Comparison of right- and left-sided pectoral implantation parameters with the Jewel active can cardiodefibrillator. The World Wide Jewel Investigators

Additional coils mitigate elevated defibrillation threshold in right-sided implantable cardioverter defibrillator generator placement: a simulation study

AIMS

The standard implantable cardioverter defibrillator (ICD) generator (can) is placed in the left pectoral area; however, in certain circumstances, right-sided cans may be required which may increase defibrillation threshold (DFT) due to suboptimal shock vectors. We aim to quantitatively assess whether the potential increase in DFT of right-sided can configurations may be mitigated by alternate positioning of the right ventricular (RV) shocking coil or adding coils in the superior vena cava (SVC) and coronary sinus (CS).

METHODS AND RESULTS

A cohort of CT-derived torso models was used to assess DFT of ICD configurations with right-sided cans and alternate positioning of RV shock coils. Efficacy changes with additional coils in the SVC and CS were evaluated. A right-sided can with an apical RV shock coil significantly increased DFT compared to a left-sided can [19.5 (16.4, 27.1) J vs. 13.3 (11.7, 19.9) J, P < 0.001]. Septal positioning of the RV coil led to a further DFT increase when using a right-sided can [26.7 (18.1, 36.1) J vs. 19.5 (16.4, 27.1) J, P < 0.001], but not a left-sided can [12.1 (8.1, 17.6) J vs. 13.3 (11.7, 19.9) J, P = 0.099). Defibrillation threshold of a right-sided can with apical or septal coil was reduced the most by adding both SVC and CS coils [19.5 (16.4, 27.1) J vs. 6.6 (3.9, 9.9) J, P < 0.001, and 26.7 (18.1, 36.1) J vs. 12.1 (5.7, 13.5) J, P < 0.001].

CONCLUSION

Right-sided, compared to left-sided, can positioning results in a 50% increase in DFT. For right-sided cans, apical shock coil positioning produces a lower DFT than septal positions. Elevated right-sided can DFTs may be mitigated by utilizing additional coils in SVC and CS.

Safety and Long-term Outcomes of Defibrillator Therapy in Patients With Right-Sided Implantable Cardiac Devices in Adults With Congenital Heart Disease

BACKGROUND

Implantable cardioverter-defibrillators (ICDs) have been proven to prevent sudden cardiac death in adult congenital heart disease (ACHD) patients. Although the left side is chosen by default, implantation from the right side is often required. However, little is known about the efficacy and safety of right-sided ICDs in ACHD patients.

METHODS

In this study we reviewed a total of 191 ACHD patients undergoing ICD/cardioverter resynchronisation therapy-defibrillator (CRT-D) implantation at our hospital between 2001 and 2019 (134 men and 57 women; age [mean ± standard deviation], 41.5 ± 14.8 years).

RESULTS

Twenty-seven patients (14.1%) had right-sided devices. The most common causes of right-sided implantation were persistent left superior vena cava and vein occlusion (37.0%). Although procedure time (202.8 ± 60.5 minutes vs 143.8 ± 69.1 minutes, P = 0.008) was longer and the procedural success was lower (92.6% vs 99.4%, P = 0.008) for right-sided devices, no difference in R-wave and pacing threshold were noted. Among the 47 patients (24.6%) who underwent defibrillation threshold testing (DFT), no difference in DFT was observed (25.2 ± 5.3 J vs 23.8 ± 4.1 J, P = 0.460). During the median follow-up of 42.4 months, appropriate ICD therapy was observed in 5 (18.5%) and 30 (18.3%) patients for right- and left-sided ICDs/CRTDs, respectively (P = 0.978). No significant difference was seen in complications between them.

CONCLUSIONS

Implantation of an ICD on the right side is technically challenging, but it is feasible as an alternative approach for ACHD patients with contraindications to left-sided device implantation.

