Risk assessment in patients with symptomatic and asymptomatic pre-excitation

AIMS

Controversy remains as to whether the exercise stress test (EST) is sufficient for risk evaluation in patients with pre-excitation. This study aims to clarify the usefulness of EST in risk stratification in both asymptomatic and symptomatic patients presenting with pre-excitation.

METHODS AND RESULTS

This prospective study includes consecutive asymptomatic and symptomatic patients with pre-excitation referred for risk assessment. All participants performed an incremental EST (bicycle) prior to an electrophysiology study (EPS). Primary data from the EST included loss of pre-excitation during exercise, and primary data from the EPS included the measurement of accessory pathway effective refractory period (APERP), shortest pre-excited RR interval (SPERRI), and inducible arrhythmia with the use of a beta-adrenergic receptor agonist if deemed necessary. One hundred and sixty-four patients (59 asymptomatic, 105 symptomatic) completed an EST and EPS. Forty-five patients (27%) demonstrated low-risk findings on EST, of which 19 were asymptomatic and 26 were symptomatic. Six patients with low-risk EST findings had SPERRI/APERP ≤ 250 ms at EPS, and two of them were asymptomatic. The sensitivity, specificity, positive predictive value, negative predictive value (NPV), and accuracy of low-risk EST for excluding patients with SPERRI/APERP ≤ 250 ms were 40, 91, 87, 51, and 60%, respectively. The number of patients with inducible arrhythmia at EPS was similar in the asymptomatic (36, 69%) and symptomatic (73, 61%) groups.

CONCLUSION

Sudden loss of pre-excitation during EST has a low NPV in excluding high-risk APs. The EPS with the use of isoproterenol should be considered to accurately assess the risk of patients with pre-excitation regardless of symptoms (ClinicalTrials.gov Identifier: NCT03301935).

Association between catheter ablation of atrial fibrillation and mortality or stroke

OBJECTIVE

Catheter ablation of atrial fibrillation effectively reduces symptomatic burden. However, its long-term effect on mortality and stroke is unclear. We investigated if patients with atrial fibrillation who undergo catheter ablation have lower risk for all-cause mortality or stroke than patients who are managed medically.

METHODS

We retrospectively included 5628 consecutive patients who underwent first-time catheter ablation for atrial fibrillation between 2008 and 2018 at three major Swedish electrophysiology units. Control individuals with an atrial fibrillation diagnosis but without previous stroke were selected from the Swedish National Patient Register, resulting in a control group of 48 676 patients. Propensity score matching was performed to produce two cohorts of equal size (n=3955) with similar baseline characteristics. The primary endpoint was a composite of all-cause mortality or stroke.

RESULTS

Patients who underwent catheter ablation were healthier (mean CHA2DS2-VASc score 1.4±1.4 vs 1.6±1.5, p<0.001), had a higher median income (288 vs 212 1000 Swedish krona [KSEK]/year, p<0.001) and had more frequently received university education (45.1% vs 28.9%, p<0.001). Mean follow-up was 4.5±2.8 years. After propensity score matching, catheter ablation was associated with lower risk for the combined primary endpoint (HR 0.58, 95% CI 0.48 to 0.69). The result was mainly driven by a decrease in all-cause mortality (HR 0.51, 95% CI 0.41 to 0.63), with stroke reduction showing a trend in favour of catheter ablation (HR 0.75, 95% CI 0.53 to 1.07).

CONCLUSIONS

Catheter ablation of atrial fibrillation was associated with a reduction in the primary endpoint of all-cause mortality or stroke. This result was driven by a marked reduction in all-cause mortality.

The labels and models used to describe problematic substance use impact discrete elements of stigma: A registered report

OBJECTIVES

Problematic substance use is one of the most stigmatized health conditions leading research to examine how the labels and models used to describe it influence public stigma. Two recent studies examine whether beliefs in a disease model of addiction influence public stigma but result in equivocal findings-in line with the mixed-blessings model, Kelly et al. (2021) found that while the label "chronically relapsing brain disease" reduced blame attribution, it decreased prognostic optimism and increased perceived danger and need for continued care; however, Rundle et al. (2021) conclude absence of evidence. This study isolates the different factors used in these two studies to assess whether health condition (drug use vs. health concern), etiological label (brain disease vs. problem), and attributional judgment (low vs. high treatment stability) influence public stigma toward problematic substance use.

