88:, the chest wall expands and causes the intrathoracic pressure to become more negative (akin to a vacuum). The increased negative pressure allows the lungs to fill with air and expand. While doing so, it also induces an increase in venous blood return from the body into the right atrium via the superior and inferior venae cavae, and into the right ventricle by increasing the pressure gradient (blood is being pulled by the vacuum from the body and towards the right side of the heart). Simultaneously, there is a reduction in blood volume returning from the lungs into the left atrium (the blood wants to stay in the lungs because of the vacuum surrounding the lungs, and
74:) are not synchronized during inspiration. The second heart sound (S2) is caused by the closure of the aortic and pulmonic valves, which causes vibration of the valve leaflets and the adjacent structures. The aortic valve closes slightly before the pulmonic, and this difference is accentuated during inspiration when S2 splits into two distinct components (physiological splitting). During expiration, the pulmonic valve closes at nearly the same time as the aortic, and splitting of S2 cannot be heard.
138:, the chest wall collapses and decreases the negative intrathoracic pressure (compared to inspiration). Therefore, there is no longer an increase in blood return to the right ventricle versus the left ventricle and the right ventricle volume is no longer increased. This allows the pulmonary valve to close earlier such that it overlaps the closing of the aortic valve, and the split is no longer heard.
29:
264:". On physical exam, paradoxical splitting is appreciated as increased splitting on expiration relative to inspiration, versus normal splitting where inspiration will increase splitting. It is seen in conditions that delay left ventricular emptying (e.g., aortic stenosis, left bundle branch block).
166:
According to
Harrison's Principles of Internal Medicine, "Normally, blood pressure falls during inspiration (equal or less than 10 mmHg), due to an increase in blood flow into the right ventricle with displacement of the interventricular septum to the left, decreasing left ventricular filling and
243:(ASD). The ASD creates a left to right shunt that increases the blood flow to the right side of the heart, thereby causing the pulmonary valve to close later than the aortic valve independent of inspiration/expiration.
170:
The pressure in the right ventricle tries to open the pulmonary valve. The pressure in the pulmonary artery tries to close the pulmonary valve. The higher pressure will "win". Hence, the closure of the pulmonary valve
141:
It is physiologically normal to hear a "splitting" of the second heart tone in younger people, during inspiration and in the "pulmonary area", i.e. the second ICS (intercostal space) at the left edge of the sternum.
452:
175:) will be delayed since the pressure in the right ventricle is increased in inspiration, opposing the pressure in the pulmonary artery and keeping it open longer than in expiration. The change in A
445:
438:
77:
Exercise increases the intensity of both the aortic and pulmonic components of S2, whereas deep inspiration increases the intensity of the pulmonic component only.
128:
is heard as a slight broadening or even "splitting" of the second heart sound; though it is usually only heard in the pulmonic area of the chest because the P
302:
Loscalzo, Joseph; Charles M. Wiener; Bloomfield, Gerald T.; Fauci, Anthony S.; Braunwald, Eugene; Dennis L. Kasper; Hauser, Stephen L; Longo, Dan L. (2008).
92:
is lower because of lung expansion). Since there is an increase in blood volume in the right ventricle during inspiration, the pulmonary valve (P
418:
391:
364:
339:
311:
214:). Delay in RV emptying causes delayed pulmonic sound (regardless of breath); it is an exaggeration of normal splitting sounds.
217:
Split during expiration: Reverse splitting (paradoxical splitting) indicates pathology due to delay of aortic valve closing.
100:) stays open longer during ventricular systole due to an increase in ventricular emptying time, whereas the aortic valve (A
89:
875:
1039:
1080:
222:
847:
157:
Venous return from the body to the right heart increases, venous return from the lungs to the left heart decreases
211:
108:) closes slightly earlier due to a reduction in left ventricular volume and ventricular emptying time. Thus the P
603:
226:
703:
565:
928:
766:
560:
1033:
543:
430:
1059:
966:
870:
775:
588:
570:
240:
1113:
1086:
915:
803:
788:
727:
582:
798:
250:), will produce continuous splitting but the degree of splitting will still vary with respiration.
229:(LBBB), and a ventricular pacemaker could all cause a reverse splitting of the second heart sound.
