Cardiac resynchronization therapy pacemaker implant in a patient with ARTO mitral device in situ.

The ARTO device is a percutaneous device for functional mitral regurgitation composed of a transseptal anchor and a T-bar sitting in the coronary sinus which reduce the minor axis of the mitral valve. We present a case showing the technical feasibility of an LV lead implant in patients with an ARTO device in situ.

Assessing long-term survival and hospitalization following transvenous lead extraction in patients with cardiac resynchronization therapy devices: A propensity score-matched analysis.

BACKGROUND: Longer-term outcomes of patients post transvenous lead extraction (TLE) are poorly understood in patients with cardiac resynchronization therapy (CRT) devices. OBJECTIVES: A propensity score (PS)-matched analysis evaluating outcomes post TLE in CRT and non-CRT populations was performed. METHODS: Data from consecutive patients undergoing TLE between 2000 and 2019 were prospectively collected. Patients surviving to discharge and reimplanted with the same device were included. The cohort was split depending on presence of CRT device. Associations with all-cause mortality and hospitalization were assessed by Kaplan-Meier estimates. An exploratory endpoint was evaluated whether early (<7 days) or late (>7 days) reimplantation was associated with poorer outcomes. RESULTS: Of 1005 patients included, 285 (25%) had a CRT device. Median follow-up was 57.00 [27.00-93.00] months, age at explant was 67.7 ± 12.1 years, 83.3% were male, and 54.4% had an infective indication for TLE. PS was calculated using 43 baseline characteristics. After matching, 192 CRT patients were compared with 192 non-CRT patients. In the matched cohort, no significant difference with respect to mortality (hazard ratio [HR] = 1.01, 95% confidence interval [CI] [0.74-1.39], P = .093) or hospitalization risk (HR = 1.2, 95% CI [0.87-1.66], P = .265) was observed. In the matched CRT group, late reimplantation was associated with increased mortality (HR = 1.64, [1.04-2.57], P = .032) and hospitalization risk (HR = 1.57, 95% CI [1.00-2.46], P = .049]. CONCLUSION: Outcomes of CRT patients post TLE are similarly as poor as those of non-CRT patients in matched populations. Reimplantation within 7 days was associated with better outcomes in a CRT population but was not observed in a non-CRT population, suggesting prolonged periods without biventricular pacing should be avoided.

A comparison of left ventricular endocardial, multisite, and multipolar epicardial cardiac resynchronization: an acute haemodynamic and electroanatomical study.

AIMS: Alternative forms of cardiac resynchronization therapy (CRT), including biventricular endocardial (BV-Endo) and multisite epicardial pacing (MSP), have been developed to improve response. It is unclear which form of stimulation is optimal. We aimed to compare the acute haemodynamic response (AHR) and electrophysiological effects of BV-Endo with MSP via two separate coronary sinus (CS) leads or a single-quadripolar CS lead. METHODS AND RESULTS: Fifteen patients with a previously implanted CRT system received a second temporary CS lead and left ventricular (LV) endocardial catheter. A pressure wire and non-contact mapping array were placed into the LV cavity to measure LVdP/dtmax and perform electroanatomical mapping. Conventional CRT, BV-Endo, and MSP were then performed (MSP-1 via two epicardial leads and MSP-2 via a single-quadripolar lead). The best overall AHR was found using BV-Endo pacing with a 19.6 ± 13.6% increase in AHR at the optimal endocardial site over baseline (P < 0.001). There was an increase in LVdP/dtmax with MSP-1 and MSP-2 compared with conventional CRT, but this was not statistically significant. Biventricular endocardial pacing from the optimal site was significantly superior to conventional CRT (P = 0.039). The AHR achieved when BV-Endo pacing was highly site specific. Within individuals, the best pacing modality varied and was affected by the underlying substrate. Left ventricular activation times did not predict the optimal haemodynamic configuration. CONCLUSION: Biventricular endocardial pacing and not MSP was superior to conventional CRT, but was highly site specific. Within individuals, however, different methods of stimulation are optimal and may need to be tailored to the underlying substrate.

