Cardiac implantable electronic device-induced tricuspid regurgitation: Implications and management.

Tricuspid regurgitation (TR) secondary to cardiac implantable electronic devices (CIEDs) has been well documented and is associated with worse cardiovascular outcomes. A variety of mechanisms have been proposed including lead-induced mechanical disruption of the tricuspid valvular or subvalvular apparatus and pacing-induced electrical dyssynchrony. Patient characteristics such as age, sex, baseline atrial fibrillation, and pre-existing TR have not been consistent predictors of CIED-induced TR. While two-dimensional echocardiography is helpful in assessing the severity of TR, three-dimensional echocardiography has significantly improved accuracy in identifying the etiology of TR and whether lead position contributes to TR. Three-dimensional echocardiography may therefore play a future role in optimizing lead positioning during implant to reduce the risk of CIED-induced TR. Optimal lead management strategies in addition to percutaneous interventions and surgery in alleviating TR are very important.

Predictors of cardiovascular implantable electronic device dependence at long-term follow-up after alcohol septal ablation in hypertrophic cardiomyopathy patients.

BACKGROUND: The most common complication of alcohol septal ablation (ASA) is transient periprocedural high-grade AV block (HGAVB). To date, no long-term follow-up of cardiovascular implantable electronic device (CIED) utilization after ASA has been reported. We hypothesized that CIED dependence on long-term follow-up can be predicted by ECG or procedural characteristics. METHODS: We analyzed all patients with HCM who underwent ASA from December 1998 to December 2019 and received their first CIED within 30 days after ASA for HGAVB. All follow-up interrogations were reviewed. CIED dependence was defined as ventricular pacing of ≥ 5%. RESULTS: A total of 138 patients with HCM underwent ASA. Of these, 35 had a prior device and were excluded. Of the remaining 103 patients, 25 patients received a CIED for HGAVB within 30 days after ASA. Average follow-up duration was 10.1 years. On long-term follow-up, 16 patients (64%) were found to be CIED-dependent. Baseline characteristics, including pre- and post-ASA ECG, were not significantly different between dependent and non-dependent patients. The only predictor for CIED dependence was > 1 ml of alcohol injected (OR 6.0, p = 0.031). CONCLUSIONS: CIED implantation after ASA is common. Almost two thirds of patients who received a CIED for post-procedural HGAVB were CIED-dependent on long-term follow-up. CIED dependence can be predicted by the amount of injected alcohol > 1 ml.

Explanting Chronic Coronary Sinus Leads.

Cardiac resynchronization therapy (CRT) has become the gold standard for patients with systolic left ventricular function, left ventricular ejection fraction less than or equal to 35%, wide complex QRS, and symptomatic heart failure. Annual implantation volume has steadily increased because of expanding indications for CRT. Improved survival resulted in many of these patients having their CRT devices for many years and eventually requiring an increased number of device-related procedures, including coronary sinus lead revisions and replacements following a coronary sinus lead extraction.

Does prior valve surgery change outcome in patients treated with cardiac resynchronization therapy?

AIMS: Cardiac valve surgery (CVS) has been implicated as a potential barrier to optimal response after cardiac resynchronization therapy (CRT) though prospective data regarding outcome remains limited. We sought to determine CRT response in patients with a prior history of CVS. METHODS AND RESULTS: We performed a retrospective analysis of a prospectively acquired cohort of CRT patients with history of CVS. Echocardiographic response was evaluated at baseline and 6 months. The coprimary endpoints were time to first heart failure (HF) hospitalization and a composite of all-cause mortality, transplantation and left ventricular assist device (LVAD) assessed over a 3-year follow-up period. The study group consisted of 569 patients undergoing CRT. Of these, 86 patients had a history of CVS (46.5% aortic, 37.2% mitral, 16.3% combined, and tricuspid), and were compared to 483 patients with no history of CVS. Baseline clinical and echocardiographic characteristics were not significantly different between the groups except for a higher incidence of atrial fibrillation (AF; 74.4% vs. 55.3%; P = 0.001), coronary artery bypass surgery (CABG; 58.1% vs. 38.7%; P = 0.001), and longer QRS duration (167.6 ± 29.3 milliseconds vs. 159.4 ± 27.5 milliseconds; P = 0.01) in those with prior CVS. Survival with respect to HF hospitalization and composite outcome was comparable in both groups. Echocardiographic response (improvement in left ventricular ejection fraction of ≥10%) was similar. No difference in clinical or echocardiographic outcome was found by type of valve surgery performed. CONCLUSION: Despite a higher incidence of AF, CABG, and longer QRS duration, history of CVS is not associated with worse clinical or echocardiographic outcome after CRT.

Pulmonary vein isolation with complex fractionated atrial electrogram ablation for paroxysmal and nonparoxysmal atrial fibrillation: A meta-analysis.

