Published online: 2019-12-03 THIEME Clinical Rounds 165 Systolic Murmurs Maddury Jyotsna1 1Department of Cardiology, Nizam's Institute of Medical Sciences, Address for correspondence M. Jyotsna, MD, DM, FACC, FESC, Punjagutta, Hyderabad, Telangana, India FICC, Department of Cardiology, Nizam's Institute of Medical Sciences, Punjagutta, Hyderabad, Telangana 500082, India (e-mail: [email protected]). Ind J Car Dis Wom 2019;4:165–174 Murmur is the vibration of heart components or great ves- The areas to be auscultated other than above mentioned sels.1 Systolic murmurs are those murmurs that can be heard classical five areas are as follows: between S1 and S2. 1. The right parasternal region, 2. The right and left the base of the neck, Basics of Murmur 3. The right and left carotid arteries, 4. The left axilla, The turbulent flow generates murmurs, but the acoustic 5. The interscapular area. force generated by the turbulence is not sufficient to produce an audible sound on the chest wall.2 Brun proposed the con- cept of vortex shedding for the mechanism of generation of Characteristics of the Systolic Murmur the murmurs. Vortices are produced from the diseased valves or great vessels. These vertices can be produced by increased 1. Intensity (loudness)—Intensity of the systolic murmur flow with normal valves or great vessels. These vortices can is graded into six grades. Grade 1 refers to a murmur so produce sustained vibrations to generate audible murmur on faint that it can be heard only with special effort. A grade 2 the chest wall. murmur is faint but is immediately audible. Grade 3 refers Another important factor for the generation of murmur to a moderately loud murmur and grade 4 to a murmur along with turbulence is the velocity. In laminar flow, the that is very loud and palpable. A grade 5 murmur is ex- velocity, as well as vortex shedding, is minimal. In increase tremely loud and is audible with one edge of the stetho- flow conditions (e.g., increase cardiac output states), as veloc- scope touching the chest wall. A grade 6 murmur is so ity increases, the vortex shedding also increases. Even vortex loud that it is audible with the stethoscope just removed shedding may increase with normal velocities if associated from contact with the chest wall. with additional areas of disruption of laminar flow. These 2. Frequency (pitch)—Frequency of the murmurs mainly vortices will determine the pitch of generated murmur. depends on the velocity of the blood flow. If velocity is Vortices in downstream may coalesce and represent lower high, then the pitch of the murmur increases. When blood frequency than at the site of generation. It is always better to flows from a high-pressure chamber (left ventricular, LV) hear the sound at site of generation (e.g., at the site of steno- to low-pressure chamber (left artery, LA) such as mur- sis), then in the downstream. mur due to mitral regurgitation (MR) will have high pitch due to high velocity. Murmur taking origin at the stenotic areas is of a low or medium pitched. Technique of Auscultation 3. Quality—Quality depends upon the tone of the sound. The Auscultation should be done in a calm and quiet room with a descriptions used to define quality are as follows: stethoscope that is 25 to 30 cm long with the stiff diaphragm a. Blowing—e.g., high-pitched murmur of MR, and shallow bell. Auscultation should be in lying, sitting, or b. Musical—e.g., functional or innocent murmurs; usually standing, left lateral decubitus position, and after specific these are low or medium pitched murmurs, maneuvers. On chest, right second intercostal space (ICS) is c. Squeaking—e.g., aortic stenosis murmur. This is high called as aortic area, left third ICS is called as neoaortic area, pitched squeaking and whistling quality, left second ICS is called as pulmonary area, left fourth ICS d. Whooping—e.g., late diastolic whoop in severe aortic is called as tricuspid area and at the cardiac apex as mitral regurgitation, area. Levine and Harvey recommended to do the auscul- e. Honking—e.g., systolic murmur in ballooning mitral tation from the mitral area and then move inch by inch to valve, other areas.3-5 published online DOI https://doi.org/ ©2019 Women in Cardiology and December 3, 2019 10.1055/s-0039-3401063 Related Sciences 166 Systolic Murmurs Jyotsna f. Harsh—e.g., these are usually high velocity murmur as 3. Sudden Squatting—Squatting causes decrease in the ve- in case atrial septal (AS) or pulmonary stenosis (PS) or- nous return to right heart and increase in the peripheral ventricular septal defect (VSD), vascular resistance. g. Rasping, a. Isometric Hand Grip Exercise—The changes in the sys- h. Grunting, temic circulation because of isometric handgrip exer- i. Rumbling—e.g., murmur of mitral stenosis. cise are as follows: Even though many descriptions are there to mention the a) Increase in peripheral vascular resistance, quality of sound, none of them are characteristics of the par- b) Increase in systemic blood pressure, ticular disease. Many people may interchangeably use these c) Increase in heart rate, words to describe the quality. d) Increase in cardiac output, 4. Duration—Systolic murmurs are classified depending e) Increase in LV volume, upon a phase of systole, which is described detailed below. f) Increase in LV filling pressure. 