Hyperactive first heart sound

Introduction In the mitral stenosis, the left ventricular filling is reduced, and the mitral valve position is lower in the late diastolic. Secondly, due to the decrease of left ventricular blood volume, the systolic period is shortened accordingly. At this time, the left ventricular pressure rises rapidly, resulting in a low mitral valve. Suddenly nervous and closed, resulting in 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". ".

Cause

There are four factors that affect the strength of the first heart sound:

1. Anatomical lesions of the atrioventricular valve.

2. The rate of rise of ventricular pressure during systole.

3. Filling of ventricular diastolic phase.

4. The position of the atrioventricular valve when the ventricle contracts. The first heart sound hyperthyroidism is common in mitral stenosis, because the blood flow through the stenotic mitral valve into the left ventricle is obstructed, the diastolic left ventricular filling is less, and the mitral valve is still in the maximum open state before ventricular contraction. The free edge of the cuspidate leaves away from the valve orifice, and the free edge of the ventricular contraction moves to a greater extent, resulting in greater vibration, so the first heart sound of the apex is hyperthyroidism. The sound of the second heart sound of the mitral stenosis is hyperthyroidism and open, and the sound is the first heart sound of complete atrioventricular block.

an examination

Related inspection

Doppler echocardiography heart sound map examination

The best auscultation site is in the fifth intercostal space of the midline of the clavicle or on the right rim of the sternum. The first heart sound of the apex is abruptly blunt, the intensity is louder, and it lasts longer (lasting about 0.1s). It appears at the same time as the apex beat, and it is the loudest at the apex.

Physical examination:

The surface of the cusp is pale and the lips are slightly purpura. The anterior region of the heart rises, the apex can touch the diastolic fine tremor, and the heart expands to the left in the third intercostal space. The apex of the apex is S1, which is slap-up. The sound can be heard on the upper edge of the sternal border from III to IV to the top of the apex. If the leaflet loses its elasticity, the S1 and open sound can disappear. The apex of the apex can be heard and the middle and late rumbling murmurs are progressive, with the left lateral position, the end of the breath and the post-activity murmur more obvious. The P2 sound of the pulmonary valve is divided into fissures, and the short-term diastolic water-like murmur is heard in the II~III intercostals of the left sternal border of the pulmonary valve. (Graham-Steell murmur) is strengthened when deep inhalation.

Auxiliary inspection:

X-ray examination showed that the pulmonary artery was prominent, the left atrium was large, the right ventricle was large, the left main bronchus was lifted, and the left atrium was seen in the esophagus. The upper vascular shadow of the lung increased and thickened, and the Kerley's B line was visible at the rib angle. ECG showed: P wave widening >0.11s, with notch, right ventricular hypertrophy, and atrial fibrillation later. UCG showed mitral valve thickening, adhesion, calcification, stenosis of the valve, enlargement of the left atrium and right ventricle, thrombus in the atria, and Doppler ultrasound showed diastolic turbulence spectrum under the mitral valve.

Differential diagnosis

1, heart sounds low blunt: refers to the low heart rate. Low heart bluntness is not necessarily morbid. When the chest wall is thick, obesity, etc., the auscultation heart sound can be low and blunt. In some cases, it can also occur, such as pericardial effusion, heart failure, shock, etc.

2, heart sounds far away: when the doctor uses a stethoscope for cardiac auscultation, if the first heart sound and the second heart sound are weak, heavy turbid, fuzzy and distant sense, the heart sound is far away. Patients are often forced to take a semi-recumbent position and lean forward. If they are supine, the heart sound is far more obvious.

3, gallop heart sound: normal adult heart beat has two heart sounds, called the first heart sound and the second heart sound, galloping for the second heart sound after the additional heart sound, and the original first and second The rhythm of the heart sounds is similar to the sound of the horseshoes touching the ground when the horse runs, so it is called the galloping horse. According to the different time of the occurrence of galloping, it can be divided into early diastolic galloping, diastolic late galloping and overlapping galloping, which is the most common early diastolic galloping, which appears after the second heart sound 0.12-0.18 Within seconds, the late diastolic gallop occurs later, appearing before the start of the systole, which is 0.1 second before the first heart sound, so it is also called the systolic gallop. When there are both early diastolic galloping and diastolic late galloping, plus the first heart sound and the second heart sound, it sounds like four sounds that occur in parallel, also known as "four temperament", "the locomotive galloping ". It is generally believed that early diastolic galloping is caused by excessive ventricular diastolic load, decreased myocardial tension and decreased compliance, so that when the ventricle is dilated, blood filling causes wall vibration. Therefore, the appearance of galloping horse is an important sign of severe myocardial damage.

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