Download Mitral Valve Prolapse

HISTORY
30-year-old woman.
CHIEF COMPLAINT: Palpitations of three years duration.
PRESENT ILLNESS: The patient has had brief, fleeting “flip-flop”sensations
in her chest. At other times she occasionally has sharp chest pains at rest
lasting 1 to 3 seconds. There is no past history of rheumatic fever, chest
trauma or heart murmur.
FAMILY HISTORY: Her 25-year-old sister has a murmur.
Question:
Is a specific diagnosis suggested by this history?
9-1
Answer:
No. Both her palpitations, which suggest premature contractions,
and her chest pain, are nonspecific and may be entirely innocent.
PHYSICAL SIGNS
a. GENERAL APPEARANCE – Normal slender young woman with
mild scoliosis.
b. VENOUS PULSE - The CVP is estimated to be 3 cm H2O.
UPPER RIGHT STERNAL EDGE
JUGULAR VENOUS PULSE
Question:
How do you interpret the venous pulse?
9-2
Answer:
The venous pulse is normal.
c. ARTERIAL PULSE - (BP = 120/70 mm Hg)
S1
S2
UPPER RIGHT
STERNAL EDGE
CAROTID
ECG
Question:
How do you interpret the carotid arterial pulse?
9-3
Answer:
The arterial pulse is normal.
d. PRECORDIAL MOVEMENT
PHONO
UPPER RIGHT
STERNAL EDGE
S1
S2
APEXCARDIOGRAM
Question:
How do you interpret the apical pulsation?
9-4
Answer:
The apical impulse is normal.
e. CARDIAC
AUSCULTATION
4L
APEX
S1
S2
Questions:
1. How do you interpret the
acoustic events at the left
sternal edge and apex?
CAROTID
ECG
2. What additional bedside
maneuvers will help to
assess this murmur?
9-5
Answers:
1. There are multiple systolic clicks and a late systolic murmur. These findings
indicate mitral valve prolapse. The clicks are likely due to acute tensing of
the valve as it everts into the left atrium, or less likely may emanate from the
chordae tendineae.
2. Examine the patient standing and squatting as shown below.
2L
APEX
STANDING
Question:
SQUATTING
What is your explanation for these postural changes?
9-6
Answer:
Standing decreases venous return, reducing ventricular size,
resulting in earlier and more marked prolapse of the redundant mitral leaflet,
and hence earlier and more often louder clicks and murmur.
Squatting, by increasing peripheral resistance and hence afterload, increases
ventricular size, and the murmur is later and often fainter.
Through similar mechanisms amyl nitrite makes the ventricle smaller (like
standing), allows more mitral valve prolapse, and the murmur begins earlier.
Vasopressors or isometric handgrip (like squatting) increase ventricular size,
allow less prolapse, and make the murmur begin later in systole.
These changes are in contrast to patients with rheumatic mitral regurgitation.
For example, in such patients, a reduction in afterload enhances forward flow,
reducing the degree of regurgitation and the murmur.
Proceed
9-7
e. CARDIAC AUSCULTATION (continued)
ECG
2
1
1
1
2L
A2 P2
EXPIRATION
Question:
0.6
sec
A2
P2
INSPIRATION
How do you interpret the acoustic events at the upper left
sternal edge?
9-8
Answer:
There is normal splitting of the second heart sound in inspiration.
f. PULMONARY AUSCULTATION
Question:
How do you interpret the acoustic events in the pulmonary lung fields?
Proceed
9-9
Answer:
In all lung fields, there are normal vesicular breath sounds.
ELECTROCARDOGRAM
I
II
III
aVR
aVL
aVF
V1
V2
V3
V4
V5
V6
NORMAL STANDARD
RHYTHM
STRIP
Question:
How do you interpret this ECG?
9-10
Answer:
There are nonspecific ST-T wave changes and an isolated
ventricular premature contraction (VPC) in the rhythm strip. Such ST-T
changes are common in patients with mitral valve prolapse, especially in the
inferolateral leads. In many patients, especially those with the isolated clicks
and no murmur, the ECG is normal. Premature atrial and ventricular
contractions are also common and are the usual cause of “palpitations.” Atrial
tachycardia and atrial fibrillation are sometimes present. Exercise stress
testing results in a high percentage of “false positives.”
Proceed
9-11
CHEST X RAYS
Questions:
1. How do you interpret these chest X rays?
2. Based on the history, physical examination, ECG and X rays, what is your
diagnostic impression and plan to further evaluate this patient?
