1 Lumax DX FAQ Topics Lead selection Lead properties Implantation techniqueSensing and signal optimizationProgramming recommendationsFollow-Up considerationsOther questions
2 Lumax DX FAQ Lead selection What tip to coil distance is suitable for which patient? The tip to coil distance should be choosen based on the anatomical characteristics of the patient (height, size of the heart, positioning of the lead)Why is the Linoxsmart S DX available in a single shock coil version, only? This is a single-coil ICD lead with an additional atrial dipole.Is there only an active fixation version available? Yes. Active fixation ICD leads are the most common used ICD leads and are more easy to explant. This is espacially important for primary prevention patients facing a lifelong device history.
3 Lumax DX FAQ Lead selection Will there be an IS-4 version of the lead? Penta-polar electrodes can not be covered under the DF4/IS4 standard because there are five electrical contacts. DF4 has only four contact surfaces available.
4 Lumax DX FAQ Lead properties (1) Is there an influence of the modified lead design on the mechanical or electrical properties of the Linoxsmart S DX lead? No. The lead is designed so that the additional cable has no impact on mechanical or electrical properties.Is pacing via the atrial dipole possible? No, the ring electrodes are exclusively for sensing the atrium. If the patient has a known indication for atrial pacing before implantation a dual chamber device is indicated.
5 Lumax DX FAQ Lead properties (2) Why does Lumax DX not measure atrial pacing impedance as an indication of lead integrity? There is no pacing via the atrial dipole and therefore no impedance measurement possible with. Even though in the cutline for impedance trend (diagnostics/pacing-shock/impedance trend) in the Renamic software 1007.A one can see an atrial annotation.Is there anything to be considered if the Linoxsmart S DX has to be explanted? No, precautions should be taken as with any other ICD lead.
6 Lumax DX FAQ Lead properties (3) Is a more complex (penta-polar) lead more prone to lead problems? No, the lead design and the insulation material and thickness are identical to regular Linox smart leads. The Linoxsmart S DX lead only has one additional cable. The design was already developed for penta-polar leads.Cumulative survival probability of Linox S (data from Product Performance Report Jan. 2011)Insualtion material and thickness (t) are identical to regular Linoxsmart S leads.t
7 Lumax DX FAQ Lead properties (4) Is there a difference in DFT between a single and a dual-coil lead?There are several studies that show no difference in DFT between single- and dual-coil leads. The Gold study measured the DFT after several shocks. The DFT of the dual coil lead resulted in 9,8J and in single coil lead 10,2J. The difference is so small that it is not significant. Also the Rinaldi study does not show any difference.Gold M. et al. Optimization of superior vena cava coil position and usage for transbenous defibrillation. Heart Rhythm 2005;5:Rinaldi CA. et al. A Randomized Prospective Study of Single Coil Versus Dual Coil Defibrillation in Patients with Ventricular Arrhythmias Undergoing Implantable Cardioverter Defibrillator Therapy. Pacing Clin Electrophysiol Aug;26(8):
8 Lumax DX FAQ Implantation technique (1) Where is the optimal position for the atrial rings of the Linoxsmart S DX ? Atrial septum, auricular, higher position in the atrium or close to the valves? Place the atrial dipole so that it will lie in the middle third of the lateral atrial wall. Confirm position by X-ray.Do the atrial rings have to have contact to the atrial wall? How can I ensure this? No, there is no need for wall contact. Nevertheless positions close to the atrial wall are recommended.Important: In an effort to position the atrial dipole to have optimum wall contact to the endocardium, a preformed stylet is sometimes introduced and used to press the lead against the wall. This can result in an impermissible level of pressure being placed on the ventricular myocardium via the lead tip with undesirable consequences. Do not place pressure on the lead in this way.
9 Lumax DX FAQ Implantation technique (2) May I position the Linoxsmart S DX with atrial wall contact? Yes. This is the preferred position. In this position optimal sensing and low fluctuation of the measured values is expected.May one position the Linoxsmart S DX a medium-high or high septal ventricular position? What should be considered regarding the positioning of the atrial rings? Yes. The atrial dipole should still be positioned so that it comes to rest in the middle third of the lateral atrial wall.
10 Lumax DX FAQ Implantation technique (3) How many revolutions are necessary to fixate the Linoxsmart S DX reliably? Run only as many turns during fixation as are necessary for complete extension of the screw. Watch the position of the fixation screw on the X-ray. Maximum number of revolutions for extension and retraction is 20 turns.Is it possible to position an additional SVC shock coil in case of high DFT? An additional transvenous shock coil is is not recommended. It may influence espacially the sensing and could even result in damage of the Linoxsmart S DX by the floating shock coil.An additional subcutaneous shock coil can be used together with Lumax 540 VR-T DX.
