Education Corner

What is an ECG test? Can it detect hidden heart disease risks? Heart disease is one of the three leading causes of death in Hong Kong. Regular check-ups are one of the most effective ways to prevent it.An electrocardiogram (ECG) is a quick, painless test commonly used to assess heart health. It records electrical changes in the heart muscle as waveforms, essentially creating a visual record of the heart’s electrical activity. Through analysis of these patterns, healthcare professionals can understand basic heart information such as heart rate and electrical potential changes.ECG testing can be used both as part of a routine health check and as a preoperative heart assessment. The results help doctors diagnose various cardiac problems, including arrhythmia (irregular heartbeat), abnormal blood flow to the heart muscle, cardiac hypertrophy, congenital heart defects, and valvular diseases.ECG tests are broadly categorized into three main types: resting ECG, exercise ECG (treadmill test), and 24-hour Holter monitoring.   Which type of ECG should I choose? Resting ECG (ECG) The resting ECG is the most common method. It is quick, painless, and safe, taking only about 10 seconds to complete. The procedure is simple: metal electrodes are attached to specific points on the body to record electrical waves generated during heart muscle contractions.This test detects abnormalities in the heart while at rest, such as irregular rhythms or enlargement of heart chambers.   2. Exercise ECG (Treadmill Test) The exercise ECG evaluates heart function under physical stress. The test is performed while walking or running on a treadmill, during which medical staff record heart rate and ECG changes from rest to exertion and recovery.It takes approximately 10 minutes and can more accurately reveal issues such as myocardial ischemia (reduced blood flow), coronary artery disease, or other cardiovascular problems like blockage or infarction.   3. 24-hour Holter Monitoring (Continuous ECG) Because both resting and treadmill ECGs only capture heart activity at the time of the exam, they may miss irregular heart rhythms or transient symptoms. The Holter monitor addresses this by continuously recording heart activity for 24 to 48 hours (or longer) as the person goes about daily activities.This provides a more complete record for identifying intermittent heart conditions.   What should I be aware of during an ECG test? The resting ECG is painless and safe. You may feel slight discomfort when the electrode stickers are removed. The Holter monitor also involves no pain or risk. Electrodes attached to the chest with adhesive patches may cause mild skin irritation.Inform medical staff if you are allergic to any tape or adhesive materials. Avoid strenuous exercise, smoking, or consuming coffee, strong tea, and other stimulants within one hour before testing. Remove all items that may interfere with electrical signals—such as watches, metal jewelry, or nylon stockings—to ensure accurate results.

Is arrhythmia dangerous? Arrhythmia is one of the most common heart conditions in Hong Kong. It refers to any abnormality in the rhythm or rate of heartbeat. It is estimated that about 1% of Hong Kong’s population suffers from arrhythmia, most commonly atrial fibrillation and ventricular fibrillation.The risk increases with age. Although arrhythmia is not immediately life-threatening, if not detected and treated in time, the risk of stroke and heart failure is approximately five times and three times higher, respectively, than in people without it. Mortality risk also doubles.   What is arrhythmia? Arrhythmia refers to any abnormality in the heart’s rhythm or rate. In a healthy person at rest, the heart beats steadily between 60 and 100 times per minute. A resting heart rate lower than 60 beats per minute (bradycardia) or higher than 100 (tachycardia) is considered abnormal.Some people have a normal heart rate but irregular rhythm, which may suggest premature beats (extrasystoles) or atrial fibrillation.   What problems can arrhythmia cause? 1. Ventricular Fibrillation (VF) VF is a type of sudden cardiac arrest that can be fatal. Multiple parts of the ventricles beat chaotically, preventing the heart from pumping blood and oxygen to the brain and body.Without immediate cardiopulmonary resuscitation (CPR), the patient can die within minutes once the heart stops completely.   2. Atrial Fibrillation (AF) AF occurs when the atria quiver rapidly and irregularly, causing the heartbeat to become erratic (up to 200 beats per minute). It can last from a few seconds to several days.While not directly fatal, it can cause noticeable symptoms such as: Palpitations or irregular heartbeat Shortness of breath Dizziness or fainting Because blood flow becomes turbulent, clots may form in the heart. If a clot travels to the brain, it can cause a stroke.   