Autonomic Effects of Pulsed Field vs Thermal Ablation for Treating Atrial Fibrillation: Subanalysis of ADVENT.

BACKGROUND: Autonomic denervation is an ancillary phenomenon during thermal ablation of atrial fibrillation (AF), that may have synergistic effects on symptomatic improvement and long-term freedom from AF. Pulsed field ablation (PFA), a nonthermal ablation modality, was noninferior to thermal ablation in treating AF; however, PFA's relative myocardial selectivity may minimize autonomic effects. OBJECTIVES: This study sought to compare heart rate (HR) and heart rate variability (HRV) metrics as markers of autonomic function after ablation using PFA vs thermal ablation. METHODS: ADVENT (FARAPULSE ADVENT PIVOTAL Trial PFA System vs SOC Ablation for Paroxysmal Atrial Fibrillation) was a randomized pivotal study comparing PFA (pentaspline catheter) with thermal ablation (radiofrequency [RF] or cryoballoon [CB]) for treating paroxysmal AF. Baseline HR was acquired from a pre-ablation 12-lead electrocardiogram, whereas follow-up HRs, as well as HRV (standard deviation of all normal to normal RR intervals, standard deviation of 5-minute average RR intervals) metrics, were derived from 72-hour Holter monitors at 6 and 12 months. RESULTS: This study included 379 paroxysmal AF patients undergoing PFA (n = 194) or thermal ablation (n = 185; n = 102 RF, n = 83 CB) completing 6- and 12-month Holter monitoring. Compared with PFA, thermal patients had significantly greater increases in HR from baseline to 6 months (ΔHR; 10.1 vs 5.9 beats/min; P = 0.02) and 12 months (ΔHR; 8.8 vs 5.2 beats/min; P = 0.03). This increase in HR at 6 and 12 months was similar between CB and RF (P = 0.94 and 0.83, respectively). HRV, both standard deviation of all normal to normal RR intervals and standard deviation of 5-minute average RR intervals, were significantly lower at both 6 and 12 months after thermal ablation compared with PFA (P < 0.01). CONCLUSIONS: PFA's effect on the autonomic nervous system was attenuated compared with thermal ablation. Whether this affects long-term freedom from AF or symptomatic bradycardia/pauses after AF ablation requires further study.

Feasibility and safety of same-day discharge after implantable cardioverter defibrillator placement for primary prevention.

BACKGROUND: In the current age of ever-increasing healthcare costs, it is of utmost importance to adopt strategies that reduce hospital stay and cost, while still maintaining patient safety. In this study we review our approach of same-day discharge following implantable cardioverter defibrillator (ICD) placement for primary prevention of sudden cardiac death (SCD). METHODS: We conducted a retrospective chart review of 415 consecutive patients who underwent ICD implantation for prevention of SCD between 2007 and 2010. Patients were divided into an outpatient group (Group A) and an inpatient group (Group B). We evaluated the patients' demographics, comorbidities, and the rate of short-term surgical complications on or before the 2-week follow-up appointment. RESULTS: Of 252 patients included in Group A, 198 (78.6%) were successfully discharged on the same day (Group A1). At the 2-week wound check appointment, four patients (2%) had minor surgical site bleeding, one patient had a hematoma, and one patient developed fever and swelling around the implantation site. Of the Group A patients, 54 (21.4%) were not discharged on the same day (Group A2). A total of 53 patients were included in Group B, four (7.5%) developed a hematoma at the 2-week follow-up wound check visit. CONCLUSIONS: Procedure-related complications after ICD placement are rare. Same-day discharge is safe and feasible following ICD placement for primary prevention of SCD and hence a reduction in healthcare costs can be achieved by decreasing the length of hospital stay.

Atrial fibrillation: an independent risk factor for nonaccidental falls in older patients.