BACKGROUND: Pulmonary vein isolation (PVI) is recognized as a potentially curative treatment for atrial fibrillation (AF). Ablation of complex fractionated atrial electrograms (CFAEs) in addition to PVI has been advocated as a means to improve procedural outcomes, but the benefit remains unclear. OBJECTIVE: This study sought t synthesize the available data testing the incremental benefit of adding CFAE ablation to PVI. METHODS: We performed a meta-analysis of controlled studies comparing the effect of PVI with CFAE ablation vs. PVI alone in patients with paroxysmal and nonparoxysmal AF. RESULTS: Of the 481 reports identified, 8 studies met our inclusion criteria. There was a statistically significant increase in freedom from atrial tachyarrhythmia (AT) with the addition of CFAE ablation (relative risk [RR] 1.15, P = .03). In the 5 reports of nonparoxysmal AF (3 randomized controlled trials, 1 controlled clinical trial, and 1 trial using matched historical controls), addition of CFAE ablation resulted in a statistically significant increase in freedom from AT (n = 112 of 181 [62%] for PVI+CFAE vs. n = 84 of 179 [47%] for PVI alone; RR 1.32, P = .02). In trials of paroxysmal AF (3 randomized controlled trials and 1 trial using matched historical controls), addition of CFAE ablation did not result in a statistically significant increase in freedom from AT (n = 131 of 166 [79%] for PVI+CFAE vs. n = 122 of 164 [74%] for PVI alone; RR 1.04, P = .52). CONCLUSION: In these studies of patients with nonparoxysmal AF, addition of CFAE ablation to PVI results in greater improvement in freedom from AF. No additional benefit of this combined approach was observed in patients with paroxysmal AF.

Catheter ablation of atrial fibrillation the search for substrate-driven end points.

Indications for catheter ablation of atrial fibrillation (AF) have expanded to include increasingly complex cases, such as long-standing persistent AF and structural heart disease. Although pulmonary vein isolation remains essential for most ablation procedures, the role of substrate modification has taken on increasing importance. Despite the various ablation strategies available, single-procedure efficacy remains suboptimal among patients with structural heart disease or long-standing persistent AF, where recurrence rates may exceed 50% after a single procedure. These high rates of AF recurrence support the notion that currently available procedural end points are ineffective in identifying which patients are most likely to benefit from substrate modification and defining when that substrate has been sufficiently modified such that additional ablation is unnecessary. In order to improve outcomes, the next generation of procedural end points should seek to define specific properties of the underlying atrial electrical substrate and characterize the impact of catheter ablation on those electrophysiologic properties. The use of substrate-driven end points would be a major step in the process of moving from empiric ablation lesions to a customized ablation strategy based on atrial physiology. In this article, we review current approaches to catheter ablation of AF and discuss specific procedural end points as they pertain to each ablation strategy. We also provide a paradigm for the future development of novel substrate-driven procedural end points.

Impact of tricuspid regurgitation and prior coronary bypass surgery on the geometry of the coronary sinus: a rotational coronary angiography study.

INTRODUCTION: The coronary sinus (CS) is often distorted in patients with advanced cardiomyopathy, making CS cannulation difficult. The objective of this study was to examine the impact of the underlying cardiac pathology on the variability of the CS anatomy, using rotational coronary venous angiography (RCVA). METHODS AND RESULTS: Seventy-nine patients undergoing RCVA for cardiac resynchronization therapy (CRT) were evaluated: age 63 +/- 15 years, 43% with prior coronary artery bypass grafting (CABG). Aspects of the CS anatomy which could impact cannulation were examined: the CS ostial angle, the posterior displacement of the CS away from the atrioventricular groove, a measure of CS curvature, and the presence of stenoses and aneurysmal dilatations. The CS ostial angle was variable (65-151 degrees, mean 119 +/- 19 degrees, <90 degrees in 8 patients) and decreased significantly (P = 0.0022) with increasing severity of tricuspid regurgitation (TR), reaching 94 +/- 18 degrees in patients with severe TR. The posterior displacement of the CS was significantly more accentuated in patients with prior CABG when compared with the patients without CABG (7.1 +/- 3.7 vs 4.5 +/- 2.8 mm; P = 0.0246). The decrease in luminal diameter at the CS-great cardiac vein (GCV) junction was 2.0 +/- 1.0 mm, being more pronounced in patients with prior CABG versus nonCABG (26 vs 20%; P = 0.042). Stenoses and aneurysmal dilatations of the CS-GCV were encountered in 4 (5%) and 6 (8%) of patients, respectively, all of them with prior CABG, representing 12% and 18% of the CABG group. CONCLUSION: The CS anatomy in patients undergoing CRT is variable, and is impacted by the severity of the underlying TR and history of a prior CABG.

