Download Echocardiographic studies of the motion of the mitral valve in

FIGURE2. Echocardiogram of region of aortic root and left atrium (LA) in patient with 3:2
atrioventricular conduction. P, Atrial deflections; AAR, anterior aortic root; AV, aortic valve;
PAR, posterior aortic mot; and LAPW, left a t r d posterior w d (case 1).
minute and atrioventricular conduction varying from 1:l to
2: 1. Second-degree atrioventricular block of Wenckebach
type with 3:2, 4:3, or 5:4 ratios was observed frequently.
During seconddegree atrioventricularblock with 3:2 atrioventricular conduction in this patient, every P wave was followed by a sharp, brief anterior excursion of the left atrial
posterior wall ( Fig 1, arrows). The excursions of the left
atrial posterior wall that were produced by blocked atrial impulses differed from those produced by conducted atrial impulses because of the passive motion of the left atrial posterior
wall that accompanies ventricular systole.* During this arrhythmia, when the atrial rate was 160 impulses per minute,
the R-R
were
long (mean, Ooe2 second
and short ( mean 0.48 second). Correspondingly, the duration
of the systolic owning of the pulmonary valve (right ventri&
ejection period) was bnger (mean, 0.34 second) in
beats terminating long R-R intervals than in beats terminating
short R-R intervals ( mean, 0.22 second) ( Fig 1 ) .
Similarly, inspection of the aortic root and left atrium during the same arrhythmia ( Fig 2 ) showed that beats termin a h g long R-R intervals exhibited longer systolic owning
of the
v h (left ventricular ejection period) and larger systolic anterior excursions of the aortic root as a whole
than ventricular beats terminating short R-R intervals.
The hernodynamic effects of second-degree atrioventricular
block were more evident when the left ventricle was 0%served at the level of the chordae tendineae ( Fig 3A). Because of the presence of 3:2 atrioventricular conduction of
~enckebachtype, the R-R intervals were alternately long
(0.48 second). Consequently the
(0.62 second) and
systolic excursions of the left ventricular posterior wall and
ventricular septum were approximately twice as large in the
beats terminating long R-R intervals (long diastoles) as in
the beats terminating short R-R intervals (short diastoles).
Left ventricular stroke volume. calculated as the maximal left
ventricular diameter cubed minus the minimal systolic left
ventricular diameter cubed, was two to three times larger
in the stronger beats than in the weaker beats ( Fig 3A ) and
was a linear function of left ventricular end-diastolic volume
( Fig 3C, right).
The effects of the R-R interval on stroke volume were also
apparent when the atrioventricular conduction ratio became
4:3 ( Fig 3B ) . Thus, the systolic excursions of the ventricular
septum and left ventricular posterior wall, as well as the
stroke volume, were largest in the beats terminating the longest R-R intervals, smallest in the beats terminating the shortest R-R intervals, and intermediate in beats terminating R-R
intervals of intermediate duration. As before, stroke volume
was a linear function of left ventricular enddiastolic volume
( Fig 3C, kft)
.
CASE2
Patient 2 was a 72-year-old man with stenosis of the aortic
valve and chronic left
failure. A H~ bundle elec-,t
revealed sinus rhythm with 2: 1 atrioven
block above the level of the His bundle. The ECG (Fig 4 )
showed a regular venGcular rate of 44 beats per minute, me
rate was exactly double (88 impulses per minute), but
th, blocked p waves were not easily recognizable because
they were superimpose, on the T waves of the preceding
beats. This electrocardiographic interpretation is supported
by -ful
dysis
of the e ~ d i o g r a p h i cscan taken frorn
th, hicuspid valve and right atrial
to the left
valve (Fig 4). In the middle of
at the level of the
posterior wall came into view
and
the sweep, the left
showed small, but sharp, regular anterior deflections ( F ~ ~
4, A) at a rate equal to h t of P waves in the ECG. Each
uspike- of the left
posterior wall was p-ded
by a P
wave.
