LBBB and heart failure-Relationships among QRS amplitude, duration, height, LV mass, and sex.

BACKGROUND: Height, left ventricular (LV) size, and sex were proposed as additional criteria for patient selection for cardiac resynchronization therapy (CRT) but their connections with the QRS complex in left bundle branch block (LBBB) are little investigated. We evaluated these. METHODS: Among patients with "true" LBBB, QRS duration (QRSd) and amplitude, and LV hypertrophy indices, were correlated with patient's height and LV mass, and compared between sexes. RESULTS: In this study cohort (n = 220; 60 ± 12 years; left ventricular ejection fraction [LVEF] 21 ± 7%; mostly New York Heart Association II-III, QRSd 165 ± 19 ms; 57% female; 70% responders [LVEF increased ≥5%]), LV mass was increased in all patients. QRS amplitude did not correlate with LV mass or height in any individual lead or with Sokolow-Lyon or Cornell-Lyon indices. QRSd did not correlate with height. In contrast, QRSd correlated strongly with LV mass (r = .51). CRT response rate was greater in women versus men (84% vs. 58%, p < .001) despite shorter QRSd [7% shorter (p < .0001)]. QRSd normalized for height resulted in a 2.7% and for LV mass 24% greater index in women. CONCLUSION: True LBBB criteria do not exclude HF patients with increased LV mass. QRS amplitudes do not correlate with height or LV mass. Height does not affect QRSd. However, QRSd correlates with LV size. QRSd normalized for LV mass results in 24% greater value in women in the direction of sex-specific responses. LV mass may be a significant nonelectrical modifier of QRSd for CRT.

Cryoballoon pulmonary vein isolation versus radiofrequency ablation of the pulmonary veins and left atrial posterior wall: Patient-reported outcomes.

BACKGROUND: Data are lacking on patient-reported outcomes (PRO) following cryoballoon ablation (CBA) versus radiofrequency ablation (RFA). We sought to evaluate QoL and clinical outcomes of cryoballoon pulmonary vein isolation only (CRYO-PVI-ONLY) versus RFA with PVI and posterior wall isolation (RF-PVI+PWI) in a large prospective PRO registry. METHODS: Patients who underwent AF ablation (2013-2016) at our institution were enrolled in an automated, prospectively maintained PRO registry. CRYO-PVI-ONLY patients were matched (1:1) with RF-PVI+PWI patients based on age, gender, and type of AF (paroxysmal vs. persistent). QoL and clinical outcomes were assessed using PRO surveys at baseline and at 1-year. The atrial fibrillation symptom severity scale (AFSSS) was the measure for QoL. Additionally, we assessed patient-reported clinical improvement, arrhythmia recurrence, and AF burden (as indicated by AF frequency and duration scores). RESULTS: A total of 296 patients were included (148 in each group, 72% paroxysmal). By PRO, a significant improvement in QoL was observed in the overall study population and was comparable between CRYO-PVI-ONLY and RF-PVI+PWI (baseline median AFSSS of 11.5 and 11; reduced to 2 and 4 at 1 year, respectively; p = 0.44). Similarly, the proportion of patients who reported improvement in their overall QoL and AF related symptoms was high and similar between the study groups [92% (CRYO-PVI-ONLY) vs. 92.8% (RF-PVI+PWI); p = 0.88]. Arrhythmia recurrence was significantly more common in the CRYO-PVI-ONLY group (39.7%) compared to RF-PVI+PWI (27.7 %); p = 0.03. Comparable results were observed in paroxysmal and persistent AF. CONCLUSION: CRYO-PVI-ONLY and RF-PVI+PWI resulted in comparable improvements in patient reported outcomes including QoL and AF burden; with RF-PVI+PWI being more effective at reducing recurrences.

Impact of redo ablation for atrial fibrillation on patient-reported outcomes and quality of life.