Effect of presenting rhythm on image integration to direct catheter ablation of atrial fibrillation.

INTRODUCTION: Magnetic resonance (MR) imaging of the left atrium (LA) can be integrated with electroanatomic mapping systems to guide catheter ablation of atrial fibrillation (AF). The usefulness of this technique is dependent on the accuracy of image integration. OBJECTIVE: The aim of this study is to determine the effect of heart rhythm at the time of pre-procedure MR imaging and heart rhythm at the time of ablation on integration error. METHODS: Fifty-two consecutive patients who underwent catheter ablation for AF were included. All patients underwent MR imaging of LA and pulmonary veins and image integration with real-time electroanatomic mapping. The rhythm at the time of MR imaging and on the day of ablation was recorded. CARTO-Merge software (Biosense-Webster) was used to calculate the average accuracy of integration of electroanatomic points with MR-derived reconstructions. RESULTS: There was no significant difference in integration error between patients who were in AF at the time of their MR vs. those who were in sinus rhythm at the time of their MR (1.76 +/- 0.26 vs. 1.88 +/- 0.31 mm, p = 0.15). There was also no significant difference in integration error between patients who were in concordant vs. discordant rhythms at the time of MR vs. day of ablation (1.81 +/- 0.23 vs. 1.89 +/- 0.32 mm, p = 0.40). There was a trend toward less integration error between patients who were in AF on the day of ablation vs. those in sinus rhythm (1.74 +/- 0.26 vs. 1.89 +/- 0.31 mm, p = 0.07). CONCLUSIONS: Image integration can be performed to direct catheter ablation of AF regardless of the rhythm at the time of imaging and ablation.

Short PR interval in the absence of preexcitation: a characteristic finding in a patient with Fabry disease.

Fabry disease (FD) is a rare lysosomal storage disease characterized by intracellular deposition of glycosphingolipids that can involve various organs including the heart. Here, we report the finding of a short PR interval in a patient with FD and recurrent syncope associated with short atrial-His (A-H) and His-ventricular (H-V) intervals in the absence of preexcitation. While electrocardiographic abnormalities are not uncommon among FD patients, there have been few reports on electrophysiological studies performed on these patients. The exact mechanism for the short A-H and H-V intervals remains unclear, but they may result from accelerated conduction in the AV node-His-Purkinje system.

Atrial tachycardia after ablation of persistent atrial fibrillation: identification of the critical isthmus with a combination of multielectrode activation mapping and targeted entrainment mapping.

BACKGROUND: Atrial tachycardia (AT) that develops after ablation of atrial fibrillation often poses a more difficult clinical situation than the index arrhythmia. This study details the use of an impedance-based electroanatomic mapping system (Ensite NavX) in concert with a specialized multielectrode mapping catheter for rapid, high-density atrial mapping. In this study, this activation mapping was combined with entrainment mapping to eliminate ATs developing late after atrial fibrillation ablation. METHODS AND RESULTS: All study patients developed AT after ablation for atrial fibrillation. The approach to AT ablation consisted of 4 steps: use of a 20-pole penta-array catheter to map the chamber rapidly during the rhythm of interest, analysis of the patterns of atrial activation to identify wave fronts of electric propagation, targeted entrainment at putative channels, and catheter ablation at these "isthmuses." All ablations were performed with irrigated radiofrequency ablation catheters. Forty-one ATs were identified in 17 patients (2.4+/-1.6 ATs per patient). Using the multielectrode catheter in conjunction with the Ensite NavX system, we created activation maps of 33 of 41 ATs (81%) (mean cycle length, 284+/-71 seconds) with a mean of 365+/-108 points per map and an average mapping time of 8+/-3 minutes. Of the 33 mapped ATs, 7 terminated either spontaneously or during entrainment maneuvers. Radiofrequency energy was used to attempt ablation of 26 ATs; 25 of 26 of the ATs (96%) were terminated successfully by ablation or catheter pressure. CONCLUSIONS: This study demonstrates a strategy for rapidly defining and eliminating the scar-related ATs typically encountered after ablation of atrial fibrillation.

Increased incidence of subacute lead perforation noted with one implantable cardioverter-defibrillator.

