Cardiovascular Physiology 2024 PDF

Welcome to Cardiovascular Physiology November 2024 Eric Accili PhD Rm 2320 LSC Department of Cellular & Physiological Sciences [email protected]  Topic 1 Objectives Using anatomically correct terminology for all s...

Welcome to Cardiovascular Physiology November 2024 Eric Accili PhD Rm 2320 LSC Department of Cellular & Physiological Sciences [email protected]  Topic 1 Objectives Using anatomically correct terminology for all structures, and starting from the Vena Cavae, trace the flow of blood as it moves through the heart. In terms of structure, differentiate between the atrio-ventricular and semilunar valves. In terms of valve function, describe the role of the papillary muscles and the chordae tendinae. Match the relative heart chamber or valve pressures with the corresponding valve position (i.e. open or closed). Using the Wiggers Diagram, identify diastole and systole and relate left ventricular pressure, left ventricular volume, left atrial pressure and valve position to the four phases of the cardiac cycle (ventricular filling, isovolumetric contraction, ventricular ejection and isovolumetric relaxation). Define the two principle heart sounds (S1 & S2) and explain the phenomenon of “physiological splitting of S2” Identify three causes of murmurs in the heart. TBA.  Mini Case Topic 1 Baby Carl Nine days after Carl was born his heart rate became abnormally high, he sweat profusely when feeding and slept the rest of the time. A chest X-Ray shows that the left side of his heart was enlarged, and there were markings in the lungs that indicate increased blood flow to the lungs.  The Heart What are the parts called? Cardiac Anatomy  SVC Ao PA PVe PV 4 Chambers: LA PVe RA Ao M 4 Valves: 2 atrio-ventricular T (AV) valves LV 2 semi-lunar RV valves IVC Figure 9-4 Sherwood Kell  SVC A PA PVe PV 4 Chambers: LA PVe RA Ao M 4 Valves: 2 atrio-ventricular T (AV) valves 2 semi-lunar valves Papillary Chordae Muscles Tendinae Figure 9-4 Sherwood Kell The Cardiac Cycle The pressures, volumes & sounds as the heart goes through one cycle of contraction and relaxation.  P A M How Valves Work T Open Tricuspid Rap > Rvp Pulmonary Mitral Aortic Rap = Right Atrial Press Rvp = Right Ventricular Press  How Valves Work Open Tricuspid Rap > Rvp Pulmonary Rvp > Pap Mitral Lap > Lvp Aortic Lvp > Aop Rap = Right Atrial Press Rvp = Right Ventricular Press Lap = Left Atrial Press Lvp = Left Ventricular Press PAp = Pulmonary Art. Press Aop = Aortic Press  Diastole: Gr. dia= apart & stellein= to draw to draw apart or dilate ventricular relaxation and filling Systole: Gr. syn= together, stellein= to draw. to draw together or contract ventricular contraction and ejection  The Wiggers Diagram only left side shown Fig 9-16 Sherwood & Kell  The Atrial Waveforms a= atrial contraction c= ventricular contraction v= atrial filling a c v Fig 9-16 Sherwood & Kell  Recap Systole: Isovolumetric Contraction: Both AV valves and Semilunar valves closed, ventricular pressure is rising Ventricular Ejection: AV valves closed, Semilunar valves are open, ventricular volume decreasing Diastole: Isovolumetric Relaxation: Both AV valves and Semilunar valves closed, ventricular pressure is decreasing Ventricular Filling: AV valves are open, Semilunar Valves closed, ventricular volume is increasing Fig 9-16 Sherwood & Kell Heart Sounds  Heart Sounds First heart sound (S1) closure of atrio-ventricular valves in early Systole  Heart Sounds First heart sound (S1) Nice to know: loudness of S1 (in part) determined by how far apart the leaflets are before next systole Faster the HR, louder the S1  Heart Sounds Second heart sound (S2): closure of Semilunar valves (Aortic & Pulmonary)  Heart Sounds Second heart sound (S2): Heard during expiration as only one sound but heard during inspiration as two sounds (1st aortic then pulmonary closure), called “Physiological Splitting of S2”  Physiological splitting During Inspiration: enhanced venous return to right heart and lungs, prolongs RV ejection therefore delays PV closure. Reduced venous return to left heart shortens LV ejection therefore AV closes earlier  Physiological Splitting of S2 Expiration 1 A P sound Time (seconds) Inspiration 2 A P sounds Time (seconds) Murmurs  Murmurs A sound that you hear as a result from turbulent flow in the heart – Normal flow across a narrowed valve e.g. aortic stenosis  Murmurs A sound that you hear as a result from turbulent flow in the heart – Normal flow across a narrowed valve – Across a valve which doesn’t close correctly e.g. mitral regurgitation  Murmurs A sound that you hear as a result from turbulent flow in the heart – Normal flow across a narrowed valve e.g aortic stenosis – Across a valve which doesn’t close correctly e.g. mitral regurgitation – through a hole, from a high pressure to low pressure chamber e.g. ventricular septal defect  Mini Case Topic 1 Nine days after Carl was born his Baby Carl heart rate became abnormally high, he sweat profusely when feeding and slept the rest of the time. A chest X-Ray shows that the left side of his heart was enlarged, and there were markings in the lungs that indicate increased blood flow to the lungs.  What’s wrong with baby Carl? What heart defect would cause persistent increased blood flow to the lungs and an enlarged left heart?  from from body lungs Normal Heart RA LA V V RV LV to To lungs body  from from body lungs Ventricular Septal Defect RA LA V V Which direction? RV LV to to lungs body  from from Ventricular body lungs Septal Defect RA LA V V < 25 mmHg >100mmHg RV LV Increased Blood flow to lungs to to lungs body  from from body lungs Ventricular Septal Defect RA LA V V Left < 25 mmHg >100mmHg Heart Enlargement RV LV to to lungs body  Why isn’t the right side of the heart enlarged in a Ventricular Septal Defect?  P LA RA A M Right side T does not enlarge LV RV  What’s wrong with Baby Carl Ventricular Septal Defect producing a heart murmur due to turbulent blood flow across the defect. Nine days after Carl was born his heart rate became abnormally high, he sweat profusely when feeding and slept the rest of the time. – High heart rate to compensate for low heart output (more blood going back to lungs than out to body) – Like being in a state of persistent exercise –hence sweating- thus baby is fatigued and sleeps a lot.  What will happen to Baby Carl ? The cardiologist will likely recommend a surgical repair of the Ventricular Septal Defect. Depending on the severity of the defect, it can be done “percutaneously” or “invasively” which means open heart surgery. The reason they have to do something is that the defect will get worse with age and there will be increased potential for complications. Worse case scenario he will need a heart transplant.  Topic 1 Objective # 8 Based on the case of Baby Carl, describe the anatomical defect present in his heart, the physiological explanation for his murmur, and the consequence of taking no action to repair the defect.