INTRODUCTION: Catheter ablation for atrial fibrillation (AF) is frequently used for the purpose of rhythm control and improved quality of life (QoL). Although success rates are high, a significant proportion of patients require redo ablation. Data are scarce on patient-centered outcomes and QoL in patients undergoing redo AF ablation. We aimed to assess QoL and clinical outcomes using a large prospectively maintained patient-reported outcomes (PRO) registry. METHODS: All patients undergoing redo AF ablation (2013-2016) at our center were enrolled in a prospective registry for outcomes and assessed for QoL using automated PRO surveys (baseline, 3 and 6 months after ablation, every 6 months thereafter). Data were collected over 3 years of follow-up. The atrial fibrillation symptom severity scale (AFSSS) was used as the main measure for QoL. Additional variables included patient-reported improvement, AF burden, and AF-related healthcare utilization including emergency room (ER) visits and hospitalizations. RESULTS: A total of 848 patients were included (28% females, mean age 63.8, 51% persistent AF). By automated PRO, significant improvement in QoL was noted (baseline median AFSSS of 12 [5-18] and ranged between 2 and 4 on subsequent assessments; p < .0001), with ≥70%of patients reported remarkable improvement in their AF-related symptoms. The proportion of patients in AF at the time of baseline survey was 36%, and this decreased to <8% across all time points during follow-up (p < .0001). AF burden was significantly reduced (including frequency and duration of episodes; p < .0001), with an associated decrease in healthcare utilization after 6 months from the time of ablation (including ER visits and hospitalizations; p < .0001). The proportion of patients on anticoagulants or antiarrhythmics decreased on follow-up across all time points (p < .0001 for all variables). CONCLUSION: Most patients derive significant QoL benefit from redo AF ablation; with reduction of both AF burden and healthcare utilization.

A case series of very slow atrioventricular nodal reentrant tachycardia resembling junctional tachycardia.

INTRODUCTION: The surface electrocardiography of typical atrioventricular nodal reentrant tachycardia (AVNRT) shows simultaneous ventricular-atrial (RP) activation with pseudo R' in V1 and typical heart rates ranging from 150 to 220/min. Slower rates are suspicious for junctional tachycardia (JT). However, occasionally we encounter typical AVNRT with slow ventricular rates. We describe a series of typical AVNRT cases with heart rates under 110/min. METHODS: A total of 1972 patients with AVNRT who underwent slow pathway ablation were analyzed. Typical AVNRT was diagnosed when; (1) evidence of dual atrioventricular nodal conduction, (2) tachycardia initiation by atrial drive train with atrial-His-atrial response, (3) short septal ventriculoatrial time, and (4) ventricular-atrial-ventricular (V-A-V) response to ventricular overdrive (VOD) pacing with corrected post pacing interval-tachycardia cycle length (cPPI-TCL) > 110 ms. JT was excluded by either termination or advancement of tachycardia by atrial extrastimuli (AES) or atrial overdrive (AOD) pacing. RESULTS: We found 11 patients (age 20-78 years old, six female) who met the above-mentioned criteria. The TCL ranged from 560 to 782 ms. Except for one patient showing tachycardia termination, all patients demonstrated a V-A-V response and cPPI-TCL over 110 ms with VOD. AES or AOD pacing successfully excluded JT by either advancing the tachycardia in 10 patients or by tachycardia termination in one patient. Slow pathway was successfully ablated, and tachycardia was not inducible in all patients. CONCLUSIONS: This case series describes patients with typical AVNRT with slow ventricular rate (less than 110/min) who may mimic JT. We emphasize the importance of using pacing maneuvers to exclude JT.

Influence of "high" defibrillation thresholds on patient survival and impact of system modification.