METHOD

Overall, 1,613 participants were assigned randomly to one of the eight vignette conditions that manipulated these factors. They completed self-report measures of discrete and general public stigma and an indirect measure of discrimination.

RESULTS

Greater social distance, danger, and public stigma but lower blame were ascribed to drug use relative to a health concern. Greater (genetic) blame was reported when drug use was labeled as a "chronically relapsing brain disease" relative to a "problem." Findings for attributional judgment were either inconclusive or statistically equivalent.

DISCUSSION

The labels used to describe problematic substance use appear to impact discrete elements of stigma. We suggest that addiction is a functional attribution, which may explain the mixed literature on the impact of etiological labels on stigma to date. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Electrical cardioversion for early recurrences post pulmonary vein isolation

BACKGROUND

To study the association between timing and success of electrical cardioversion (ECV) for the treatment of early recurrences (ERs) of atrial fibrillation post pulmonary vein isolation (PVI) on long-term rhythm outcome.

METHODS

Data of 133 patients ablated for paroxysmal or persistent atrial fibrillation receiving ECV for ERs, i.e., atrial tachyarrhythmia recurrences within 90 days post ablation were analyzed. During 1-year follow-up, patients were screened for late recurrences (LRs), i.e., recurrences after the blanking period.

RESULTS

In 114 patients (85.7%), ECV was successful compared to 19 patients (14.3%) with failed ECV. A higher body mass index (odds ratio (OR) 1.19 (95% CI 1.02-1.39), p = 0.029), a lower left ventricular ejection fraction (OR 1.07 (95% CI 0.99-1.15), p = 0.079), and performance of ECV > 7 days from ER onset (OR 2.99 (95% CI 1.01-8.87), p = 0.048) remained independently associated with ECV failure. During 1-year follow-up, the rate of LR was significantly higher among patients with failed ECV as compared to patients with successful ECV (hazard ratio (HR) 3.00 (95% CI, 1.79-5.03), p < 0.001). Patients with ECV performed > 7 days from ER onset had a significantly higher risk of developing LR as compared to patients with ECV performed within ≤ 7 days from ER onset (HR 1.73 (95% CI 1.15-2.62), p = 0.009). Performance of ECV > 7 days from ER onset (HR 1.76 (95% CI 1.16-2.67), p = 0.008) and failed ECV (HR 3.32 (95% CI 1.96-5.64), p < 0.001) remained independently associated with LR.

CONCLUSIONS

A failed ECV and performance of ECV > 7 days from ER onset were independently associated with LR.

Accuracy of identifcation of traumatic brain injuries in routine hospital data

Background

Traumatic brain injury (TBI) is a leading cause of death and disability worldwide. Much work on the epidemiology of TBI uses routinely collected health care data. There is no separate code for TBI in ICD-10, a common coding system for acute care. One reason for reported variations in TBI prevalence between countries is differences in the identification of TBI from routine data. This study assessed the performance of an Australian classification system (Pozzatto et al 2019), using a standardised approach to ICD-10 codes to identify cases of likely TBI in routine hospital discharge data.

Methods

The original study was done on hospital data from New South Wales. We replicated their approach using Irish hospital data, held by Health Intelligence, from 2013 to 2020. Cases not classified as TBI by this system, but with codes, such as loss-of-consciousness, skull fracture or intra-cranial injury were manually reviewed.

Results

All 98,419 discharges with any code in S00 to S99 were reviewed. 27,851 (28.3%) had a skull fracture or intracranial injury. 12,106 (12.3%) had loss-of-consciousness and/or post-traumatic amnesia. 11,976 (98.9%) of these (12.2% of the total) had either a skull fracture or an intra-cranial injury reported. 26,085 (26.5%) of the original 98,419 cases were classified as TBI using the NSW classification. Manual review of 1.3% (1,356) cases added a maximum of 0.32% (321) further possible cases of TBI, suggesting a sensitivity of the classification of 98.8% (95% CI 98.6% - 98.9%).