5. Configuration—Shape of murmur is called a configuration 4. Valsalva Maneuver—►Table 1 describes phases of the Val- of the murmur. It depends on the intensity and duration salva, along with the physiological changes and their effects. of the murmur. The descriptions used to describe the con- 5. Passive Leg Rising—Venous return of the right side of the figuration of murmurs are as follows: heart is increased by passive leg raising. a. Crescendo, 6. Post-Extrasystolic Pause—As there is an increase in the b. Decrescendo, ventricular filling, a beat after an extrasystole myo- c. Crescendo decrescendo, cardial contractility increases (according to Frank– d. Plateau, Starling law). 7. Pharmacological Maneuvers—The pharmacological effects 6. Primary Location (point of maximum intensity)—The of below drugs are used to distinguish few of systolic mur- source of origin of murmur is determined by the site murs etiology (►Table 2). where the maximum murmur intensity is heard, even though the murmur may be heard throughout the chest. 7. Site(s) Of Radiation—Some murmurs radiate. The direction Systolic Murmurs—Source of Origin of the radiation may give information about the etiology Many involve stenosis of the semilunar valves or regurgi- of murmur. tation of the atrioventricular valves. All systolic murmurs Dynamic Auscultation Table 1 Valsalva’s maneuver phases and its effects Phase of Physiological Effect The physiologic maneuvers are as follows: Valsalva's changes 1. Respiration—Greater effect of the breathing is seen on the maneuver right side of the heart. Inspiration or Mueller's maneuver Phase 1 (initial ↑ Intrathoracic ↑ LV output (forced inspiration on a closed glottis) causes increase in phase) pressure venous return right side of heart, so right side originat- Phase 2 (strain ↓Venous return ↑ Heart rate ed increase in murmurs with inspiration with good right phase) ↓ Stroke volume ↓ Mean arterial pressure ventricular function. Because of the pooling of blood in ↓ Pulse pressure the low resistance pulmonary capacitance vessel during Phase 3 (release ↑ Venous – inspiration, the blood flow decreases to the left heart. The phase) return opposite occurs during expiration. Phase 4 (over – The normalization of 2. Standing—Standing causes decrease in venous return to stood phase) features of phase 2 the right side of heart first then to left side, whereas lying There is six to eight beats time delay for left-sided events than right- down increases venous return. sided events. Table 2 Drugs used for dynamic osculation Drug Route of administration Dose Duration Pharmacological changes Amyl nitrite Inhalation – 10–15 sec ↓ Peripheral vascular resistance ↑ Stroke volume ↑Venous return Phenylephrine Intravenous 0.5 mg – ↑ Systolic blood pressure for 3–5 min Reflex bradycardia ↓ Myocardial contractility Methoxamine Intravenous 3–5 mg – ↑Systolic blood pressure by 20–40 mm Hg for 10–20 min Reflex bradycardia ↓ Myocardial contractility Indian Journal of Cardiovascular Disease in Women WINCARS Vol. 4 No. 3/2019 Systolic Murmurs Jyotsna 167 are more prominent in the presence of pregnancy, fever, sequences of events are S1, isovolumetric contraction anemia, or thyrotoxicosis. period, then ejection systolic murmurs, hangout inter- Pictogram of the systolic murmurs is in ►Fig. 1. val, and lastly S2. The short crescendo about midsys- tole is an invariable feature of all ejection murmurs.3 Classification of Systolic Murmurs Causes of midsystolic ejection murmurs include: I) Already mentioned previously that systolic murmurs can a) Outflow obstruction (aortic stenosis, pulmonic ste- be classified depending on the phase of systole. nosis, hypertrophic obstructive cardiomyopathy [HOCM]), 1. Early Systolic Murmur—Starts with S1, peaks in early b) Increased flow through normal semilunar valves systole. Causes of early systolic murmurs are as follows: (atrial septal defects), a. Small VSD, c) Dilation of the aortic root or pulmonary trunk, b. VSD with high pulmonary vascular resistance, d) Diseased semilunar valves without obstruction. c. An innocent murmur of childhood, 3. Late Systolic Murmur—Late systolic murmurs (LSM) d. Acute MR, are crescendo in nature and start after S1 and, if left e. Normal-pressure TR, sided, extend up to S2. f. Organic TR, Causes of LSM are as follows: 2. MidSystolic Murmur—Midsystolic ejection murmurs are generated across the semilunar valves. This mur- a. Mitral valve prolapse (MVP), mur starts at the time of ejection, which is after S1 and b. Tricuspid valve prolapse, ends with the cessation of blood flow means before c.