Pulmonary vein isolation: the impact of pulmonary venous anatomy on long-term outcome of catheter ablation for paroxysmal atrial fibrillation.

BACKGROUND: Circumferential pulmonary vein (PV) isolation is the cornerstone of catheter ablation for atrial fibrillation (AF); however, PV reconnection remains problematic. OBJECTIVE: To assess the impact of PV anatomy on outcome after AF ablation. METHODS: One hundred two patients with paroxysmal AF underwent cardiac magnetic resonance (60%) or computed tomography (40%) before AF ablation. PV anatomy was classified according to the presence of common PVs, accessory PVs, PV branching pattern, and the dimensions of the PV ostia, intervenous ridges (IVRs), and the left PV-left atrial appendage ridge. RESULTS: Four discrete PVs were present in 48(47%) of the patients: a left common PV in 38(37%), a right common PV in 2(2%), an accessory right PV in 20(20%), and left PV in 4(4%). At a mean follow-up of 12 ± 4 months, 75 of 102 (74%) patients were free of recurrent AF. A LCPV was associated with an increase in freedom from AF (87% vs 66% for 4 PV anatomy; P = .03). Greater left IVR length (16.9 ± 3.5 mm vs 14.0 ± 3.0 mm; P ≤ .001) and width (1.4 ± 0.6 mm vs 1.1 ± 0.6 mm; P = .02) were associated with increased AF recurrence. After multivariate analysis, abnormal anatomy (LCPV or accessory PV) and left IVR length were found to be the only independent predictors of freedom from AF. CONCLUSIONS: Four discrete PVs are present in the minority of patients with paroxysmal AF undergoing PV isolation. The presence of a LCPV is associated with an increased freedom from AF after catheter ablation. PV anatomy may in part explain the variable outcome to electrical isolation in patients with paroxysmal AF.

The estimation of patient-specific cardiac diastolic functions from clinical measurements.

An unresolved issue in patients with diastolic dysfunction is that the estimation of myocardial stiffness cannot be decoupled from diastolic residual active tension (AT) because of the impaired ventricular relaxation during diastole. To address this problem, this paper presents a method for estimating diastolic mechanical parameters of the left ventricle (LV) from cine and tagged MRI measurements and LV cavity pressure recordings, separating the passive myocardial constitutive properties and diastolic residual AT. Dynamic C1-continuous meshes are automatically built from the anatomy and deformation captured from dynamic MRI sequences. Diastolic deformation is simulated using a mechanical model that combines passive and active material properties. The problem of non-uniqueness of constitutive parameter estimation using the well known Guccione law is characterized by reformulation of this law. Using this reformulated form, and by constraining the constitutive parameters to be constant across time points during diastole, we separate the effects of passive constitutive properties and the residual AT during diastolic relaxation. Finally, the method is applied to two clinical cases and one control, demonstrating that increased residual AT during diastole provides a potential novel index for delineating healthy and pathological cases.

Cardiac magnetic resonance-derived anatomy, scar, and dyssynchrony fused with fluoroscopy to guide LV lead placement in cardiac resynchronization therapy: a comparison with acute haemodynamic measures and echocardiographic reverse remodelling.

AIMS: Left ventricular (LV) lead positioning for cardiac resynchronization therapy (CRT) is largely empirical and operator-dependent. Our aim was to determine whether cardiac magnetic resonance (CMR)-guided CRT may improve the acute and the chronic response. METHODS AND RESULTS: CMR-derived anatomical models and dyssynchrony maps were created for 20 patients. The CMR targets (three latest activated segments with <50% scar) were overlaid on to live fluoroscopy. Acute haemodynamic response (AHR) to LV pacing was assessed using an intra-ventricular pressure wire. Chronic CRT response (end-systolic volume reduction ≥15%) was assessed 6 months post-implantation. All patients underwent successful CMR-guided LV lead placement. A CMR target segment was paced in 75% of patients. The mean change in LVdP/dtmax for the CMR target was +14.2 ± 12.5 vs. +18.7 ± 11.9% for the best AHR in any segment and +12.0 ± 13.8% for the segment based on coronary sinus (CS) venography. Using CMR guidance, the acute responder rate was 60 vs. 50% on the basis of venography. At 6 months 60% of patients were echocardiographic responders. Of the echocardiographic responders, 92% were successfully paced in a CMR target segment compared with only 50% of non-responders (P = 0.04). CONCLUSION: CMR guidance compared well when validated against the AHR. Lead placement was possible in the CMR target region in most patients with an AHR comparable with the best achieved in any CS branch. The chronic response was significantly better in patients paced in a CMR target segment. These results suggest that CMR guidance may represent a clinically useful tool for CRT.

