Cardiac Auscultation (Paramedic)

00:01 In this lecture, we will focus on the auscultation of the heart.

00:05 I would like to begin with an introduction to the anatomical location of the heart.

00:10 The heart is located within the mediastinum.

00:13 The interstitial space behind the sternum.

00:16 Its superior border is attached to the carina, the bifurcation of the trachea into the two main bronchi.

00:24 It extends interiorly to the diaphragm, where the pericardial fuses with a small segment of the diaphragm muscle.

00:31 Anteriorly, the heart is adjacent to the sternum, and extends posteriorly to the spine.

00:39 The medial and lateral aspects of the heart are situated between the two lungs and their respective thoracic folds.

00:47 The heart is well protected within the bony thorax and is surrounded by various organ systems.

00:56 Knowledge of the four heart valves is particularly important when discussing cardiac auscultation.

01:03 The heart has two pocket-like valves and two sail-like leaflet valves. The pocket valves are the aortic valve and the pulmonary valve, the latter also being called the semilunar valve. The leaflet valves, on the other hand, include the tricuspid valve, and the mitral valve or bicuspid valve.

01:32 Now let's take a look at the locations of the various heart valves projected onto the thorax. The aortic valve is located approximately at the level of the third rib beneath the sternum.

01:44 The pulmonic valve is located on the left side of the sternum approximately at the level of the 3rd costal cartilage.

01:51 The tricuspid valve is posterior to the sternum, approximately at the level of the fourth costal cartilage and the mitral valve is located approximately between the fourth and fifth costal cartilages along the left border of the sternum.

02:05 Next, we turn our attention to heart sounds.

02:08 Heart sounds are transmitted through the chest wall and may be particularly audible in certain areas.

02:15 This is especially for murmurs.

02:18 This sound can continue into the axilla and even the carotid arteries.

02:24 All heart sounds can be graphically displayed with a phonocardiogram, though only the first two heart sounds should be physiologically audible by auscultation. Children and adolescents are exceptions to this rule. So where is the best place to listen to heart sounds.

02:41 Heart sounds and murmurs are best ausculated with the stethoscope over Erb's point, the third intercostal space on the left parasternal border.

02:55 Its loudest expression, the point of maximal impact, can then be determined by the specific auscultation site.

03:04 The first heart sound, also called S1, is produced by the contraction of the ventricular myocardium once the ventricle is filled.

03:14 Its muffled sound is produced by the vibration of the muscle and valves.

03:19 Temporally, it correlates with the beginning of the ejection phase of blood from the ventricles, or systole and the QRS complex in the ECG.

03:29 The second heart sound, S2, is produced by the closing of the aortic and pulmonic valves.

03:35 It correlates with the onset of ventricular muscle, relaxation, or diastole. In the ECG, it can be associated with the end of the T-wave.

03:47 The second heart sound is slightly higher and shorter than the first.

03:51 Deep inspiration may also cause the second heart sound to split because the aortic valve would close slightly earlier than the pulmonary valve.

04:00 This results in the examiner perceiving two S2 sounds.

04:04 As mentioned above, the following are heart sounds that should not be physiologically audible with the stethoscope, with the exception being children and adolescents.

04:13 The third heart sound represents the confinement of blood in the left ventricle and its filling during diastole.

04:20 It may be physiologically audible in children as well as some adolescents.

04:24 The fourth heart sound is a quiet heart sound that is associated with atrial contraction and increased ventricular pressure.

04:32 While in adults it indicates pathology, it is physiological in children.

04:38 We distinguish heart murmurs from heart sounds, which are physiologically produced during cardiac activity.

04:45 Murmurs are specifically caused by the heart valves, but only when the valves are damaged or no longer function properly.

04:53 On auscultation, heart sounds are perceptible as murmurs between the first two heart sounds.

05:02 As I indicated earlier, the respective sounds of the individual heart valves and their murmurs, if present, are transmitted to specific areas in the chest where they can be best heard.

05:15 Global heart sounds are best heard at Erb's point, while other sites lend themselves to the auscultation of individual valves.

05:22 The aortic valve is heard particularly clearly in the second intercostal space to the right of the sternum.

05:29 At the same level, but on the opposite side of the sternum, the pulmonary valve can be easily heard.

05:35 So in the second intercostal space to the left of the sternum.

05:40 If we go a little lower to the fourth intercostal space, we can hear the tricuspid valve well.

05:51 And a little lower at the fifth intercostal space along the midclaviclar line, we hear the mitral valve.

05:57 It cannot be heard next to the sternum like the others but on the midclavicle line that is on the vertical line through the middle of the clavicle.

06:08 Because this region is not so easy to remember, I would like to give you a mnemonic. This reads: Anton Pullman drinks three liters of milk at 22:45.

06:22 The words "Anton" "Pullman" "drinks" and "milk" represent the order of the heart valve names that is aortic, pulmonary, tricuspid and mitral.

06:36 The two 2's symbolize the second intercostal space on the left and right for the aortic and pulmonary valves.

06:43 Similarly, four and five show the fourth and fifth intercostal spaces on the left side for tricuspid and mitral valves, respectively.

06:52 Finally, three liters means the third intercostal space on the left parasternal border, which you already know as Erb's point.

07:00 In the technique video, you will now see how to find these individual points.

07:05 I will also reveal some useful tips that you should keep in mind when auscultating as the patient's behavior and posture can play an important role.

07:18 The patient has just been informed about the upcoming exam.

07:22 Now the upper body is completely undressed and the patient is positioned with the upper body elevated.

07:30 Let's review the individual auscultation points.

07:33 Erb's point in the third intercostal space, the aortic valve in the second ICR right parasternal, the pulmonary valve in the second ICR at the left parasternal border, the tricuspid valve, in the fourth ICR along the left parasternal border and the mitral valve in the fifth ICR along the left mid-claviclar line.

07:54 Usually, cardiac auscultation is started at Erb's point.

07:59 For good auscultation, ask the patient to take a deep breath and hold it for a short moment.

08:08 Auscultation of the aortic valve in the second ICR along the right parasternal border follows .

08:19 Then that of the pulmonary valve in the second ICR along the left parasternal border.

08:27 This is followed by the tricuspid valve in the fourth ICR on the left parasternal border. Finally, the mitral valve is located in the fifth ICR along the left medioclaviclar line.

08:47 During auscultation of the heart, a peripheral pulse should always be palpated to reliably differentiate the first and second heart sounds.

09:05 In conclusion, I will summarize the main points of this presentation.

09:09 You know now, physiological heart sounds are ventricle contraction and valve closure sounds. They're usually heard best at Erb's point.

09:17 The third intercostal space on the left parasternal border.

09:22 Pathological heart murmurs occur when valve function is impaired and blood turbulence occurs at the valves.

09:30 This may be the case with valve stenosis or valve insufficiency.

09:34 The sound waves generated at the heart valves are projected as vibrations onto the thorax, where they can be auscultated in specific sound fields.