OBJECTIVE: To test whether a high defibrillation threshold (DFT) marks patients with poor outcomes which are improved when DFT is decreased by system modification (subcutaneous coil implant; SM). BACKGROUND: The electrical substrate generating fast ventricular arrhythmias may generate poor outcomes among patients treated with implantable cardioverter-defibrillators (ICDs), even when arrhythmias are treated successfully. Since patients with high DFTs have increased mortality, we contrasted survival among patients with high DFT treated with and without SM. METHODS: We studied consecutive patients undergoing ICD implantation and DFT testing at Cleveland Clinic over a 14-year period. High DFT was defined as successful defibrillation by shock strength >25 J or ≤10 J of maximal device output. Mortality was recorded using the Social Security Death Index. Survival was compared among those high DFT patients receiving SM versus the remainder. RESULTS: Out of 6353 patients tested, 191 (3%) had high DFT (32.1 ± 3.7 J) versus 13.9 ± 4.9 J in the remainder ("acceptable DFT," p < .001). One hundred twenty-one high DFT patients (63%; 33.3 ± 3.4 J) underwent SM, which significantly decreased DFT (24.8 ± 5.9 J; p < .001). Seventy patients (37%; 30.3 ± 3.3 J) did not undergo SM. During follow-up, 38% (2363/6162; 7.8 yrs) patients with acceptable DFT died versus 48% high DFT patients (91/191; 5.6 yrs.; p < .001). Concomitantly, 48% patients with SM (58/121) died, as compared to 47% patients (33/70) without SM (p = .91); median follow-up 4.9 yrs). CONCLUSION: Patients with high DFT have a higher mortality than those with acceptable DFT. The additional subcutaneous coil implant decreases DFT to an acceptable range but does not appear to improve survival. The electrical substrate underlying high DFT appears to determine survival.

The utility of a novel mapping algorithm utilizing vectors and global pattern of propagation for scar-related atrial tachycardias.

BACKGROUND: Activation maps of scar-related atrial tachycardias (AT) can be challenging to interpret due to difficulty in inaccurate annotation of electrograms, and an arbitrarily predefined mapping window. A novel mapping software integrating vector data and applying an algorithmic solution taking into consideration global activation pattern has been recently described (Coherent™, Biosense Webster "Investigational"). OBJECTIVE: We aimed to assess the investigational algorithm to determine the mechanism of AT compared with the standard algorithm. METHODS: This study included patients who underwent ablation of scar-related AT using the Carto 3 and the standard activation algorithm. The mapping data were analyzed retrospectively using the investigational algorithm, and the mechanisms were evaluated by two independent electrophysiologists. RESULTS: A total of 77 scar-related AT activation maps were analyzed (89.6% left atrium, median tachycardia cycle length of 273 ms). Of those, 67 cases with a confirmed mechanism of arrhythmia were used to compare the activation software. The actual mechanism of the arrhythmia was more likely to be identified with the investigational algorithm (67.2% vs. 44.8%, p = .009). In five patients with dual-loop circuits, 3/5 (60%) were correctly identified by the investigational algorithm compared to 0/5 (0%) with the standard software. The reduced atrial voltage was prone to lead to less capable identification of mechanism (p for trend: .05). The investigational algorithm showed higher inter-reviewer agreement (Cohen's kappa .62 vs. .47). CONCLUSIONS: In patients with scar-related ATs, activation mapping algorithms integrating vector data and "best-fit" propagation solution may help in identifying the mechanism and the successful site of termination.

A new machine learning approach for predicting likelihood of recurrence following ablation for atrial fibrillation from CT.

OBJECTIVE: To investigate left atrial shape differences on CT scans of atrial fibrillation (AF) patients with (AF+) versus without (AF-) post-ablation recurrence and whether these shape differences predict AF recurrence. METHODS: This retrospective study included 68 AF patients who had pre-catheter ablation cardiac CT scans with contrast. AF recurrence was defined at 1 year, excluding a 3-month post-ablation blanking period. After creating atlases of atrial models from segmented AF+ and AF- CT images, an atlas-based implicit shape differentiation method was used to identify surface of interest (SOI). After registering the SOI to each patient model, statistics of the deformation on the SOI were used to create shape descriptors. The performance in predicting AF recurrence using shape features at and outside the SOI and eight clinical factors (age, sex, left atrial volume, left ventricular ejection fraction, body mass index, sinus rhythm, and AF type [persistent vs paroxysmal], catheter-ablation type [Cryoablation vs Irrigated RF]) were compared using 100 runs of fivefold cross validation. RESULTS: Differences in atrial shape were found surrounding the pulmonary vein ostia and the base of the left atrial appendage. In the prediction of AF recurrence, the area under the receiver-operating characteristics curve (AUC) was 0.67 for shape features from the SOI, 0.58 for shape features outside the SOI, 0.71 for the clinical parameters, and 0.78 combining shape and clinical features. CONCLUSION: Differences in left atrial shape were identified between AF recurrent and non-recurrent patients using pre-procedure CT scans. New radiomic features corresponding to the differences in shape were found to predict post-ablation AF recurrence.