Quad-site pacing using a quadripolar left ventricular pacing lead.

Pacing the left ventricle (LV) from multiple sites simultaneously may result in a better response to cardiac resynchronization therapy (CRT). We sought to assess whether multisite pacing using a quadripolar LV lead improves acute hemodynamic response (AHR) to CRT. We paced four ventricular sites simultaneously using two vectors of a Quartet lead, a right ventricular apical lead, and an additional LV lead temporarily placed in an anterior branch of the coronary sinus. Multisite pacing using the Quartet lead alone did not improve the AHR but "quad-site" pacing using an additional temporary LV lead did increase dP/dt(max).

Benefits of endocardial and multisite pacing are dependent on the type of left ventricular electric activation pattern and presence of ischemic heart disease: insights from electroanatomic mapping.

BACKGROUND: There is considerable heterogeneity in the myocardial substrate of patients undergoing cardiac resynchronization therapy (CRT), in particular in the etiology of heart failure and in the location of conduction block within the heart. This may account for variability in response to CRT. New approaches, including endocardial and multisite left ventricular (LV) stimulation, may improve CRT response. We sought to evaluate these approaches using noncontact mapping to understand the underlying mechanisms. METHODS AND RESULTS: Ten patients (8 men and 2 women; mean [SD] age 63 [12] years; LV ejection fraction 246%; QRS duration 161 [24] ms) fulfilling conventional CRT criteria underwent an electrophysiological study, with assessment of acute hemodynamic response to conventional CRT as well as LV endocardial and multisite pacing. LV activation pattern was assessed using noncontact mapping. LV endocardial pacing gave a superior acute hemodynamic response compared with conventional CRT (26% versus 37% increase in LV dP/dt(max), respectively; P<0.0005). There was a trend toward further incremental benefit from multisite LV stimulation, although this did not reach statistical significance (P=0.08). The majority (71%) of patients with nonischemic heart failure etiology or functional block responded to conventional CRT, whereas those with myocardial scar or absence of functional block often required endocardial or multisite pacing to achieve CRT response. CONCLUSIONS: Endocardial or multisite pacing may be required in certain subsets of patients undergoing CRT. Patients with ischemic cardiomyopathy and those with narrower QRS, in particular, may stand to benefit.

An integrated platform for image-guided cardiac resynchronization therapy.

Cardiac resynchronization therapy (CRT) is an effective procedure for patients with heart failure but 30% of patients do not respond. This may be due to sub-optimal placement of the left ventricular (LV) lead. It is hypothesized that the use of cardiac anatomy, myocardial scar distribution and dyssynchrony information, derived from cardiac magnetic resonance imaging (MRI), may improve outcome by guiding the physician for optimal LV lead positioning. Whole heart MR data can be processed to yield detailed anatomical models including the coronary veins. Cine MR data can be used to measure the motion of the LV to determine which regions are late-activating. Finally, delayed Gadolinium enhancement imaging can be used to detect regions of scarring. This paper presents a complete platform for the guidance of CRT using pre-procedural MR data combined with live x-ray fluoroscopy. The platform was used for 21 patients undergoing CRT in a standard catheterization laboratory. The patients underwent cardiac MRI prior to their procedure. For each patient, a MRI-derived cardiac model, showing the LV lead targets, was registered to x-ray fluoroscopy using multiple views of a catheter looped in the right atrium. Registration was maintained throughout the procedure by a combination of C-arm/x-ray table tracking and respiratory motion compensation. Validation of the registration between the three-dimensional (3D) roadmap and the 2D x-ray images was performed using balloon occlusion coronary venograms. A 2D registration error of 1.2 ± 0.7 mm was achieved. In addition, a novel navigation technique was developed, called Cardiac Unfold, where an entire cardiac chamber is unfolded from 3D to 2D along with all relevant anatomical and functional information and coupled to real-time device detection. This allowed more intuitive navigation as the entire 3D scene was displayed simultaneously on a 2D plot. The accuracy of the unfold navigation was assessed off-line using 13 patient data sets by computing the registration error of the LV pacing lead electrodes which was found to be 2.2 ± 0.9 mm. Furthermore, the use of Unfold Navigation was demonstrated in real-time for four clinical cases.

