Arrhythmia Case 11 from Schamroth's text

1, Normal sinus rhythm. The P waves (red circle)are normal. The P-P intervals range from 0.80 sec to 0.85 sec, representing a sinus rate of 70 to 75 beats per minute (bpm).
2. Atrial extrasystoles. The third and eighth QRS complexes are premature but normal in configuration. They are preceded by premature and bizarre P' waves (blue arrow) which are superimposed upon, and deform, the T waves fo the preceding sinus beats. Note how the T waves of these beats are more sharply pointed than the otheres.These P' waves represent atrial extrasystoles with normal conduction to the ventricules.
3.Post-extrasystolic depression. The compensatory pause is incomplete. The sum of the pre-and post-extopic intervals measures 1.48 sec. (2-4, 6-8) This si shorter than the sum of two consecutive sinus cycles (1.88 sec).( 2x (1-2)) Nevertheless, the post extrasystolic interval (the P'-P interval) is longer than expected. It measures 1.04 sec, which is longer than the sinus sycle of 0.84 sec. These has thus been some post extrasystolic sinus depression resulting from the premature discharge of the sinus node be the atrial extrasystole.　　　

Arrhythmia Case 12 from Schamroth's text

1．Sinus rhythm. This si represented, form example, by the first, third and fifth P waves of the upper strip. The P waves are normal. The P-R interval measures 0.20 sec.
2. Atrial extrasystoles. These are reflrected by the bizarre and premature P' waves. These P' waves are more pointed than the sinus P waves and have a notched distal limb. These atrial extrasystoles occur in bigeminal rhythm (upper strip, and the beginning and end of the lower recording). The coupling intervals (P-P' interval) of these extrasystoles are almost constant, and range from 0.64 se to 0.68 sec. The P'-R intervals of these extrasystoles measure 0.20 sec.
3. Extrasystolic atrial tachycardia. This is reflected in the lower two strips which show a series of consecutive and bizarre P' waves arising from the same ectopic atrial focus a sthe atrial extrasystole, as evedenced by the identical P' configuration. These paroxysms are, in effect a series of consecutive atrial extrasystoles.

Arrhythmia Case 13 from Schamroth's text

1. Extrasystolic atrial tachycardia. This is reflected by the bizarre and rapidly inscribed P' waves. The P'-P' intervals measure 0.24 sec, representing a rate of 250 beats per minute.
2. Varing second degree A-V block. The ectopic atrial rhythm is complicated by a varing (2:1-3:1) A-V block.

Arrhythmia Case 14 from Schamroth's text

1. Normal sinus rhythm. This si represented, for example, by the first 4 P-QRS complexes. The P waves are nromal. The P-P intervals measure 0.80 sec, reflecting a rate of 75 bpm. The P-R interval measures 0.15 sec.
2. Paroxysms of extrasystolic atrial tachycardia. Each paroxysm begins with an atrial extrasystole, as reflected by an abnormal, premature P' wave. The paroxysm continues as a series of atrial extrasystoles. The ectopic atrial discharge begins with a P'-P' interval of about 0.36 sec, reflecting a rate of 170 bpm, and then accelerates so that the terminal P'-P' intervals measure about 0.20 sec, reflection a rate of 300 bpm. This terminal rhythm is chaotic, and could conceivably reprent an atrial flutter. A-V conduction is irregular.

Arrhythmia Case 15 from Schamroth's text

１．Ｅｘｔｒａｓｙｓｔｏｌｉｃ　ａｔｒｉａｌ　ｔａｃｈｙｃａｒｄｉａ．　Ｔｈｉｓ　ｉｓ　ｒｅｆｌｅｃｔｅｄ　ｂｙ　ｔｈｅ　ｆｉｒｓｔ　ｅｌｅｖｅｎ　ｂｅａｔｓ　ｏｆ　ｔｈｅ　ｔｒａｃｉｎｇ．　The　P　waves　are　abnormal.　The P'-P' interval measures 0.44 sec, representin g arate of １３６ bpm. The tachycardia ends abruptly, thereby revealing its extrasystolic character.
2. Sinus tachycardia. This follows the extrasystolic tachycardia. The P waves are normal. The P-P intervals measure 0.60 sec, representin g a rate of 100 bpm.

COMMENT
The possible alternative diagnosis of an A-V junctional reciprocating tachycardia can also be entertained on the basis of : (a) the 1:1 A-V conduction, and (b) the tall narrow pointed P waves which in lead C1 may represent retrograde atrial activation.