Discussion

The main limitation is that it is not possible to identify false positive cases - those coded as TBI, but where no TBI was present. This approach to identifying TBI works well, and is feasible for wider implementation. It provides comparability between different studies.

Pozzato I et al. (2019), Epidemiology of hospitalised traumatic brain injury in the state of New South Wales, Australia: a population-based study. Australian and New Zealand Journal of Public Health. 2019

Key messages

There are problems comparing data on TBI between different countries because no single code for TBI exists in ICD-10, and this is a real challenge for epidemiologists and health services researchers. The use of an agreed system, developed in Australia, for recoding injury data to identify TBI has promise, and shows excellent sensitivity in two countries.

Low incidence of major complications after the first six hours post-atrial fibrillation ablation – same-day discharge safe and feasible in most patients

Background/Introduction

Catheter ablation of atrial fibrillation (AF) is associated with a complication risk. It is common practice to monitor patients overnight post-procedurally which is resource craving.

Purpose

To evaluate the incidence of procedural complications related to catheter ablation of AF to assess the potential feasibility and safety of same day discharge in a large cohort.

Methods

We performed an analysis of prospectively collected data of complications of all patients staying overnight after undergoing AF ablation between 2001 and 2020 at a tertiary centre. By studying medical records, we analysed complications occurring intraprocedurally until six hours post-ablation, and between six hours post-ablation until discharge the day after ablation procedure (up to 24 hours post-procedure).

Results

In 5414 AF ablations we identified a total of 108 (2.0%) major complications occurring intraprocedural or until discharge the day after procedure. Most major complications occurred early and were detected intraprocedurally or within six hours after completed procedure (n=96, 1.8%). Twelve (0.2%) major complications occurred between six hours post-ablation and until discharge the day after procedure. The most common of these were congestive heart failure (n=6) and transient ischemic attack (TIA, n=4). In addition, there were 61 (1.1%) minor complications which occurred in this time span. Factors independently associated with major complications intraprocedurally or within 24 hours were age (p=0.046), body mass index (BMI) ≥30 kg/m2 (p=0.009), significant valvular disease (p=0.001), cardiomyopathy (p&lt;0.001), prior stroke or TIA (p=0.014), first time procedure vs. repeat procedure (p=0.013), cryoablation vs. radiofrequency (p&lt;0.001) and procedure duration (p&lt;0.001).

Conclusion

Very few complications occurred between six hours and until discharge after ablation of atrial fibrillation. Therefore, same-day discharge may be a safe option for a large proportion of patients.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Region Stockholm funding

Cryoablation of atypical atrioventricular nodal reentry tachycardia

AIM

Data on ablation for atypical recurrent atrioventricular nodal reentry tachycardia (AVNRT) and long-term follow-up are generally sparse. Furthermore, the rate of recurrence and safety of cryoablation for atypical AVNRT has not been established. We compared patients cryoablated for atypical AVNRT and typical AVNRT during long-term follow-up.

METHODS

All patients (n = 2612) who underwent catheter ablation for AVNRT at the Karolinska University Hospital between January 2009 and August 2019 were analyzed. A total of 91 patients undergoing first-time cryoablation for atypical AVNRT were included. A control group with first-time cryoablation for typical AVNRT was matched in a 1:1 ratio. Patients were followed-up for recurrences for a median of 5.0 years (interquartile range: 3.1-7.5 years).

RESULTS

After 5 years, AVNRT recurrence occurred in 10 patients (11.0%) in the atypical AVNRT group and in 8 patients (8.8%) in the typical AVNRT group (hazard ratio: 1.31 [95% confidence interval: 0.52-3.32]; p = 0.568). The duration of the index procedure was significantly longer for atypical compared to typical AVNRT ablation (132.1 ± 49.2 min vs. 110.1 ± 38.8 min; p = 0.001). Transient AV blocks occurred in a similar fashion in the atypical compared to typical group (11 [12.1%] vs. 4 [4.9%]; p = 0.103). However, no ablation induced persistent AV block developed in either group.

CONCLUSION

Cryoablation for atypical AVNRT showed similar rate of recurrences and safety compared to typical AVNRT during long-term follow-up.

Low incidence of major complications after the first six hours post atrial fibrillation ablation: Is same-day discharge safe and feasible in most patients?

