Fetal heart sound

Introduction The pendulum law: also known as fetal heart rhythm, fetal heart-like heart sound. The patient takes the supine position, and the patient is auscultated in the apical area. If the first heart sound loses its inherently low blunt tone, and the second heart sound is similar to the second heart sound, and the heart rate is too fast, it is like a pendulum. "Acoustic, called the pendulum law. If accompanied by tachycardia, when the heart rate is more than 120 beats per minute, it is called fetal heart rhythm. The pendulum law is an important sign in the clinic. If there is a serious illness, it can be seen in acute myocarditis, acute myocardial infarction, heart failure, peripheral circulatory failure, and also in tachycardia such as paroxysmal tachycardia or hyperthyroidism. By.

Cause

Caused by myocarditis.

an examination

Related inspection

Doppler echocardiography dynamic electrocardiogram (Holter monitoring)

The pendulum law is an important sign in the clinic. If there is a serious illness, it can be seen in acute myocarditis, acute myocardial infarction, heart failure, peripheral circulatory failure, and also in tachycardia such as paroxysmal tachycardia or hyperthyroidism. By.

Differential diagnosis

The diagnosis should be differentiated from the following symptoms:

First heart sound hyperthyroidism: left ventricular filling decreased during mitral stenosis, lower mitral valve position in late diastolic, and second, due to decreased left ventricular blood volume, systolic period shortened accordingly, when left ventricular pressure rapidly increased, The low-order mitral valve suddenly becomes tense and closes, thus producing a high-key and crisp first heart sound, which sounds like a slap, commonly referred to as the slap-first heart sound. In complete atrioventricular block, the atrial and ventricular beats are not related, forming a phenomenon of compartment separation. When the atrium and ventricle are simultaneously contracted, the first heart sound is extremely loud, usually called "cannon sound". ".

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