CARDIOVASCULAR JOURNAL OF AFRICA • Vol 21, No 6, November/December 2010
328
AFRICA
physiological studies have demonstrated prolonged atrio-hisian
intervals and/or abnormal responses to atrial pacing. In addition,
a significant proportion of these patients had abnormalities of
both sinus and atrio-ventricular node function, as well as distal
His-Purkinje conduction abnormalities.
Atrio-ventricular block of all three degrees are well docu-
mented in mitral valve prolapse,
2,14,15
and in some patients, it
has been shown that atropine administration led to normalisa-
tion of atrio-ventricular conduction. This has led to speculation
that in patients with mitral valve prolapse, an increased vagal
tone is responsible for many of the conduction abnormalities.
15
However, non-vagal causes are also possible and include the
following: atrio-ventricular node developmental anomalies (as
part of the floppy mitral valve) and/or compression of the atrio-
ventricular nodal artery by the prolapsing leaflet, as the artery
courses along the border of the mitral annulus.
16
The prevalence of AV conduction disturbances among patients
with mitral valve prolapse is probably higher than expected. It is
hoped that this short communication will focus attention on the
as yet unexplained association between mitral valve prolapse and
various cardiac conduction disorders.
References
1. Swartz MG, Teicholz LE, Domosso E. Mitral valve prolapse: a review of
associated arrhythmias.
Am J Cardiol
1977;
62
: 377–389.
2. Greenspon AJ, Schaal SF. AV node dysfunction in the mitral valve
prolapse syndrome.
PACE
1980;
3
: 600–604.
3. Schaal SF, Fontana ME, Wooley CF. Mitral valve prolapse syndrome
– spectrum of conduction defects and arrhythmias.
Circulation
1974;
97
(suppl III): 49–50.
4. De Maria AN, Amsterdam EA, Vismara LA, Neumann A, Mason DT.
Arrhythmias in the mitral valve prolapse syndrome.
Ann Intern Med
1976;
84
: 656–660.
5. Coghlan HC, Phares P, Cowley M, Copley D, James TN. Dysautonomia
in the mitral valve prolapse.
Am J Med
1979;
67
: 236–-244.
6. De Silva RA, Shubrook SJ. Mitral valve prolapse with atrioventricular
and sinoatrial node abnormalities of long duration.
Am Heart J
1977;
93
: 772–775.
7. Pocock WA, Barlow JB. Etiology and electrocardiographic features of
the billowing posterior mitral leaflet syndrome.
Am J Med
1971;
51
:
Fig. 2. Echocardiography showing mitral valve prolapse
involving the posterior leaflet, with mild mitral regurgita-
tion.
Fig. 3. Echocardiography showing mitral valve prolapse
involving the posterior leaflet, with mild mitral regurgita-
tion.
Fig. 4. Telemetric ECG showing multiple episodes of asystole.
