Overview
Block of ECG signal conduction to the right ventricle with QRS time less than 0.12 seconds.
Generally asymptomatic, some patients show symptoms of primary disease such as fatigue, shortness of breath, angina pectoris, etc.
Mostly due to rheumatic heart disease, coronary heart disease and other organic heart disease, the right heart is overloaded.
Healthy people generally do not need treatment, and those with other serious heart disease should be treated mainly for the primary disease.
Definition
Incomplete right bundle branch block is a type of arrhythmia in which there is a block in the conduction of electrical signals to the right ventricle, and the electrocardiogram shows a widening of the QRS time, but the QRS time is less than 0.12 seconds, and there are no Q-waves in the I, V5, and V6 leads.
Incomplete right bundle branch block is an ECG manifestation in itself and usually presents without symptoms. When the patient has organic heart disease, it can mostly manifest as symptoms of the primary disease such as weakness, shortness of breath, and angina pectoris; when incomplete block is present in a healthy population, it is usually asymptomatic [1-2,5].
Classification
Classification according to whether symptoms are significant or not
Typical incomplete right bundle branch block is seen in people with a history of coronary artery disease, hypertension, rheumatic heart disease, congenital heart disease, and atrial septal defect, etc., and requires active treatment of the primary disease to slow down the progression of the disease.
Atypical incomplete right bundle branch conduction block is common in men, athletes and other healthy people, no treatment is needed, and regular follow-up is sufficient [3].
Morbidity
There is no accurate data on the incidence of incomplete right bundle branch block, but statistics show that incomplete right bundle branch block occurs in people with organic heart disease, pulmonary heart disease, or pulmonary embolism.
However, it can also occur in men, athletes and other healthy people [2-3,5].
Causes
Causes
Organic heart disease
Rheumatic heart disease, congenital heart disease, atrial septal defect, hypertension, coronary artery disease, cardiomyopathy, etc. are common.
Right heart overload due to various diseases
Such as pulmonary embolism, pulmonary heart disease, etc. lead to the heart right heart overload.
Medical injury
Interventional procedures such as catheter ablation and cardiac surgery may damage the right bundle branch, leading to incomplete right bundle branch block.
Predisposing factors
Long-term smoking may cause chronic lung disease, leading to mild right ventricular hypertrophy or dilatation and thus triggering incomplete right bundle branch block [4].
Risk factors
Lenergre’s syndrome is a risk factor for incomplete right bundle branch block, and early electrocardiograms of patients with Lenergre’s syndrome often show incomplete right bundle branch block [3].
Symptoms
Main Symptoms
Clinical symptoms
Incomplete right bundle branch block is an ECG manifestation in itself and is asymptomatic. When combined with organic heart disease, patients tend to present with symptoms of the primary disease such as fatigue, shortness of breath, and angina pectoris [1].
Complications
A.S. syndrome
Incomplete right bundle branch block can lead to a sharp decrease in cardiac output in a short period of time and cause A-S syndrome, which is also known as cardiogenic cerebral ischemia syndrome.
The main manifestations are sudden syncope, loss of consciousness and convulsions, among which sudden syncope is the most prominent manifestation [1].
Consultation
Department of Medicine
Cardiovascular medicine
When the patient has symptoms such as fatigue and shortness of breath, it is recommended to consult the cardiovascular internal medicine department in time.
Emergency Department
When the patient develops serious symptoms such as angina pectoris, chest pain, dyspnea, etc., it is recommended to go to the Emergency Department immediately.
Preparation for medical treatment
Preparation for medical consultation: registration, preparation of documents, common problems
Tips for seeking medical attention
Wear loose-fitting, easy-to-put-on/take-off clothing to facilitate ECG and physical examination.
Preparation Checklist
Symptom list
Pay particular attention to the time of onset of symptoms and special symptoms.
Are there symptoms such as fatigue, shortness of breath, dizziness, etc.?
Are there any symptoms such as angina, chest pain, dyspnea, etc.?
How long have the symptoms lasted?
Are there any aggravating or alleviating factors for the above symptoms?
List of medical history
Any previous history of organic heart disease such as coronary heart disease, rheumatic heart disease, atrial septal defect, cardiomyopathy, etc.?
Any previous history of pulmonary embolism, pulmonary heart disease, etc.?
Checklist
Test results in the last six months, which can be brought to the doctor’s office
Imaging tests: echocardiography, coronary angiography, etc.
Laboratory tests: myocardial injury markers and brain natriuretic peptide test, etc.
Cardiac specialty tests: electrocardiogram
Diagnosis
Diagnosis is based on
Medical history
The patient has a past history of organic heart disease such as coronary artery disease, rheumatic heart disease, cardiomyopathy, and congenital heart disease with atrial septal defect.
The patient has a past history of primary disease such as pulmonary embolism and pulmonary heart disease.
Clinical manifestations
Clinical symptoms
Incomplete right bundle branch block itself is an ECG manifestation without symptoms. When the patient is comorbid with organic heart disease, the patient tends to show symptoms of the primary disease such as fatigue, shortness of breath, and angina pectoris.
Physical signs
On physical examination auscultation, a splitting of the second heart sound can be heard and is more pronounced when the patient is inspiratory.
Laboratory Tests
Myocardial marker test
Helps to understand the condition of the heart and determine whether there is myocardial damage.
In patients with incomplete right bundle branch block, myocardial markers, i.e., cardiac troponin I or cardiac creatine kinase isoenzymes, are usually within the normal range.
Imaging
Echocardiography
To understand the cardiac lesions in order to clarify the presence of organic cardiac lesions such as coronary artery disease, rheumatic heart disease and congenital heart disease.