11 Lumax DX FAQ Implantation technique (4) Are there any references, if the lead can be implanted in the high septum ? The lead can be positioned as a usual ventricular lead. As long as the atrial rings are positioned in the atrium there should be no difference in the sensing. The interim results of the PME Masterstudy does not show any differences in performance and atrial sensing.
12 Lumax DX FAQ Sensing and signal optimization (1) What is the minimum recommended P-wave amplitude for the Lumax 540 VR-T DX, measured with an external PSA? For regular dual-and triple-chamber devices readings of 2mV are desirable with measurements via PSA. Due to 4-fold gain of the atrial inputstage a P-wave amplitude of min. 0.5mV via PSA is acceptable. The minimum P-wave measured via PSA should be 0.5mV.Why is there a large difference of the atrial amplitude comparing PSA and device measurements? The external P-measurement via PSA has shown 2.5mV, via Lumax 540 VR-T DX it was 8.0mV. This is a result of the 4-fold gain of the atrial input stage. Amplitudes measured larger than 8mV will be displayed as 8mV.
13 Lumax DX FAQ Sensing and signal optimization (2) Is it normal when the atrial signal amplitude is larger than the ventricular amplitude (P = 8 mV, R = 6 mV)? Due to the above mentioned input stage it is well possible that the atrial signal is larger than the measurement for the ventricle.After repeated repositioning of the Linoxsmart S DX lead there is still far-field-sensing to be seen (post Vs). What can be done? In this case a decision has to be made wether the far-field-sensing can be blanked by reprogramming Lumax 540 VR-T DX (Far-field-protection after Vs), or if it is of benefit to change to a regular single chamber or dual chamber device. It should be considered that an extended far-field-blanking may impair atrial sensing and thereby may influence sensetivity of SMART detection.
14 Lumax DX FAQ Sensing and signal optimization (3) What can be done if ventricualr pacing causes far-field sensing in the atrium? In this case, the atrial blanking after ventricular pacing (far-field-protection after Vp) should be prolonged accordingly.What can I do if atrial signals are so broad that double counting of the P-waves occurs (double marker)? This problem was adressed with the new programmer software SW 1006 and SW If still broad atrial signals are seen technical service (Hotline) should be contacted for troubleshooting.What can be done if atrial fibrillation is not adequately sensed (undersensing/lack of atrial markers)? In this case, the Hotline should be contacted for troubleshooting.
15 Lumax DX FAQ Sensing and signal optimization (4) May a regular atrial (brady) lead be connected to the atrial channel if atrial signals with the Linoxsmart S DX lead are not satisfactory? There is nothing to be said against it. Take into account that there will be high P-values measured with the modified input stage of Lumax 540 VR-T DX.
16 Lumax DX FAQ Programming recommendations Under what conditions SMART should be turned off and onset/stability should be used? Can I rely on SMART, even though I've only measured very small P-amplitude in sinus rhythm? The new software allows Lumax 540 VR-T DX to switch between SMART and onset/stability. In case of a valid atrial signal SMART is used, in case of an invalid atrial signal the algorithm switches to onset/stability. Thus, a general deactivation of SMART is not necessary and therefore not recommended.Is there a reason why to switch on ATM in a none-pacemaker dependant patient? In order to substantiate the lead intergrity, it makes sense to activate ATM.
17 Lumax DX FAQ Programming recommendations Do the atrial arrhythmia statistics get suspended when there is loss of atrial sensing and undersense detection is used in case of SMART?This undersense detection only works in the VT zones and it is not active in case of normal / slow ventricular rhythms.As a consequence the statistics will not be suspended in case of atrial undersense, if the ventricular rhythm is slower than the VT zones.
18 Lumax DX FAQ Follow-Up considerations Do I have to perform special tests during the Follow-Up of the Lumax 540 VR-T DX ? No, the Lumax 540 VR-T DX system should not create an extra Follow-Up effort. Follow-Up should be done as with a regular single chamber ICD additionally checking atrial sensing (marker/P-wave amplitudes).
19 Lumax DX FAQ Other Questions What does “DX” stand for ? Since Lumax DX has extended diagnostic feasibilities, the short cut DX stands for Diagnostic eXtendedWhat is the main difference between Lumax DX and Lexos A+?Lumax 540 VR-T DX is based on the Lumax 540 platform with all the benefits the Lumax 540 family offers. Furthermore Lumax DX provides more atrial statistics and diagnostic options. The input stage has been modified with the atrial upper threshold which is now set to 75% vs. the previous setting of 50% to overcome QRS far-field sensing. Also the initial noise interval has been adjusted to 110 ms (the previous setting was 80 ms) to overcome double sensing of atrial signals. The standard setting in the brady pacing mode has been programmed to VVI. SMART Detection has been optimized and the counter have been slightly changed.