Proarrhythmic effects from competitive atrial pacing and potential programming solutions.

BACKGROUND: Programmed long AV delays and intrinsic long first degree AV block may increase risk for competitive atrial pacing (CAP) in devices without CAP avoidance algorithms. METHODS: Patients identified with CAP-induced mode switch episodes were followed clinically from September 2013 to August 2019. Attempts to avoid CAP included shortening of postventricular atrial refractory period (PVARP) or postventricular atrial blanking period (PVAB), or change to AAI or DDI modes. After observing associations with sensor-driven pacing, rate response was inactivated in a subset. RESULTS: Among 23 patients identified with CAP (22 St Jude Medical [Abbott]; one Boston Scientific Corporation devices), atrial fibrillation (AF) was induced in 12 (52%), lasting 10 seconds to 28 hours and 32 minutes. In one patient with an ICD CAP-induced AF with rapid ventricular rates that triggered a shock, inducing ventricular fibrillation, syncope, and another shock. Changing AV delays and shortening of PVARP failed to resolve CAP. After noting that all had CAP during sensor-driven pacing, rate response was inactivated in seven, resolving further device-induced AF in the three of seven that had prior CAP-induced AF. In two patients with intact AV conduction, AAI(R) pacing resolved further documentation of CAP. CONCLUSIONS: CAP predominantly occurs during sensor-driven atrial pacing that competes with intrinsic atrial events falling in PVARP. Inactivation of the activity sensor or change to atrial-based pacing modes (AAI/R) appears to effectively prevent induction of device-induced atrial proarrhythmia. Ultimately, a corrective algorithm is needed to avoid CAP-induced proarrhythmia.

Analysis of cardiac motion without respiratory motion for cardiac stereotactic body radiation therapy.

PURPOSE/OBJECTIVE(S): To study the heart motion using cardiac gated computed tomographies (CGCT) to provide guidance on treatment planning margins during cardiac stereotactic body radiation therapy (SBRT). MATERIALS/METHODS: Ten patients were selected for this study, who received CGCT scans that were acquired with intravenous contrast under a voluntary breath-hold using a dual source CT scanner. For each patient, CGCT images were reconstructed in multiple phases (10%-90%) of the cardiac cycle and the left ventricle (LV), right ventricle (RV), ascending aorta (AAo), ostia of the right coronary artery (O-RCA), left coronary artery (O-LCA), and left anterior descending artery (LAD) were contoured at each phase. For these contours, the centroid displacements from their corresponding average positions were measured at each phase in the superior-inferior (SI), medial-lateral (ML), and anterior-posterior (AP). The average volumes as well as the maximum to minimum ratios were analyzed for the LV and RV. RESULTS: For the six contoured substructures, more than 90% of the measured displacements were <5 mm. For these patients, the average volumes ranged from 191.25 to 429.51 cc for LV and from 91.76 to 286.88 cc for RV. For each patient, the ratios of maximum to minimum volumes within a cardiac cycle ranged from 1.15 to 1.54 for LV and from 1.34 to 1.84 for RV. CONCLUSION: Based on this study, cardiac motion is variable depending on the specific substructure of the heart but is mostly within 5 mm. Depending on the location (central or peripheral) of the treatment target and treatment purposes, the treatment planning margins for targets and risk volumes should be adjusted accordingly. In the future, we will further assess heart motion and its dosimetric impact.

