Cardiology - Introduction to Cardiology

From Iusmicm

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(dttKx4 Very neat blog.Really looking forward to read more. Will read on...)
(Thanks a lot for the blog.)
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dttKx4 Very neat blog.Really looking forward to read more. Will read on...
dttKx4 Very neat blog.Really looking forward to read more. Will read on...
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==Cardiology - Introduction==
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Thanks a lot for the blog.
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*Lots of pts have CVD (cardiovascular disease), especially above 60yo.
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**Here CVD includes coronary heart disease, heart failure, stroke and hypertension.
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*CVD is a major cause of death in both sexes.
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**Far more than anything except cancer (which is still less).
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*Since about 1970, we've been able to plateau the otherwise-increasing number of deaths from CVD.
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**We have even decreased deaths a bit in the last 3 decades.
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**Prof says CVD is "very treatable".
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*Hospital discharges for CVD are rising; that is, CVD is a major cause of hospitalization.
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*We have several operations and procedures for CVD.
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**Catheterizations, PCIs, and pacemakers are increasing.
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===Course Objectives===
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*Develop an adequate knowledge base pertaining to common cardiovascular disorders
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*Understand the pathophysiology of common cardiovascular disorders
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*Begin to formulate differential diagnoses and evaluation strategies for undifferentiated cardiovascular symptoms
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*Understand the basics of treatment for common cardiovascular disorders
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*Recognize selected ECG abnormalities
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**Later we'll get a list of the ECGs we need to recognize
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*Prepare you to excel in the care of cardiovascular patients during clinical clerkships
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*Prepare you to perform well on standardized exams
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*Impress upon you that cardiology is cool!
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===Course Outline===
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*The Clinical Evaluation
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*The Patient With a Murmur
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*The Patient With Dyspnea
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*The Patient With Chest Pain
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*The Patient With Palpitations and Syncope
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*Case Studies and Exam Preparation
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===Course Materials===
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*Harrison’s On-line 17th Edition 2008
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**Can be found online
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*Letcures
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*Learning Objectives for each lecture
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*ANGEL website
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*ECG tutorial
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===The Exam===
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*38 multiple choice questions worth 3 points each
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*Largely clinical vignettes
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*Selected ECGs
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*No murmur sound identification
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===A Case===
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*64 yo man
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*Referred to you for an abnormal ECG done as part of a routine physical. He has not seen a MD for years, has no known health problems and reports no symptoms.
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*On exam, BP 164/82 in the right arm and 170/86 in the left. His rhythm is regular, normal S1 & S2, no murmurs. His PMI is in the left 5th interspace in the mid-clavicular line and sustained. A soft, low pitched sound is heard at the apex just before S1. The remainder of the exam is normal.
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*What is this low pitched sound before S1?
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*What is this business about the PMI?
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*What is his exam consistent with?
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===The Clinical Evaluation===
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*Focused cardiovascular system history
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*General medical history
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**Comorbidities that affect the CV system or its treatment
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**Family history of CV disease
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**Exposures that may affect CV system
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**Medications (including OTC, vitamins, herbals)
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*Physical exam
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*ECG
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===Cardinal Symptoms of Cardiovascular Disease===
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*Chest pain (angina)
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*Dyspnea
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*Orthopnea
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*Paroxysmal Nocturnal Dyspnea
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*Edema
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*Palpitations
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*Syncope
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===Chest Pain History===
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*Location
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*Character
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*Radiation
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*Intensity
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*Duration
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*Frequency
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*Associated symptoms
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*Exacerbating / relieving factors
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*Pattern over time
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===New York Heart Association Classification===
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*Class I- No dyspnea
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*Class II- Dyspnea on more than usual activities (able to climb 2 flights/ walk 2 blocks)
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*Class III- Dyspnea on less than usual activities (unable to climb 2 flights/ 2 blocks)
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*Class IV- Dyspnea at rest or with any activity
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===Cardiac Cycle===
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http://howmed.net/wp-content/uploads/2010/09/cardiac-cycle.bmp
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*Know the following components of the cardiac cycle and their timing:
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**Isovolemic contraction
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**Ejection
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**Isovolemic relaxation
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**Early diastolic filling
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**Atrial systole
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*Appropriately place the following within the cardiac cycle:
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**S1,
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**S2,
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**S3,
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**S4
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===Prognostic Importance of Elevated Jugular Venous Pressure and S3===
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*The cardiac physical exam really is important.
