Annotations

Of paroxysmal

nocturnal

dyspnea

In the wee hours of the morning the patient with left ventricular congestive heart failure is suddenly awakened from his sleep with an acute onset of suffocation and dyspnea-a frightening experience for him. He suddenly and properly rises from his bed and walks in search of fresh air and stands by an open window. Within a few minutes he feels fine. Why? His clinical state improves, in large part, because of the assistance of the force of gravity, a force exploited by evolutionary processes and physiologic development. Upon standing, a part of the blood pumped from the lungs by the left ventricle to the legs and feet and areas of the body below the heart remains in the systemic veins located below the heart.

Stability

of permanently

electrodes

during

implanted

open

heart

December,

1979, Vol. 98, No.

6

George E. Tulane University School and Charity Hospital New

Burch, M.D. of Medicine of Louisiana Orleans, La.

endocardial

surgery

Much has been written about the stability of transvenous electrodes during the first few weeks of implantation, but little is known about long-term anatomical stability when these electrodes are subjected to vigorous surgical manipulation.’ It has been shown that ventricular electrodes become encapsulated in a fibrous sheath which presumably holds them securely in position, and in fact makes extraction difficult at times.’ Nevertheless, the stability under unusual circumstances has not been demonstrated up to now. We have had the opportunity to observe electrode stability in 15 open heart operations on 14 patients over the past six years. Nine of the 15 procedures were aortocoronary bypasses, three of them combined with valve replacements or ventricular aneurysm resection. There were two aortic valve replacements, one repair of a paravalvular leak, and three cases of surgical ligation of the AV node or bundle of Kent. The rather complex cardiac surgical procedures in this series reflect the extent of myocardial disease that would be associated with atrioventricular block or complex tachyarrhythmias. In one patient it was essential to restore atrioventricular synchrony, and therefore an atria1 synchronous pacemaker (VAT) was implanted at the time of valve replacement and double bypass. In another patient an unexplained rise in pacing threshold was seen a year after surgery, and the electrode was replaced; it is problematic whether this could have been related to subtle movement of the electrode at the time of the open heart procedure. Of the 14 electrodes, eight were 2 mm. Cordis models with a small silicone rubber shoulder near the tip, four were bipolar Medtronic electrodes (Model 6901) and two were small Cordis

812

This shifts blood away from the congested pulmonary circulation, relieving the lungs of the excess engorging blood which, through respiratory reflexes (Hering-Breuer, etc.), causes the respiratory discomfort (suffocation and dyspnea), and the patient then feels better. This special form of hemometakinesia provides comfort for the patient. Other readjusting physiologic factors are probably involved, but they are probably of less importance.

“thumb tack’ (or ball tip) electrodes. The electrodes had been in place for 2 to 52 months, with an average of 18.8 months. During the operation the implanted pacemaker was managed in a variety of ways. Usually its presence was ignored. However, when the firing of the pacemaker became troublesome the pulse generator output was suppressed by external overdrive with an external pacemaker whose pacing electrodes were placed on the skin over the implant. In two instances the pacing mode was converted to fixed rate by application of a sterile magnet. In one case the pulse generator was temporarily explanted. In the course of these operations the heart was usually manipulated rather vigorously, particularly during coronary bypass surgery, where anastomoses to obtuse marginal vessels required elevation and rotation of the heart to a rather extreme degree. Most patients also had apical ventricular sump drains, which required further manipulation of the apex. Despite this there were no electrode dislodgements. and in all cases satisfactory pacing continued postoperatively. These results suggest that permanently implanted transvenous electrodes are securely positioned in the heart, probably by virtue of the fibrous sheath that forms around the tip, and that this fixation is secure enough to withstand the manipulation of the heart during open heart surgery.

The Department

000%8703/79/120812

Victor Parsonnet, M.D. Director of Surgery of Surgery and the Pacemaker Center Newark Beth Israel Medical Center Newark, N. J. 07112

+ 01$00.10/O

,r’ 1979 The

C. V. Mosby

Co.

Of paroxysmal nocturnal dyspnea.

Annotations Of paroxysmal nocturnal dyspnea In the wee hours of the morning the patient with left ventricular congestive heart failure is suddenly...
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