Should fast pathway ablation be reconsidered in typical atrioventricular nodal re-entrant tachycardia?

INTRODUCTION: Atrioventricular nodal re-entry tachycardia (AVNRT) is the most common, regular narrow-complex tachycardia. The established treatment is catheter ablation of the AV nodal slow pathway (SP). However, in a select group of patients with long PR intervals in sinus rhythm, SP ablation can lead to AV block due to the absence of robust anterograde conduction through the fast pathway (FP). This report aims to demonstrate that AV nodal FP ablation is a reasonable approach in patients with AVNRT and poor or absent anterograde FP conduction. METHODS AND RESULTS: Standard electrophysiology study techniques were used in the electrophysiology laboratory. Catheter ablations were performed using radiofrequency energy. Mapping of intracardiac activation was performed with electroanatomical mapping systems. Outcomes were assessed acutely during the procedure and during routine clinical follow-up. Six patients with first-degree AV block and recurrent AVNRT who underwent ablation of their tachycardia at our institution are presented. One patient underwent ablation of AV nodal SP resulting in high-degree AV block necessitating pacemaker implantation. The remaining five patients underwent ablation of the AV nodal FP guided by electroanatomical mapping of the earliest atrial activation in tachycardia. These five had successful treatment of the tachycardia with preservation of anterograde AV nodal conduction. Mapping and ablation approach to eliminate retrograde FP conduction are described. CONCLUSION: In select patients with AVNRT and poor anterograde FP conduction, retrograde FP ablation is reasonable and is less likely to result in AV block and pacemaker dependency.

Repeat ablation or medical management alone for recurrent arrhythmias after ablation of persistent atrial fibrillation.

INTRODUCTION: Management of persistent atrial fibrillation (PersAF) remains challenging, and many patients are left on medical therapy after a failed first ablation. In patients with recurrent symptomatic arrhythmias after PersAF ablation, we aimed to compare outcomes of repeat ablation and medical therapy versus medical therapy alone. METHODS AND RESULTS: All 682 consecutive patients with recurrent symptomatic arrhythmia after a first ablation for PersAF at our institution (2005-2012) were included. Repeat ablation with continuation of medical therapy was performed in 364 patients (Group 1) and 318 were only medically managed (Group 2). The outcome of interest was freedom from arrhythmia recurrence beyond a 3-month blanking period. Separate analyses were performed to assess this endpoint totally off antiarrhythmics (primary endpoint) or alternatively with/without use of antiarrhythmics (secondary endpoint). Over a median follow-up of 26 months, 41.5% of Group 1 patients met the primary endpoint and remained free from arrhythmia recurrence off antiarrhythmics (vs. 14.5% in Group 2, P < 0.0001). At last follow-up, antiarrhythmics continued to be required for rhythm control in 40.1% and 46.2% of patients in Groups 1 and 2, respectively (P < 0.0001). The secondary endpoint was met in 60.2% versus 32.1% of patients in Groups 1 and 2, respectively (P < 0.0001). In multivariable Cox analyses, repeat ablation was associated with significant reduction in arrhythmia recurrences compared to medical therapy alone (HR 0.48, 95% CI 0.35-0.65, P < 0.0001). CONCLUSION: In patients with recurrent symptomatic arrhythmia after ablation of PersAF, repeat ablation was associated with significant reduction in arrhythmia recurrences compared to routine medical therapy alone.

Dofetilide for suppression of atrial fibrillation in hypertrophic cardiomyopathy: A case series and literature review.