9-12
Answers:
1. The heart and lungs are normal. There is a mild scoliosis of the thoracic
spine. On the lateral view, the spine is quite “straight,” rather than mildly
kyphotic as it usually is in normal adults. Thoracic skeletal abnormalities
are quite frequent in this syndrome of mitral valve prolapse, particularly
“straight back,” pectus excavatum, and mild thoracic scoliosis.
2. The history, physical examination, ECG and chest X rays are essentially
diagnostic of the systolic click - systolic murmur (Barlow’s) syndrome.
Echocardiography is a non-invasive procedure likely to show the mitral
prolapse and confirm the clinical diagnosis.
The patient’s study follows.
9-13
LABORATORY - ECHOCARDIOGRAM
TWO-DIMENSIONAL ECHOCARDIOGRAM (SYSTOLE)
RV
AoV
LV
LA
AL
PL
LV
RV
RA
AL
PL
LA
RV
= Right Ventricle
LV
= Left Ventricle
LA
= Left Atrium
RA
= Right Atrium
AL
= Anterior Mitral
Leaflet
PL
= Posterior Mitral
Leaflet
AoV = Aortic Valve
PARASTERNAL LONG AXIS APICAL FOUR CHAMBER
Question:
What are the diagnostic features of this echocardiogram?
9-14
Answer:
There is a marked systolic displacement of the posterior leaflet
into the left atrium that is diagnostic of mitral valve prolapse.
The size of the chambers and function of the left ventricle are normal. This,
together with absence of leaflet thickening, implies a good prognosis.
Proceed
9-15
The Doppler ultrasound examination can help confirm the presence and
determine the severity of mitral regurgitation. The patient’s color Doppler flow
map below shows mild MR.
PARASTERNAL LONG AXIS VIEW (Systole)
RV
RV
= right ventricle
LV
= left ventricle
AoV = aortic valve
AoV
LV
MV
= mitral valve
LA
= left atrium
MV
LA
Question:
Blue
(large
arrow)
represents
the
mild
regurgitant
jet.
Red
represents LV outflow.
Is cardiac catheterization necessary?
9-16
Answer:
No. The precise diagnosis has been established by non-invasive
techniques, the most valuable of which is auscultation. However, if cardiac
catheterization were performed, the result would be similar to the
following case.
LABORATORY (continued)
LEFT VENTRICULAR
ANGIOGRAM - Right Anterior
Oblique (Systolic Frame)
Left Atrium (LA)
Ao
LA
= 5mm Hg MEAN
Left Ventricle (LV) = 120/4mm Hg
Aorta (AO)
= 120/70 mm Hg
Cardiac Index
= 3.5L/Min/M2
LV
POST
ANT
Question: How do you interpret the hemodynamics and angiographic data?
9-17
Answer:
Intracardiac pressures and cardiac output are all normal, as is
usually the case, since the mitral regurgitation is minimal. The angiogram
shows scalloping (arrows) of the prolapsing posterior leaflet as well as some
prolapse of the anterior leaflet (broken arrow) as they balloon into the left
atrium in late systole.
Question:
The patient has received some conflicting advice about her
cardiac status and about antibiotics. Some clinicians have told her to take
penicillin daily, while others have said to take it only one hour prior to dental
work. One healthcare provider advised both. What is your advice?
9-18
Answer:
The patient should be reassured, as the natural history of the
great majority of patients with mitral prolapse is benign.
She requires prophylaxis for infective endocarditis, not rheumatic fever.
Therefore, she should take antibiotics whenever she is exposed to bacteremia,
e.g., dental procedures likely to cause gingival bleeding, cystoscopies, etc.
Rheumatic fever prophylaxis (Penicillin) should be reserved for patients who
previously had rheumatic fever. It is inadequate for the prevention of infectious
endocarditis.
The patient was advised that her younger sister should be checked, as she
also has a murmur, and this syndrome may occasionally be familial. Her
sister’s evaluation follows.
9-19
The patient’s sister’s evaluation in the supine position, was entirely normal.
Auscultation in the standing position revealed a click and systolic murmur, as
shown below. The examination must include listening in multiple positions (and
occasionally even at different times), as these vasoactive maneuvers may vary
ventricular size and hence vary the murmur.
2L
APEX
CAROTID
SUPINE
STANDING
This patient was also instructed to undergo infective endocarditis prophylaxis
for any surgical or dental procedures likely to induce bacteremia.
Proceed for Summary
9-20
SUMMARY
Mitral valve prolapse is an extremely common disorder and is sometimes
familial. Young women are most commonly affected. It is usually a very mild
disorder, and in some cases may also involve the tricuspid valve.
