Fibroplasty (venoplasty) to facilitate transvenous lead placement: A single-center experience.

INTRODUCTION: Venous stenosis is a well-recognized complication of transvenous leads (TVLs) that is encountered during lead revisions or device upgrades. We here report the outcomes of TVL placement facilitated by fibroplasty or tunneling (TUN) procedure. METHODS: We conducted a single-center retrospective cohort study of all patients undergoing TVL implantation requiring fibroplasty or TUN from 2005 to 2017. Medical records and procedure reports were reviewed for relevant data. Outcomes for fibroplasty and TUN to facilitate TVL placement were compared. RESULTS: Sixty patients had fibroplasty and thirty-five patients had a TUN procedure. There was no difference in procedure success rates between the two groups (97% fibroplasty vs. 100% TUN; p = .98). The fluoroscopy time was longer (fibroplasty = 39.7 ± 21.5 min vs. TUN = 29.2 ± 21.3 min; p = .01) and the total procedural time was shorter in the fibroplasty group (fibroplasty = 247 ± 77.8 min vs. TUN = 287 ± 77.1 min; p = .01). TUN was associated with a significantly higher incidence of acute complications (fibroplasty = 0 vs. TUN = 8; p = .002) most requiring invasive intervention and/or transfusion with blood products. Long-term complications requiring additional device-related procedures were comparable between the two groups (fibroplasty = 6 vs. TUN = 6; logrank p = .21). CONCLUSIONS: For patients with venous stenosis requiring additional TVL, balloon fibroplasty is associated with similar rates of success and a significantly decreased incidence of acute complications when compared with subcutaneous TUN.

Super-response to cardiac resynchronization therapy reduces appropriate implantable cardioverter defibrillator therapy.

Aims: To determine the frequency of implantable cardioverter defibrillator (ICD) therapy following cardiac resynchronization therapy (CRT-D) implantation in super and non-super responders and whether greater improvement in left ventricular (LV) function after CRT is associated with a reduced burden in ICD therapy. Methods and results: This is a two-centre, retrospective study between January 2002 and September 2011. Patients were classified as non-super responders and super-responders based on the post-CRT ejection fraction (EF) of < 50% and ≥50%, respectively. Of 629 recipients of CRT-D, 37 (5.9%) were super-responders. Implantable cardioverter defibrillator follow-up was available for a mean duration of 6.2 ± 2.7 years. The 5-year rate of antitachycardia pacing (ATP) in super-responders was significantly lower than in non-super responders (2.7% vs. 22.1%, P = 0.004). Super-responders also had a lower 5-year rate of appropriate ICD shock compared with non-super responders (2.7% vs. 14.3%, P = 0.03). On multivariable analysis, factors associated with appropriate ICD therapy (ICD shock/ATP) include male gender (hazard ratio, HR 1.97, 95% confidence interval, 95% CI 1.15-3.35), secondary prevention indication (HR 2.09, 95% CI 1.13-3.85), increased baseline LV end-systolic diameter (HR 1.03 per mm, 95% CI 1.01-1.06) and higher baseline EF (HR 1.03 per %, 95% CI 1.00-1.06) while super-responder status was highly protective (HR 0.13, 95% CI 0.02-0.91). Conclusion: Recipients of CRT-D that normalize their EF have very low rates of ventricular arrhythmias requiring appropriate ICD therapy compared with those that do not.

Right Parasternal Lead Placement Increases Eligibility for Subcutaneous Implantable Cardioverter Defibrillator Therapy in Adults With Congenital Heart Disease.