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===Cardiovascular Physical Exam===
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*Vital signs (including pulse pressure):
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**Upper extremity BP within 10mm of each other
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**Lower extremity BP usually 10-20mm Hg higher
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**Use the correct size cuff!
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***Too small over estimates BP.
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***Too large under estimates BP.
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*Pulse pressure = systolic – diastolic
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**Wide pulse pressure: aortic regurgitation, anemia, thyrotoxicosis, pregnancy
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**Narrow pulse pressure: aortic stenosis, severe LV dysfunction, severe volume depletion, mitral stenosis, shock of any cause
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*Blood Presuure
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**Normal: < 120 / 80
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**Prehypertension: 120-139 / 80-89
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**Stage I hypertension: 140-159 / 90-99
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**Stage II hypertension: > 160 / 100
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*General appearance
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*Chest and lungs
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*Carotid & peripheral pulses
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**Volume
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**Contour
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**Bruits
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**Equal bilaterally
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====Pulsus parvus et tardus====
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*Pulsus parvus et tardus = poor and slow pulse
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*Pulsus parvus et tardus is '''due to severe aortic stenosis'''.
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*Pulsus parvus et tardus is characterized by '''slow upstroke''', '''low amplitude''', and '''narrow pulse pressure'''.
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http://www.ailehekimirehberi.com/dah-kalpsemptom/Slayt2.JPG
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====Corrigan’s (waterhammer) pulse====
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*Corrigan's (waterhammer) pulse is due to '''severe aortic regurgitation'''.
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*Corrigan's pulse is characterized by '''rapid upstroke''', '''high amplitude''', and '''wide pulse pressure'''.
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**Note that each of these characteristics is ''exactly opposite to parvus et tardus'' (caused by aortic stenosis).
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http://1.bp.blogspot.com/_m7f1iV3WaEI/TUaEMYB05TI/AAAAAAAAFbY/cYSpbTLs6gQ/s1600/Corrigan+%2527s+pulse.jpg
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�====Pulsus paradoxus====
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*Pulsus paradoxus is caused (classically) by '''pericardial tamponade''' (tamponade: compression of the heart by an accumulation of fluid in the pericardial sac).
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**Pulsus paradoxus can also be caused by ''pericardial restriction, obstructive lung disease, massive PE (pulmonary embolism), and RV infarction''.
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*Recall that normal physiology demonstrates a fall in systolic blood pressure with inspiration.
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**This phenomenon usually does not decrease systolic more than 10mmHg.
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*Pulsus paradoxus is characterized by '''exaggeration of the normal inspiratory fall in systolic blood pressure''' (>10mm Hg is abnormal).
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**In this way, ''"pulsus paradoxus"'' should really be called "''pulsus exageratus''" because this is really an exaggeration of normal physiology, not a paradox.
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*When pulsus paradoxus is severe (recall the causes: tamponade, restriction, obstructive lung disease, PE, and RV failure), the palpated pulse will be imperceptible during inspiration.
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**That is, when inspiratory systemic pressure is do decreased, it can be lost to palpation at the radius.
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http://medlibes.com/uploads/Screen%20shot%202010-08-09%20at%2012.07.00%20PM.png
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http://www.rightdiagnosis.com/bookimages/5/2795.1.jpg
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�====Jugular Venous Pulse====
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*We often want to know the right atrial pressure, as it can tell us about cardiac filling and blood volume.
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*'''Jugular venous pulse is an estimate of central venous pressure''' (and the best non-catheter estimation of '''right atrial pressure''').
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*The Jugular Venous Pulse (JVP) can be measured by placing the pt at a 45 degree angle and measuring the distance from the sternal angle to the horizontal of the highest observable pulsation of the jugular vein and then adding 5 cm H20.
