Rationale and design of the SPICE study—septal positioning of ventricular ICD electrodes

Influence of the Right Ventricular Lead Location on Ventricular Arrhythmias in Cardiac Resynchronization Therapy

Background:

The influence of different right ventricular lead locations on ventricular arrhythmias (VTA) in patients with a cardiac resynchronization therapy (CRT) is not clear. This study aimed to evaluate the influence on VTA in patients with a CRT when right ventricular lead was positioned at the right ventricular middle septum (RVMS) and the right ventricular apical (RVA).

Methods:

A total of 352 patients implanted with a CRT-defibrillator (CRT-D) between May 2012 and July 2016 in the Department of Cardiology of Anhui Provincial Hospital were included. Two-year clinical and pacemaker follow-up data were collected to evaluate the influence of the right ventricular lead location on VTA. Patients were divided into the RVMS group (n = 155) and the RVA group (n = 197) based on the right ventricular lead position. The VTA were compared between these two groups using a Kaplan-Meier curve and Cox multivariate analysis.

Results:

When the left ventricular lead location was not considered, RVMS and RVA locations did not affect VTA. However, the subgroup analysis results showed that when the left ventricular lead was positioned at the anterolateral cardiac vein (ALCV), the RVMS group had an increased risk of ventricular arrhythmias and appropriate defibrillation (hazard ratio [HR] = 3.29, P = 0.01 and HR = 4.33, P < 0.01, respectively); when the left ventricular lead was at the posterolateral cardiac vein (PLCV), these risks in the RVMS group decreased (HR = 0.45, P = 0.02 and HR = 0.33, P < 0.01, respectively), and when the left ventricular lead was at the lateral cardiac vein, there was no difference between the two groups. In regard to inappropriate defibrillation, there was no significant difference among all these groups.

Conclusions:

When the left ventricular lead was positioned at ALCV or PLCV, the right ventricular lead location was associated with VTA and appropriate defibrillation after CRT. Greater distances between leads not only improved cardiac function but also may reduce the risk of VTA.

Right Bundle Branch Block-Like Pattern During Uncomplicated Right Ventricular Pacing and the Effect of Pacing Site

Right bundle branch block (RBBB) configuration is an unexpected finding during right ventricular (RV) pacing that raises the suspicion of inadvertent left ventricular lead positioning. The aim of this study was to evaluate the prevalence of paced RBBB pattern in relation to RV lead location. This is a secondary analysis of a prospective, multicenter study, which randomized implantable cardioverter defibrillator recipients to an apical versus midseptal defibrillator lead positioning. A 12-lead electrocardiogram was recorded during intrinsic rhythm and RV pacing. Paced RBBB-like pattern was defined as positive (>0.05 mV) net amplitude of QRS complex in leads V1 and/or V2. In total, 226 patients (65.6 ± 12.0 years, 20.8% women, 53.1% apical site) were included in the study. The prevalence of paced RBBB pattern in the total population was 15.5%. A significantly lower percentage of patients in the midseptal group demonstrated RBBB-type configuration during RV pacing compared with the apical group (1.9% vs 27.5%, p <0.001). Baseline RBBB, prolonged QRS duration during intrinsic rhythm, and reduced ejection fraction were not associated with increased likelihood of paced RBBB. In the subgroup of patients with RBBB type during pacing, 91.4% of patients had a paced QRS axis from -30° to -90°, whereas 100% of patients displayed a negative QRS vector at lead V3. In conclusion, RBBB configuration is encountered in a considerable percentage of device recipients during uncomplicated RV pacing. Midseptal lead positioning is associated with significantly lower likelihood of paced RBBB pattern compared with apical location.

A stepwise electrocardiographic algorithm for differentiation of mid-septal vs. apical right ventricular lead positioning: the SPICE ECG substudy

AIMS

Right ventricular (RV) septum is a non-apical site targeted during lead implantation. Electrocardiographic (ECG) recognition of mid-septal lead location is challenging. The aim of the study is to determine ECG correlates of RV mid-septal pacing.

METHODS AND RESULTS

The present study is a pre-specified analysis of a prospective, multicenter study, which randomized recipients of an implantable cardioverter defibrillator to an apical vs. mid-septal RV lead positioning. Following implantation, a 12-lead ECG was recorded during intrinsic rhythm and RV pacing. In total, 227 patients, 121 in the apical group (76.9% males, 67.1 ± 11.3 years) and 106 in the mid-septal group (82.1% males, age 64.7 ± 12.7 years) were included. Apically as compared with septally paced patients had significantly longer paced QRS duration (177.0 ± 25.0 vs. 170.4 ± 21.7, respectively, P = 0.03) and significantly more leftward paced QRS axis (-71.6 ± 33.3° vs. 9.4 ± 86.5°, respectively, P < 0.001). A significantly higher proportion of patients in the mid-septal as compared with the apical group displayed predominantly positive QRS in lead V6 (62.3 vs. 4.1%, P < 0.001), predominantly positive QRS in any of the inferior leads (53.8 vs. 4.1%, P < 0.001), and a QR pattern in lead aVL (53.3 vs. 3.3%, P < 0.001). These ECG correlates were incorporated in a stepwise algorithm with total sensitivity of 87% and specificity of 90% for the identification of a mid-septal lead location.

CONCLUSION

A mid-septal lead location may be identified using a simple stepwise algorithm, based on the presence of positive QRS in lead V6, positive QRS in any of the inferior leads, and a QR pattern in lead aVL.

Electrocardiographic identification of prior myocardial infarction during right ventricular pacing--effect of septal versus apical pacing

BACKGROUND

Electrocardiographic (ECG) identification of prior myocardial infarction (MI) during right ventricular (RV) pacing is of clinical importance. Proposed ECG criteria have been evaluated only during apical pacing. We evaluated the effect of pacing site on the predictive performance of ECG signs of prior MI.

METHODS

The present study is a secondary analysis of a prospective, multicenter study which randomized recipients of an implantable cardioverter defibrillator to an apical versus septal RV lead positioning. ECGs of patients with or without prior MI were analyzed for the presence of the following criteria: Cabrera sign, Chapman sign, QR pattern in leads I, aVL, V5 or V6, QR in inferior leads and notching in the descending slope of the QRS complex in inferior leads.

RESULTS

The MI group included 89 patients (55.1% apically paced), while 99 patients had no prior MI (50.5% apically paced). In the total population, the Cabrera sign presented the highest specificity (97%) and diagnostic accuracy (62.2%), with a sensitivity of 23.6%. The Cabrera sign was the only significant predictor of a prior MI [OR=9.9, (95%CI:2.8-34.5), p<0.001], among all ECG markers. Pacing site did not significantly influence the sensitivity and specificity of the Cabrera sign for detection of prior MI.

CONCLUSIONS

In our study, the Cabrera sign was the only ECG marker that predicted the presence of prior MI during ventricular paced rhythm. Septal RV lead positioning did not affect the predictive performance of the Cabrera sign.