AIMS

This study evaluates the incidence of procedural complications related to catheter ablation of atrial fibrillation (AF) to assess the potential feasibility and safety of same-day discharge in a large cohort.

METHODS

We performed an analysis of prospectively collected data of complications of all patients staying overnight after undergoing AF ablation between 2001 and 2020 at a tertiary center. Using medical records, we analyzed complications occurring intraprocedurally until 6 h postablation and between 6 h postablation and discharge the day after the ablation procedure.

RESULTS

In 5414 AF ablations, we identified a total of 108 (2.0%) major complications occurring intraprocedural or before discharge. Most major complications occurred intraprocedurally or within 6 h after the procedure (n = 96, 1.8%). Twelve (0.2%) major complications occurred between 6 h Postablation and discharge. The most common of these major complications were congestive heart failure (n = 6) and transient ischemic attack (TIA, n = 4). During this time span, 61 (1.1%) minor complications occurred. Factors independently associated with major complications intraprocedurally and until discharge were body mass index (BMI) ≥ 30 kg/m² (p = .009), significant valvular disease (p = .001), cardiomyopathy (p < .001), prior stroke or TIA (p = .014), first-time procedure versus repeat procedure (p = .013), cryoablation versus radiofrequency (p < .001), and procedure duration (p < .001).

CONCLUSION

After AF ablation, very few complications occurred between 6 h postprocedure and discharge the next day. Therefore, same-day discharge is a safe option for a majority of patients.

Cryoablation as standard treatment of atrial flutter: a prospective, 2-center study (CASTAF)

BACKGROUND

Cryoablation (CRYO) of cavotricuspid isthmus (CTI)-dependent atrial flutter (AFL) has been shown to be non-inferior to radiofrequency ablation (RF) in terms of ablation success and is associated with less pain. However, procedural time has been significantly longer with CRYO compared to RF. A possible explanation for this could be that operators had less experience with CRYO than with RF. The purpose of this study was to test the hypothesis that in the hands of experienced operators, cryoablation of CTI-dependent AFL is effective with procedure-time similar to what is reported for RF.

METHODS

This prospective 2-center study included 184 patients with CTI-dependent AFL - median age 66 years (range 28-83), 159 men (86%). Cryoablation was performed using a 9 F, 8 mm tip catheter (Freezor MAX, Medtronic, Inc, MN, USA). Ablation endpoint was bidirectional CTI-block. Pain was evaluated with a visual analogue scale (VAS 0-10). All operators had experience of at least 25 previous CTI-ablations with CRYO.

RESULTS

The acute success rate was 89%. Procedural time including an observation period of 30 min, was 115 ± 36 min which is similar to procedural times for RF in previous studies. Fluoroscopy time was 11 ± 9 min. Cryoablation was perceived as almost pain- free by the patients, VAS (mean) 1.8 ± 1.2. Success rate at 12-month follow-up (FU) was 88% in patients with primary success. No major adverse events occurred.

CONCLUSIONS

Cryoablation of CTI-dependent AFL is effective, with a low level of procedure-related pain. In experienced hands, the procedure time in this prospective non-randomised trial seems to be in the level of reported procedure times for RF. The long-term relapse rate appears to be higher than for RF.

Sinus heart rate post pulmonary vein ablation and long-term risk of recurrences

PURPOSE

Cather ablation is known to influence the autonomic nervous system. This study sought to investigate the association of sinus heart rate pre-/post-ablation and recurrences in patients with atrial fibrillation undergoing pulmonary vein isolation (PVI).

METHODS

Between January 2012 and December 2017, data of 482 patients undergoing their first PVI were included. Sinus heart rate was recorded before (PRE), directly post-ablation (POST) and 3 months post-ablation (3 M). All patients were screened for atrial tachyarrhythmia recurrences during the one-year follow-up.