BACKGROUND: Nonaccidental falls are often the result of a combination of factors including cardiovascular disorders such as orthostatic hypotension and unspecified cardiac arrhythmias. The objective of this study was to determine if there is an association between atrial fibrillation (AF) and nonaccidental falls. METHODS: We reviewed the records of 442 consecutive patients >65 years old who presented to the Emergency Department at the University of Utah Medical Center with a complaint of fall. RESULTS: Two-hundred eleven patients presented with nonaccidental fall, 231 patients with accidental fall. Patients with nonaccidental fall were more likely to be older, have a history of hypertension and neurological disorders, and taking five or more medications when compared to patients with accidental fall. Despite a similar prevalence of sinus rhythm at presentation, the prevalence of a history of AF was significantly higher in patients with nonaccidental fall compared to patients with accidental fall (26% vs 15%; P = 0.003). After adjusting for clinically and statistically significant predictors with a multivariate logistic regression analysis, AF, neurological disorders, and age ≤81 years were independent predictors of nonaccidental fall. In patients ≤81 years old (median age), the risk of nonaccidental falls was 2.5 times greater in patients with a history of AF when compared to those without a history of AF (odds ratio = 2.53 [confidence interval 95% 1.3-5], P = 0.007). CONCLUSION: AF is an independent risk factor for nonaccidental falls. Our results emphasize the need to screen for AF in patients presenting with nonaccidental fall.

Renal dysfunction and atrial fibrillation recurrence following cardioversion.

BACKGROUND: No previous study has assessed the role of renal impairment in predicting the long-term risk of atrial fibrillation recurrence after cardioversion. METHODS: One hundred and fifty-nine consecutive patients with persistent atrial fibrillation undergoing successful cardioversion were enrolled. Renal function was assessed based on the estimated glomerular filtration rate (eGFR) at baseline and during follow-up. Patients were prospectively followed up for eGFR and recurrence of atrial fibrillation up to 1 year. RESULTS: Patients were divided into 4 groups based upon their eGFR (group 1 >90 mL/min: 33 patients, group 2: 60-90 mL/min: 55 patients, group 3: 30-59 mL/min: 53 patients, group 4: <30 mL/min: 18 patients). Overall, 101 out of 159 (64%) patients experienced atrial fibrillation recurrence within 1 year follow-up. Atrial fibrillation recurrence was independently associated with the level of reduction of eGFR at baseline (eGFR < 30 mL/min: hazard ratio [HR] 6.82, P < 0.001; eGFR 30-59 mL/min: HR 3.31, P = 0.01; eGFR 60-90 mL/min: HR 2.10, P = 0.13; eGFR > 90 mL/min reference group). In patients with maintained sinus rhythm after 12-month follow-up eGFR was increased (8.46 ± 9.49 mL/min [range -7 to 43]), whereas patients with atrial fibrillation recurrence showed a decrease in eGFR over time (-5.75 ± 9.4 [range -32 to 25], P < 0.001). CONCLUSION: Among a group of patients with persistent atrial fibrillation undergoing successful cardioversion, impaired renal function (based on estimated GFR) was associated with an increased risk of atrial fibrillation recurrence. Maintenance of sinus rhythm was associated with improvement in eGFR in patients with mild or moderate renal insufficiency.

Atrial fibrosis helps select the appropriate patient and strategy in catheter ablation of atrial fibrillation: a DE-MRI guided approach.

UNLABELLED: MRI for AF Patient Selection and Ablation Approach. INTRODUCTION: Left atrial (LA) fibrosis and ablation related scarring are major predictors of success in rhythm control of atrial fibrillation (AF). We used delayed enhancement MRI (DE-MRI) to stratify AF patients based on pre-ablation fibrosis and also to evaluate ablation-induced scarring in order to identify predictors of a successful ablation. METHODS AND RESULTS: One hundred and forty-four patients were staged by percent of fibrosis quantified with DE-MRI, relative to the LA wall volume: minimal or Utah stage 1; <5%, mild or Utah stage 2; 5-20%, moderate or Utah stage 3; 20-35%, and extensive or Utah stage 4; >35%. All patients underwent pulmonary vein (PV) isolation and posterior wall and septal debulking. Overall, LA scarring was quantified and PV antra were evaluated for circumferential scarring 3 months post ablation. LA scarring post ablation was comparable across the 4 stages. Most patients had either no (36.8%) or 1 PV (32.6%) antrum circumferentially scarred. Forty-two patients (29%) had recurrent AF over 283 ± 167 days. No recurrences were noted in Utah stage 1. Recurrence was 28% in Utah stage 2, 35% in Utah stage 3, and 56% in Utah stage 4. Recurrence was predicted by circumferential PV scarring in Utah stage 2 and by overall LA wall scarring in Utah stage 3. No recurrence predictors were identified in Utah stage 4. CONCLUSIONS: Circumferential PV antral scarring predicts ablation success in mild LA fibrosis, while posterior wall and septal scarring is needed for moderate fibrosis. This may help select the proper candidate and strategy in catheter ablation of AF.