In addition, the mitral valve exhibited abnormal diastolic
motion, with an extra peak occurring between the E and A
peaks. me anterior motion of the tricuspid ledets Uewise
was abnormal, showing four peaks instead of the usual two.
In this patient, mechanical ahial mh produced by the
blocked atrial impulses occurred during venGcular diastole
and
were
for the abnormal extra
diastolic undulations of the
and tricuspid leaflets.
Echocardiographic studies of the motion of the
mitral valve in complete atrioventricular block5"
and in first-degree atrioventricular block7 have
shown that closure of the mitral valve can result
from atrial systole, independently of ventricular
460 D'CRUZ ET A 1
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CHEST, 72: 4, OCTOBER, 1977
Echocardi~g~raphic
Features of Second Degree
Atrioventricular Block*
Ivan A. D'Cruz, M .D.; Ravindra Prabhu, M.D.;
Howard C . Cohen, M.D., F.C.C.P.; and GezId Glick, M.D.
Echocardiographic studies demonstrrded honuatitiea
of motion of the pulmonary valve, the aortic root and
valve, the mitml and tricpspid valves, the left ventricle,
and the left &ium in two patients with accoad-degme
atdoventricular block. D d q Weuckebnch 3:2 d o
venMcular condnetion, ventricular beets uhiMted alternately long and short periods of systolic opening d
the pulmonary and aortic valvea and altenmtely large
and small left ventricular stroke volumes. Dwing 4:3
and 3:2 Wenckebach atrioventricular conduction, the
left ventricular stroke volume wan directly proportiod
to the preceding enddiastolic volume. hving 2:l afrjo.
ventrialac condnction, the blocked Ptrtl conhctbm
may produce movements of the left atrial wa& thereby
revealing the true atrial rate when the blocked P wavea
are obecored in the e1ectrocudiog.m by their superimposition on pncediag T waves.
describe herein the echocardiographic h d W eings
in two patients with second-degree atrio-
certain hemodynamic aspects of Wenckebach
atrioventricular block.
ventricular block. The abnormalities associated with
motion of all four cardiac valves, the left atrial wall,
and the left ventricular wall help to identify
blocked atrial impulses that are not easily discernible in the electrocardiogram because of superimposition of P waves on T waves of preceding beats.
Echocardiographic studies also help to elucidate
*From the Cardiovascular Institute, Department of Medicine, Michael Reese Hospital and Medical Center, and the
University of Chica o Pritzker School of Medicine, Chicago.
Supported in part%y funds contributed by the Oppenheimer Family Foundation and by the Michael Reese
Medical Research Institute Counc&
Manuscript received February 9; rewion accepted March 22
Reprint requests: Dr. D'Cnrz, Michael Reese Hospital and
Medical Center, 29th and EU6, Chicogo 60616
bfATEXUN3 AND ~
~
0
D
S
Data were collected using an ultrasonoscope (Picker Echoview 10) connected to a strip-chart recorder (Honeywell
1856). The ECG (lead 1 ) was recorded simultaneously. The
cardiac valves, left atrium, and left ventricle were examhe.d
by established techniques.14
CASEREFORTS
CASE 1
Patient 1 was a 15-year-old boy with chronic left ventricular dilation and failure secondary to a cardiomyopathy.
possibly endocardial fibroelastosis. He had a chronic ectopic
atrial tachycardia with atrial rates of 150 to 200 impulses per
FIGURE
1. Echocardiogram of region of pulmonary valve ( PV ) and left aMum ( LA) hi pitient with 3:2 atrioventricular conduction. Atrial deflections ( P ) are indicated on ECG.
Arrows indicate sharp, brief anterior excursion of left atrial posterior wall. APS, "Atriopulmonary sulcus;" and LAPW, left atrial posterior wall (case 1).
