Sudden fainting may indicate a slow heart rate.

Many people who experience sudden fainting spells only discover they have bradycardia (slow heart rate) years later. Bradycardia has no warning symptoms and is often only discovered incidentally during a health checkup.

A heart rate below 50 beats per minute will severely reduce the amount of blood supplying the body - Photo: BVCC

In cases of excessively slow heart rate, if it occurs suddenly, it can cause insufficient blood flow to the brain, leading to confusion, near-fainting or fainting, heart failure, cardiac arrest, etc.

Repeated fainting spells for many years, life-threatening conditions... but no illness was detected.

For many years, Ms. NTL (49 years old, Cu Chi, Ho Chi Minh City) has often experienced fatigue, occasional dizziness, palpitations, and sudden fainting spells. The frequency of fainting spells has gradually increased, and on one occasion, she had to stop her motorbike by the roadside to call for help from relatives because she suddenly felt dizzy and fainted.

She had previously undergone health checkups at several places but only received the diagnosis of cerebral ischemia. Recently, in the middle of the night, she suddenly experienced shortness of breath, severe chest pain, and fainted. Her family rushed her to Xuyen A General Hospital for emergency treatment.

All basic paraclinical results, such as electrocardiograms and brain MRIs, at the time of examination showed no obvious abnormalities. Suspecting the sudden fainting spells were due to cardiac arrhythmias, the doctors ordered a 24-hour Holter electrocardiogram (ECG) – a compact device that continuously records all electrical activity of the heart over a 24-hour period.

Upon reviewing the results, doctors discovered that the patient had multiple cardiac arrests, including one lasting over 18 seconds – something completely undetectable by a standard electrocardiogram. This is a sign of dangerous bradycardia, a condition that can cause sudden death if not treated promptly.

Similarly, Bac Giang General Hospital has also successfully implanted permanent pacemakers for two elderly patients with dangerously slow heart rates.

The first case involves a female patient named Hoang Thi N. (69 years old, residing in Huu Lung, Lang Son ) who experienced dizziness, prolonged fatigue, and a decline in health even while walking. Upon admission, the patient's heart rate was only 40 beats per minute.

The second case involves a 65-year-old male patient named Truong Minh L. from Lang Giang, Bac Giang, who frequently experienced palpitations and a pounding heart. 24-hour electrocardiogram (ECG) monitoring using a Holter ECG device revealed periods when the patient's heart rate slowed to only 35 beats per minute, accompanied by rapid atrial fibrillation – the primary cause of the palpitations and pounding heart. Diagnosis indicated severe weakening of the sinoatrial node – the heart's natural pacemaker.

Dr. Nguyen Van Long, Head of the Cardiology Department at Bac Giang Provincial General Hospital, stated: "A heart rate that is too slow due to obstruction of the heart's conduction pathways (complete atrioventricular block) or sinus node dysfunction are dangerous conditions. If not detected and treated promptly, patients may experience fainting spells, heart failure, and even life-threatening situations."

A heart surgery procedure - Photo: Provided by the hospital.

Bradycardia (slow heart rate) - the silent danger behind fainting spells that can easily lead to sudden death.

Dr. Dinh Minh Tri, from the Vietnam Cardiology Association, stated that the normal heart rate is a regular sinus rhythm, with heart rate depending on age and level of physical activity. In adults, the average heart rate is between 60-100 beats per minute.

A heart rate below 60 beats per minute is considered bradycardia (slow heart rate). Bradycardia can occur in anyone but is more common in older adults. It is less common in children and infants because the younger the child, the higher their normal heart rate tends to be.

120-160 beats/minute. The range of normal, fast, and slow heart rates varies depending on age.

Dr. Tri explained that the heart rate range for a healthy adult is 60-100 beats per minute. However, in cases of bradycardia (slow heart rate), the heart rate is below 60 beats per minute and is accompanied by abnormal symptoms.

In healthy individuals who engage in regular physical activity, a slow heart rate is usually benign, but if this condition persists along with other symptoms, a doctor should be consulted for examination and appropriate treatment. In some cases, such as in young, healthy individuals or athletes, this condition is not a cause for concern.

Physiological bradycardia (slow heart rate) can occur in some people who engage in strenuous physical activity, such as professional athletes, and does not affect daily life.

Pathological bradycardia can be caused by cardiovascular diseases such as congenital or genetic disorders, sinus node dysfunction, ischemic heart disease, infective endocarditis, and myocarditis.