1074:
1007:
985:
979:
750:
594:
577:
526:
465:
461:
1069:
793:
866:
740:
735:
658:
553:
548:
521:
414:
408:
387:
381:
360:
335:
307:
247:
246:
A bundle branch block either LBBB or RBBB, (although RBBB is known to be associated only with
207:
329:
971:
942:
783:
698:
670:
663:
648:
491:
960:
904:
897:
218:
67:
32:
1027:
999:
880:
842:
808:
838:
833:
756:
708:
1107:
1064:
1020:
993:
618:
531:
481:
36:
909:
828:
686:
538:
511:
503:
59:
52:
281:
857:
819:
745:
643:
638:
608:
715:
473:
28:
691:
304:
Harrison's principles of internal medicine: self-assessment and board review
235:
If splitting does not vary with inspiration, it is termed a "fixed split S
1014:
22:
951:
921:
486:
630:
613:
1051:
434:
154:
Intrathoracic pressure becomes more negative to form a vacuum
260:
the aortic valve, this is known as a "paradoxically split S
206:
Wide splitting: seen in conditions that delay RV emptying (
328:
Mayra Perez; Lindsay K. Botsford; Winston Liaw (2007).
239:" and is usually due to a septal defect, such as an
1050:
950:
941:
889:
856:
817:
774:
765:
726:
679:
629:
502:
472:
413:. Lippincott Williams & Wilkins. p. 379.
318:Question 29 disorders of the cardiovascular system
232:Split during both inspiration and expiration:
446:
203:Split during inspiration: normal. (See above)
8:
359:. McGraw Hill Medical. pp. 1826–1827.
199:can be associated with medical conditions:
947:
771:
453:
439:
431:
386:. Elsevier Health Sciences. p. 215.
334:. McGraw Hill Professional. p. 28.
27:
282:"The Auscultation Assistant – Split S2"
273:
132:is soft and not heard in other areas.
51:is a finding upon auscultation of the
151:Chest wall expands during inspiration
58:It is caused when the closure of the
7:
116:is delayed relative to that of the A
14:
256:When the pulmonary valve closes
357:Principles of Internal Medicine
195:The different types of split S
1:
410:Advanced Pediatric Assessment
331:Deja Review: Family Medicine
1081:superior vena cava syndrome
380:Salvatore Mangione (2000).
223:hypertrophic cardiomyopathy
179:is not that evident. Thus P
1130:
383:Physical diagnosis secrets
120:component. This delay in P
20:
994:radial artery sufficiency
212:right bundle branch block
66:) and the closure of the
604:Pericardial friction rub
227:left bundle branch block
21:Not to be confused with
1040:Nicoladoni–Branham sign
704:Jugular venous pressure
566:Pulmonary insufficiency
306:. McGraw-Hill Medical.
35:of various events of a
929:Gallavardin phenomenon
767:Cardiovascular disease
407:Ellen Chiocca (2010).
44:
43:heart sound at bottom.
1034:arteriovenous fistula
848:Bracht–Wachter bodies
31:
871:Pericardial effusion
776:Aortic insufficiency
589:Mitral insufficiency
571:Graham Steell murmur
241:atrial septal defect
162:Analysis of pressure
804:Austin Flint murmur
583:Carey Coombs murmur
81:Physiological split
1075:Trendelenburg test
1008:pseudohypertension
986:Right heart strain
980:pulmonary embolism
595:Presystolic murmur
466:circulatory system
462:Signs and symptoms
191:Pathological split
86:During inspiration
45:
1101:
1100:
1097:
1096:
1060:Friedreich's sign
967:Cardarelli's sign
937:
936:
867:Cardiac tamponade
659:Pulsus bisferiens
549:Functional murmur
420:978-0-7817-9165-6
393:978-1-56053-164-7
366:978-0-07-174890-2
341:978-0-07-148568-5
208:pulmonic stenosis
167:cardiac output".
136:During expiration
16:Medical diagnosis
1121:
1087:Pemberton's sign
948:
943:Vascular disease
789:De Musset's sign
784:Collapsing pulse
772:
671:Pulsus alternans
664:Pulsus bigeminus
649:Pulsus paradoxus
464:relating to the
455:
448:
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432:
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404:
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377:
371:
370:
352:
346:
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325:
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187:in inspiration.