CHEST, 72: 4, OCTOBER, 1977
SECOND DEGREE ATRIOVENTRICULAR BLOCK 459
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Echocardiographic Manifestations of
Ruptured Aortic Valvular Leaflets in the
Absence of Valvular Vegetations*
Gopd Dm,M.D.; C . C . Lee, M.D.; and A. M . Weissler, M . D .
The diagnosis of ruptured (perforated or torn) aortic
valvolar leafiets due to various causes has been made
primarily at surgery or postmortem examination. Although angiocardiographic studies readily reveal aortic
regurgitation, they rarely establish the presence of a
ruptured aortic cusp as the cause of the aortic leak Recent echocardiographic experience has brought to our
attention seven patients with ruptured aortic valvular leaflets in whom the absence of valvnlar vegetatiom was confirmed at surgery in six and at autopsy in one. The echocardiogram of the aortic root in these snbjects revealed
little or no increment in the diameter of the aortic root.
In systole the usual box-like configuration of the leaflets,
similar to that observed in normal sobjects, was seen;
however, in diastole the normal thin midaortic Unear
echoes were replaced by a thick band of echoes which
often revealed high-frequency oscillation& In addition,
high-frequency vibrations of the anterior mitral leaflet
in diastole and increased systolic e x c d o n of the interventricular septum and left ventricular posterior wall
were observed.
chocardiography has become a well-established
cardiac diagnostic tml, particularly due to its
noninvasive nature and its ability to delineate in
v i m the size and motion of cardiac structure^.^.^ In
contrast to mitral valvular disease, the application of
echocardiographic studies in the diagnosis of aortic
valvular disease has been somewhat limited, due to
technical difficulty in recording motion of the aortic
however, with growing experience and
refinement, echocardiographic studies have added
significantly to the identification of various pathologic changes in the aortic valve.= Characteristic
echocardiographic findings in valvular vegetaaneut i o n ~ , ~membranous
.~
subaortic stenosi~,~
~
aneurysm of a sinus of V a l ~ a l v a dissecting
rysm,1° bicuspid aortic valve," and supravalvular
aortic stenosis12have been described in recent publications. In this report, echocardiographic manifestations are described in patients with ruptured
aortic valvular leaflets in the absence of valvular
vegetations (confirmed either at surgery or postmortem examination ) .
had bacterial endocarditis in the past, for which they had
received appropriate antibiotic therapy. At the time of echocardiographic studies, none had evidence of infection, and
cultures of their blood on repeated examinations were negative for bacteria or fungi. Each patient was hospitalized with
signs and symptoms of congestive failure, and all but one
patient underwent right and left cardiac catheterization and
cineangiographic studies. Each patient demonstrated grade3/4 aortic regurgitation, with marked elevation in the left
ventricular enddiastolic pressure (29 2 10 mm Hg). Surgical resection of the aortic valve and replacement with a
prosthetic valve was performed in six of the patients. One
patient (patient 1 ) died as a result of intractable cardiac
failure prior to cardiac surgery. In all patients, careful direct
inspection of the aortic valve revealed the presence of either
a ~erforationor tear in one or more of the c u s ~ sand no
evidence of valvular vegetations. The interval between the
echoaudiographic studies and the surgical (or autopsy)
confirmation of the diagnosis ranged from 2 to 11 weeks
mean. five weeks ) .
~ch&ardio-s
were performed with an echocardiographic unit (Unirad 100 Ultrasonic Unit) and a 2.25-MHz
transducer of 1.25-cm diameter, focused at 7.5 cm. All of the
echocardiograms were recorded on a continuous strip-chart
recorder (Tektronix 154). The technique of recording the
echocardiogram of the aortic root and leaflets was similar to
that described bv Grarniak and Shah.3.4 In brief. the hansducer was placed in the third or fourth intercostal space left
of sternal border. After the characteristic echocardiographic
features of the anterior mitral leaflet were identified, the
transducer was rotated slightly to a medial and cephalic
position to detect the aortic root and valve. At times the
transducer was moved to the second interspace in order to
better record the aortic echocardiogram. The entire valvular
area was scanned by tilting the transducer at different angles,
as recommended by Dillon et al.8 All recordings were made
at a paper speed of 50 mm/sec.