Percutaneous extraction of cardiac implantable electronic devices (CIEDs) in octogenarians.

BACKGROUND: As the population receiving cardiac device therapy ages, the number of extraction procedures performed in octogenarians is increasing. This group has more comorbidities and may be at higher risk of such procedures. OBJECTIVES: Document the safety and success of percutaneous lead extraction in octogenarians. METHODS: All extraction cases performed between January 2001 and April 2011 entered into a computer database were analyzed for patient characteristics and indications, extraction technique, procedural success, and complications. Success and complications were classified according to the Heart Rhythm Society consensus statement. Outcomes in octogenarians were compared to younger patients undergoing extraction during the same period. RESULTS: Four hundred and six cases were performed: 72 procedures in octogenarians (mean age 84, range 80-95) and 334 in younger adults (mean age 62, range 20-79). Octogenarians had a greater number of comorbidities per case. Infection was the commonest indication for extraction in both groups. One hundred forty-one leads were extracted in octogenarians and 657 in younger patients. Laser assistance was required in 51.4% of octogenarians versus 49.7% of younger patients. Procedural success was achieved in 71/72 (98.6%) octogenarians versus 329/334 (98.5%) younger patients. No procedural mortality occurred in either group. Overall, complications were more frequent in octogenarians with major and minor complications occurring in 2.8 and 8.3% of octogenarians versus 0.6 and 3.0% of younger patients (P = 0.014). CONCLUSIONS: Procedural success was equally high in octogenarians and younger patients. Percutaneous lead extraction can be performed effectively and safely in octogenarians and is associated with a higher complication rate but no increased mortality.

Elimination of phrenic nerve stimulation occurring during CRT: follow-up in patients implanted with a novel quadripolar pacing lead.

BACKGROUND: Phrenic nerve stimulation (PNS) occurs at follow-up in approximately 20% of patients with bipolar leads. The quadripolar Quartet model 1458Q (St. Jude Medical, Sylmar, CA, USA) left ventricular lead (LV) has four electrodes (one distal tip and three ring) capable of ten different pacing vectors which may allow reprogramming to eliminate PNS. METHODS: Forty patients underwent attempted CRT-D implantation between October 2009 and October 2010 with the Quartet lead. Pacing parameters, lead position, complications and presence of PNS were collected at implant, pre-discharge and at 3 and 6 months follow-up. RESULTS: A quadripolar LV lead was successfully implanted in 95% (38/40) of patients. During follow-up, one patient (3%) had a lead displacement requiring reposition. LV pacing parameters remained stable at 6 months follow-up (mean threshold 1.3 V at 0.6 ms and impedance 948 Ω). PNS at the time of implant was observed in 12 patients (32%) all of which were overcome by using the additional vectors available on the quadripolar LV lead or by repositioning the lead at the time of index implant. During 6 months follow-up there were five (13%) cases of PNS, all of which were successfully treated by reprogramming to a different vector. No cases required reintervention, surgical epicardial lead placement, or that lead be turned off. CONCLUSION: The quadripolar Quartet lead is associated with a high implant success rate, stable pacing parameters and a low displacement rate during the first 6 months after implant. The ten LV pacing vectors available with this lead allowed PNS and capture threshold problems to be overcome at implant, and importantly at follow-up, thus obviating the need for lead reposition.

