Non-invasive electrical synchrony method to guide para-hisian stimulation implant technique

Introduction

Right ventricular apex stimulation solves electrical disorder but electrical disynchrony can be generated. Left bundle branch block results in heart failure and device upgrade is needed in some cases. Para-hisian stimulation generates a physiological cardiac activation through normal conduction system. Sheaths and special leads are used with current techniques. We developed an implantation technique guided by non-invasive electric synchrony using conventional screw-in leads. Synchromax is a novel device used to evaluate non-invasive cardiac electrical synchrony. It is easy to understand, fast to obtain, non-invasive and reproducible. Synchromax was analyzed in previous studies and correlated with other methods.

Objective

Usefulness and safety of non-invasive cardiac electrical synchrony method using conventional screw-in leads to guide para-hisian device implantation.

Materials and methods

421 patients were evaluated. All patients had indication of ventricular stimulation (pacemaker and ICD). Non-invasive electrical synchrony was performed with Synchromax study during the device implantations in all patients. Synchrony index and curves were analyzed. Type 2 curve and index between 0,1 and 0,4 were considered synchronous. Type 8 curve and index more than 0.7 were considered dyssynchronous. Attempt numbers, thresholds, fluoroscopy time and dislodgments were analyzed.

Results

Mean age 69 years (±8 years). 67,9% males. 421 devices were implanted (334 pacemakes and 87 ICDs). Sick sinus syndrome was the main pacemaker aetiology and dilated cardiomyopathy was in patients with ICD. Conventional screw-in leads were used in all cases. An implant technique was designed. A J-shaped curve with a small perpendicular curve at the tip is performed in the stylet. On average 1,9 attempts were made. Thresholds average 1,2 mV. High thresholds in 4 patients with selective parahisian stimulation. 7 dislodgments was evidenced (1,6%). Fluoroscopy time average 8,4 min. Type 2 curve and index under 0,4 was obtained in 94,5% of cases.

Conclusions

Para-hisian pacemaker implantation guided by Synchromax method using conventional screw-in leads is safe and useful achieving a physiological stimulation. Few attempts were needed with this new technique. Thresholds were similar to those used in conventional technique.

Funding Acknowledgement

Type of funding source: None

A novel non-invasive electrical synchrony method to improve cardiac resynchronization therapy responders

Introduction

Cardiac resynchronization therapy (CRT) has emerged as an important treatment for patients with heart failure and reduced ejection fraction (EF) despite optimal pharmacological therapy. Some studies showed non-responders rate near 30%. Nowaday there is no gold standard method for selection, evaluation and follow up on this group of patients. Multiple techniques used and operator dependence made echocardiogram failed. Synchromax 2 is a device designed to evaluate non-invasive electrical synchrony. It is fast, reproducible and non-operator dependent. Synchromax was evaluated and correlated with other techniques in previous studies.

Objective

Evaluate CRT response rate guided by electrical synchrony during the device implantation and follow up.

Material and methods

43 patients were evaluated in an institution in Buenos Aires. A ICD-CRT was implanted in all patients due dilated cardiomyopathy, low EF (less than 35%) and left bundle branch block (LBBB). Non-invasive electrical synchrony evaluation (Synchromax 2) was performed in all patients in baseline condition, during device implantation and the follow up. Synchrony index and curves were analyzed. Curve type 4 and index between 0,4 and 0,7 were considered synchronous. Curve type 6 and 10 and index more than 0.7 were considered disynchronous. Interventricular intervals were modified to achieve the best curve and synchrony index. Super responders were considered when EF increased >50%. Baseline and 6 month after implantation echocardiogram were performed.

Results

Mean age 64 years. 39% females. Non-coronary dilated cardiomyopathy was main aetiology (63,1%). EF baseline average was 27%. A baseline index more than 0,7 was in 73,3% of the patients. Curve 6 was the most frequent (55,2%). Follow up average EF was 39% (increased 12%), the super responders rate was 18,6% (8 patients). Type 4 curve and index between 0,4 and 0,7 were achieved in 28 cases (65,1%). EF increased from 23% (baseline) to 42% (follow up). Average 19%. Type 4 curve was not achieved in 15 patients (34,9%). In this group, EF increased from 29% (baseline) to 34% (follow up). Average 5%.

Conclusion

Electrical synchrony evaluation using Synchromax 2 during ICD-CRT device implantation improves responders rate. When synchronous type 4 curve is achieved EF improves significantly. If type 4 curve is not found results will be unsuccessfully. Synchromax is fast, simple and non-operator dependent.

Funding Acknowledgement

Type of funding source: None

Non-selective para-hisian stimulation used for QRS normalization guided by non-invasive electrical synchrony method in patients with electrical conduction disorders

Introduction

Para-hisian stimulation produces a physiological cardiac activation through normal conduction system. Frequently it is used in patients with no electrical conduction disorders. We developed an implant technique guided by non-invasive electrical synchrony using conventional screw-in leads. Non-selective para-hisian stimulation can normalize electrical conduction disorders. Synchromax is a novel device used to evaluate non-invasive cardiac electrical synchrony. It is easy to understand, fast to obtain, non-invasive and reproducible. Synchromax was analyzed in previous studies and correlated with other methods.

Objective

Evaluate usefulness and safety of non-selective para-hisian stimulation guided by non-invasive cardiac electrical synchrony method using conventional screw-in leads to normalize electrical conduction disorders.

Materials and methods

421 patients with para-hisian stimulation were analyzed retrospectively. 139 patients had different intraventricular and auriculo-ventricular electrical disorders. Non-selective para-hisian stimulation guided by no-invasive electrical synchrony method (Synchromax) was performed in all cases. Synchrony index and curves were analyzed according curves chart. Type 2 curve and index between 0,1 and 0,4 were considered synchronous. Type 8 curve and index more than 0.7 were considered dyssynchronous.

Results

Mean age 71 years (±7 years). 65,4% males. 30,9% had 2° and 3° grade AV block associated. Patients were divided in 5 groups:

1-Right bundle branch block (RBBB): 43 patients

2-Left bundle branch block (LBBB): 33 patients

3-Brugada Syndrome: 8 patients

4-Left anterior hemi-block (LAHB) 30 patients.

5-RBBB associated with LAHB: 25 patients.

QRS normalization was achieved in 87% of the cases using non-selective para-hisian stimulation guided by Synchromax with conventional screw in leads. A ventricular approach was performed during implantation. Electrical synchrony was not solved in 13% of patients mostly in LBBB and RBBB associated with LAHB. Two dislodgments were evidenced.

Conclusions

Non-selective para-hisian stimulation guided by Synchromax method using conventional screw in leads solved most of intraventricular electrical disorders. It is also safe to use in patients with auriculo-ventricular electrical disorder.

Funding Acknowledgement

Type of funding source: None