Pacemaking according to a system of building blocks

Three different electrodes, i.e. conventional large and small surface endocardial electrodes and a new large contact area‐small active surface electrode, have been compared with respect to their stimulation thresholds for cardiac pacing in 94 patients with 96 electrodes. Both capacitor discharge and constant current pulses were used for the measurements. The average 2 msec impulse threshold for the 47 mm2 electrode reached its maximum on the 14th postoperative day and was 3.6±1.4 V and 4.4±1.8 mA. One month after insertion, the threshold was 3.2±1.4 V and 3.9±1.7 mA. Corresponding values after one month for the 6 mm2 electrode were 2.0±1.0 V and 1.7±0.9 mA and for the new electrode 1.7±0.9 V and 1.4±0.8 mA. Thresholds increased by about 20% when the impulse duration was diminished from 2 to 0.5 msec. The new large area‐small active surface electrode offers the advantages of significantly smaller increases in stimulation thresholds during the first month after insertion and good attachment to the endocardium.

Section: Methodsmentioning

confidence: 99%

Low Threshold Endocardial Electrodes for Permanent Cardiac Pacing

Wahlberg¹,

Edhag²,

Lagergren³

1977

“…EMT 588) (14) had previously been introduced through the right external jugular vein, with its tip positioned in the apical region of the right ventricle. The electrode cable had been passed subcutaneously to the right groin, where it went out through the skin together With the cable of the indifferent electrode placed in the fatty tissue of the abdominal wall (16). In all patients except one (no.…”

Section: Methods and Proceduresmentioning

confidence: 99%

Haemodynamic Effect of Atrial Triggered Versus Fixed Rate Pacing at Rest and During Exercise in Complete Heart Block

Kariöf

1975

230

The central haemodynamics at rest and during exercise have been studied in 25 patients with complete AV block who were treated with fixed rate (FRP) and atrial triggered pacemakers (ATP). The aim of the investigation has been to study the effect of a synchronized atrial contraction for the filling of the ventricles and for the cardiac output (Q̇). Pressures and Q̇ have been determined during heart catheterization. The P wave for triggering the atrial synchronized pacemaker has been obtained with an electrode in close contact with the atria, introduced by means of mediastinoscopy. The study consists of two series. In the first series (12 patients) the central haemodynamics were recorded with each patient connected first the FRP (about 70 impulses/min) and later to the ATP. Most patients were studied both at rest and during exercise, the work loads being identical with both types of pacemakers. Q̇ at rest is 10% higher with ATP (p < 0.02) than with FRP and during exercise 20 % higher with ATP (p < 0.01). Stroke volume (SV) at rest is equal with both types of pacemakers, but significantly larger with FRP during work (p < 0.001). The left ventricular (LV) filling pressure is significantly lower (p < 0.01) with ATP at rest, but not during exercise (p < 0.8). In the second series 13 patients were studied at rest and during exercise. The recordings of pressures and Q̇ were first performed with the patient on ATP. After 30 min rest an identical study was performed with the patient connected to FRP, the rate of which was matched (FRPm) to that previously recorded with ATP. Q̇ at rest is 18% higher (p < 0.01) with ATP than with FRPm and during work 8 % higher (p < 0.05) with ATP. SV at rest is significantly larger (p < 0.01) with ATP than with FRPm, whereas during exercise no significant difference is observed between the two types of pacemakers. LV filling pressure at rest is significantly lower on the 5 % level with ATP; during exercise no significant difference is observed. The investigation shows that in many patients, especially younger ones, treatment with ATP makes it possible to obtain a larger Q̇ during exercise, and thus to increase the oxygen transporting capacity of the circulation. This benefical effect may be more pronounced in patients with low compliance of the ventricular myocardium.

“…The endocardial electrode to be used in pacemaker treatment of chronic heart block was introduced by Lagergren and Johansson (1 7). Since then several reports on this method have been published (3,7,8,11,12,15,18,29,30). The major advantage of this method is the relatively simple procedure during which only local anesthesia is needed.…”

mentioning

confidence: 99%

Permanent Endocardial Pacing

Inberg

Kallio

Linna

et al. 1971

Abstract. Forty‐nine patients have been treated with permanent pacing, 48 of them with endocardial electrode. In four patients the pacing was begun with epicardial electrodes, which were later substituted by endocardial electrodes in three of them. Altogether 101 impulse generators were implanted. The early postoperative mortality was 2% (1/48). The cumulative survival rates at one, two and three years were 90, 69 and 63%, respectively. The battery life‐time was 15.2 months on the average. The commonest complication was dislocation of the endocardial electrode, which happened in five patients as an early complication and in three patients later during the follow‐up period. This complication was treated successfully in all instances. The advantages of endocardial in comparison to epicardial electrode technique are discussed.