The purpose of electrocardiographic investigation is to find out something about the heart itself by means of an accurate knowledge of its electric action. This may be represented by the so-called heart-vector, a directed quantity, indicating in which direction electricity is propagated by the heart. The amount of each lead at a given instant depends on the heart-vector. The latter changes during the heart beat in direction and magnitude and, consequently, the value of the lead, too, changes with time.The relation between heart disease and leads is, at the root, very complicated. One can, however, analyse this relation by dividing it into a relation between heart disease and heartvector and a relation between heart-vector and leads. The first relation is only to be found on the ground of medical experience. The second relation, on the contrary, is of a purely physical nature, and will be the subject of our discussion.A long time ago Einthoven et al. (1913) with his so-called triangle rule, tried to formulate the relation between the heart-vector (which he called the manifest potential difference) and the three limb leads. Einthoven himself realized very well that this rule gives only an approximation of the truth. What the significance is of this approximation can be decided only by measurement. We have tried to formulate the physical problem and next to obtain, by measurements on a phantom, the data necessary for the application of the fundamental solution of the physical problem.
Aims
The GermAn Laser Lead Extraction GallerY (GALLERY) is a retrospective, national multicentre registry, investigating the safety and efficacy of laser lead extraction procedures in Germany.
Methods and results
Twenty-four German centres that are performing laser lead extraction have participated in the registry. All patients, treated with a laser lead extraction procedure between January 2013 and March 2017, were consecutively enrolled. Safety and efficacy of laser lead extraction were investigated. A total number of 2524 consecutive patients with 6117 leads were included into the registry. About 5499 leads with a median lead dwell time of 96 (62–141) months were treated. The mean number of treated leads per patient was 2.18 ± 1.02. The clinical procedural success rate was 97.86% and the complete lead removal was observed in 94.85%. Additional extraction tools were used in 6.65% of cases. The rate of procedural failure was 2.14% with lead age ≥10 years being its only predictor. The overall complication rate was 4.32%, including 2.06% major and 2.26% minor complications. Procedure-related mortality was 0.55%. Female sex and the presence of abandoned leads were predictors for procedure-related complications. The all-cause in-hospital mortality was 3.56% with systemic infection being the strongest predictor, followed by age ≥75 years and chronic kidney disease.
Conclusion
In the GALLERY, a high success- and low procedure-related complication rates have been demonstrated. In multivariate analysis, female sex and the presence of abandoned leads were predictors for procedure-related complications, while the presence of systemic infection, age ≥75 years, and chronic kidney disease were independent predictors for all-cause mortality.
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