Should I be Worried?: Difference between revisions

Should I be Worried? (view source)

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 [[Puzzle_2006_1_33 - Answer|Answer]]
-The ECG shows sinus rhythm of 59 beats/min. Conduction
-parameters are abnormal; the PQ interval is a
-little over 200 msec and the QRS width is 120 msec
-(nonspecific conduction delay). It should be noted
-that the P-wave morphology is abnormal and that the
-P-wave duration is at the upper limit of normal as well.
-The electrical axis is at -30. The ST-T segments are
-normal in all leads. QT interval is well within normal
-limits and there is no right precordial ST elevation.
-The chance that a familiar cardiac disorder is the cause
-of the sudden death of a young (<40 years of age) close
-relative is at least 40%.<cite>Tan</cite> Hence, the presence of an
-abnormal ECG should alert the physician and specific
-cardiac abnormalities should be looked for. A familial
-structural cardiac abnormality seems unlikely because
-no abnormalities were identified in his deceased brother
-(idiopathic atrial fibrillation indicates the absence of
-structural heart disease) nor in your patient. QT
-prolongation is not present.
-Delayed conduction in all cardiac compartments
-should raise the suspicion of an abnormal cardiac
-sodium channel, i.e. a sodium channelopathy which
-includes Brugada syndrome, long-QT syndrome type
-and isolated conduction disease or combinations
-thereof. Brugada syndrome can be unmasked by
-placing the right precordial leads one intercostal space
-(ICS) more cranially (i.e. in the third ICS). In figures
-and 3 the leads V5 and V6 have been replaced by leads
-V1 and V2 positioned in the third ICS. A clear type 2
-(saddle back) Brugada ECG becomes visible.<cite>Wilde</cite>
-The strong suspicion of Brugada syndrome can now
-be confirmed by a drug challenge. In this case, 100 mg
-flecainide was infused (for protocol see reference 2)
-and in addition to significant additional conduction
-delay at all levels, the right precordial ST segments in
-the third ICS turn into a coved type (figure 3). Brugada
-syndrome should be diagnosed and DNA diagnostics
-should be ordered. In this patient a mutation in the
-SCN5a gene was identified (G1743E).
-An electrophysiological study was performed and
-ventricular fibrillation could reproducibly be induced.
-An ICD was implanted.
-==References==
-<biblio>
-#Tan pmid=15998675
-#Wilde pmid=12448445
-</biblio>