Rheumatic heart disease, cardiomyopathy, and congenital heart disease with atrial septal defect can be seen as abnormal changes in cardiac structure and hemodynamic abnormalities.
Coronary Angiography
Coronary angiography can help to understand the ischemic condition of the heart and further define the cause of the disease.
If the patient has organic heart disease such as coronary artery disease, it can clearly show the malformation of coronary arteries and the location, degree and extent of obstructive lesions.
Drink more water after the examination to promote the excretion of contrast medium and avoid kidney injury. The patient should take proper bed rest; pay attention to observe whether there is any blood seepage and ooze, hematoma, etc. at the site.
Other Tests
Electrocardiogram
The electrical activity of the heart is displayed as a tracing curve on paper to determine whether there is any abnormality in the heart rhythm.
It can clarify the diagnosis and exclude other arrhythmias.
Differential Diagnosis
Incomplete right bundle branch block needs to be differentiated from complete right bundle branch block and time-phase bundle branch block.
Complete right bundle branch block
Similarities: both can have symptoms such as weakness and shortness of breath.
Differences:
The electrocardiogram of complete right bundle branch block is characterized by QRS wave time limit ≥0.12 seconds, S wave widening and tangential in leads I, V5 and V6, and its time limit >0.04 seconds, and the difference in electrocardiogram changes is the main point of differentiation between the two [1].
Incomplete right bundle branch conduction block ECG is characterized by QRS wave time widening but time limit <0.12 seconds, and R wave amplitude is higher and larger, and there is no Q wave in leads I, V5, and V6, which is an abnormal electrocardiographic phenomenon.
Time-phase bundle branch block
Similarities: both can have symptoms such as weakness and shortness of breath.
Differences:
Chronophasic bundle branch block is due to the characteristics of the intraventricular conduction system. When the heart rate is too fast or too slow, the repolarization of the bundle branch conduction system is incomplete, which can produce bundle branch block electrocardiographic pattern, which disappears when the heart rate is normal, and is usually a normal electrocardiographic phenomenon.
Incomplete right bundle branch conduction block ECG is characterized by widened QRS wave time but with a time limit of <0.12 seconds, high R wave amplitude, and no Q wave in leads I, V5, and V6, which is an abnormal ECG phenomenon.
Treatment
Aim of treatment: Elimination of physical discomfort.
Treatment principle: asymptomatic patients do not need special treatment, and those with underlying diseases should actively treat the primary disease.
General treatment
Patients with underlying diseases need general treatment, which mainly includes the following measures:
If necessary, patients with organic heart disease should have electrocardiographic monitoring, and closely observe the patient’s heart rhythm, heart rate, pulse rate, blood pressure and other indicators.
Patients need to rest in bed and try to relax so as not to aggravate the condition with nervousness.
Patients with a history of pulmonary heart disease need to prevent infection, boost immunity, and undergo oxygen therapy or use a ventilator to maintain effective gas exchange.
Allopathic treatment
If there is a primary disease, patients with incomplete right bundle branch block need to actively treat the primary disease.
If the block is caused by coronary artery disease, it may be treated with lipid-lowering drugs, vasodilating drugs, anticoagulants, antiplatelet drugs, and coronary stents.
If the disease is caused by hypertensive heart disease, it may be treated with antihypertensive drugs.
If it is caused by pulmonary heart disease, it will be treated with antihypertensive drugs and statins, and in severe cases, surgery will be required.
Prognosis
Cure
Incomplete right bundle branch block usually has no significant effect in healthy people.
Untreated patients with comorbid organic heart disease, such as coronary artery disease, can lead to serious complications such as A.S. syndrome and sudden cardiac death.
Patients with incomplete right bundle branch block without underlying heart disease can be effectively relieved with aggressive treatment and have a favorable prognosis.
Patients with combined underlying heart disease can effectively reduce mortality with aggressive treatment.
Hazards
Patients with incomplete right bundle branch block who develop A.S. syndrome tend to die within one year of the onset of the disease.
Incomplete right bundle branch block can develop into complete right bundle branch block, which will affect the patient’s daily life and reduce the patient’s quality of life.
Daily
Daily management
Daily management
Patients should ensure sufficient rest and avoid over-exertion.
Exercise appropriately to improve physical fitness.
Keep a relaxed and happy mood and avoid excessive mental stress.
Patients with implanted pacemakers should avoid going to places with excessive electromagnetic waves as much as possible, so as not to affect the work of pacemakers.
Diet management
Food types should be diversified and attention should be paid to low-fat and low-salt diet.
Patients should try to quit smoking and drinking, and drink less coffee and strong tea.
Eat more food that is good for the heart, such as corn, kelp, black sesame, spinach and so on.
Disease monitoring
Patients with underlying heart disease should have their blood pressure and pulse measured and recorded daily.
Patients should pay attention to changes in their symptoms and seek medical advice when they experience discomfort such as dizziness, fatigue and shortness of breath.
Follow-up
Regular checkups can help to detect the worsening of conduction block in time for timely treatment.
Patients with incomplete right bundle branch block need to follow the doctor’s instructions for timely review; patients with pacemaker implantation need to be reviewed 1, 3, 6 months after the operation, and every year thereafter.
Items to be checked at the time of review: electrocardiogram, echocardiogram, and so on.
Prevention
Incomplete right bundle branch block has no specific preventive measures, and its occurrence is related to a variety of primary diseases, which should be actively treated.
Patients with a history of organic heart disease should be actively treated for heart disease to avoid deterioration.
Patients with hypertensive heart disease should pay attention to low-salt diet, quit smoking and alcohol, and exercise appropriately to avoid aggravation of the condition.