The acute hemodynamic response to LV pacing within individual branches of the coronary sinus using a quadripolar lead.

BACKGROUND: It is not clear whether there is a large difference in acute hemodynamic response (AHR) to left ventricle (LV) pacing in different regions of the same coronary sinus (CS) vein. Using the four electrodes available on a Quartet LV lead, we evaluated the AHR to pacing within individual branches of the CS. METHODS: An acute hemodynamic study was attempted in 20 patients. In each patient, we assessed AHR in a number of CS veins and along a significant proportion of each CS branch using three different bipolar configurations. We compared the AHR achieved when pacing using each different vector and also the highest AHR achieved in any position within the same patient with the lowest achieved in that patient. RESULTS: Sixty-four different CS positions in 19 patients were successfully assessed. No significant difference in AHR was found overall between the three vectors tested. The mean percentage difference in AHR between the CS branch vectors with the lowest and highest dP/dt(max) was +6.5 ± 5.4% (P < 0.001). A much larger difference of +16.9 ± 6.1% (P < 0.001) was seen when comparing the highest and lowest AHR achieved using any vector in any position within the same patient. CONCLUSION: A small difference in AHR is seen when pacing within the same branch of the CS compared to pacing in different branches in the same patient. This suggests that although the site of LV lead placement is important, the position within a CS branch is less important than choosing the right vein.

Invasive acute hemodynamic response to guide left ventricular lead implantation predicts chronic remodeling in patients undergoing cardiac resynchronization therapy.

OBJECTIVES: We evaluated the relationship between acute hemodynamic response (AHR) and reverse remodeling (RR) in cardiac resynchronization therapy (CRT). BACKGROUND: CRT reduces mortality and morbidity in heart failure patients; however, up to 30% of patients do not derive symptomatic benefit. Higher proportions do not remodel. Multicenter trials have shown echocardiographic techniques are poor at improving response rates. We hypothesized the degree of AHR at implant can predict which patients remodel. METHODS: Thirty-three patients undergoing CRT (21 dilated and 12 ischemic cardiomyopathy) were studied. Left ventricular (LV) volumes were assessed before and after CRT. The AHR (maximum rate of left ventricular pressure [LV-dP/dt(max)]) was assessed at implant with a pressure wire in the LV cavity. Largest percentage rise in LV-dP/dt(max) from baseline (atrial antibradycardia pacing or right ventricular pacing with atrial fibrillation) to dual-chamber pacing (DDD)-LV was used to determine optimal coronary sinus LV lead position. Reverse remodeling was defined as reduction in LV end systolic volume ≥15% at 6 months. RESULTS: The LV-dP/dt(max) increased significantly from baseline (801 ± 194 mm Hg/s to 924 ± 203 mm Hg/s, p < 0.001) with DDD-LV pacing for the optimal LV lead position. The LV end systolic volume decreased from 186 ± 68 ml to 157 ± 68 ml (p < 0.001). Eighteen (56%) patients exhibited RR. There was a significant relationship between percentage rise in LV-dP/dt(max) and RR for DDD-LV pacing (p < 0.001). A similar relationship for AHR and RR in dilated cardiomyopathy and ischemic cardiomyopathy (p = 0.01 and p = 0.006) was seen. CONCLUSIONS: Acute hemodynamic response to LV pacing is useful for predicting which patients are likely to remodel in response to CRT both for dilated cardiomyopathy and ischemic cardiomyopathy. Using AHR has the potential to guide LV lead positioning and improve response rates.

Percutaneous lead and system extraction in patients with cardiac resynchronization therapy (CRT) devices and coronary sinus leads.