1129:
1128:
1124:
1123:
1122:
1120:
1119:
1118:
1104:
1103:
1102:
1093:
1070:Kussmaul's sign
1046:
961:aortic aneurysm
933:
905:Anitschkow cell
898:rheumatic fever
885:
852:
813:
794:Duroziez's sign
761:
722:
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498:
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219:Aortic stenosis
198:
193:
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183:appears after A
182:
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164:
148:
131:
127:
123:
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115:
111:
107:
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99:
95:
83:
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68:pulmonary valve
65:
33:Wiggers diagram
26:
17:
12:
11:
5:
1127:
1125:
1117:
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1023:
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845:
839:Janeway lesion
836:
824:
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815:
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811:
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801:
796:
791:
786:
780:
778:
769:
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757:Template:Shock
753:
748:
743:
738:
732:
730:
724:
723:
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718:
713:
712:
711:
709:Cannon A waves
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580:
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568:
558:
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556:
554:Still's murmur
551:
536:
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365:
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144:
129:
125:
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112:component of S
109:
105:
104:component of S
101:
97:
96:component of S
93:
82:
79:
71:
63:
53:S2 heart sound
15:
13:
10:
9:
6:
4:
3:
2:
1126:
1115:
1112:
1111:
1109:
1088:
1085:
1084:
1083:
1082:
1078:
1076:
1073:
1071:
1068:
1066:
1065:Caput medusae
1063:
1061:
1058:
1057:
1055:
1053:
1049:
1041:
1038:
1037:
1036:
1035:
1031:
1029:
1026:
1022:
1021:Lines of Zahn
1019:
1018:
1017:
1016:
1012:
1010:
1009:
1005:
1001:
998:
997:
996:
995:
991:
987:
984:
983:
982:
981:
977:
973:
972:Oliver's sign
970:
968:
965:
964:
963:
962:
958:
957:
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953:
949:
946:
944:
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927:
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868:
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840:
837:
835:
832:
830:
826:
825:
823:
821:
816:
810:
807:
805:
802:
800:
799:MĂĽller's sign
797:
795:
792:
790:
787:
785:
782:
781:
779:
777:
773:
770:
768:
764:
758:
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752:
749:
747:
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742:
739:
737:
734:
733:
731:
729:
725:
719:
717:
714:
710:
707:
706:
705:
702:
700:
699:CĹ“ur en sabot
697:
693:
690:
689:
688:
685:
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682:
678:
672:
669:
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584:
581:
579:
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572:
569:
567:
564:
563:
562:
559:
555:
552:
550:
547:
546:
545:
542:
541:
540:
537:
533:
532:Gallop rhythm
530:
528:
525:
523:
520:
518:
515:
514:
513:
510:
509:
507:
505:
501:
493:
492:Levine's sign
490:
489:
488:
485:
483:
482:Referred pain
480:
479:
477:
475:
471:
467:
463:
456:
451:
449:
444:
442:
437:
436:
433:
422:
416:
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411:
403:
400:
395:
389:
385:
384:
376:
373:
368:
362:
358:
351:
348:
343:
337:
333:
332:
324:
321:
315:
313:0-07-149619-X
309:
305:
298:
295:
283:
277:
274:
267:
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259:
249:
245:
242:
234:
233:
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228:
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220:
216:
213:
209:
205:
202:
201:
200:
190:
188:
168:
161:
156:
153:
150:
149:
145:
143:
139:
137:
133:
91:
87:
80:
78:
75:
69:
61:
56:
54:
50:
42:
38:
37:cardiac cycle
34:
30:
24:
19:
1079:
1032:
1028:Adson's sign
1013:
1006:
1000:Allen's test
992:
978:
959:
914:
910:Aschoff body
896:
881:Ewart's sign
876:Beck's triad
865:
843:Osler's node
829:endocarditis
827:
809:Mayne's sign
755:See further
751:Distributive
687:Palpitations
653:
587:
539:Heart murmur
516:
512:Heart sounds
504:Auscultation
409:
402:
382:
375:
356:
350:
330:
323:
303:
297:
285:. Retrieved
276:
257:
255:
194:
169:
165:
140:
135:
134:
85:
84:
76:
60:aortic valve
57:
48:
46:
40:
18:
858:Pericardium
834:Roth's spot
820:endocardium
746:Hypovolemic
741:Obstructive
736:Cardiogenic
644:Bradycardia
639:Tachycardia
609:Heart click
355:Dan Longo.
1114:Cardiology
716:Hyperaemia
578:Continuous
474:Chest pain
268:References
692:Apex beat
561:Diastolic
287:9 January
1108:Category
1015:thrombus
952:Arterial
544:Systolic
517:Split S2
248:S1 split
124:versus A
49:split S2
654:doubled
619:carotid
39:, with
23:Split S
1052:Venous
922:J wave
818:Other
487:Angina
417:
390:
363:
338:
310:
258:before
890:Other
728:Shock
680:Other
631:Pulse
614:Bruit
146:Steps
415:ISBN
388:ISBN
361:ISBN
336:ISBN
308:ISBN
289:2009
916:EKG
90:PVR
41:2nd
1110::
527:S4
522:S3
225:,
221:,
210:,
171:(P
70:(P
62:(A
55:.
47:A
900::
873::
869:/
841:/
831::
454:e
447:t
440:v
423:.
396:.
369:.
344:.
316:.
291:.
262:2
237:2
197:2
185:2
181:2
177:2
173:2
130:2
126:2
122:2
118:2
114:2
110:2
106:2
102:2
98:2
94:2
72:2
64:2
25:.
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