RESULTS

In the total study cohort, the mean resting sinus heart rate at PRE [mean 57.9 bpm (95% CI 57.1-58.7 bpm)] increased by over 10 bpm to POST [mean 69.4 bpm (95% CI 68.5-70.3 bpm); p < 0.001] followed by a slight decrease at 3 M [mean 67.3 bpm (95% CI 66.4-68.2 bpm)] but still remaining higher compared to PRE (p < 0.001). This pattern was observed in patients with and without recurrences at POST and 3 M (both p < 0.001 compared to PRE). However, at 3 M the mean sinus heart rate was significantly lower in patients with compared to patients without recurrences (p = 0.031). In this regard, patients with a heart rate change < 11 bpm (PRE to 3 M) or, as an alternative parameter, patients with a heart rate < 60 bpm at 3 M had a significantly higher risk of recurrences compared to the remaining patients (Hazard ratio (HR) 1.82 (95% CI 1.32-2.49), p < 0.001 and HR 1.64 (95% CI 1.20-2.25), p = 0.002, respectively).

CONCLUSION

Our study confirms the impact of PVI on cardiac autonomic function with a significant sinus heart rate increase post-ablation. Patients with a sinus heart rate change < 11 bpm (PRE to 3 M) are at higher risk for recurrences during one-year post-PVI.

Sinus heart rate post pulmonary vein ablation and long-term risk of recurrences

Aim

To investigate the association of sinus heart rate pre- and post-ablation and recurrence rates in patients undergoing catheter ablation for atrial fibrillation.

Methods

Between January 2012 and December 2017, data of 482 patients undergoing their first pulmonary vein isolation (PVI) were included. All patients were followed-up for 12 months and were screened for any atrial tachyarrhythmia. Sinus heart rate measurements were recorded before (PRE), directly post ablation (POST) and 3 months post ablation (3M).

Results

In the total study population, the mean resting sinus heart rate at PRE (mean 57.9 bpm (95% CI, 57.1–58.7 bpm)) increased by over 10 bpm to POST (mean 69.4 bpm (95% CI, 68.5–70.3 bpm); p&lt;0.001) followed by a slight decrease at 3M (mean 67.3 bpm (95% CI, 66.4–68.2 bpm)) but still remaining higher compared to PRE (p&lt;0.001). This pattern was observed in patients with and without recurrences at PRE, POST and 3M respectively (both p&lt;0.001). However, only at 3M, there was a significant difference in mean heart rate being lower in patients with compared to patients without recurrences (p=0.031). In this regard, patients with a heart rate ≥60 bpm at 3M and a heart rate change ≥11 bpm (PRE to 3M) had a favorable outcome in terms of recurrences compared to the remaining patients (HR 0.61 (95% CI, 0.44–0.84), p=0.002 and HR 0.55 (95% CI, 0.40–0.76), p&lt;0.001, respectively). These variables remained independently associated in multivariable analysis.

Conclusion

Our study confirms the impact of PVI on cardiac autonomic function with a significant heart increase post-ablation. A heart rate ≥60bpm at 3M and a heart rate change ≥11 bpm (PRE to 3M) are associated with a favorable outcome in terms of recurrences.

Funding Acknowledgement

Type of funding source: Foundation. Main funding source(s): German Research Foundation

Long-term outcome of patients with invasive electrophysiology procedure related cardiac tamponade

Aims

Iatrogenic cardiac tamponades are a rare but dreaded complication of invasive electrophysiology procedures (EPs). Their long-term impact on clinical outcomes is unknown. This study analyzed the risk of death or serious cardiovascular events in patients suffering from EP related cardiac tamponade requiring pericardiocentesis during long-term follow-up.

Methods and results

Out of 19997 invasive EPs at our university hospital between January 1998 and September 2018, all patients with EP related periprocedural cardiac tamponade were identified (n=60) and matched (1:3 ratio) to a control group (n=180). After a follow-up of 5 years, the composite primary end point - death from any cause, acute myocardial infarction, TIA/stroke and hospitalization for heart failure – occurred in significantly more patients in the tamponade than in the control group (12 patients (20.0%) vs 19 patients (10.6%); Hazard ratio (HR) 2.53 (95% CI, 1.15–5.58); p=0.021). This was mainly driven by a higher incidence of TIA/stroke in the tamponade than in the control group (HR 3.75 (95% CI, 1.01–13.97); p=0.049). Death from any cause, acute myocardial infarction and hospitalization for heart failure did not show a significant difference between the groups. Hospitalization for pericarditis occurred in significantly more patients in the tamponade than in the control group (HR 36.0 (95% CI, 4.68–276.86); p=0.001).