BACKGROUND: The subcutaneous implantable cardioverter defibrillator (S-ICD) provides an attractive option for patients with congenital heart disease (CHD) in whom a transvenous defibrillator is contraindicated. Given the unusual cardiac anatomy and repolarization strain, the surface electrocardiogram (ECG) is frequently abnormal, potentially increasing the screen failure rate. METHODS AND RESULTS: We prospectively screened 100 adult CHD patients regardless of the presence of clinical indication for ICD utilizing a standard left sternal lead placement, as well as a right parasternal position. Baseline patient and 12-lead ECG characteristics were examined to assess for predictors of screen failure. Average patient age was 48±14 years, average QRS duration was 134±37 ms, and 13 patients were pacemaker dependent. Using the standard left parasternal electrode position, 21 patients failed screening. Of these 21 patients with screen failure, 9 passed screening with the use of right parasternal electrode positioning, reducing screening failure rate from 21% to 12%. QT interval and inverted T wave anywhere in V2-V6 leads were found to be independent predictors of left parasternal screening failure (P=0.01 and P=0.04, respectively). CONCLUSIONS: Utilization of both left and right parasternal screening should be used in evaluation of CHD patients for S-ICD eligibility. ECG repolarization characteristics were also identified as novel predictors of screening failure in this group. (Circ J 2016; 80: 1328-1335).

Predictors and outcomes of "super-response" to cardiac resynchronization therapy.

BACKGROUND: Cardiac resynchronization therapy (CRT) has been shown to improve heart failure (HF) symptoms and survival. We hypothesized that a greater improvement in left-ventricular ejection fraction (LVEF) after CRT is associated with greater survival benefit. METHODS AND RESULTS: In 693 patients across 2 international centers, the improvement in LVEF after CRT was determined. Patients were grouped as non-/modest-, moderate-, or super-responders to CRT, defined as an absolute change in LVEF of ≤5%, 6-15%, and >15%, respectively. Changes in New York Heart Association (NYHA) functional class and left ventricular end-diastolic dimension (LVEDD) were assessed for each group. There were 395 non-/modest-, 186 moderate-, and 112 super-responders. Super-responders were more likely to be female and to have nonischemic cardiomyopathy, lower creatinine, and lower pulmonary artery systolic pressure than non-/modest- and moderate-responders. Super-responders were also more likely to have lower LVEF than non-/modest-responders. There was no difference in NYHA functional class, mitral regurgitation grade, or tricuspid regurgitation grade between groups. Improvement in NYHA functional class (-0.9 ± 0.9 vs -0.4 ± 0.8 [P < .001] and -0.6 ± 0.8 [P = .02]) and LVEDD (-8.7 ± 9.9 mm vs -0.5 ± 5.0 and -2.4 ± 5.8 mm [P < .001 for both]) was greatest in super-responders. Kaplan-Meier survival analysis revealed that super-responders achieved better survival compared with non-/modest- (P < .001) and moderate-responders (P = .049). CONCLUSIONS: Improvement in HF symptoms and survival after CRT is proportionate to the degree of improvement in LV systolic function. Super-response is more likely in women, those with nonischemic substrate, and those with lower pulmonary artery systolic pressure.

Effects of atrioventricular conduction delay on the outcome of cardiac resynchronization therapy.

BACKGROUND AND PURPOSE: First-degree atrioventricular (AV) block in relation to the outcome of cardiac resynchronization therapy (CRT) has not been well examined. METHODS: Patients who received a CRT defibrillator or pacemaker between January 2002 and September 2010 at Mayo Clinic were classified into 2 groups: normal PR interval and prolonged PR interval. Standard sensed (100 milliseconds) and paced (130 milliseconds) AV delay was programmed after CRT. Clinical presentations and echocardiography were assessed before CRT and at a median of 6 months after CRT. RESULTS: The normal PR interval group (n=199) had greater improvements in heart failure functional class (mean [SD], 0.7 [0.8] vs 0.5 [0.9]; P=.03) and left ventricular ejection fraction (9.4% [12.4%] vs 5.9% [9.5%]; P=.007) than the prolonged PR group (n=204). CONCLUSION: Compared with prolonged PR interval, the presence of normal PR interval was associated with a greater improvement in heart failure.

Outcomes of cardiac resynchronization therapy in the elderly.