BACKGROUND: The rapid evolution of implantable cardioverter-defibrillator (ICD) leads has resulted in thinner active fixation leads. While these advances have made the leads more versatile, new configurations may be associated with unforeseen complications. OBJECTIVE: The purpose of this study was to determine the incidence of perforation and dislodgement of defibrillator leads in a single center in the year 2005. METHODS: All patients who underwent percutaneous ICD implantation at the Massachusetts General Hospital using an endocardial right ventricular lead were included in this study. The specific leads analyzed were the Riata (1580/1581 and 1590/1591, St. Jude Medical, St Paul, Minnesota, USA;) and Sprint Fidelis (6949-65, Medtronic, Minneapolis, Minnesota, USA.). Information was collected retrospectively. RESULTS: A total of 130 Riata leads and 111 Sprint Fidelis leads were implanted at the Massachusetts General Hospital during this time period. A total of five lead perforations occurred in patients implanted with the Riata lead as compared with none with the Sprint Fidelis lead (3.8% vs. 0%, respectively; P <.05). Two of the five patients with perforation required pericardiocentesis for tamponade. Clinical symptoms of perforation developed 1-10 days after implant. Moreover, there were five additional lead revisions in the Riata group, which were likely due to dislodgement and/or microperforation, as compared with none in the Sprint Fidelis group (7.7% vs. 0%, respectively; P <.005). CONCLUSIONS: In 2005, at one institution, there were significantly more cardiac perforations and lead revisions with the Riata lead as compared with the Sprint Fidelis right ventricular defibrillator lead. Further data are required to determine whether certain lead characteristics are responsible for this observation.

Fungal infection of implantable cardioverter-defibrillators: case series of five patients managed over 22 years.

BACKGROUND: With the increasing use of implantable cardioverter-defibrillators (ICDs), device complications are becoming more common. Fungal-related ICD infections have rarely been reported, and little is known about the presentation, prevalence, and treatment options for these morbid infections. OBJECTIVES: The purpose of this study was to characterize the clinical features, treatment, and outcomes of patients with fungal ICD infections. METHODS: We performed a retrospective review of ICD procedures performed at a single academic center and identified all ICD-related infections managed between 1983 and 2005. RESULTS: Among a total of 3,648 ICD-related procedures performed between 1983 and 2005, we identified 47 (1.3%) cases of ICD infections, of which 5 (0.1%) were due to a fungal pathogen. Fungal infections were more likely to be associated with abdominal devices, to have a local rather than systemic infection, and to have a longer duration from the original implant to presentation. All patients were treated with ICD system explantation and antifungal therapy. CONCLUSION: Fungal infection of ICDs is a rare but serious complication of device implantation that must be treated aggressively with complete hardware explantation and prolonged antifungal therapy. Because most infections are late complications and have indolent onsets, a high level of clinical suspicion is required for early diagnosis.

Factors affecting error in integration of electroanatomic mapping with CT and MR imaging during catheter ablation of atrial fibrillation.

OBJECTIVE: Integration of 3-D electroanatomic mapping with Computed Tomographic (CT) and Magnetic Resonance (MR) imaging is gaining acceptance to facilitate catheter ablation of atrial fibrillation. This is critically dependent on accurate integration of electroanatomic maps with CT or MR images. We sought to examine the effect of patient- and technique-related factors on integration accuracy of electroanatomic mapping with CT and MR imaging of the left atrium. MATERIALS AND METHODS: Sixty-one patients undergoing catheter-based atrial fibrillation (AF) ablation procedures were included. All patients underwent cardiac CT (n = 11) or MR (n = 50) imaging, and image integration with real-time electroanatomic mapping of the aorta and left atrium (LA). CARTO-Merge software (Biosense-Webster) was used to calculate the overall average accuracy of integration of electroanatomic points with the CT and MR-derived reconstructions of the LA and aorta. RESULTS: There was a significant correlation between LA size assessed by electroanatomic mapping (112 +/- 31 ml) and average integration error (1.9 +/- 0.6 mm) (r = 0.46, p = 0.0003). There was also greater integration error for patients with LA volume >/= 110 ml (n = 31) versus < 110 ml (n = 30) (p = 0.004). In contrast, there was no significant association between average integration error and paroxysmal versus persistent AF, left ventricular ejection fraction, days from imaging to electroanatomic mapping, or images derived from CT versus MR. CONCLUSIONS: Patients with larger LA volume may be prone to greater error during integration of electroanatomic mapping with CT and MR imaging. Strategies to reduce integration error may therefore be especially useful in patients with large LA volume.

Utility of implantable cardioverter defibrillator electrograms to estimate repolarization alternans preceding a tachyarrhythmic event.

Electrical alternans is a pattern of variation in the shape of the ECG waveform that appears on an every-other-beat basis. In humans, alternation in ventricular repolarization, namely, repolarization alternans, has been associated with increased vulnerability to ventricular tachycardia/ventricular fibrillation and sudden cardiac death. This study investigates the utility of implantable cardioverter defibrillator electrograms to estimate repolarization alternans preceding a tachyarrhythmic event. It is demonstrated that microvolt-level repolarization alternans is present prior to an arrhythmic event, and one can record low-amplitude-noise signals that can be used to obtain reliable estimates of repolarization alternans. This study eventually may lead to new methods that would prevent the onset of malignant tachyarrhythmias.