Conclusion

Patients with EP related cardiac tamponade are at higher risk for cerebrovascular events during the first two weeks and hospitalization for pericarditis during the first months after index procedure. Despite the increased risk for early complications tamponade patients have a good long-term prognosis without increased risk for mortality or other serious cardiovascular events.

Funding Acknowledgement

Type of funding source: Foundation. Main funding source(s): German Research Foundation

Long-term outcome of patients with invasive electrophysiology procedure-related cardiac tamponade

AIMS

Iatrogenic cardiac tamponades are a rare but dreaded complication of invasive electrophysiology procedures (EPs). Their long-term impact on clinical outcomes is unknown. This study analysed the risk of death or serious cardiovascular events in patients suffering from EP-related cardiac tamponade requiring pericardiocentesis during long-term follow-up.

METHODS AND RESULTS

Out of 19 997 invasive EPs at the Karolinska University Hospital between January 1998 and September 2018, all patients with EP-related periprocedural cardiac tamponade were identified (n = 60) and matched (1:3 ratio) to a control group (n = 180). After a follow-up of 5 years, the composite primary endpoint - death from any cause, acute myocardial infarction, transitory ischaemic attack (TIA)/stroke, and hospitalization for heart failure - occurred in significantly more patients in the tamponade than in the control group [12 patients (20.0%) vs. 19 patients (10.6%); hazard ratio (HR) 2.53 (95% confidence interval, CI 1.15-5.58); P = 0.021]. This was mainly driven by a higher incidence of TIA/stroke in the tamponade than in the control group [HR 3.75 (95% CI 1.01-13.97); P = 0.049]. Death from any cause, acute myocardial infarction, and hospitalization for heart failure did not show a significant difference between the groups. Hospitalization for pericarditis occurred in significantly more patients in the tamponade than in the control group [HR 36.0 (95% CI 4.68-276.86); P = 0.001].

CONCLUSION

Patients with EP-related cardiac tamponade are at higher risk for cerebrovascular events during the first 2 weeks and hospitalization for pericarditis during the first months after index procedure. Despite the increased risk for early complications tamponade patients have a good long-term prognosis without increased risk for mortality or other serious cardiovascular events.

Biophysical parameters during radiofrequency catheter ablation of scar-mediated ventricular tachycardia: epicardial and endocardial applications via manual and magnetic navigation

BACKGROUND

There is a paucity of data on biophysical parameters during radiofrequency ablation of scar-mediated ventricular tachycardia (VT).

METHODS AND RESULTS

Data were collected from consecutive patients undergoing VT ablation with open-irrigation. Complete data were available for 372 lesions in 21 patients. The frequency of biophysical parameter changes were: >10Ω reduction (80%), bipolar EGM reduction (69%), while loss of capture was uncommon (32%). Unipolar injury current was seen in 72% of radiofrequency applications. Both EGM reduction and impedance drop were seen in 57% and a change in all 3 parameters was seen in only 20% of lesions. Late potentials were eliminated in 33%, reduced/modified in 56%, and remained after ablation in 11%. Epicardial lesions exhibited an impedance drop (90% vs. 76%, P = 0.002) and loss of capture (46% vs. 27%, P < 0.001) more frequently than endocardial lesions. Lesions delivered manually exhibited a >10Ω impedance drop (83% vs. 71%, P = 0.02) and an EGM reduction (71% vs. 40%, P < 0.001) more frequently than lesions applied using magnetic navigation, although loss of capture, elimination of LPs, and a change in all 3 parameters were similarly observed.

CONCLUSIONS

VT ablation is inefficient as the majority of radiofrequency lesions do not achieve more than one targeted biophysical parameter. Only one-third of RF applications targeted at LPs result in complete elimination. Epicardial ablation within scar may be more effective than endocardial lesions, and lesions applied manually may be more effective than lesions applied using magnetic navigation. New technologies directed at identifying and optimizing ablation effectiveness in scar are clinically warranted.