What are the symptoms of arrhythmia? At rest, normal heart rates range from 60 to 100 beats per minute.When the heartbeat becomes abnormal, you may experience: Fatigue Shortness of breath Dizziness Chest tightness Chest pain Tiredness Fainting or loss of consciousness   Why do I have arrhythmia? Common risk factors include: Thyroid disorders Hypertension Ischemic heart disease Heart failure or valvular heart disease Side effects of medication Idiopathic causes (no identifiable reason)   How is arrhythmia diagnosed? Electrocardiogram (ECG): The primary diagnostic test. For long-term monitoring, a 24-hour ECG or event recorder may be used. Blood tests: To assess electrolyte balance and thyroid function. Further evaluations: Exercise ECG, CT coronary angiography, or electrophysiological catheter tests for detailed assessment.   How can arrhythmia be treated? Effective treatment depends on the underlying cause. Medication: Antiarrhythmic drugs are used to manage various irregular heart rhythms. Catheter Ablation: A common and standard minimally invasive procedure performed under local anesthesia. A cardiologist guides a catheter into the heart, locates areas causing abnormal electrical activity, and ablates them. It offers high success rates for many arrhythmia types. Implantable Devices: For slow heart rates with fainting episodes, a pacemaker may be needed. For abnormally fast heart rhythms or risk of sudden cardiac death, an implantable cardioverter-defibrillator (ICD) may be recommended.

What is Flat Foot? Flat foot occurs when the navicular bone shifts downward, causing the arch on the inner side of the foot to collapse.A normal foot has a noticeable arch known as the “medial longitudinal arch,” which provides flexibility and shock absorption when walking or running, helping bear body weight and maintain balance.In people with flat feet, the arch is flattened and the sole nearly touches the ground when standing. Flat feet are common among children and often improve naturally after the age of ten as the arch develops. However, in some adults, especially with aging or weight gain, flat feet may develop later due to acquired factors.   Why do I have flat feet? The causes of flat feet can be congenital (present from birth) or acquired (developed later in life). Congenital causes include: Tarsal coalition: fusion of bones such as the calcaneus and talus, often seen in children. Congenital ligament laxity: loose ligaments throughout the body, including around the feet, preventing proper arch formation. Incomplete arch development before age 8: because tendons and ligaments are still soft, some children appear flat-footed temporarily. Genetic factors: those with family members who have flat feet are more likely to develop it. Acquired causes include: Posterior tibial tendonitis: a common cause of adult flat feet due to tendon strain or injury, more frequent in middle-aged women.Early signs include inner ankle pain and reduced ability to invert the foot. Without timely treatment, ankle degeneration and permanent deformity may occur. Excess body weight: increased pressure on the foot can collapse the arch. Lack of exercise: weak foot muscles and ligaments provide poor support. Injury: trauma that causes ligament laxity can contribute to flat feet.   What are the symptoms of flat feet? Flat foot may not cause obvious symptoms initially.However, when standing or walking for long periods, the flattened arch prevents proper shock absorption and support, leading to strain on joints such as the ankles, knees, and hips.Common symptoms include: Soreness, numbness, or pain in the feet Poor stability when walking, with higher risk of injury Gait abnormalities such as inward or outward turning of feet, or knock-knees Secondary complications: plantar fasciitis, bunions, knee or spinal problems   Treatments and Correction Methods For children under age 8, flat feet are often physiological because the arches are still developing and ligaments remain soft. Most cases improve naturally after the arch forms.If symptoms are severe, physical therapy or corrective insoles may be recommended. For adults, custom insoles may help maintain proper foot alignment and prevent long-term complications. Physical therapy can also strengthen muscles and relieve discomfort. In cases of severe pain, anti-inflammatory medications may be prescribed.Surgery is only required in rare, severe cases that do not respond to conservative treatment.   How can I prevent flat feet? 1. Foot exercisesRegular foot exercises can help strengthen the feet and prevent flat feet. Activities such as jumping rope and standing on tiptoe enhance muscle and ligament strength in the thighs, calves, and soles.Stretching the toe flexors and massaging the arch (e.g., pressing the plantar fascia with the elbow) can also help maintain arch flexibility. 2. Choosing suitable footwearSelect well-fitting and breathable shoes with good arch support, slip resistance, and cushioning.Ensure the heel provides adequate stability to prevent injury, and avoid narrow-toe or high-heeled shoes (heels over 2 inches). 3. Regular check-upsChildren still in growth or individuals who suspect flat feet should have periodic foot assessments or pressure tests to monitor arch development. 4. Healthy lifestyleMaintain a balanced lifestyle and healthy body weight to reduce stress on the feet and help prevent collapse of the arches.