The dilemma of ICD implant testing

Ventricular fibrillation (VF) has been induced at implantable cardioverter defibrillator (ICD) implant to ensure reliable sensing, detection, and defibrillation. Despite its risks, the value was self-evident for early ICDs: failure of defibrillation was common, recipients had a high risk of ventricular tachycardia (VT) or VF, and the only therapy for rapid VT or VF was a shock. Today, failure of defibrillation is rare, the risk of VT/VF is lower in some recipients, antitachycardia pacing is applied for fast VT, and vulnerability testing permits assessment of defibrillation efficacy without inducing VF in most patients. This review reappraises ICD implant testing. At implant, defibrillation success is influenced by both predictable and unpredictable factors, including those related to the patient, ICD system, drugs, and complications. For left pectoral implants of high-output ICDs, the probability of passing a 10 J safety margin is approximately 95%, the probability that a maximum output shock will defibrillate is approximately 99%, and the incidence of system revision based on testing is < or = 5%. Bayes' Theorem predicts that implant testing identifies < or = 50% of patients at high risk for unsuccessful defibrillation. Most patients who fail implant criteria have false negative tests and may undergo unnecessary revision of their ICD systems. The first-shock success rate for spontaneous VT/VF ranges from 83% to 93%, lower than that for induced VF. Thus, shocks for spontaneous VT/VF fail for reasons that are not evaluated at implant. Whether system revision based on implant testing improves this success rate is unknown. The risks of implant testing include those related to VF and those related to shocks alone. The former may be due to circulatory arrest alone or the combination of circulatory arrest and shocks. Vulnerability testing reduces risks related to VF, but not those related to shocks. Mortality from implant testing probably is 0.1-0.2%. Overall, VF should be induced to assess sensing in approximately 5% of ICD recipients. Defibrillation or vulnerability testing is indicated in 20-40% of recipients who can be identified as having a higher-than-usual probability of an inadequate defibrillation safety margin based on patient-specific factors. However, implant testing is too risky in approximately 5% of recipients and may not be worth the risks in 10-30%. In 25-50% of ICD recipients, testing cannot be identified as either critical or contraindicated.

Comparison of defibrillation efficacy and survival associated with right versus left pectoral placement for implantable defibrillators

The preferred location for an implantable cardioverter-defibrillator (ICD) generator is the left pectoral region as a result of the shock vector formed by the active can and the lead system. However, a right pectoral site is necessary when left-sided implantation is contraindicated. The Low Energy Safety Study was a prospective, randomized trial conducted to assess chronic defibrillation efficacy in 627 patients, including 37 (5.9%) who received right pectoral implants and 590 (94.1%) who received left pectoral implants. Patients were followed for a mean of 24 +/- 13 months. There were no significant differences observed between patients who received left versus right pectoral implants in age, gender, indications, New York Heart Association classification, or ejection fraction. Patients who received a right pectoral implant had higher defibrillation thresholds at implantation (10.6 +/- 3.8 J) than those who received a left pectoral implant (8.9 +/- 4.2 J, p = 0.01) despite similar shock impedances. The conversion efficacy for spontaneous arrhythmia episodes among patients who received right and left pectoral implants were not significantly different (33 of 33 [100%] vs 255 of 263 [97%], respectively; p = 0.31). In addition, the conversion efficacy for induced ventricular fibrillation episodes were also similar (187 of 188 [99%] on the right vs 2429 of 2475 [98%] on the left, p = 0.18). However, the all-cause mortality rate was higher for patients who received right-sided implants (hazard ratio 1.93, p <0.004). In conclusion, defibrillation thresholds are higher with right pectoral implants compared with left-sided implants, but with a proper energy safety margin, there are no significant differences in spontaneous or induced shock conversion efficacy. However, the near doubling of the mortality rate among patients with right-sided implants needs to be considered when recommending such device therapy.

Implantation of a biventricular pacing and defibrillator device via a persistent left superior vena cava

A persistent left superior vena cava was discovered in a 66-year-old man with heart failure undergoing implantation of a biventricular pacing and defibrillator device. An active fixation right ventricular defibrillator lead was placed through a curved guiding catheter. A sub-selection catheter and a guidewire allowed the engagement of a posterior-lateral branch of the coronary sinus, performance of an angiogram without an occlusive balloon, and optimal lead placement. The right atrial lead was positioned using a standard stylet. Despite the technical challenges, implantation of a biventricular pacing and defibrillator device via a persistent left superior vena cava is safe and feasible.