BACKGROUND: Limited medical options are available for rhythm control in patients with atrial fibrillation (AF) and hypertrophic cardiomyopathy (HCM). There are no published reports of dofetilide use in this population. METHODS: A retrospective chart review was conducted on 1,404 patients loaded on dofetilide for AF suppression at the Cleveland Clinic from 2008 to 2012, 25 of whom were found to have HCM. RESULTS: The HCM cohort was 32% female, 76% with persistent AF, mean age of 59 ± 10 years, and mean ejection fraction of 54 ± 9 %. Of the 25 patients, 21 were discharged on dofetilide, three discontinued during loading due to QTc prolongation, and one due to inefficacy. There were no adverse events during loading. Of those discharged on dofetilide, 11/21 (52%) were still on it at a median follow-up of 396 (198, 699) days at the time of the chart review. For those in whom it was discontinued, the median time on the drug was 301 (111, 738) days. Of the 10 patients who discontinued dofetilide during follow-up, six were due to inefficacy, one postablation, one postheart transplant, one due to death secondary to lung cancer, and one due to worsening edema. CONCLUSIONS: Dofetilide was well tolerated in this group of patients with AF and HCM and it facilitated management of AF in 21/25 (84%) patients. Further research is needed to assess the safety and efficacy of dofetilide in order to develop evidence-based guidelines for the pharmacological management of AF in this population.

Persistent Atrial Fibrillation Ablation With or Without Contact Force Sensing.

INTRODUCTION: Arrhythmia recurrences remain common after ablation of persistent atrial fibrillation (PersAF). Contact force (CF)-sensing catheters have been introduced for objective assessment of contact during radiofrequency application and have been suggested to improve outcomes in ablation of paroxysmal AF, but little is known about their role in PersAF ablation. We aimed to compare the procedural profiles and outcomes of (PersAF) ablation with or without using CF-sensing catheters. METHODS: All consecutive patients undergoing first time ablation for PersAF between April 2014 and January 2015 at the Cleveland Clinic were included. Substrate modification was performed in addition to isolation of the pulmonary veins. Success rates were determined off antiarrhythmics over 1 year of follow-up. RESULTS: The study included 174 patients (77 CF and 97 non-CF). Ablation with CF-sensing catheters resulted in shorter procedures (median 204 vs. 216 minutes, P = 0.04) and shorter fluoroscopy time (36 vs. 48 minutes, P = 0.0005), without statistical difference in radiation dose (225 vs. 270 milligrays, P = 0.1). Arrhythmia recurrences were less likely to be observed in the CF-sensing group (27.6% vs. 46.4%, P = 0.01, log-rank P = 0.004). In multivariable Cox analyses, the use of CF-sensing catheters was associated with a lower risk of arrhythmia recurrence (hazard ratio 0.49, 95% confidence interval 0.27-0.85, P = 0.01). CONCLUSIONS: Compared to non-CF sensing, the use of CF-sensing catheters for PersAF ablation is associated with shorter procedures, shorter fluoroscopy time, and reduction in arrhythmia recurrences.

Early Changes in QRS Frequency Following Cardiac Resynchronization Predict Hemodynamic Response in Left Bundle Branch Block Patients.

INTRODUCTION: QRS characteristics are the cornerstone of patient selection in cardiac resynchronization therapy (CRT) and the presence of left bundle branch block (LBBB) and baseline QRS ≥150 milliseconds portends a good outcome. We previously showed that baseline QRS frequency analysis adds predictive value to LBBB alone and have hypothesized that a change in frequency characteristics following CRT may produce additional predictive value. METHODS: We examined the QRS frequency characteristics of 182 LBBB patients before and soon after CRT. Patients were assigned to responder and nonresponder groups. Responders were defined by a decrease in left ventricular end-systolic volume (LVESV) ≥15% following CRT. We analyzed the QRS in ECG leads I, AVF, and V3 before and soon after CRT using the discrete Fourier transform algorithm. The percentage of total QRS power within discrete frequency intervals before and after CRT was calculated. The reduction in lead V3 power <10 Hz was the best indicator of response. RESULTS: Baseline QRS width was similar between the responders and nonresponders (162.2 ± 17.2 milliseconds vs. 158 ± 22.1 milliseconds, respectively; P = 0.180). Responders exhibited a greater reduction in QRS power <10 Hz (-17.0 ± 11.9% vs. -6.6 ± 12.5%; P < 0.001) and a significant AUC (0.743; P < 0.001). A ≥8% decline in QRS power <10 Hz produced the best predictive values (PPV = 84%, NPV = 59%). Importantly, when patients with baseline QRS <150 milliseconds were compared, the AUC improved (0.892, P < 0.001). CONCLUSIONS: Successful CRT produces a significant reduction in QRS power below 10 Hz, particularly when baseline QRS <150 milliseconds. These results indicate that QRS frequency changes after CRT provide additional predictive value to QRS alone.