Syncope in the emergency department: comparison of standardized admission criteria with clinical practice.

AIMS: Syncope is a major health care problem that accounts for many emergency department (ED) and hospital admissions. This study was conducted to investigate the short-term risk of serious events in patients presenting to the ED with syncope and to compare guideline-based admission criteria with those adopted in clinical practice. METHODS AND RESULTS: A single-centre retrospective analysis was performed on ED visits between January and June 2009. We used the ICD-9 code 780.2 for syncope as the primary diagnosis. The prevalence of serious events within 7 days of the index presentation was evaluated. In addition, admissions and discharges were classified as being appropriate or inappropriate based on standardized guideline-based criteria integrated in a new Faint-Algorithm developed at the University of Utah. Two hundred and fifty-four ED visits met the inclusion criteria. One hundred and thirty-six patients were discharged home and the remaining 118 were admitted. The prevalence of serious events in the discharged and admission groups were 5 and 10, respectively, (P= NS). According to the Faint-Algorithm, the number of inappropriate discharges and admissions were 8 out of 136 and 69 out of 118, respectively. Using the Faint-Algorithm, only 57 patients instead of 118 patients should have been admitted resulting in a 52% reduction in admission rate. Furthermore, in the remaining 197 patients who should have been discharged, the prevalence of serious events was not significantly different than that observed in the 136 patients who were actually discharged (3% vs. 4%). CONCLUSION: There are significant numbers of inappropriate discharges and admissions in patients presenting with syncope. The standardized guideline-based criteria integrated in the new Faint-Algorithm provide promise but require further prospective evaluation.

The prevalence and cost of the faint and fall problem in the state of Utah.

BACKGROUND: Understanding the frequency and economic impact of faint and fall is a prerequisite for the creation of cost-effective diagnostic approaches. METHODS: We evaluated the total number of patients presenting with faint or fall to the University of Utah Health Care System between November 1, 2008, and October 31, 2009. Using these data, we estimated the prevalence and total cost of the faint and fall problem in the state of Utah. RESULTS: A total of 1,936 and 6,043 patients presented with faint and fall resulting in a total number of visits equal to 2,701 and 8,163, respectively. The yearly prevalence of faints was 9.5 patients (13.2 visits) per 1,000 inhabitants and the yearly prevalence of falls was 29.8 patients (40.2 visits) per 1,000 inhabitants. The prevalence of faints and falls progressively increased with age, reaching the values of 40 and 115 per 1,000 inhabitants in subjects aged >80 years. In both patient populations, two-thirds of visits were outpatient evaluations. While the cardiovascular service was involved in the outpatient evaluation of faint visits in 24% of the cases, <1% of outpatient fall visits resulted in a cardiovascular consultation. The average payments received per faint and fall patient evaluations were $2,517 and $3,200, respectively, resulting in an estimated yearly cost equal to $90,901,958 and $351,959,040, respectively. CONCLUSION: This study highlights the magnitude of the faint and fall problem in the state of Utah. Our results provide all stakeholders with a frame of reference for the creation of cost-effective diagnostic approaches.

An animal model for ectopy-induced cardiomyopathy.

