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Reply from Dr. T. Cueni, Ospedale Italiano Di Lugano, Viganello, Switzerland
334 fibrillation. The absence of this awareness and the omission of the pertinent references concerning the cause of ventricular fibrillation by the anodal stimulus is a significant omission in this manuscript. Rather than simply adding to the number of cases in which competitive pacing has caused ventricular fibrillation, this report has added to the large preponderance of instances in which bipolar pacing has been the cause while leaving unchanged stimulus
the only
three
reported
was the cause
and
documented
of the fibrillation
instances
in
which
a unipolar
cathodal
[6,7.8].
1 Cueni TA, White RA, Burkart F. Pacemaker-induced ventricular inferior myocardial infarction. Int J Cardiol 1981; 1: 93-97. 2 Preston TA. Anodal stimulation as a cause of pacemaker-induced 1973; 86: 366-372.
tachycardia ventricular
in patients fibrillation.
with acute Am Heart
J
3 Preston TA. A new temporary pacing catheter with improved sensing and safety characteristics. Am Heart J 1974; 88: 289-293. 4 Mehra R, Furman S, Crump JF. Vulnerability of the mildly ischemic ventricle to cathodal, anodal and bipolar stimulation. Circ Res 1977; 41: 159-166. 5 Mehra R, Furman S. A comparison of cathodal, anodal and bipolar strength-interval curves with temporary and permanent electrodes. Br Heart J 1979; 41: 468-476. 6 Vera Z, Janzen D, Mason DT. Longevity of programmable energy output pacemakers, early results and experiences. Br Heart J 1977; 39: 1364-1373. 7 Zipes D. Electrophysiological mechanisms involved in ventricular fibrillation. Circulation (Suppl 111) 1975; 51: 120. 8 Seipel L. Bub E, Loogen F. Ventricular fibrillation induced by a unipolar implanted pacemaker (cathodal stimulation). Am Heart J 1976; 92: 810-811.
Reply from Dr. T. Cueni, Ospedale Italian0 Di Lugano, Viganello, Switzerland Dr. Furman’s point is well taken. We are aware of the problem of bipolar stimulation, which has not been discussed clearly enough in our paper. In view of the problem. we have, for several years, used temporary bipolar electrodes with remote anodes which are, as a matter of fact, outside the ventricles. In Cases 1 and 3, this type of electrode has been used to eliminate anodal stimulation which might induce ventricular fibrillation. As mentioned in our paper, Patient 2 had a permanent electrode of the unipolar type, which is usually inserted in almost all permanent implantations in Europe. This again eliminates anodal stimulation. Therefore, cathodal stimulation seems to be involved in all three cases which adds them to the few described so far in the literature. The important point, however, was the association of acute inferior myocardial infarction and the potential danger of sensing failure in this clinical setting.
the only
three
reported
was the cause
and
documented
of the fibrillation
instances
in
which
a unipolar
cathodal
[6,7.8].
1 Cueni TA, White RA, Burkart F. Pacemaker-induced ventricular inferior myocardial infarction. Int J Cardiol 1981; 1: 93-97. 2 Preston TA. Anodal stimulation as a cause of pacemaker-induced 1973; 86: 366-372.
tachycardia ventricular
in patients fibrillation.
with acute Am Heart
J
3 Preston TA. A new temporary pacing catheter with improved sensing and safety characteristics. Am Heart J 1974; 88: 289-293. 4 Mehra R, Furman S, Crump JF. Vulnerability of the mildly ischemic ventricle to cathodal, anodal and bipolar stimulation. Circ Res 1977; 41: 159-166. 5 Mehra R, Furman S. A comparison of cathodal, anodal and bipolar strength-interval curves with temporary and permanent electrodes. Br Heart J 1979; 41: 468-476. 6 Vera Z, Janzen D, Mason DT. Longevity of programmable energy output pacemakers, early results and experiences. Br Heart J 1977; 39: 1364-1373. 7 Zipes D. Electrophysiological mechanisms involved in ventricular fibrillation. Circulation (Suppl 111) 1975; 51: 120. 8 Seipel L. Bub E, Loogen F. Ventricular fibrillation induced by a unipolar implanted pacemaker (cathodal stimulation). Am Heart J 1976; 92: 810-811.
Reply from Dr. T. Cueni, Ospedale Italian0 Di Lugano, Viganello, Switzerland Dr. Furman’s point is well taken. We are aware of the problem of bipolar stimulation, which has not been discussed clearly enough in our paper. In view of the problem. we have, for several years, used temporary bipolar electrodes with remote anodes which are, as a matter of fact, outside the ventricles. In Cases 1 and 3, this type of electrode has been used to eliminate anodal stimulation which might induce ventricular fibrillation. As mentioned in our paper, Patient 2 had a permanent electrode of the unipolar type, which is usually inserted in almost all permanent implantations in Europe. This again eliminates anodal stimulation. Therefore, cathodal stimulation seems to be involved in all three cases which adds them to the few described so far in the literature. The important point, however, was the association of acute inferior myocardial infarction and the potential danger of sensing failure in this clinical setting.