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**That is, JVP is measured by the vertical height of pulsations above sternal angle.
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*These measurements are normally around
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*Note that '''JVP is measured at the bedside in cm H20''' ''but a catheter will measure the pressure in mm Hg''.
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**1.36 cm H20 = 1 mm Hg
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http://www.n3wt.nildram.co.uk/exam/cardio/jvp.jpg
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http://medicscientist.com/wp-content/uploads/2011/02/JugularVenousPulseJVP1_thumb.jpg
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====Jugular Venous Waveform====
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*Similar to the JVP indicating filling and volume, the waveform can indicate disease states.
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*http://www.rjmatthewsmd.com/Definitions/img/figure%20203-b.jpg
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*The normal V wave is during systole; V is a peak because during systole, blood is forced through the SVC / IVC and into the RA, increasing the pressure.
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**Therefore, an '''exaggerated V wave''' observed at the jugular vein indicates excessively high pressure in the RA--'''most commonly due to tricuspid regurgitation'''.
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***When blood from the right ventricle regurgitates into the RA, it elevates the pressure beyond that normally caused by SVC / IVC venous return; thus a large V wave occurs.
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*The normal A wave is during atrial contraction, when RA pressure is very high because it is contracting to force blood through the open tricuspid valve into a ''relaxed'' ventricle.
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**'''Cannon A waves''' occur when there is a '''complete heart block''' such that the '''RA contracts against a close tricuspid valve onto a pressurized ventricle'''.
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**Cannon A waves are characterized as large amplitude, short duration, '''episodic''', and dysynchronous with ventricular contraction
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**It makes sense that cannon A waves are large in amplitude because the atrium is contracting against a pressurized ventricle so the blood cannot move forward but the atrium is contracting, thus increasing the pressure.
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**During cannon A waves ''no (little) blood goes through TV into RV'' and more blood goes back into SVC / IJ.
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====Hepatojugular reflex====
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*Recall that the IVC sits behind the liver.
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*Manual pressure on the liver will cause a normal physiological increase in JVP as it forces more blood up the IVC to the RA.
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*'''Exaggerated increases in JVP with hepatic pressure indicates abnormal central venous pressure.'''
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====Kussmaul sign====
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*Recall that inspiration causes a fall of systolic pressure (normal is a fall in pressure < 10mmHg).
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**Recall that when this phenomenon of ''decreasing systolic pressure'' is exaggerated it is called ''pulsus paradoxus''.
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*Similarly, inspiration causes a fall of JVP with inspiration.
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*'''When JVP fails to decrease or even ''increases'', it is called the Kussmaul sign.'''
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*A positive Kussmaul sign is classically seen in '''pericardial constriction''' but can also be seen in RV infarction or severe RV failure.
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*That is, Kussmaul sign and pulsus paradoxus are both signs seen from the same causes: normal inspiratory physiology, cardiac tamponade, RV infarction, or severe RV failure.
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====PMI====
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*During the cardiac exam, one should palpate the heart and great vessels.
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*One should '''determine the location and nature of the PMI--the point of maximal impulse.'''
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**Note that it is hard to find the PMI; in 50% of pts over 50yo the lateral decubitus position must be assumed to feel the PMI.
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*The PMI usually lies in the '''4th-5th intercostal space in the mid-clavicular line'''.
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*PMI may be '''prominent in thin people, in high flow states, and in mitral regurgitation / aortic regurgitation.'''
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*'''A PMI lateral to the mid-clavicular line suggests cardiac ''dilation''.'''
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**Notet that thoracic cage abnormalities obfuscate this guideline.
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*A '''''sustained'' PMI suggests ''left ventricular hypertrophy''.'''
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*Similar to the PMI indicating left ventricular hypertrophy (when PMI is sustained), '''a parasternal heave at the left sternal border suggests right ventricular dilation or hypertrophy'''.
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====Other Palpable findings====
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*'''A palpable pulmonary artery in the 2nd, left, intercostal space (ICS) suggests pulmonary hypertension (HTN).'''