BACKGROUND: Octogenarians (>80 years) have been underrepresented in clinical trials of cardiac resynchronization therapy (CRT). OBJECTIVE: To determine the benefit of CRT with or without a defibrillator in older elderly patients. METHODS: We retrospectively studied consecutive patients who received CRT at our institution from 2002 through 2008. New York Heart Association (NYHA) class and echocardiographic parameters were assessed before and after CRT. Thirty-day complications after device implant were collected. Survival data were obtained from the national death and location database. Data were compared between those 80 years and younger and those older than 80 years. RESULTS: Of 728 patients identified, 90 (12.4%) were older than 80 years. After CRT, older and younger patients had similar improvements in NHYA class (P = 0.41), ejection fraction (P = 0.48), and mitral valve regurgitation (MR) severity (P = 0.42). In the older patients, defibrillator implantation was associated with comparable improvement in NYHA class, ejection fraction, and MR grade severity (P > 0.05), as in those without a defibrillator. Overall survival was worse in octogenarians than in the younger patients by Kaplan-Meier estimates (P = 0.001). Multivariate analysis showed similar survival between the younger and older subjects (hazard ratio, 1.23; 95% confidence interval, 0.83-1.84; P = 0.31). The observed complication rate in all study subjects was 12.2%, with no difference between the two age groups. CONCLUSION: Octogenarian patients who received CRT with or without a defibrillator for advanced heart failure had similar clinical benefits as younger patients. CRT should not be withheld from octogenarians meeting current selection guidelines.

Cardiac resynchronization therapy: do women benefit more than men?

INTRODUCTION: Women are underrepresented in cardiac resynchronization therapy (CRT) trials. Whether there is a gender difference in the benefit derived from CRT has not been well studied. METHODS: This study included 728 consecutive CRT recipients at our institution who met guidelines for placement of a CRT device. Clinical characteristics and echocardiographic parameters were collected at baseline and after CRT; Kaplan-Meier survival analysis was performed using a national death and location database. The effects and outcome of CRT were compared between women and men. RESULTS: Of 728 patients, 166 were female (22.8%). Female patients were younger than male patients (66.0 ± 11.9 years vs 69.4 ± 10.9 years; P < 0.001) and more often had nonischemic cardiomyopathy (68% vs 36%; P < 0.001). Both female and male patients had significantly improved clinical and echocardiographic parameters after CRT. The magnitude of improvement was similar in women and men, except that improvement in New York Heart Association (NYHA) class was greater in women than in men (-0.79 ± 0.78 vs -0.56 ± 0.85; P = 0.009). Although women were at lower risk of death than men after CRT (hazard ratio, 0.51; 95% confidence interval, 0.35-0.75; P < 0.001, unadjusted), multivariate analysis indicated gender was not, but age at CRT placement, cardiomyopathy cause, NYHA class, and lead location were independent predictors of survival. CONCLUSION: Female CRT recipients seem to achieve greater survival benefit than male recipients. However, this benefit is majorly driven by nonischemic cardiomyopathy and other clinical factors.

Left ventricular lead position for cardiac resynchronization: a comprehensive cinegraphic, echocardiographic, clinical, and survival analysis.

AIMS: We sought to determine the clinical and survival outcomes of cardiac resynchronization therapy (CRT) associated with left ventricular (LV) lead location. The lateral left ventricle has been considered the optimal LV lead location for CRT. METHODS AND RESULTS: Left ventricular lead cinegrams taken in 30° right and left anterior oblique views were evaluated in 457 recipients of CRT with a pacemaker or a defibrillator from 1 January 2002 to 31 December 2008 in this retrospective study. Left ventricular lead placement was prioritized at implantation into posterolateral (PL), anterolateral (AL), middle cardiac, and anterointerventricular coronary veins. Using echocardiographic LV 16-segment analysis, we grouped the leads as anterior, AL, PL, and posterior locations. New York Heart Association (NYHA) class and echocardiography were assessed before and after CRT. Clinical and survival outcomes after CRT were compared among the four LV lead locations.  Patient baseline demographic characteristics were similar among these four groups. Improvement in NYHA class was significantly greater in the AL (P= 0.04) and PL (P= 0.03) locations than in the anterior location. There was a tendency for greater improvement in LV ejection fraction among the AL (P= 0.11) and PL (P= 0.08) locations than the anterior location. Kaplan-Meier survival estimate at 4 years varied for location: AL, 72%; anterior, 48%; PL, 62%; and posterior, 72% (P= 0.003). CONCLUSION: Cardiac resynchronization therapy recipients are profiting from all lead positions. However, LV lead placed in the AL and PL positions is more preferential for achieving optimal CRT benefit than leads placed in the anterior position.