Interruption of Pacing Following Nonsustained Ventricular Tachycardia in an AAI Programmed Implantable Cardioverter Defibrillator.

BACKGROUND: Unnecessary ventricular pacing from cardiac implantable electronic devices has been associated with long-term risks (heart failure, atrial fibrillation, and possibly stroke). Several device programming strategies are available to minimize ventricular pacing, each potentially associated with unintended consequences. Occasionally, the only effective means is to program to the AAI(R) pacing mode. However, in one manufacturer's implantable cardioverter defibrillators (ICDs), the AAI(R) mode has the potential risk of prolonged pacing cessation following a nonsustained ventricular tachycardia (NSVT). METHOD: Patients with ICDs, managed through the Cleveland Clinic device clinic, follow the Heart Rhythm Society consensus document recommendations for device monitoring with remote interrogations (every three months) and yearly in-person evaluations. Clinically significant findings also trigger additional evaluations by the nurse and physician. RESULTS: Two patients having Boston Scientific ICDs (E110 Teligen 100; Boston Scientific Corp., Natick, MA, USA), had asystole and marked bradycardia following untreated NSVT. These pauses in pacing were due to use of the AAI(R) pacing mode. In order to enhance ventricular tachycardia detection, by design atrial pacing is disabled during, and for a time after, an episode of ventricular tachycardia when the device operates in the "ventricular tachycardia response" (VTR) phase. Thus, following spontaneous termination of the NSVT, no pacing occurred in these patients until the VTR period ended. Nonconventional programming was utilized to permit AAI(R) pacing while avoiding these asystolic and bradycardic events during VTR. CONCLUSIONS: Unintended consequences can occur when complex VT detection parameters interact with specific pacing modes. At times, nonconventional programming can avoid these interactions while still achieving effective AAI(R) pacing.

Survival in octogenarians undergoing cardiac resynchronization therapy compared to the general population.

BACKGROUND: Many patients eligible for cardiac resynchronization therapy (CRT) are over 80 years of age. Survival in this population and how it compares to the general octogenarian population has not been established. METHODS: We extracted clinical data on a cohort of 800 consecutive patients undergoing the new implantation of a CRT device between April 15, 2004 and August 6, 2007. Patients over age 80, with class III-IV New York Heart Association heart failure symptoms on optimal medical therapy undergoing initial CRT implantation, were included in the final cohort. Using the United States Social Security Period Life Table for 2006, fractional survival for octogenarians in the general population was calculated and matched to our cohort based on age and gender. A comparison was then made between octogenarians undergoing CRT compared to the general population. RESULTS: A total of 95 octogenarians who met inclusion criteria were identified, of whom 86.3% received a biventricular defibrillator and the remainder a biventricular pacemaker. Over a mean follow-up of 3.6 ± 1.5 years, there were 47 deaths (47.4%). The mean survival time was 4.1 years (95% CI 3.7-4.5), and survival at 2 years was 78.9%. Compared to the general octogenarian population, octogenarians receiving CRT had only modestly worse survival over the duration of follow-up with the survival curves diverging at 2 years of follow-up (P = 0.03). CONCLUSIONS: Octogenarians with advanced heart failure have a reasonable mean survival time following CRT. All-cause mortality in this patient population is only modestly worse compared to the general octogenarian population. Therefore, in octogenarians deemed to be reasonable candidates, CRT should not be withheld based on age alone.