Active-can implantable cardioverter defibrillator placement from a femoral approach

This report describes a case of an active-can ICD placed in the thigh. A 74-year-old man on chronic renal dialysis had no venous access from cephalic, subclavian, or jugular approaches. Using long active-fixation leads the device was placed from a femoral approach with good sensing, pacing, and defibrillation parameters.

Left superior vena cava persistence in patients undergoing pacemaker or cardioverter-defibrillator implantation: a 10-year experience

OBJECTIVE

The persistence of a left superior vena cava (LSVC) has been observed in 0.3% of the general population as established by autopsy. In the adult population, it is an important anatomic finding if a left superior approach to the heart is considered. The aim of the study was to evaluate the prevalence of a LSVC in patients undergoing pacemaker (PM) and cardioverter-defibrillator (CD) implantation.

DESIGN

We observed the prevalence of LSVC during a 10-year period; each patient undergoing PM or transvenous CD implantation received a left cephalic/left subclavian venous approach to the heart. With this technique, LSVC persistence is easily diagnosed during lead placement.

RESULTS

A total of 1,139 patients consecutively underwent PM implantation during 10 years: 4 patients had persistent LSCV (0.34%). Among 115 patients undergoing CD implantation, 2 patients with LSVC (1.7%) were observed. Overall LSVC persistence was found in 6 of 1,254 patients (0.47%). Two patients, one of whom had no right superior vena cava (RSVC), received a left-sided PM, whereas two other patients received right-sided devices. Both CD patients received a left-sided active-can device: the first patient with a right-sided lead tunneled to the left pectoral pocket, as a result of poor catheter handling through the LSVC and coronary sinus, and the second patient with a screw-in lead from LSVC. Long-term follow-up of these patients (average +/- SD, 41 +/- 26 months) revealed absence of lead dislodgment and appropriate device function regardless of lead implantation site.

CONCLUSIONS

Persistence of LSVC in adults undergoing PM/CD implantation is similar to that of the general population (0.47% in our study). The left-sided implant can be achieved by stylet shaping and by use of active fixation leads in most patients, with a reliable outcome at short term in addition to appropriate device performance at follow-up. Assessment of the RSVC is advisable when planning a right-sided implantation, since a minority of patients lacks this vessel.

Placement of a defibrillation lead in the left subclavian vein from the right cephalic vein

This case report highlights the feasibility and stability of transvenous placement of a second defibrillation lead in the left subclavian vein from a right cephalic vein approach. This was undertaken in a right-sided implant of an active can cardioverter defibrillator to lower defibrillation thresholds that would have otherwise precluded implant.

Increased defibrillation threshold with right-sided active pectoral can

The aim of this study was to identify the optimal position on the chest wall to place an implant able cardioverter defibrillator in a two-electrode system, consisting of a right ventricular electrode and active can.

METHODS AND RESULTS

Defibrillation thresholds (DFT) were measured in 10 anaesthetised pigs (weight 33-45 kg). An Angeflextrade mark lead was introduced transvenously to the right ventricular apex. The test-can (43 cc) was implanted submuscularly in each of four locations: left pectoral (LP), right pectoral (RP), left lateral (LL) and apex (A). The sequence in which the four locations were tested was randomized. Ventricular fibrillation (VF) was induced using 60 Hz alternating current. Rectangular biphasic shocks were delivered 10 seconds after VF induction. The DFT was measured using a modified four-reversal binary search. The results of the four configurations were: LP, 14.6+/- 4.0 J; RP, 18.8+/- 4.2 J; LL, 14.7+/- 4.1 J; A, 14.9+/- 3.1 J. Repeated measures analysis of variance showed that the DFT of RP was significantly higher than LP, LL and A (p < 0.05).

CONCLUSIONS

Implanting an active can in the RP position increases the DFT by 29% compared to LP, LL and A sites. The can position on the left thorax does not appear to have a significant influence on DFT.

Failure of left-sided implantable cardioverter defibrillator implantation due to absence of left brachiocephalic vein

Implantation of an implantable cardioverter defibrillator by the transvenous approach was impossible from the left side in a patient with on absence of the left brachiocephalic vein; the left subclavian vein was connected by a large left superior intercostal vein to the accessory hemiazygos vein that joined the azygos vein; then the blood flowed into the superior vena cava. Implantation was successfully attempted using the right-sided venous access.