The Road to Successful CRT System Implantation: A Step-by-Step Approach

The Road to Successful CRT Implantation: A Step-by-Step Approach

The stylet and lead are then threaded through the sheath as usual. With this technique, the lead slides with minimal friction through the laser sheath and allows the operator to reduce the force applied to the lead and sheath. With less friction to overcome, the physician can control the movement of the laser sheath with more accuracy and less traction on the tissues.

The lead, in conjunction with the stylet and suture, is kept in line with the sheath and an appropriate amount of countertraction is held. Slowly rotating the sheath when advancing the laser sheath adds mechanical dilatation to the laser energy at the sheath tip. The J shape of the atrial lead can usually be straightened out as the sheath is advanced over it, before countertraction is applied.


This could damage the lead so that the locking stylet may not reach the end of the lead tip and decide the success or failure of the extraction. If at this point the lead still does not come out with minimal traction, mechanical sheaths or laser sheaths can be used for extraction. The transmitral filling profile improves acutely in most patients with the initiation of CRT. For more information, visit the JACC: Cardiac resynchronization therapy in a patient with atrial fibrillation and evidence of loss of left ventricular capture resulting in ineffective resynchronization.

Patience, attention to detail, and avoidance of overzealous traction is usually rewarded with successful extraction. Dislodgement of a lead when advancing the laser sheath over another lead. Laser sheath being advanced over the lead, locking stylet, and suture. Considering the frail state of many patients who require lead extraction, it is not unexpected that despite diligent technique, cardiac and vascular injury can occur.

These injuries can range from minor hematomas to catastrophic bleeding and even cardiac tamponade with pending death. A significant number of patients requiring lead extraction have had prior open heart surgery. When major vascular injury occurs in these patients, an emergency redo sternotomy will have to be performed. It is thus imperative that all preparations be in place for supporting circulation and to perform emergency sternotomy.

We routinely have an open heart surgical set laid out and a cardiopulmonary bypass machine set up in the room. The scrub nurse and perfusionist must be present or near the room during extraction. As mentioned before, the entire anterior chest and both groins are prepped and draped to allow for ease of surgical access in the event of an emergency. We also routinely place heparin-flushed sheaths in a femoral vein and femoral artery to allow for rapid deployment of cannulas for cardiopulmonary bypass via modified Seldinger technique.

We believe that emergent institution of percutaneous bypass is the safest method of managing the circulation in a patient with a major vascular or cardiac injury.

Implantacija srčane resinkronizacije - CRT

After full heparinization, we employ an Fr wire-reinforced long venous cannula and apply vacuum-assisted drainage to the venous reservoir. Our strategy for arterial cannulation is with a Fr wire-reinforced femoral arterial cannula. With bypass established, a midline sternotomy is performed.

Procedural Aspects of Lead Positioning for Cardiac Resynchronization Therapy

This allows for access to major vascular or cardiac structures that might have been injured. Common sites of injury are the innominate and subclavian veins, the superior vena cava SVC , the right atrium, posterior right ventricle, or the coronary sinus CS. The injuries are usually traction-induced injuries that can be repaired either by direct suturing or with biological patch repair.

It is important to avoid air being sucked into the venous system via the injury defect, which might cause a venous return lock and may shut the bypass circuit down. Simple reverse Trendelenburg positioning usually avoids this complication. If the emergency occurred prior to complete extraction, we would proceed with open extraction by placing an SVC cannula and snare.

In addition, we would retract the femoral venous cannula out of the atrium and snare the inferior vena cava, allowing for a right atriotomy and removal of residual leads under direct vision. Occasionally, it might be necessary to arrest the heart to free up the lead from its ventricular location.

Injury to the tricuspid valve is usually well tolerated and can be addressed on an elective surgery basis should the patient become symptomatic from tricuspid regurgitation. Sternotomy might also afford the opportunity to place epicardial leads such as a left ventricular LV lead in non-infected extraction cases. If more than one lead is being extracted, always extract the lead that is newer, as it will be easier to extricate. While trying to extract one lead, the laser sheath may not be able to advance past fibrosis at such areas of the SVC or right atrium—inferior vena cava junction. This back-and-forth approach while the locking stylets are in place stabilizes the lead that is not being worked on while guiding the laser sheath over the alternative lead.

If this approach is also unsuccessful, upsizing the laser sheath to a Fr sheath in conjunction with an outer sheath may be necessary. Despite the use of a larger laser sheath, the sheath may still not pass over the lead due to severe fibrosis and calcification, which is often seen in patients with end-stage renal disease.

Fibrotic adhesions and myocardial tissue attached to extracted right ventricular lead. When extracting leads with vegetations, we start with a Fr sheath and upsize to a larger size Fr sheath as needed, as the vegetation usually adheres to the lead. Extraction of leads with fractures can be very difficult. Advancing the locking stylet in a known fractured lead, such as the Sprint Fidelis Medtronic Inc. As the locking stylet is advanced, it may come out of the lumen at the site of the fracture and penetrate outside of the lead. Figure 1 A shows typical LBBB in a year-old female with nonischemic origin of dilated cardiomyopathy.