Sometimes this condition is not due to cardiovascular disease, such as hypothyroidism, severe kidney failure, hyperkalemia, etc. It can also be caused by the use of certain medications.

In most cases, a slow heart rate has no warning symptoms and is only discovered incidentally during a health checkup. Some people experience symptoms such as shortness of breath, chest tightness, dizziness, fatigue, difficulty concentrating, and easy exhaustion during strenuous activity.

However, in cases where the heart rate is excessively slow and appears suddenly, it can cause insufficient blood flow to the brain, leading to serious consequences such as confusion, near-fainting or fainting, and cardiac arrest. Patients need to be hospitalized immediately to determine the cause.

Cardiologist Pham Thanh Binh stated that bradycardia (slow heart rate) can progress silently but carries a high risk of sudden death if not detected and treated promptly. Diagnosis of arrhythmias is usually based on an electrocardiogram (ECG) or 24-hour Holter ECG, and the most effective treatment in many cases is the implantation of a permanent pacemaker, which helps maintain a stable and safe heart rhythm for the patient.

Ways to prevent a slow heart rate.

Exercise regularly. Eat a healthy diet low in fat, salt, and sugar. Maintain a healthy weight, as being overweight or obese increases the risk of developing heart disease. Eat plenty of fruits, vegetables, whole grains, and fish. Limit fast food, pickled foods, and high-fat foods. Manage your emotions and reduce stress. Have regular health checkups. Take medication as prescribed by your doctor.

Is a consistently slow heart rate dangerous?

In clinical practice, bradycardia typically refers to a resting heart rate below 60 beats per minute in adults. However, a bradycardia reading alone is not sufficient to conclude a pathological condition. The context, accompanying symptoms, and underlying medical conditions determine the significance of bradycardia.

Understanding bradycardia correctly

People who regularly engage in high-intensity exercise or sleep may have a low heart rate while still being perfectly healthy. Conversely, a slow heart rate accompanied by dizziness, fainting, low blood pressure, or chest pain are warning signs that require medical attention.

A slow heart rate reduces the amount of blood the heart pumps to the body. In people with coronary artery disease or heart failure, a heart rate that is too slow can worsen myocardial ischemia or cause pulmonary edema. Signs of hypotension, chest pain, acute shortness of breath, or altered consciousness are all cardiovascular emergencies that require immediate medical attention.

Is a slow heart rate dangerous?

Not all bradycardia is dangerous. The majority of cases of bradycardia due to physiological causes do not require treatment. Danger arises when bradycardia is accompanied by symptoms of reduced blood flow (syncope or presyncope, hypotension, chest pain, shortness of breath, confusion, transient blindness) or when it is a high-grade or complete atrioventricular block with no reversible cause. This group carries a risk of cardiac arrest and often requires permanent pacemaker implantation.

What should be done if a slow heart rate is suspected?

Monitor your pulse and blood pressure 1-2 times a day during symptomatic periods. Keep a log of the time, activities performed, and accompanying symptoms (dizziness, fainting, chest pain, shortness of breath). Wearable devices (smartwatches, wrist blood pressure monitors) can be helpful in identifying heart rate trends, but diagnosis should still rely on an electrocardiogram (ECG).

When to seek medical attention early: persistent heart rate <50 beats/minute accompanied by fatigue and dizziness; any fainting spells; new bradycardia appearing after taking cardiovascular medication; bradycardia accompanied by chest pain, shortness of breath, and hypotension.

What should you pay attention to when engaging in daily activities and exercising?

If your baseline heart rate is slow, avoid situations that excessively stimulate the vagus nerve, especially if you are experiencing symptoms. Examples include straining, holding your breath while lifting weights, massaging the neck, and wearing tight collars. Maintain soft stools to reduce Valsalva maneuver pressure. Carefully manage any underlying conditions that worsen bradycardia.

Regarding physical training: Physiological bradycardia in well-trained and asymptomatic individuals is permitted for normal exercise; priority should be given to gradually increasing intensity, with adequate warm-up and recovery time.

Bradycardia or conduction abnormalities accompanied by symptoms of reduced perfusion, unassessed second- or third-degree AV block, require temporary suspension of moderate-to-vigorous exercise until investigation is complete and treatment is optimized. After pacemaker implantation: avoid exercise for 1-2 weeks.

MSc. NGO THANH HUNG

(University of Health Sciences, Vietnam National University Ho Chi Minh City)

HA TUONG

Source: https://tuoitre.vn/ngat-dot-ngot-coi-chung-nhip-tim-cham-20251111234350174.htm