Josephson Clinical Cardiac Electrophysiology

160

■ Josephson’s Clinical Cardiac Electrophysiology

1

2

V1

A

A

A

A

A

A

A

A

A

A

HRA

380

V

V

V

H

H

H

A

A

A

A

A

A

A

A

A

A

HBE

1,340

T

D.I.

FIGURE 6.1 Atrial tachycardia in the absence of P waves on the surface QRS. Leads 1, 2, and V1 are shown with electrograms from the high right atrium (HRA) and His bundle (HBE) and time lines (T). There is a dissociation of atrial activity and ventricular activity; thus, a complete heart block is present. Simultaneously, a regular atrial rhythm at a cycle length of 380 msec is seen in the intracardiac recordings, yet there are no distinct P waves on the surface electrocardiogram (ECG). Hyperkalemia with the so-called “sinoventricular rhythm” was assumed to be present in the patient.

1

F

V1

A

A

A

A

A

A

A

A

V

V

V

V

AS

T

FIGURE 6.2 Atrial tachycardia with the absence of P waves on the surface electrocardiogram (ECG). ECG leads 1, F, and V1 are shown with an atrial electrogram recorded at the low atrial septum (AS). The surface ECG demonstrates an irregular rhythm and no P waves, suggesting atrial fibrillation. However, an intra-atrial electrogram from the AS revealed atrial tachycardia (A-A = 375 msec) with variable block. T, time line.

P

APD

1

F

V1

13

77

LA

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T

FIGURE 6.3 Atrial mapping to localize the origin of atrial premature depolarization (APD). Multiple APDs with bizarre P-wave morphology arise in the left atrium (LA) near the left inferior pulmonary vein. The local electrogram at that site begins before the onset of the P wave, with the rapid deflection occurring 13 msec after the onset of the P wave in the surface electrocardiogram (ECG). This was the earliest site recorded from either atria. T, time line. (Reprinted from Josephson ME, Scharf DL, Kastor JA, Kitchen JG III. Atrial endocardial activation in man. Electrode catheter techniques for endocardial mapping. Am J Cardiol . 1977;39:972, with permission from Elsevier.)