Heart rate: What's normal? - Mayo Clinic
2022年10月8日 · A normal resting heart rate for adults ranges from 60 to 100 beats per minute. Generally, a lower heart rate at rest implies more efficient heart function and better cardiovascular fitness. For example, a well-trained athlete might have a normal resting heart rate closer to 40 beats per minute.
Heart arrhythmia - Symptoms and causes - Mayo Clinic
2023年10月13日 · A heart arrhythmia (uh-RITH-me-uh) is an irregular heartbeat. A heart arrhythmia occurs when the electrical signals that tell the heart to beat don't work properly. The heart may beat too fast or too slow. Or the pattern of the heartbeat may be inconsistent. A heart arrhythmia may feel like a fluttering, pounding or racing heartbeat.
Heart arrhythmia - Diagnosis and treatment - Mayo Clinic
2023年10月13日 · A pacemaker helps the heart keep a steady beat. If the device finds a slow heartbeat, it sends electrical signals to correct the beat. A dual chamber pacemaker checks, or paces, the heart signals in the right upper and lower heart chambers. A biventricular pacemaker paces both lower heart chambers.
Atrial fibrillation - Symptoms and causes - Mayo Clinic
2024年3月8日 · Minerals in the blood called electrolytes — such as potassium, sodium, calcium and magnesium — help the heart beat. If these substances are too low or too high, irregular heartbeats may occur. Family history. An increased risk of atrial fibrillation occurs in some families. Heart problems or heart surgery.
Premature ventricular contractions (PVCs) - Mayo Clinic
2022年4月30日 · The contractions usually beat sooner than the next expected heartbeat. The cause of premature ventricular contractions isn't always clear. Certain things including heart diseases or changes in the body can make cells in the lower heart chambers electrically unstable. Heart disease or scarring may cause the heart's signals to be misrouted.
Bradycardia - Symptoms and causes - Mayo Clinic
2024年12月13日 · Bradycardia (brad-e-KAHR-dee-uh) is a slow heart rate. The hearts of adults at rest usually beat between 60 and 100 times a minute. If you have bradycardia, your heart beats fewer than 60 times a minute. Bradycardia can be a serious problem if the heart rate is very slow and the heart can't pump enough oxygen-rich blood to the body.
Fetal development: The 1st trimester - Mayo Clinic
2022年6月3日 · Growth is rapid this week. Just four weeks after conception, the neural tube along your baby's back is closing. The baby's brain and spinal cord will develop from the neural tube. The heart and other organs also are starting to form. Structures necessary to the formation of the eyes and ears develop. Small buds appear that will soon become arms.
Heart disease - Symptoms and causes - Mayo Clinic
2024年8月13日 · Heart failure. This is one of the most common complications of heart disease. The heart can't pump enough blood to meet the body's needs. Heart attack. A heart attack can happen if a piece of plaque in an artery or a blood clot moves to the heart. Stroke. The risk factors that lead to heart disease also can lead to an ischemic stroke.
Tachycardia - Symptoms and causes - Mayo Clinic
2023年12月15日 · In a healthy heart, this signaling process usually goes smoothly. The resting heart rate is typically 60 to 100 beats a minute. But in tachycardia, something causes the heart to beat faster than 100 beats a minute. Risk factors. In general, things that may raise the risk of irregular heart rhythms that commonly cause tachycardia include ...
Heart disease - Diagnosis and treatment - Mayo Clinic
2024年8月13日 · Heart CT scan, also called cardiac CT scan. In a cardiac CT scan, you lie on a table inside a doughnut-shaped machine. An X-ray tube inside the machine rotates around your body and collects images of your heart and chest. Heart magnetic resonance imaging (MRI) scan.