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**Similarly, if one can feel the pulmonic valve close (P for pulmonic, 2 for the second heart sound), there is likely pulmonic HTN.
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*One may also feel thrills--the rushing of blood through a structure.
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====Heart Sounds====
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http://howmed.net/wp-content/uploads/2010/09/cardiac-cycle.bmp
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http://upload.wikimedia.org/wikipedia/commons/5/5b/Cardiac_Cycle_Left_Ventricle.PNG
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http://rfumsphysiology.pbworks.com/f/r2.bmp
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http://www.med.umich.edu/lrc/coursepages/m1/anatomy2010/html/surface/thorax/heart_label.jpeg
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=====S1=====
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*S1, the first heart sound, is heard at the '''beginning of systole''' when '''the mitral and tricuspid valves close'''.
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*S1 is best heard at the apex (think of the sound starting at the valves which are between the atria and ventricles and then the sound is conducted down through the ventricles to the apex).
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*S1 can split as part of normal physiology, though the tricuspid component is often not heard.
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*'''S1 is observed as being very loud secondary to mitral stenosis (pliable leaflets), short PR, or rapid heart rate.'''
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=====S2=====
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*S2, the second heart sound, is heard at the '''beginning of diastole''' when '''the aortic and pulmonary valves close'''.
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*S2 is best heard at the base of the heart (think of the sound starting at the valves at the very superior aspects of the ventricles).
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*'''S2 is normally split.'''
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**So pathology is determined by abnormal characteristics of splitting: width, fixed (not changing with inspiration).
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*'''Physiologic split of S2''' with accompanied '''sinus arrythmia''':
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**S2 is often split, especially upon inspiration.
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**During inspiration, the intrathoracic pressure is lower causing more blood from the SVC and IVC to enter the right atrium / ventricle.
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**Increased right heart filling results in a longer duration of systole and therefore a later closure of the pulmonic valve.
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**Thus P2 (the pulmonic component of S2--that is, the closing of the pulmonic valve) occurs later than A2 (the aortic component of S2--that is, the closing of the aortic valve).
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**Initially, the return of blood from the pulmonic bed to the left heart will be relatively decreased so the left heart reflex induces '''sinus arrythmia'''.
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**Sinus arrythmia is an increased heart rate after respiration and is a misnomer because it is not a true arrythmia.
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*http://www.cvphysiology.com/Heart%20Disease/HD002%20cardiac%20cycle%202007r1.gif
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*http://www.ctsnet.org/graphic/5_3_1.jpg
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*There are four states of S2 to know: normal, paradoxic, wide, and fixed.
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http://4.bp.blogspot.com/_mNOioMRt3qA/SABw9iDb_1I/AAAAAAAADZM/pl3Kpmz0fRY/s1600/2ndHS.JPG
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*Normal S2:
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**Inspiration: A2 and P2 are split
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**Expiration: A2 and P2 are ''barely split''
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*Paradoxic S2: caused by left bundle branch block (lbbb)
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**Inspiration: no split
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**Expiration: split
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*Persistent (Wide) S2: caused by right bundle branch block (rbbb)
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**Inspiration: exaggerated split
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**Expiration: split
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*Fixed S2: caused by an atrial septal defect
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**Inspiration: split
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**Expiration: split
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http://www.uptodate.com/contents/images/CARD/3015/Split_S2.gif?title=Split+S2
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*'''Pulmonary HTN results in an exaggeration of P2'''
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**Recall, also, that in pulmonary HTN, the pulmonary artery may be palpable in the 2nd, left ICS.
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http://www.ebme.co.uk/arts/general/cardiology/valves.jpg
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http://www.uptodate.com/contents/images/CARD/3015/Split_S2.gif?title=Split+S2
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=====S3=====
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*S3, the third heart sound, occurs when there is '''rapid ventricular filling''' ''early in diastole''.
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*S3 may be normally heard in children and young adults.
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*When not normal, '''S3 indicates ventricular dysfunction to filling (CHF)'''.
