Joris Mekel

Use of advanced mapping and remote magnetic navigation to ablate left ventricular fascicular tachycardia.

Ablation of idiopathic left ventricular, or fascicular tachycardia can be aided by electroanatomical mapping. The addition of a floppy, magnetically enabled ablation catheter may improve maneuvering as well as decrease mechanically induced arrhythmias and mechanical block. We describe a case of fascicular tachycardia in which both these modalities were used in a sequential fashion. Integration of these modalities should prove even more helpful.

Open lung ventilation does not increase right ventricular outflow impedance: An echo-Doppler study.

Objective:Ventilation according to the open lung concept (OLC) consists of recruitment maneuvers, followed by low tidal volume and elevated positive end-expiratory pressure (PEEP). Elevated PEEP is associated with an increased right ventricular afterload. We investigated the effect of OLC ventilation on right ventricular outflow impedance during inspiration and expiration in patients after cardiac surgery using transesophageal echo-Doppler. Design:A prospective, single-center, crossover, randomized, controlled clinical study. Setting:Cardiothoracic intensive care unit of a university hospital. Patients:Twenty-eight patients scheduled for elective cardiac surgery with cardiopulmonary bypass. Interventions:In the intensive care unit, each patient was ventilated for approximately 30 mins according to both OLC and conventional ventilation. During OLC ventilation, recruitment maneuvers were applied until Pao2/Fio2 was >375 torr (50 kPa); during conventional ventilation no recruitment maneuvers were performed. Measurements and Main Results:Transesophageal echo-Doppler measurements were performed at end-inspiration and end-expiration in a steady-state condition, 20 mins after initiation of a ventilation strategy. Mean acceleration of flow was determined in the long axis of the pulmonary artery in a transverse axis view. During OLC ventilation, a total PEEP of 14 ± 4 cm H2O was applied vs. 5 cm H2O during conventional ventilation. Mean acceleration during expiration was comparable between groups. During inspiration, OLC ventilation did not cause a decrease of mean acceleration compared with expiration, whereas this did occur during conventional ventilation. Conclusions:Despite the use of elevated PEEP levels, ventilation according to OLC does not change right ventricular outflow impedance during expiration and decreases right ventricular outflow impedance during inspiration.

Superior vena cava collapsibility as a gauge of volume status in ventilated septic patients

authors even reported occasional total collapse of the SVC during the ventilation cycle. Like Vieillard-Baron and colleagues [2], we also examined the SVC in the shortand in the long-axis views. However, while examining the SVC in the short-axis view we occasionally observed a left-right shift of the SVC during tidal ventilation. This motion of the SVC is sometimes as great as the radius of the SVC. Vieillard-Baron and colleagues [2] also examined the SVC from the short axis, but did not mention motion of the SVC. However, it is conceivable that this motion of the SVC could mimic collapse of the SVC during tidal ventilation when assessed in the long-axis view. Therefore, it would seem to be advisable to exclude motion of the SVC during tidal ventilation in the short-axis view before measuring the diameter of the SVC in the long-axis view. We would appreciate a response from the authors as to their experience in this regard. References

Left Ventricular Lead Placement Within a Coronary Sinus Side Branch Using Remote Magnetic Navigation of a Guidewire: A Feasibility Study

Background: A novel magnetic navigation system (MNS) allowing remote guidance of catheters and guidewires might assist in implantation of left ventricular (LV) pacing leads.

Targets and endpoints in ablation therapy for atrial fibrillation in the light of pathophysiological mechanisms

Atrial fibrillation (AF), an important public health problem is a complex and multifactorial arrhythmia. Non-pharmacological treatment for symptomatic patients is of increasing importance. The different catheter ablation techniques in AF treatment developed during recent years, all based on different pathophysiological insights, are discussed. The non-standardized use of different follow-up methods after ablation make interpretation and comparison of results difficult.