Long-term stability of endocardial left ventricular pacing leads placed via the coronary sinus.

BACKGROUND: Left ventricular endocardial pacing leads placed via the coronary sinus (CS) are increasingly implanted to achieve cardiac resynchronization therapy (CRT); however, the long-term stability of these leads is unknown. We sought to determine the implant success and long-term stability of CS leads in our single center experience. METHODS: All consecutive patients who underwent CRT via implantation of the CS lead between January 1999 and December 2005 were included. Pacing thresholds at implant and during long-term follow-up were reviewed and the rate of acute (within 24 hours of implant) and chronic (>24 hours) lead failure was determined. RESULTS: A total of 512 patients (mean age 68 +/- 12 years; 409 [80%] male) underwent CRT device implantation and were included. The CS lead implantation was successful on the initial implantation in 487 patients (95%) and subsequently successful in six patients (24%) in whom initial attempts were unsuccessful. Acute lead failure occurred in 25 patients (5.1%) and was most commonly due to persistent extra-cardiac stimulation. The rate of chronic lead failure was 4% in the first year and remained stable during long-term follow-up. The CS lead pacing thresholds remained stable with only minimal increase (1.42 +/- 0.85 V/0.42 +/- 0.25 ms vs 1.51 +/- 1.05 V/0.47 +/- 0.29 ms; P = 0.04). CONCLUSIONS: Placement of a left ventricular pacing lead via the CS is feasible and safe in the vast majority of patients. Once placed, the CS leads remain stable with excellent pacing thresholds over the longer term.

Palliative Care Consultation and Associated End-of-Life Care After Pacemaker or Implantable Cardioverter-Defibrillator Deactivation.

The presence of cardiac pacemakers and defibrillators complicates making end-of-life (EOL) medical decisions. Palliative care/medicine consultation (PCMC) may benefit patients and primary providers, but data are lacking. We retrospectively reviewed 150 charts of patients who underwent device deactivation at our tertiary care center (between November 1, 2008, and September 1, 2012), assessing for PCMC and outcomes. Overall, 42% of patients received a PCMC, and 68% of those PCMCs specifically addressed device deactivation. Median survival following deactivation was 2 days, with 42% of deaths occurring within 1 day of deactivation. There was no difference in survival between the groups. The EOL care for patients with implanted cardiac devices is complex, but PCMC may assist with symptom management and clarification of goals of care for such patients.

Outcomes After Implantable Cardioverter-Defibrillator Generator Replacement for Primary Prevention of Sudden Cardiac Death.