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*Because S3 can be caused by the left or right ventricle, it '''can be heard at the apex (LV CHF) or the left sternal border (RV CHF)'''.
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*S3 can be augmented by increasing cardiac output: passive leg raising or isotonic exercises.
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http://acousticheart.com/library/AuscultationSitesWeb2.jpg
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http://www.cvphysiology.com/Heart%20Disease/HD002%20cardiac%20cycle%202007r1.gif
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=====S4=====
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*S4, the fourth heart sound, occurs when the atria contract into a stiff ventricle.
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*S4 is '''always pathologic''' and may indicate '''left ventricular hypertrophy (LVH), ischemia, or HTN'''.
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*Because '''S4 is only produced by atrial contraction''' (into a stiff ventricle), '''S4 is not heard in atrial fibrillation''' (because there is no contraction, just fluttering).
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*Like S3 (generated by poor filling function of ventricles), S4 can be made by the right or left side of the heart and therefore '''is best heard at the left sternal border or apex (right heart issue and left heart issue, respectively).
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*Like S3 (augmented by increasing cardiac output), '''S4 can be augmented with isometric exercise'''.
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=====Early Diagnostic Sounds=====
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*'''Mitral stenosis results in an opening snap''' (at S2, when the mitral and tricuspid open for diastole).
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*A ''pericardial knock'' is heard with '''constrictive pericarditis'''.
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*Tumor ‘plop’ is heard with atrial myxoma (a benign tumor that grows in the atrial wall).
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*S3 is considered an early diagnostic sound but must be differentiated as normal or pathologic.
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=====Systolic sounds=====
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*A systolic ejection click can be heard early-to-mid-systole when the bicuspid aortic valve leaks due to the pressure against it.
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*Mid-systolic click can indicate mitral valve prolapse (prolapsing during systole, until it finally lets blood flow through a hole).
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=====Murmurs=====
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*Murmurs originate from turbulent flow.
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*Turbulant flow can result from:
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**Normal flow over abnormal valves
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**Increased flow over normal valves
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**Normal flow through abnormal communications
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**Normal flow into abnormal, dilated, receiving chamber
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*Murmurs are classified as systolic, diastolic, or continuous.
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*See the murmurs lecture.
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====Other Physical Exam Findings Relevant to Cardiovascular Disease====
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*Cardiovascular disease often results in several signs that should be detected in an abdominal exam:
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**Organomegaly
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**Pulsatile mass (aortic aneurysm)
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**Bruits (renal artery stenosis, also in carotids)
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**Ascites
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*S&S of CVD in the extremities:
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**Clubbing (cyanotic congenital heart disease)
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**Cyanosis
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**Edema
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*S&S of CVD in the skin:
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===A Case===
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*64 yo man referred to you for an abnormal ECG done as part of a routine physical. He has not seen a MD for years, has no known health problems and reports no symptoms.
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*On exam, BP 164/82 in the right arm and 170/86 in the left. His rhythm is regular, normal S1 & S2, no murmurs. His PMI is in the left 5th interspace in the mid-clavicular line and sustained. A soft, low pitched sound is heard at the apex just before S1. The remainder of the exam is normal.
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*What is this low pitched sound before S1?
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**Because the sound is heard at the apex, it could be consistent with rapid filling of the left ventricle (as S3 sound, may or may not be pathologic) or the left atrium contracting against a contracted left ventricle (an S4 sound, always pathologic).  Because the sound is heard just before S1, it is an S4 sound which means it is from the left atrium contracting against a stiff left ventricle.
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*What is this business about the PMI?
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**The pt's PMI (point of maximal impulse) is in a normal location, but is sustained.  Sustained PMI indicates LVH.
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*What is his exam consistent with?
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**BP is in the hypertensive range, consistent with hypertension.
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**S4 sounds suggests left ventricular stiffness.
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**Sustained PMI indicates LVH.
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**'''You just diagnosed hypertensive heart disease at the bedside (no fancy tests needed)!'''
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Revision as of 23:05, 20 March 2012

dttKx4 Very neat blog.Really looking forward to read more. Will read on...

Thanks a lot for the blog.

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