Electrocardiography of a year-old female cardiac resynchronization therapy recipient with left bundle branch block A, before resynchronization; B, after cardiac resynchronization therapy implantation. Note the changes in leads I new S wave and V 1 new R wave indicating initial activation from a left ventricular site. It is also important to evaluate whether the patient is in normal sinus rhythm or in atrial fibrillation. Newly onset episodes of paroxysmal or persi stent atrial fibrillation are associated with worse outcome in CRT patients. The role of pulmonary vein isolation PVI is still under debate.

Some smaller studies showed benefit of this procedure in HF patients; however, none of them was conducted in CRT patients. Cardiac resynchronization therapy in a patient with atrial fibrillation and evidence of loss of left ventricular capture resulting in ineffective resynchronization. Atrial lead was inactivated in this patient due to permanent atrial fibrillation.

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Frequent ventricular ectopic beats, more frequently observed in patients with an ischemic origin of the cardiomyopathy, inhibit LV pacing and reduce the efficacy of CRT. Patients with a high burden of ventricular unifocal ectopic beats might be considered for catheter ablation; however, clinical data are still limited. After determining the underlying rate and rhythm, we need to assess LV capture.

LV noncapture is a common cause of CRT nonresponders. Beats with biventricular pacing are showing frontal plane QRS axis in the right superior quadrant and a dominant R wave in lead V 1.

Device interrogation provides broad spectrum of information on the HF status of the patient. Atrial, right ventricular, and LV sensing and pacing parameters have to be checked. Noncapture is a common late complication of CRT and may result in no response. Phrenic nerve stimulation is also often observed in CRT recipients and in some cases might be associated with LV lead dislocation.

It might be lower in case of LV lead dislocation, paroxysmal or permanent atrial fibrillation, and frequent ventricular ectopic beats. It is recommended to perform AV-delay optimization in all patients, guided either by the device or by echocardiography; this will be discussed more in detail in Step 4.

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CRT nonresponders should always be assessed and optimized with regard to VV-timing. Integrated device sensors are continuously monitoring physical activity, heart rate variability, and parameters like the change in minute ventilation reflecting thoracic impedance that have been shown to provide clinically relevant information on the HF status of CRT patients.

Heart rate variability is an effective measure representative of the severity of HF. Therefore, improvement in heart rate variability provides evidence of favorable CRT response. LV lead location is probably one of the most important contributing factors for CRT response; therefore it is crucial to assess the LV lead position in all CRT nonresponders. Chest X-ray images posterior-anterior and lateral projection or fluoroscopy are preferred to evaluate the LV lead location. The left anterior oblique view, representative of the short-axis view of the heart, helps to classify the LV wall into anterior, anterolateral, lateral, posterolateral, and posterior LV lead positions.

The right anterior oblique view, which represents the long axis, is used to define basal, mid-ventricular, and apical lead positions. It is generally recommended to implant the LV lead in a basal to mid-lateral or posterolateral side-branch of the coronary sinus, if there is an eligible vein. However, a recent substudy published by Singh et al. Additionally, in this study, any apical LV lead location was associated with significantly higher risk of HF or death when compared to basal or mid-ventricular LV lead locations.

This helps to understand that apical pacing in CRT might induce more heterogeneity in the LV activation and more dyssynchrony, and therefore should be avoided. However, the individual activation pattern might be highly variable even in LBBB patients and also in patients with RBBB or intraventricular conduction delay; therefore, there is a rationale for individually optimized CRT during the implantation.

Graphical abstract

Cardiac resynchronization therapy patient with suboptimal, mid-anterior left ventricular lead position. A stepbystep approach 4 Assessment of ventricular dyssynchrony by new echocardiographic analyses. A stepbystep approach 5 What are the mechanisms of improvement during CRT? A stepbystep approach 6 Clinical situations where CRT is unlikely to be of therapeutic value. A stepbystep approach 7 Preimplantation checklist.

A stepbystep approach 22 How to implant a CRT system in the presence of a left superior vena cava. A stepbystep approach 23 Dilatation of the target cardiac vein by angioplasty techniques. A stepbystep approach 24 Stenting for recurrent dislodgment of the left ventricular lead. A stepbystep approach 25 Assessment of the electrical signal sensed by the left ventricular lead. A stepbystep approach 26 How to avoid stimulating the left phrenic nerve. A stepbystep approach 27 Dye extravasation and venous perforation or dissection. A stepbystep approach 28 How to avoid a cardiac vein dissection by the balloon catheter.

A stepbystep approach 29 How to remove the guiding sheath using the slitting technique. A stepbystep approach 8 Right versus leftsided approach to implant the CRT system.

A stepbystep approach 9 Right ventricular pacing in CRT. A stepbystep approach 10 How to achieve reliable sensing and pacing of the right atrium. A stepbystep approach 11 Is it safe to pace the left ventricle via a coronary sinus tributary? A stepbystep approach 12 Why perform a coronary sinus venogram before placement of the left ventricular lead?