BACKGROUND: The effectiveness of implantable cardioverter-defibrillators (ICDs) for primary prevention of sudden death in patients with an ejection fraction (EF) ≤ 35% and clinical heart failure is well established. However, outcomes after replacement of the ICD generator in patients with recovery of EF to >35% and no previous therapies are not well characterized. METHODS AND RESULTS: Between 2001 and 2011, generator replacement was performed at 2 tertiary medical centers in 253 patients (mean age, 68.3 ± 12.7 years; 82% men) who had previously undergone ICD placement for primary prevention but subsequently never received appropriate ICD therapy. EF had recovered to > 35% in 72 of 253 (28%) patients at generator replacement. During median (quartiles) follow-up of 3.3 (1.8-5.3) years after generator replacement, 68 of 253 (27%) experienced appropriate ICD therapy. Patients with EF ≤ 35% were more likely to experience ICD therapy compared with those with EF > 35% (12% versus 5% per year; hazard ratio, 3.57; P = 0.001). On multivariable analysis, low EF predicted appropriate ICD therapy after generator replacement (hazard ratio, 1.96 [1.35-2.87] per 10% decrement; P = 0.001). Death occurred in 25% of patients 5 years after generator replacement. Mortality was similar in patients with EF ≤ 35% and > 35% (7% versus 5% per year; hazard ratio, 1.10; P = 0.68). Atrial fibrillation (3.24 [1.63-6.43]; P < 0.001) and higher blood urea nitrogen (1.28 [1.14-1.45] per increase of 10 mg/dL; P < 0.001) were associated with mortality. CONCLUSIONS: Although approximately one fourth of patients with a primary prevention ICD and no previous therapy have EF >35% at the time of generator replacement, these patients continue to be at significant risk for appropriate ICD therapy (5% per year). These data may inform decisions on ICD replacement.

Effects of tricuspid valve regurgitation on outcome in patients with cardiac resynchronization therapy.

Cardiac resynchronization therapy (CRT) has a symptomatic and survival benefit for patients with heart failure (HF), but the percentage of nonresponders remains relatively high. The aims of this study were to assess the clinical significance of baseline tricuspid regurgitation (TR) or worsening TR after implantation of a CRT device on the response to therapy. This is a multicenter retrospective analysis of prospectively collected databases that includes 689 consecutive patients who underwent implantation of CRT. The patients were divided into groups according to baseline TR grade and according to worsening TR within 15 months after device implantation. Outcome was assessed by clinical and echocardiographic response within 15 months and by estimated survival for a median interquartile range follow-up time of 3.3 years (1.6, 4.6). TR worsening after CRT implantation was documented in 104 patients (15%). These patients had worse clinical and echocardiographic response to CRT, but worsening of TR was not a significant predictor of mortality (p = 0.17). According to baseline echocardiogram, 620 patients (90%) had some degree of TR before CRT implant. Baseline TR was an independent predictor of worse survival (p <0.001), although these patients had significantly better clinical and echocardiographic response compared with patients without TR. In conclusion, worsening of TR after CRT implantation is a predictor of worse clinical and echocardiographic response but was not significantly associated with increased mortality. Baseline TR is associated with reduced survival despite better clinical and echocardiographic response after CRT implantation.

Features and outcomes of patients who underwent cardiac device deactivation.

IMPORTANCE: Little is known about patients who undergo cardiovascular implantable electronic device deactivation. OBJECTIVE: To describe features and outcomes of patients who underwent cardiovascular implantable electronic device deactivation. DESIGN, SETTING, AND PARTICIPANTS: Retrospective review of medical records of 150 patients at a tertiary academic medical center (Mayo Clinic, Rochester, Minnesota). EXPOSURE Cardiovascular implantable electronic device deactivation. MAIN OUTCOMES AND MEASURES: Demographic and clinical data and information regarding advance directives, ethics consultations, palliative medicine consultations, and cardiovascular implantable electronic device deactivations. RESULTS: Of the 150 patients (median age, 79 years; 67% were male), 149 (99%) had poor or terminal prognoses. Overall, 118 patients (79%) underwent deactivation of tachycardia therapies only, and 32 (21%) underwent deactivation of bradycardia therapies with or without tachycardia therapies (6 patients [4%] were pacemaker-dependent). Half of the deactivation requests (51%) were made by surrogates. A majority of deactivations (55%) were carried out by nurses. Although 85 patients (57%) had advance directives, only 1 mentioned the device in the directive. Ethics consultations occurred in 3 patients (2%) and palliative medicine consultations in 64 (43%). The proportions of patients who died within 1 month of device deactivation were similar for those who underwent deactivation of tachycardia therapies only and those who underwent deactivation of bradycardia therapies with or without tachycardia therapies (85% vs 94%; P = .37). CONCLUSIONS AND RELEVANCE: Most requests for cardiovascular implantable electronic device deactivation were for implantable cardioverter-defibrillator-delivered tachycardia therapies only. Many of these requests were made by surrogates. Advance directives executed by patients with these devices rarely addressed device management. Regardless of device therapy, most patients died shortly after device deactivation. Hence, a device deactivation decision may reflect the seriousness of a given patient's underlying illness. Patients with devices should engage in advance care planning to ensure that future care is consistent with their preferences.