BACKGROUND: Cardiac resynchronization therapy (CRT) device and coronary sinus (CS) lead extraction is required due to the occurrence of system infection, malfunction, or upgrade. Published series of CS lead extraction are limited by small sample sizes. We present a 10-year experience of CRT device and CS lead extraction. METHODS: All lead extractions between 2000 and 2010 were entered into a computer database. From these, a cohort of 71 cases involving a CRT device or CS lead was analyzed for procedural method, success, and complications. RESULTS: Sixty coronary sinus leads were extracted in 71 cases (median age 71 years; 90% male) by manual traction/locking stylets (n = 54) or using a laser sheath (n = 6). Procedural success was achieved in 98% of CS leads. A total of 143 non-CS leads were extracted, with laser required in 46% of cases. The mean duration of lead implantation was 35.8 months (range 1-116 months) and 2.86 ± 1.07 leads were extracted per case. CRT extraction case load increased significantly over time. Minor complications occurred in four (5.6%) cases and major complications in one (1.4%) case. There were no intraprocedural deaths, but two deaths occurred within 30 days of extraction. CONCLUSIONS: Our 10-year experience confirms that percutaneous removal of CS leads can be achieved with high procedural success. Our recorded complication rates are no higher than those of non-CS lead extraction series, and should be taken in the context of the frail nature of CRT patients. Ongoing audit of procedure success and complications will be required to further guide best practice in CS lead extraction.

Use of a quadripolar left ventricular lead to achieve successful implantation in patients with previous failed attempts at cardiac resynchronization therapy.

AIMS: Problems with implanting a left ventricular (LV) lead during cardiac resynchronization therapy (CRT) procedures are not uncommon and may occur for a variety of reasons including phrenic nerve stimulation (PNS) and high capture thresholds. We aimed to perform successful CRT in patients with previous LV lead problems using the multiple pacing configurations available with the St Jude Quartet model 1458Q quadripolar LV lead to overcome PNS or high capture thresholds. METHODS AND RESULTS: Four patients with previous failed attempts at LV lead implantation underwent a further attempt at CRT using a Quartet lead. In all four cases, successful CRT was achieved using a Quartet lead placed in a branch of the coronary sinus. Problems with PNS or high capture thresholds were seen in all four patients but were successfully overcome. Satisfactory lead parameters were seen at implant, pre-discharge, and at short-term follow-up (8.5±5 weeks). CONCLUSION: The Quartet lead allows 10 different pacing vectors to be used and may overcome common pacing problems because of the multiple pacing configurations available. Problems with either PNS or unsatisfactory pacing parameters experienced during CRT may be resolved simply by changing the pacing configuration using this quadripolar lead system.

Initial single-center experience of a quadripolar pacing lead for cardiac resynchronization therapy.

BACKGROUND: The Quartet model 1458Q (St. Jude Medical, Sylmar, CA, USA) lead is a quadripolar left ventricular (LV) lead with pace/sense capability from four electrodes (tip and three rings). The lead is capable of pacing in 10 different configurations rather than the three that are available in conventional bipolar pacing leads. We describe a single-center initial experience of the use of this lead in patients undergoing cardiac resynchronization therapy (CRT). METHODS: Twenty-eight patients for a CRT with cardiac defibrillator were implanted between October 2009 and May 2010 with a Quartet lead . Lead position, pacing parameters, stability, complications, and presence of phrenic nerve stimulation (PNS) data were collected at implant and predischarge. Follow-up data were collected at 15 ± 8 weeks for all patients. RESULTS: A Quartet lead was successfully implanted in 96% (27/28) of patients (age 61 ± 15 years; 82% male; ischemic etiology 50%; mean left ventricular [LV] ejection fraction 25 ± 7%; left bundle branch block 68%). PNS was seen at implant in 11 patients (41%) with at least one vector. In eight of these cases (72%), the need for lead repositioning was averted by programming LV pacing utilizing the additional vectors available with the Quartet lead. CONCLUSION: These initial data suggest that pacing with the Quartet lead is associated with a high implant success rate and stable pacing parameters acutely and at short-term follow-up. The 10 LV pacing vectors available with this lead may allow PNS and capture threshold problems to be easily overcome.

Quadripolar left ventricular lead implantation through the anchor struts of a mitral valve annuloplasty device.

We describe cardiac resynchronization therapy in a patient with a mitral valve annuloplasty device in situ for functional mitral regurgitation. We successfully implanted a left ventricular lead through a mitral valve annuloplasty device anchor into the coronary sinus and then through the struts of the device's proximal anchor.