., & Myers, J. L. (2022). Nursing care plans: Diagnoses, interventions, & outcomes. St. Louis, MO: Elsevier. Buy on Amazon
Ignatavicius, D. D., Workman, M. L., Rebar, C. R., & Heimgartner, N. M. (2020). Medical-surgical nursing: Concepts for interprofessional collaborative care. St. Louis, MO: Elsevier. Buy on Amazon
Silvestri, L. A. (2020). Saunders comprehensive review for the NCLEX-RN examination. St. Louis, MO: Elsevier. Buy on Amazon
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