Definition of performance metrics and methods for screening for sudden cardiac arrest risk at a tertiary care medical center.

PURPOSE: The purpose of this study is to describe the results of manual and automatic electronic medical record-based screening of patients at risk of sudden cardiac arrest (SCA) based on measurements of left ventricular ejection fraction (LVEF). METHODS: Counseling regarding SCA risk and implantable cardioverter defibrillator (ICD) therapy is underutilized in patients with reduced LVEF. We developed and implemented an electronic medical record (EMR)-based system for screening of such patients to improve care. In phase one, manual screening of electronic records and LVEF databases was initially performed by trained cardiac device nurses. In phase two, records were screened automatically by a customized program, and candidate patient records were sent to cardiac device nurses for final review and disposition. RESULTS: In phase one, 2,531 patients with LVEF ≤35% were identified over 398 days. Manual EMR review showed that 1,918 patients (76%) received appropriate counseling regarding SCA risk, received ICDs, or had disqualifying comorbidities. In phase two, 1,081 patients with LVEF ≤35% were identified after automatic screening of 44,672 echocardiograms and EMR over 251 days. Of these, 513 patients (58%) received appropriate counseling regarding SCA risk, received ICDs, or had disqualifying comorbidities. CONCLUSIONS: These data detail the utilization of consultation regarding SCA risk and ICDs in patients with reduced LVEF at a tertiary care center with ready access to arrhythmia specialists. Notification of primary providers of reduced LVEF with recommendation for consultation was not effective in improving patient care.

Differential outcome of cardiac resynchronization therapy in ischemic cardiomyopathy and idiopathic dilated cardiomyopathy.

BACKGROUND: Cardiac resynchronization therapy (CRT) is a therapy of proven benefit in patients with advanced heart failure. Identifying potential responders remains challenging, and whether the etiology of the heart failure is related to the potential hemodynamic benefit and long-term outcome of CRT is unclear. OBJECTIVE: The purpose of this study was to evaluate whether heart failure etiology (ischemic cardiomyopathy [ICM] vs nonischemic dilated cardiomyopathy [DCM]) was associated with CRT outcome and implantable cardioverter-defibrillator (ICD) shocks. METHODS: The study included 503 CRT recipients (CRT-D 90%) in a longitudinal CRT database: ICM (n = 312) and DCM (n = 191). Clinical variables and echocardiographic measures preimplant and postimplant were collected. Actuarial survival and ICD therapy data were assessed with Kaplan-Meier curve and log rank tests. RESULTS: Pre-CRT, ICM patients were older and had higher creatinine levels (P <.001). At median follow-up of 7.1 months, the DCM group experienced greater improvement in left ventricular ejection fraction (8.3% ± 10% vs 6.2% ± 10%, P = .05) and left ventricular end-diastolic volumes than did those with ICM (-28%.4 ± 53 mL vs -15.3 ± 46 mL, P = .024). Survival estimates at 4 years were 55% for ICM and 77% for DCM groups (P <.001), respectively, whereas no significant difference in the incidence of appropriate/inappropriate ICD shocks was observed. The ICM group remained at higher risk for death compared to the DCM group after controlling for preimplant variables (hazard ratio 1.6, 95% confidence interval 1.1-2.3, P = .008). CONCLUSION: In response to CRT and in contrast to ICM, DCM patients experienced greater improvement in left ventricular systolic function and reverse remodeling while also sustaining a greater survival benefit.

