What are the characteristics of a weak pulse? What causes a weak pulse?

A weak pulse is caused by a weak heartbeat, which pumps out too little blood to cause peripheral arterial pulsation. This condition can be seen in premature heart beats, but is most common in atrial fibrillation. So what causes a short pulse?

Weak pulse

A weak pulse is caused by a weak heartbeat, which pumps out too little blood to cause peripheral arterial pulsation. This condition can be seen in premature heart beats, but is most common in atrial fibrillation. During a normal heartbeat, a premature beat suddenly occurs. However, since the ventricular filling is insufficient when the heart contracts, the amount of blood pumped out must be small, insufficient to cause peripheral blood vessel pulsation. Therefore, only the heart sound can be heard but the pulse cannot be felt. During atrial fibrillation, the ventricular pulsation is extremely irregular, and the premature heart beats are just like premature beats. The small cardiac output causes pulse omission. Moreover, the faster the heartbeat in atrial fibrillation, the more obvious the pulse deficiency.

Causes

Atrial fibrillation can occur regardless of gender, age, or the presence or absence of organic disease. But it is mostly found in the elderly, and atrial fibrillation can be a clinical manifestation of both heart disease and systemic disease. There are many causes of atrial fibrillation, mainly heart disease. In developed countries, the main diseases are coronary heart disease and myocardial disease, while in developing countries, rheumatic heart valve disease is the most common. In the elderly, it may be caused by latent hyperthyroidism or atrial septal defect. A small number of cases of atrial fibrillation have no clear cause and are called lone atrial fibrillation or idiopathic atrial fibrillation.

Clinical manifestations

(1) Symptoms:

①Symptoms: When atrial fibrillation occurs, in addition to the hemodynamic changes caused by the underlying heart disease, atrial fibrillation causes the loss of atrial contraction function, ventricular contraction becomes irregular, and the ventricular rate increases. The most common symptom of patients is palpitations. If combined with coronary heart disease, the patient may experience angina pectoris, dizziness, syncope, and in severe cases, heart failure and shock. If combined with rheumatic heart disease and mitral stenosis, it often induces acute pulmonary edema, and patients with pulmonary hypertension may suffer from hemoptysis.

② Asymptomatic: Some patients with slow and moderate atrial fibrillation may have no symptoms, which is especially common in the elderly and is often discovered during physical examinations or electrocardiograms.

③Atypical symptoms: seen in slow or moderate atrial fibrillation. The patient has no palpitations but may have weakness, fatigue, discomfort or slight pain in the precordial area. Further relevant examinations are required for diagnosis.

(2) Physical signs:

① Signs of existing heart disease. The signs of atrial fibrillation vary depending on the primary heart disease.

②The three major signs of atrial fibrillation: the first heart sound at the apex is of varying strength, the heart rhythm is absolutely irregular, and the pulse is weak.

③ Embolism signs: Patients with atrial fibrillation may develop vascular embolism signs in the brain, lungs, and limbs. The incidence of embolism is related to age, atrial size, and underlying heart disease. The incidence of cerebral infarction in patients with atrial fibrillation is 5 times higher than that in the normal population. During atrial fibrillation, the atria lose their effective contractile function, the blood flow in the atria slows down, and even stagnates, which is conducive to the formation of blood clots. The detachment of thrombus can lead to various embolic complications, among which mitral valve stenosis is more likely to cause thrombosis. According to statistics, 40% of patients with mitral stenosis and atrial fibrillation have left atrial mural thrombosis, while only 2% of patients with mitral stenosis and sinus rhythm have left atrial mural thrombosis.