Sinus bradycardia can be defined as a sinus rhythm with a resting heart rate of 60 beats per minute or less. This can occur whether you have a sinus infection or not. It can even be experienced by perfectly wealthy individuals.
Symptoms are usually significant when your heart rate drops to less than 50 beats per minute. The action potential responsible for this rhythm arises from the sinus node and causes a P wave on the surface ECG that is normal in terms of both amplitude and vector. These P waves are typically followed by a normal QRS complex and T wave.
A normal baby should have a heartbeat of 150 bpm; Bradycardia decelerates the premature baby's heart to less than 100 beats per minute. Infection, anemia, change in body temperature, hypoglycemia, airway problems, neurological difficulties are caused due to bradycardia.
Symptoms
- In most cases, bradycardia is asymptomatic. However, symptoms may include the following:
* Syncope
* Dizziness
* Lightheadedness
* Chest pain
* Shortness of breath
* Exercise intolerance
- The physical examination is generally nonspecific, although it may reveal the following signs:
* Decreased level of consciousness
* Cyanosis
* Peripheral edema
* Pulmonary vascular congestion
* Dyspnea
* Poor perfusion
* Syncope
Causes
* One of the most common pathologic causes of symptomatic sinus bradycardia is the sick sinus syndrome.
* The most common medications responsible include therapeutic and supratherapeutic doses of digitalis glycosides, beta-blockers, and calcium channel-blocking agents.
* Other cardiac drugs less commonly implicated include class I antiarrhythmic agents and amiodarone.
* A broad variety of other drugs and toxins have been reported to cause bradycardia, including lithium, paclitaxel, toluene, dimethyl sulfoxide (DMSO), topical ophthalmic acetylcholine, fentanyl, alfentanil, sufentanil, reserpine, and clonidine.
* Sinus bradycardia may be seen in hypothermia, hypoglycemia, and sleep apnea.
* Less commonly, the sinus node may be affected as a result of diphtheria, rheumatic fever, or viral myocarditis.
Treatment
Treatment for asymptomatic patients is not signified, but symptomatic patients should be corrected of underlying electrolyte and acid base disorder. Intravenous atropine may provide temporary improvement in symptomatic patients, although its use should be balanced by an appreciation of the increase in myocardial oxygen demand this agent causes. Although in the past, isoproterenol was used quite commonly in patients with bradycardia, further appreciation of its substantial risks has diminished its role. Temporary pacing is recommended in symptomatic patients who are unresponsive or are only temporarily responsive to atropine, or in whom atropine therapy is contraindicated. Transcutaneous pacing, where available, is the initial procedure of choice.
The medication techniques include therapy and supratherapeutic doses of digitalis glycosides, beta-blockers and calcium channel blocking agents. Cardiac drugs are also used.
When symptoms persist in extreme cases, you may need to go to the hospital for treatment. Prehospital care may include;
* Intravenous access, supplemental oxygen, and cardiac monitoring should be initiated in the field.
* In symptomatic patients, intravenous atropine may be used.
* In rare cases, transcutaneous pacing may need to be initiated in the field.
Failure to arrange prompt follow-up care in patients with symptomatic sinus bradycardia exposes the emergency medicine practitioner to considerable medico legal risk.
Symptoms are usually significant when your heart rate drops to less than 50 beats per minute. The action potential responsible for this rhythm arises from the sinus node and causes a P wave on the surface ECG that is normal in terms of both amplitude and vector. These P waves are typically followed by a normal QRS complex and T wave.
A normal baby should have a heartbeat of 150 bpm; Bradycardia decelerates the premature baby's heart to less than 100 beats per minute. Infection, anemia, change in body temperature, hypoglycemia, airway problems, neurological difficulties are caused due to bradycardia.
Symptoms
- In most cases, bradycardia is asymptomatic. However, symptoms may include the following:
* Syncope
* Dizziness
* Lightheadedness
* Chest pain
* Shortness of breath
* Exercise intolerance
- The physical examination is generally nonspecific, although it may reveal the following signs:
* Decreased level of consciousness
* Cyanosis
* Peripheral edema
* Pulmonary vascular congestion
* Dyspnea
* Poor perfusion
* Syncope
Causes
* One of the most common pathologic causes of symptomatic sinus bradycardia is the sick sinus syndrome.
* The most common medications responsible include therapeutic and supratherapeutic doses of digitalis glycosides, beta-blockers, and calcium channel-blocking agents.
* Other cardiac drugs less commonly implicated include class I antiarrhythmic agents and amiodarone.
* A broad variety of other drugs and toxins have been reported to cause bradycardia, including lithium, paclitaxel, toluene, dimethyl sulfoxide (DMSO), topical ophthalmic acetylcholine, fentanyl, alfentanil, sufentanil, reserpine, and clonidine.
* Sinus bradycardia may be seen in hypothermia, hypoglycemia, and sleep apnea.
* Less commonly, the sinus node may be affected as a result of diphtheria, rheumatic fever, or viral myocarditis.
Treatment
Treatment for asymptomatic patients is not signified, but symptomatic patients should be corrected of underlying electrolyte and acid base disorder. Intravenous atropine may provide temporary improvement in symptomatic patients, although its use should be balanced by an appreciation of the increase in myocardial oxygen demand this agent causes. Although in the past, isoproterenol was used quite commonly in patients with bradycardia, further appreciation of its substantial risks has diminished its role. Temporary pacing is recommended in symptomatic patients who are unresponsive or are only temporarily responsive to atropine, or in whom atropine therapy is contraindicated. Transcutaneous pacing, where available, is the initial procedure of choice.
The medication techniques include therapy and supratherapeutic doses of digitalis glycosides, beta-blockers and calcium channel blocking agents. Cardiac drugs are also used.
When symptoms persist in extreme cases, you may need to go to the hospital for treatment. Prehospital care may include;
* Intravenous access, supplemental oxygen, and cardiac monitoring should be initiated in the field.
* In symptomatic patients, intravenous atropine may be used.
* In rare cases, transcutaneous pacing may need to be initiated in the field.
Failure to arrange prompt follow-up care in patients with symptomatic sinus bradycardia exposes the emergency medicine practitioner to considerable medico legal risk.