Cardiac sympathetic reserve and response to cardiac resynchronization therapy.

BACKGROUND: The objective of the present study was to investigate the effect of cardiac resynchronization therapy (CRT) on cardiac autonomic function. METHODS AND RESULTS: This prospective study included 45 consecutive patients with heart failure who received CRT devices with defibrillator and 20 age-matched, healthy control subjects. At baseline and 3 months and 6 months after CRT, we assessed New York Heart Association (NYHA) class, 6-minute walk distance, plasma sympathetic biomarker nerve growth factor, echocardiography, heart rate variability and cardiac presynaptic sympathetic function determined by iodine 123 metaiodobenzylguanidine scintigraphy. After CRT, NYHA class improved by 1 class (P<0.001), and left ventricular ejection fraction increased by 8% (P<0.001). Along with improvement in the standard deviation of all normal-to-normal R-R intervals (85.63±31.66 ms versus 114.79±38.99 ms; P=0.004) and the standard deviation of the averaged normal-to-normal R-R intervals (82.62±23.03 ms versus 100.50±34.87 ms; P=0.004), the delayed heart/mediastinum (H/M) ratio increased (1.82 [0.58] versus 1.97 [0.59]; P=0.03), whereas the mean (SD) H/M washout rate was reduced (48% [19%] versus 37% [22%]; P=0.01). Twenty-two of 45 study patients responded to CRT, with a reduction of left ventricular end-systolic volume index >15%. Compared with nonresponders, responders had a higher delayed H/M ratio (2.11 versus 1.48; P=0.003) and lower H/M washout rate (37% versus 62%; P=0.003) at baseline. CONCLUSIONS: CRT improved sympathetic function. Cardiac sympathetic reserve may be a marker for the reversibility of failing myocardial function.

Implantable cardioverter defibrillator therapy for congenital long QT syndrome: a single-center experience.

BACKGROUND: Long QT syndrome's (LQTS) marked heterogeneity necessitates both evidence-based and individualized therapeutic approaches. OBJECTIVE: This study sought to analyze a single LQTS specialty center's experience regarding the relationship between risk factors and appropriate ventricular fibrillation (VF)-terminating therapies among LQTS patients treated with an implantable cardioverter-defibrillator (ICD). METHODS: An internal review board-approved, retrospective analysis of the electronic medical records of 459 patients with genetically confirmed LQTS including the 51 patients (14 LQT1, 22 LQT2, and 15 LQT3) who received an ICD from 2000 to 2010 was performed. RESULTS: Twelve patients (24%, 4 LQT1, 8 LQT2) experienced an appropriate, VF-terminating therapy with an average follow-up of 7.3 years, including 7 of 17 LQT2 female patients but none of the 15 LQT3 patients. Conversely, 15 (29%) patients (8 LQT3) have experienced an inappropriate shock. Secondary prevention indications (P = .008), non-LQT3 genotype (P = .02), QTc ≥ 500 ms (P = .0008), documented syncope (P = .05), documented torsades de pointes (P = .003), and a negative family history (P = .0001) were most predictive of an appropriate therapy. Importantly, no LQT-related deaths have occurred among the 408 non-ICD-treated patients. CONCLUSION: The vast majority of LQTS patients can be treated effectively without an ICD. Potentially life-saving therapies were rendered at a 5% to 6% per year rate among those selected for ICD therapy; similar inappropriate shock frequencies were also noted. Secondary prevention, genotype, and QTc predicted those most likely to receive appropriate therapy. Although the ICD implant frequency is greatest among LQT3 patients, the greatest "save" rate has occurred among LQT2 women, who were assessed to be at high risk.

Atrioventricular nodal ablation predicts survival benefit in patients with atrial fibrillation receiving cardiac resynchronization therapy.

