Five Years of Palpitations: Difference between revisions

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[[Puzzle_2007_6_231_Answer|Answer]]
[[Puzzle_2007_6_231_Answer|Answer]]
[[Image:Puzzle_2007_6_231_fig2.png|Figure 2|thumb]]
[[Image:Puzzle_2007_6_231_fig3.jpg|Figure 3|thumb]]
The first part of the ECG shows sinus rhythm with a
regular rate of 130 beats/min. Four sinus P waves are
followed by normal ventricular activation with a normal
PR interval. The T wave of the 4th sinus beat is
different to the preceding ones suggesting
superimposement of a P wave (arrow 1 in figure 2 and
very well seen in lead V1 of figure 1) which is
subsequently conducted with a prolonged PR interval
to the ventricle. A short supraventricular tachycardia
(SVT) is initiated with a rate of 210 beats/min. A clear
P wave is not observed in or related to the subsequent
ventricular activation. After three beats a left bundle
branch block (LBBB) complex is observed which
might have been conducted from regular
supraventricular activation. In the distal part of the ST
segment, there is a clear sinus node P wave (figure 2,
arrow 2) conducted through the atrioventricular node
with a long PR interval, in turn followed by an RBBB
tachycardia with the same frequency as the SVT shortly
before.
In both cases the tachycardia is initiated by a
prolonged PR interval which is highly suggestive of
slow pathway conduction through the AV node.
Hence, AV nodal reentrant tachycardia (AVNRT) is
the most likely diagnosis in the second part of the ECG
with aberrant conduction over the right bundle. The
peculiarity in this ECG is the initiation of the second
part by a sinus node beat (not a supraventricular
extrasystole).
On invasive electrophysiological study AVNRT
tachycardia was confirmed. Figure 3 shows two
extremity leads, lead V1, five coronary sinus leads and
recordings from the mapping catheter, which is in the
right ventricle (100 mm/s). Two atrial extrasystoles
are given (middle part of the recording) which conduct
slowly to the ventricles and, on the right side of the
recording, are followed by a spontaneous rhythm in
which the QRS complex is immediately followed by the
atrial depolarisation. This is highly suggestive of AV
nodal reentrant tachycardia.
'''Conclusion: AVNRT induced by atrial extrasystoles and by a sinus beat. RBBB aberrant conduction. The LBBB beat is probably LBBB aberrant conduction or a ventricular extrasystole.'''