BACKGROUND: Ectopy-induced cardiomyopathy is an increasingly recognized cause of reversible left ventricular (LV) dysfunction. The underlying mechanisms remain unknown. Our goal was to create an animal model for ectopy-induced cardiomyopathy. METHODS: Eleven mongrel dogs underwent the implantation of a dual-chamber pacemaker. Four dogs served as the control group and seven as the paced group. In the paced group, the pacemaker was connected to two endocardial right ventricular leads, one inserted into the atrial port and the other one into the ventricular port with an atrioventricular delay adjusted to ensure the presence of coupled pacing simulating ventricular bigeminy. Echocardiographic measurements of LV size (LV end-diastolic diameter [LV-EDD], LV end-systolic diameter [LV-ESD]), LV ejection fraction (LVEF), and mitral regurgitation (MR) were obtained at baseline and after 4 weeks of monitoring or pacing in all dogs except one who had lead dislodgement. RESULTS: In the control group (n = 4), no significant changes in LV dimensions or function were noted. In the paced group (n = 6), LV-EDD and LV-ESD increased from 3.58 ± 0.65 cm and 2.47 ± 0.55 cm to 4.15 ± 0.59 cm and 3.21 ± 0.47 cm, respectively (P < 0.01). In addition, LVEF decreased from 60 ± 7% to 46 ± 9% (P < 0.05). No changes in MR were noted. CONCLUSION: We have shown that coupled pacing simulating ventricular bigeminy was feasible and resulted in increased LV dimensions and decreased LV function. By controlling the percentage of pacing, the coupling interval and the location of the pacing lead, this new model will allow the assessment of the relative roles of these variables in the development of ectopy-induced cardiomyopathy.

Evaluation of patients with "faint" in an American teaching hospital: a dire need for a standardized approach.

BACKGROUND: Fainting is a major healthcare problem with significant morbidity, mortality, and healthcare cost. We sought to assess the appropriateness of current clinical practice when compared to a guideline-based algorithm. METHODS: The records of 100 consecutive patients who presented with faint and were referred to the University of Utah for further evaluation by specialists were reviewed. We analyzed the clinical characteristics, tests performed, diagnosis made, and number of admissions. In addition, we applied a guideline-based algorithm to assess the appropriateness of these evaluations. RESULTS: The mean age was 49 ± 21 years with 57% being female. One-third presented with their first event. Structural heart disease was present in 22% of the cases. Twelve (36%) of 32 admissions were inappropriate. There was an underutilization of orthostatic testing, carotid sinus massage, and implantable loop recorder and overutilization of imaging studies and neurologic consultation. Specifically, active standing and tilt-table testing were performed in only 24% and 7% of the cases, respectively, none of the patients had carotid sinus massage despite 26% of them being ≥65 years old, and only 3% of the patients received an implantable loop recorder. With the current practice, a final diagnosis was made in 45 cases with 17 (38%) of the 45 final diagnoses not being sufficiently supported by the completeness of the evaluation. CONCLUSION: With the current practice at a major university hospital, the cause of faint was unexplained in a high number of cases. Our findings highlight the need for a standardized approach to patients presenting with faint.

Electromagnetic interference between external defibrillator and cardiac resynchronization therapy-pacemaker (CRT-P) devices.

BACKGROUND: Implantable heart rhythm devices are susceptible to interference in hospitals where electromagnetic interference (EMI) sources are ubiquitous. CASE DESCRIPTION: We report three cases in which EMI from the external defibrillator caused the inability to interrogate Boston Scientific cardiac resynchronization therapy-pacemaker (CRT-P) devices. We have documented interference with the Boston Scientific CRT-P Contact Renewal device model numbers H120/H125 (Natick, MA, USA) and two brands of external defibrillators: the Philips Heartstart XL model number M4735A (Andover, MA, USA) and the Hewlett-Packard Codemaster model number M1722B (Palo Alto, CA, USA). For device implants, we routinely place external pacing pads with the external defibrillator in the "standby" mode for transcutaneous pacing so that only the pacer "start/stop" button needs to be pressed when necessary. We have not been able to interrogate three consecutive Boston Scientific CRT-P devices prior to closure while the external defibrillator had the back-up pacing mode on "standby." In our initial case, a second device was opened because this interaction was not recognized. We documented EMI with the standby pacing mode ON and discovered that by disabling only the "standby" pacing mode on the external defibrillator, the device could be interrogated without difficulty. CONCLUSIONS: This is a case series reporting EMI with a Boston Scientific CRT-P Contact Renewal device H120/H125 telemetry from an external defibrillator with pacing mode on "standby." Failure to recognize this important interaction may lead to inappropriate device and resource utilization.