BACKGROUND: Cardiac resynchronization therapy (CRT) benefits patients with advanced heart failure. The role of atrioventricular nodal (AVN) ablation in improving CRT outcomes, including survival benefit in CRT recipients with atrial fibrillation, is uncertain. OBJECTIVE: The purpose of this study was to assess the impact of AVN ablation on clinical and survival outcomes in a large atrial fibrillation and heart failure population that met the current indication for CRT and to determine whether AVN ablation is an independent predictor of survival in CRT recipients. METHODS: Of 154 patients with atrial fibrillation who received CRT-D, 45 (29%) underwent AVN ablation (+AVN-ABL group), whereas 109 (71%) received drug therapy for rate control during CRT (-AVN-ABL group). New York Heart Association (NYHA) class, electrocardiogram, and echocardiogram were assessed before and after CRT. Survival data were obtained from the national death and location database (Accurint). RESULTS: CRT comparably improved left ventricular ejection fraction (8.1% +/- 10.7% vs 6.8% +/- 9.6%, P = .49) and left ventricular end-diastolic diameter (-2.1 +/- 5.9 mm vs -2.1 +/- 6.7 mm, P = .74) in both +AVN-ABL and -AVN-ABL groups. Improvement in NYHA class was significantly greater in the +AVN-ABL group than in -AVN-ABL group (-0.7 +/- 0.8 vs -0.4 +/- 0.8, P = .04). Survival estimates at 2 years were 96.0% (95% confidence interval [CI] 88.6%-100%) for +AVN-ABL group and 76.5% (95% CI 68.1%-85.8%) for-AVN-ABL group (P = .008). AVN ablation was independently associated with survival benefit from death (hazard ratio [HR] 0.13, 95% CI 0.03-0.58, P = .007) and from combined death, heart transplant, and left ventricular assist device (HR 0.19, 95% CI 0.06-0.62, P = .006) after CRT. CONCLUSION: Among patients with atrial fibrillation and heart failure receiving CRT, AVN ablation for definitive biventricular pacing provides greater improvement in NYHA class and survival benefit. Larger-scale randomized trials are needed to assess the clinical and survival outcomes of this therapy.

Upgrade and de novo cardiac resynchronization therapy: impact of paced or intrinsic QRS morphology on outcomes and survival.

BACKGROUND: Cardiac resynchronization therapy (CRT) improves outcomes in patients with left bundle branch block (LBBB), but the benefits of CRT in patients with other QRS morphologies or previous pacing are uncertain. OBJECTIVE: The purpose of this study was to describe outcomes in patients with prior right ventricular pacing and non-LBBB morphologies. METHODS: We studied 505 patients who underwent de novo CRT (n = 338) or CRT upgrade (n = 167). De novo patients were categorized by underlying QRS morphology: LBBB (67%), right bundle branch block (RBBB; 11%), intraventricular conduction delay (IVCD; 13%), and QRS <120 ms (9%). Upgrade patients were categorized by the percentage of previous ventricular pacing. RESULTS: Patients were followed for death over a median of 2.6 years (interquartile range 1.6-4.0). New York Heart Association (NYHA) functional class and echocardiographic improvements were similar in de novo and upgrade patients. However, within the de novo group, NYHA improvements were less in patients with RBBB (0.3 +/- 0.8; P = .014) or IVCD (0.2 +/- 0.7; P = .001) than in those with LBBB (0.7 +/- 0.8). These patients had less left ventricular functional improvement as well. Survival was comparable after de novo versus upgrade CRT (61% vs 63% at 4 years; P = .906). No clinical or survival differences were noted in upgrade patients based on the percentage of previous pacing. However, survival in de novo CRT recipients with RBBB (32%) was lower than in those with LBBB (66%; P <.001), and RBBB independently predicted death (hazard ratio 3.5, confidence interval 1.9-6.5; P <.001). CONCLUSION: RBBB and IVCD result in less clinical improvement or worsened survival after CRT. Additional selection criteria may be beneficial in identifying potential responders with RBBB, IVCD, or narrow QRS.