What is a Coronary Angioplasty (Stenting)? Coronary angioplasty, commonly called “stent insertion,” is a medical procedure in which a specially designed catheter is guided into a narrowed section of the heart’s coronary artery. A small balloon at the tip of the catheter is then inflated to push aside the fatty deposits (plaques) that block the vessel, restoring smooth blood flow through the artery.   Is heart disease becoming more common among younger people? In the past, most people receiving angioplasty were older adults with chronic conditions such as diabetes, hypertension, or high cholesterol.However, in recent years, there has been a noticeable trend toward younger patients—including those without symptoms or known risk factors. Some are diagnosed with blocked coronary arteries incidentally during medical check-ups and must undergo angioplasty. Atypical heart diseaseSome patients experience “atypical” symptoms of angina that mimic other conditions, such as stomachache or shoulder pain.For example, a diabetic patient was admitted for persistent stomach pain thought to be gastritis, but further cardiac tests revealed severe blockages in all three main coronary arteries—90% in one, 70% in another, and one artery completely blocked. The patient required angioplasty.This case highlights that even mild symptoms like stomach discomfort should not be ignored.   What can heart examinations detect? Cardiologists typically begin by reviewing the patient’s medical history, followed by an electrocardiogram (ECG) and cardiac CT angiography.If needed, an echocardiogram (ultrasound of the heart) may also be performed. While a standard ECG can detect heart abnormalities, it may not reveal problems in mild to moderate cases.Cardiac CT scans provide a clearer view of the coronary arteries, allowing doctors to assess the extent of blockage, estimate costs, determine equipment needs, and evaluate surgical difficulty—resulting in more accurate treatment planning. If uncertainty remains after the CT scan, additional functional heart tests may be recommended: Non-invasive functional tests: Magnetic resonance imaging (MRI) and nuclear medicine scans. MRI involves no radiation, while nuclear scans expose the patient to a limited dose. Invasive functional tests: Conducted in the operating theatre and involve inserting instruments into the blood vessels.   How should I prepare for an angioplasty? Before the procedure, the cardiologist will explain the process and confirm whether the patient requires angioplasty or bypass surgery.Once angioplasty is confirmed, the doctor will select the appropriate stent type: Bioabsorbable stents (non-drug-eluting) Metal drug-eluting stents – these are currently the most common. Because the procedure involves injecting contrast dye during coronary angiography, kidney function must be checked beforehand.Patients with kidney disease may need medication management before the operation to avoid contrast-induced acute kidney failure. Angioplasty usually requires only local anesthesia. The average procedure takes about one hour, and most patients can leave the hospital the next day.For more complex cases—such as complete or main artery blockages—two separate procedures may be required, each lasting 3–4 hours, followed by several days in the intensive care unit.   What should I do after angioplasty? Most patients return to normal activity soon after the operation and may even improve in physical endurance.If the patient had not exercised regularly before, it is advisable to gradually increase activity about one month post-surgery to help the heart adapt and strengthen cardiovascular fitness. After angioplasty, patients must take antiplatelet medication to prevent stent rejection. Depending on individual condition, the medication may be reduced or stopped within 12 to 18 months.   How risky is angioplasty? When proper preoperative assessments are conducted, the risk of complications is less than 1%.Possible risks include vascular injury, stroke, or kidney failure due to contrast dye usage.Although serious complications can occasionally be fatal, such cases are very rare.