In most instances its cause is unknown. However, irregular elongation of the
posterior or both leaflets and myxomatous changes microscopically have been
found in the valve in many of the cases studied at autopsy or surgery. These
changes are similar to those seen in Marfan’s and the “floppy valve” syndrome
which, however, are more severe and progressive disorders. The gross
pathology of a patient who developed infective endocarditis follows.
9-21
While the natural history of the systolic click-murmur syndrome is generally
benign, this specimen is from a patient who died of embolic complications of
infective endocarditis.
SCALLOPING (BALLOONING) OF MITRAL LEAFLET
JET LESION
LEFT ATRIUM
FROM
REGURGITAITON
BACTERIAL
VEGETATIONS
Proceed
9-22
SUMMARY(continued)
The mid to late systolic click(s) with or without a late systolic murmur is the
acoustic hallmark of the prolapsed valve. The click presumably originates from
sudden tensing of the valvular structures and/or deceleration of blood flow as
the mitral leaflets reach there maximally prolapsed position.
An isolated late systolic murmur may also be seen with prolapse, but in the
absence of a click it is not diagnostic, as such murmurs may also be seen with
papillary muscle dysfunction and flail chordae tendineae in the absence
of prolapse.
9-23
To Review This Case of
Mitral Valve Prolapse:
The HISTORY is typical, including palpitations reflecting VPC’s and
atypical chest pain of the musculoskeletal type. Occasionally there is chest
pain which sounds “ischemic” in nature. The exact cause of this symptom is
unknown. The syndrome may occasionally be familial, as in this case.
PHYSICAL SIGNS:
a. The GENERAL APPEARANCE reveals her slender build with slight
scoliosis and a “straight back,” common in this syndrome.
b. The JUGULAR VENOUS PULSE is normal in mean pressure and
wave form.
c. The ARTERIAL PULSE is normal.
Proceed
9-24
d. PRECORDIAL MOVEMENT is normal.
e. CARDIAC AUSCULTATION reveals normal splitting of the second
sound at the upper left sternal edge. Midsystolic clicks and a late systolic
murmur are best heard at the apex and are less intense at the left sternal
edge. The latter may reflect some degree of tricuspid valve prolapse.
The acoustic events are notoriously variable, and maneuvers which
decrease ventricular size augment the findings, with the clicks and murmur
appearing earlier in systole. No examination for mitral valve prolapse is
complete unless the patient is examined in the standing position.
On occasion the murmur associated with prolapse of the mitral valve has a
quality which has been described as a “honk.”
f. PULMONARY AUSCULTATION reveals normal vesicular breath sounds
in all lung fields.
9-25
The ELECTROCARDIOGRAM shows nonspecific ST-T changes
and occasional VPCs. Serious arrhythmias occur rarely.
The CHEST X RAY shows no abnormality of the heart or lungs,
reflecting the fact that the lesion is hemodynamically insignificant. Associated
skeletal abnormalities are seen, including slight scoliosis and a “straight back.”
LABORATORY STUDIES
include the echocardiogram which
shows late systolic posterior movement of the posterior leaflet. While invasive
study is unnecessary, a typical angiogram shows the late systolic posterior
leaflet prolapse and normal intracardiac pressures and cardiac output.
9-26
TREATMENT
is mainly reassurance and infective endocarditis
prophylaxis. Arrhythmias are usually untreated because they are brief,
infrequent and of little consequence. Considering the common occurrence of
this disorder, the rare instances of serious ventricular arryhthmias that have
been reported should not set the standard for therapy. Arrhythmias that are
frequent, prolonged and symptomatic should be evaluated and treated.
Patients with atypical chest pain should also be reassured. Beta-blockers may
help alleviate this symptom.
9-27
To Review a patient with Mitral Valve Prolapse with an
isolated click and murmur, change to disease #10 on the
keypad. You will note the following findings:
a. The JUGULAR VENOUS PULSE mean venous pressure and wave
form are normal.
b. The CAROTID PULSE is normal in upstroke, peak, and downstroke.
c. PRECORDIAL MOVEMENT reveals a normal brief apical impulse in the
fifth intercostal space at the midclavicular line, occurring at the time of the
first heart sound.
d. CARDIAC AUSCULTATION at the apex reveals the high frequency,
grade 2, late systolic crescendo murmur. The murmur is due to mitral
regurgitation associated with late systolic prolapse of the redundant mitral
leaflets. At the tricuspid area, there is an isolated high frequency mid
systolic click. This may reflect some degree of tricuspid valve prolapse or be
transmitted from the mitral area.
e.
PULMONARY AUSCULTATION reveals normal vesicular breath sounds
in all lung fields.
9-28