Left ventricular hypertrophy and antiarrhythmic drugs in atrial fibrillation: impact on mortality.

BACKGROUND: Despite sparse clinical data, current atrial fibrillation (AF) guidelines favor amiodarone as a drug of choice for patients with left ventricular hypertrophy (LVH). OBJECTIVE: This study tested the hypothesis that patients with persistent AF and LVH on nonamiodarone antiarrhythmics have higher mortality compared to patients on amiodarone. METHODS: In an observational cohort analysis of patients who underwent cardioversion for AF, patients with LVH, defined as left ventricular wall thickness ≥1.4 cm, by echocardiogram prior to their first cardioversion, were included; clinical data, including antiarrhythmic drugs and ejection fraction (LVEF), were collected. Mortality, determined via the Social Security Death Index, was analyzed using Kaplan-Meier and Cox proportional hazards models to determine whether antiarrhythmic drugs were associated with higher mortality. RESULTS: In 3,926 patients, echocardiographic wall thickness was available in 1,399 (age 66.8 ± 11.8 years, 67% male, LVEF 46 ± 15%, septum 1.3 ± 0.4, posterior wall 1.2 ± 0.2 cm), and 537 (38%) had LVH ≥1.4 cm. Among 537 patients with LVH, mean age was 67.5 ± 11.7 years, 76.4% were males, and mean LVEF was 48.3 ± 13.3%. Amiodarone was associated with lower survival (log rank P = 0.001), including after adjusting for age, LVEF, and coronary artery disease (P = 0.023). In propensity-score matched cohorts with LVH treated with no drugs, nonamiodarone antiarrhythmic drugs (non-AADs), or amiodarone (N = 65 each group), there was early lower survival in patients on amiodarone (P = 0.05). CONCLUSIONS: Patients with persistent AF and LVH on non-AADs do not have higher mortality compared to patients on amiodarone. Importantly, these findings do not support amiodarone as a superior choice in patients with LVH.

Left ventricular mass as a modulator of ventricular arrhythmia risk and sex differences after CRT for nonischemic cardiomyopathy and LBBB.

BACKGROUND: The risk of ventricular arrhythmias (VAs) after cardiac resynchronization therapy (CRT) has been associated with ischemic disease/scar, sex, and possibly left ventricular mass (LVM). OBJECTIVE: The purpose of this study was to evaluate sex differences and baseline/postimplant change in LVM on VA risk after CRT implantation in patients with nonischemic cardiomyopathy and left bundle branch block. METHODS: In patients meeting the criteria, baseline and follow-up echocardiographic images were obtained for LVM assessment. VA events were reported from device diagnostics and therapies. VA risk was stratified by receiver operating characteristic (Youden index cutoff point) for baseline LVM and baseline/postimplant change in LVM, and baseline patient characteristics by using a multivariable Cox regression model. RESULTS: One hundred eighteen patients (71 female [60.2%]; mean age 60.5 ± 11.3 years; left ventricular ejection fraction 19.2% ± 7.0%; QRS duration 165.6 ± 20 ms; LVM 313.9 ± 108.8 g) were enrolled and followed up for a median of 90 months (interquartile range 44-158 months). Thirty-five patients (29.6%) received appropriate shocks or antitachycardia pacing at a median of 73.5 months (interquartile range 25-130 months) postimplantation. Males had a higher VA incidence (male 18 of 47 [38.3%] vs female 17 of 71 [23.9%]; P = .02). Baseline LVM > 308.9 g separated patients with higher VA risk (P = .001). Less than a 20% decrease in LVM increased VA risk (P < .001). Baseline LVM was the only baseline characteristic predicting VA events in the Cox regression model (hazard ratio 1.01; 95% confidence interval 1.001-1.009; log-rank, P = .003). Sex differences in VA risk were eliminated by the baseline LVM parameters. CONCLUSION: VA risk after CRT in nonischemic cardiomyopathy was associated with baseline LV > 308.9 g and a decrease in LVM ≤ 20%, without sex differences.