The observations reported herein were made on seven
patients (all men) between the ages of 23 and 74 years
( Table 1) . Five of the patients were users of heroin and had
'From Wayne State University School of Medicine, Detroit;
the Veterans Administration Hospital, Allen Park, Mich; and
Harper Hospital, Detroit.
Manuscript received February 10; revision accepted March 22
Reprint requests: Dr. Dm,V A Hospital, Alkn Park, Michigan
48101
464 DAS, LEE, WEISSLER
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CHEST, 72: 4, OCTOBER, 1977
FIGURE4. Scan from region of tricuspid valve to region of mitral valve and left atrium and
then to left ventricle, obtained from patient during 2:1 atrioventricular block. Pericardial
effusion (PE) is seen between left ventricular posterior wall ( L W W ) and parietal pericardium ( PP). P, Atrial deflections; ATL, anterior tricuspid leaflet; VS, ventricular septum;
AML, anterior mitral leaflet; PML, posterior mitral leaflet; LAPW, left ah%dposterior wall;
and A, small, but sharp, regular anterior deflections of left atrial posterior wall (case 2).
systole; however, we are not aware of any published account of the echocardiographic findings in
second-degree atrioventricular block.
Atrioventricular block of the 2 : l variety may be
difEcult to recognize in the ECG if the blocked P
wave is small in voltage or is superimposed on the
peak of the T wave of the preceding beat. This
problem may occur not only during sinus rhythm
but also during ectopic atrial tachycardia with 2:l
atrioventricular block. In either case the clinician
may overlook the blocked P waves and assume erroneously that the atrial rate is the same as the
ventricular rate. Echocardiographic examination
can prevent such an error by revealing the mechanical manifestations produced by blocked atrial systoles on the left atrial wall and the mitral and tricuspid va~ves(Fig 4).
In normal individuals the left atrial posterior wall
moves anteriorly during atrial systole and moves
posteriorly during ventricular systole.' The left
atrial posterior wall may, therefore, exhibit less anterior motion during atrial systole when the atrium
contracts against a closed mitral valve (ventricular
systole) than it does if the atrium contracts while
the mitral valve is open (ventricular diastole).
Although atrioventricular block of Wenckebach
type has been studied extensively by electrocardiographers, little information is available about its
hemodynamic aspects. In any given Wenckebach
period the ventricular contractions terminating the
shortest cycles are preceded by the shortest diastoles and, consequently, the least ventricular filling.
In accordance with Starling's law, these beats eject
the smallest stroke volumes (Fig 3C). Echocardiographicall~, this sequence is reflected by the
smallest systolic excursions of the ventricular septum and left ventricular posterior wall, the smallest
systolic anterior excursion of the aortic root, and
the shortest duration of systolic opening of the
aortic valve. During Wenckebach atrioventricular
conduction ratios of greater than 3:2, the ventricular beats terminating cycles of intermediate
duration eject stroke volumes of intermediate magnitude, in proportion to the duration of the preceding cycle (Fig 3C, left). The various echocardiographic variables reflecting stroke volume will
change accordingly.
Analogous findings obtained by using a Doppler
ultrasonic flowmeter catheter to measure the phasic
velocity of aortic blood flow were reported by
Benchirnol et al,8 who produced atrioventricular
block of Wenckebach type by atrial pacing at
rates of 110 to 170 impulses per minute. These investigators8 found cyclic variations in the peak
velocity of aortic blood flow that generally varied
directly with the length of the preceding cycle and
inversely with the P-R interval. The variations in
the peak velocity of aortic blood flow and the intraaortic peak systolic pressure were more pronounced
with 3:2 atrioventricular conduction ratios than
with higher ratios (4:3, 5:4, etc).