Seasonal Influenza Vaccination What is Influenza? Influenza (also known as the flu) is an acute infectious disease caused by viruses from the influenza virus family. It spreads worldwide and is transmitted through droplets.Common symptoms include fatigue, sudden fever, runny nose, cough, headache, muscle pain, and sore throat. Severe cases can lead to respiratory failure or even death. Influenza viruses are divided into three main types: A, B, and C.Types A and B account for most infections. Major outbreaks are usually linked to type A viruses, while type B epidemics occur less frequently at several-year intervals.Type C infections are typically milder and rarely cause epidemics. Influenza viruses constantly mutate.Each year, the World Health Organization (WHO) reviews and recommends the composition of the next season’s vaccine. Because flu seasons differ between hemispheres, recommendations are issued at different times: For the Northern Hemisphere: Announced in February/March to ensure updated vaccines are available before the winter flu season (late in the same year or early the next year). For the Southern Hemisphere: Announced in September of the preceding year to prepare vaccines for the following winter (around June/July).   Why is it Important to Get a Seasonal Influenza Vaccine? Influenza cases occur year-round in Hong Kong, but are most common from January to March/April and July to August.People with weaker immune systems and the elderly are at greater risk of severe illness and complications such as bronchitis, pneumonia, or encephalopathy, which may result in death. Vaccination is one of the most effective ways to prevent seasonal influenza and its complications, reducing hospital admissions and deaths.It can also help lower the risk of severe illness and hospitalization for those who might contract both influenza and COVID-19 at the same time.   When Should I Get the Seasonal Influenza Vaccine? It takes about two weeks after vaccination for the body to develop protective antibodies.To ensure adequate protection, vaccination should be done at least two weeks before the flu season begins—typically in January in Hong Kong.However, vaccination is still beneficial even after the season has started.   What Are the Possible Side Effects of the Inactivated Influenza Vaccine? The inactivated flu vaccine is very safe.Common mild effects include pain, redness, or swelling at the injection site. Some people may experience fever, muscle aches, or fatigue 6–12 hours after vaccination, which usually subsides within two days.If persistent fever or discomfort occurs, consult a doctor. Rare serious allergic reactions—such as hives, tongue or throat swelling, or breathing difficulty—require immediate medical attention.Other rare adverse events include Guillain–Barré Syndrome (GBS) (about 1–2 cases per million vaccinations) and severe allergic reactions (about 9 cases per 10 million doses distributed).However, there is no proven causal link between vaccination and these events.Research shows that the risk of developing GBS after influenza infection (17.20 cases per million infections) is much higher than after vaccination (1.03 cases per million vaccinations).[The Lancet Infectious Diseases, 2013 Sep; 13(9): 769–76]   Who Should Not Receive the Inactivated Influenza Vaccine? Anyone who has had a severe allergic reaction to a vaccine component or after a previous flu vaccination should not receive it. People with mild egg allergies can safely receive the vaccine at primary healthcare facilities. Those with severe egg allergies should be vaccinated under professional supervision in medical settings equipped to handle allergic emergencies. Although the vaccine contains trace amounts of ovalbumin (egg protein), the purification process reduces the content to very low levels, making it safe for most people with egg sensitivity. Patients with bleeding disorders or those taking anticoagulants should consult a doctor before vaccination.If you have a fever on the vaccination day, it is best to wait until recovery before receiving the vaccine.   Do I Need to Get the Flu Vaccine Every Year? Yes.Because influenza virus strains change frequently, vaccine formulations are updated annually based on circulating strains.Immunity from last season’s vaccination declines over time and may no longer provide sufficient protection the following year.For example, the 2021–22 seasonal vaccine components differed from those of 2020–21.   Can Pneumococcal and Influenza Vaccines Be Given Together? Yes.Pneumococcal and seasonal influenza vaccines can be given during the same visit.If using the inactivated influenza vaccine, separate syringes and injection sites should be used.   Can the Influenza Vaccine Be Given Together with the COVID-19 Vaccine? No—the vaccines should be administered at least 14 days apart.This applies to both BioNTech and Sinovac (CoronaVac) COVID-19 vaccines.