Rsr complex in leads i v5 or v6 the s is a q wave

 rSR' complex in leads I, V5 or V6 (the S is a Q-wave equivalent occurring in
the middle of the QRS complex).
 RS complex in V5-6 rather than the usual monophasic R waves seen in
uncomplicated LBBB; (the S is a Q-wave equivalent).
 "Primary" ST-T wave changes (i.e., ST-T changes in the same direction as
the QRS complex rather than the usual "secondary" ST-T changes seen in
uncomplicated LBBB). Also, exaggerated ST deviation in same direction as
the usual LBBB ST changes in LBBB (see leads V1 and V2 in Example #14).
These changes may reflect an acute, evolving MI, and are considered part of
Sgarbossa’s criteria.

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Example #14: Acute anterior and septal MI with LBBB. Note exaggerated convex-upwards ST
elevation in V1-3 and unexpected “Primary” ST elevation in I, aVL; also note the small
unexpected q-waves I, aVL, V6 (i.e., no longer just a monophasic R wave).
Example #15: Old MI (probable septal location) with LBBB. Remember LBBB without MI should
have monophasic R waves in I, aVL, V6). This ECG has abnormal q waves in I, aVL, V5-6
suggesting a septal MI location. Note also the notching on the upslope of S wave (arrow) in V4
(“sign of Cabrera”) and the PVC couplet.
IV. Non-ST elevation MI (NSTEMI)
 ECG changes may be minimal, or may show only T wave inversion, or may show ST
segment depression with or without T wave inversion.
 Although it is tempting to localize the non-Q MI by the particular leads showing ST-T
changes, this is probably only valid for the ST segment elevation MI’s (STEMI)
 Evolving ST-T changes may include any of the following patterns:
 ST segment depression in 2 or more leads (this carries the worse prognosis)
 Symmetrical T wave inversion only (this carries a better prognosis)
 Combinations of above changes
 OR the ECG may remain normal or only show minimal change; this is usually
associated with a good prognosis due to small amount of myocardial damage.

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V. The Pseudoinfarcts
 These are ECG cases that mimic myocardial infarction either by simulating pathologic Q
or QS waves or mimicking the typical ST-T changes of acute MI.
 WPW preexcitation : ECG leads with negative delta wave may mimic pathologic Q
waves; see the next ECG. This interesting ECG has only intermittent WPW
preexcitation. The WPW pattern is seen during the first half of the ECG, but
disappeared when the precordial leads V1-6 were recorded. Note the deep Q and QS
waves in leads II, III, and aVF. These are not really infarct Q waves but negative
(down-going) delta waves. Note also the slurred upstroke of the QRS complex in
leads I, and the first half of the V5 rhythm strip (bottom channel). In the 2 nd half of
the ECG tracing the “pseudo” Q waves in the lead II rhythm strip disappear and a qR
wave QRS complex appears indicating the return of normal conduction through the
ventricles. Also the delta wave in lead V5 goes disappears on the V5 rhythm strip
during the 2 nd half of the ECG. Finally, the PR interval is shorter during the 1 st half of
the ECG when preexcitation is occurring.