S1 Heart Sounds Introduction

Introduction

Learn about the S1 heart sound, listen to examples, take short lessons and compare to other heart sounds. For all medical professionals.

Our S1 heart sound lessons can be found in this first heart sounds module. In addition, our reference index is designed to provide quick access to first heart sounds, with audio tracks, listening guides and waveforms. Use this link for quick reference to heart and lung sounds.

What is an S1 Heart Sound?

S1 heart sound is a low frequency sound, occurring at the beginning of systole. S1 can be best heard over the apex, using a stethoscope's bell or diaphragm. The first heart sound is caused by turbulence created when the mitral and tricuspid values close. S1 and S2 heart sounds are often described as lub - dub.

S1 Heart Sound Caused By

The S1 heart sound is caused by blood flow turbulence when mitral and tricuspid valves close at the start of systole.

Best Heart Position During Auscultation

Because S1 heart sounds occur when the mitral and tricuspid valve close, the best heart is locations for the stethoscope chestpiece are at the tricuspid (left lower sternal border) and mitral (cardiac apex) locations.

Listen

Listening Tips

Audio Playback

Waveform

Compare To S1 Decreased Intensity

Quick Links to Other Breath Sounds

While we have many breath sound lessons and quick references on this website. Please use the links below.

Related Lessons

Basics of Lung Sounds The goal of this basic course in lung sounds is to improve auscultation observational skills. We focus on describing important breath sounds and in providing recordings of each. Many students find that waveform tracings aid in learning lung sounds; we have included dynamic (moving cursor) waveforms with each lesson. The anatomy pages use illustrations to reveal an example of each lung sound (anatomy not yet available on smartphones).

Lesson List

Intermediate Lung Sounds The goal of this intermediate course is to expand your observational skills when auscultating breath sounds. The course lessons include voiced sounds: bronchophony, egophony and whispered pectoriloquy. We also provide auscultation lessons on several types of wheezes, crackles and stridor. Each of these lung sound lessons includes audio, text and dynamic waveform. The anatomy pages use illustrations to reveal an example of each lung sound (anatomy not yet available on smartphones).

Lesson List