Whether the mitral and tricuspid valves show abnormal diastolic motion or not in patients with 2 : l
atrioventricular block depends on whether the
blocked atrial systoles occur during ventricular systole or after it, which, in turn, depends on the R-P
interval. If the blocked atrial contraction takes
place during systolic mitral closure, the motion of
the mitral and tricuspid valves during the ensuing
diastole will be normal. On the other hand, if
462 D'CRUZ ET A 1
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CHEST, 72: 4, OCTOBER, 1977
mechanical atrial systole resulting from the blocked
atrial impulse occurs after ventricular systole, when
the mitral and tricuspid valves have already
opened, it will cause one or two diastolic deflections
on the echoes of the mitral and tricuspid valves, in
addition to the normal E and A peaks (Fig 4).
These abnormal mitral and tricuspid patterns of
diastolic motion are attributable to the superimposition of the hemodynamic effects of the blocked
atrial systole-on the normal pattern of blood flow
across the mitral and tricuspid orifices and within
the ventricles. Diastolic mitral closure is known to
depend on two main factors: the production of a
vortex through the mitral orifice towards the end of
early rapid ventricular filling and again towards
These
~ ' ~ two factors are
the end of atrial s y s t ~ l e . ~
modified by the contractions from blocked atrial
beats occuning early during diastole. Whereas one
extra diastolic peak appears on the mitral valve,
two extra peaks occur during diastole on the anterior tricuspid leaflet in our second patient (Fig 4).
Perhaps this difference in the motion of the valves
is the result of differences in shape and compliance
between the left and right ventricles. Bellhouses has
shown that the motion of the cusps in diastole is
influenced by the presence and strength of the vortex, which, in turn, is determined by ventricular
shape and size. It should be added that one or more
undulations on the mitral cusps are sometimes seen
between the E and A peaks in individuals with
sinus bradycardia but without atrioventricular
CHEST, 72: 4, OCTOBER, 1977
block; however, these deflections are usually slow
and inconstant from beat to beat, unlike the brisk
and sharp "extra peaksn which remained constant
from beat to beat in our patient 2.
1 Feigenbaum H: Echocardiography (2nd ed). Philadelphia, Lea and Febiger, 1976
2 Gramiak R, Shah PM: Echocardiography of the aortic
root. Invest Radio1 3:356-366, 1968
3 Gramiak R, Nanda NC, Shah PM: Echocardiographic detection of pulrnonic valve. Radiology 102: 153-157, 1972
4 Winsberg F, Goldman HS: Echo patterns of cardiac posterior wall. Invest Radio1 4:173-177, 1969
5 Zaky A, Steinmetz E, Feigenbaum H: Role of atrium in
closure of m i d valve in man. Am J Physiol 217:16521659,1969
6 Shah PM, Kramer DH, Grarniak R: Iduence of the timing of atrial systole on mitral valve closure and on the first
heart sound in man. Am J Cardiol26: 231-237.1970
7 Thompson ME, Shaver JA, Leon DF, et al: Pathodynamics of the first heart sound. In Leon DF, Shaver JA (eds) :
Physiologic Principles of Heart Sounds and Murmurs
(monograph 46). American Heart Association, 1975, pp
8-18
8 Benchimol A, Desser KB, Gartlan JL: Aortic blood flow
velocity during Wenckebach periods in man. Am Heart J
82:796-801,1971
9 Bellhouse BJ: The fluid mechanics of heart valves In
Bergel DH ( e d ) : Cardiovascular Fluid Dynamics. New
York, Academic Press, Inc, 1972, p 261
10 Madeira HC, Ziady G, Oakley CM, et al: Echocardiographic assessment of left ventricular volume overload.
Br Heart J 36: 1175,1974
SECOND DEGREE ATRIOVENTRICULAR BLOCK 463
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