Feedback responses rapidly scale with the urgency to correct for external perturbations

Healthy subjects can easily produce voluntary actions at different speeds and with varying accuracy requirements. It remains unknown whether rapid corrective responses to mechanical perturbations also possess this flexibility and, thereby, contribute to the capability expressed in voluntary control. Paralleling previous studies on self-initiated movements, we examined how muscle activity was impacted by either implicit or explicit criteria affecting the urgency to respond to the perturbation. Participants maintained their arm position against torque perturbations with unpredictable timing and direction. In the first experiment, the urgency to respond was explicitly altered by varying the time limit (300 ms vs. 700 ms) to return to a small target. A second experiment addresses implicit urgency criteria by varying the radius of the goal target, such that task accuracy could be achieved with less vigorous corrections for large targets than small target. We show that muscle responses at ∼60 ms scaled with the task demand. Moreover, in both experiments, we found a strong intertrial correlation between long-latency responses (∼50–100 ms) and the movement reversal times, which emphasizes that these rapid motor responses are directly linked to behavioral performance. The slopes of these linear regressions were sensitive to the experimental condition during the long-latency and early voluntary epochs. These findings suggest that feedback gains for very rapid responses are flexibly scaled according to task-related urgency.

Atrial Fibrillation Ablation: Do We Really Need Preprocedural Imaging?

Atrial fibrillation is the most common human arrhythmia, causing significant mortality and morbidity. Because of the potential for complications, it is important that procedures be made as safe and effective as possible by combining safe procedural planning with effective therapy delivery. To change the current approach, large randomized studies are needed to guide the selection of patients who may safely undergo ablation without transesophageal echocardiography to exclude thrombus. For institutions routinely using computed tomography and magnetic resonance imaging to assess pulmonary vein anatomy before procedures, the possibility of excluding intracardiac thrombi using these imaging modalities should be considered.

Unipolar and bipolar electrogram characteristics predict exit block during pulmonary vein antral isolation

INTRODUCTION

 The usefulness of unipolar electrograms (EGMs) has been reported in assessing lesion transmurality and conduction block along ablation lines. It is unknown whether unipolar and bipolar EGM characteristics predict exit block during pulmonary vein isolation (PVI) procedures.

METHODS AND RESULTS

 Twenty patients (63 ± 7 years; 14 males [70%]) undergoing PVI with a circular mapping catheter (CMC) placed outside each PV ostium were retrospectively studied. After entrance block was achieved, pacing at each bipole around the CMC was performed to assess for absence of atrial capture (exit block). Bipolar EGMs recorded before pacing were examined for voltage, duration, fractionation, and monophasic morphology. Unipolar EGMs were examined for positive and negative amplitude, PQ segment elevation, fractionation, and monophasic morphology. The association of these parameters with atrial capture (absence of exit block) at each site was analyzed. After achievement of entrance block, only 23 of 64 PV antra (36%) exhibited exit block. Unipolar EGMs at sites with persistent capture were more likely to be fractionated and had larger negative deflections. Bipolar EGMs at sites with persistent capture showed higher amplitude, longer duration, were more likely to be fractionated, and were less likely to be monophasic. In a multivariate logistic regression model, bipolar and unipolar fractionation, bipolar duration, and lack of bipolar monophasic morphology were independently associated with persistent atrial capture.

CONCLUSION

 Specific unipolar and bipolar EGM characteristics are associated with left atrium capture after PV antral isolation. These parameters might be useful in predicting the need for further ablation to achieve exit block.

Friedreich's Ataxia: a review from a cardiology perspective

BACKGROUND

Neuromuscular disorders are not among the common causes of cardiomyopathy in the general population; however, cardiomyopathy is known to occur in several neuromuscular disorders including Friedreich's Ataxia (FA). In patients with neuromuscular disorders, concomitant cardiac involvement contributes significantly to morbidity and mortality and often leads to premature death.

METHODS

An extensive literature search of Medline and Pubmed was conducted to include all published reports on cardiac involvement in FA. Secondary articles were identified from key paper reference listings.

CONCLUSION

Hypertrophic cardiomyopathy is a cardinal feature of FA; therefore all FA patients should be screened for cardiomyopathy. A cardiac examination, ECG and ECHO are advised at diagnosis, and also on the development of any cardiac symptoms. Treatment is determined by the presence of symptoms, the presence of left ventricular outflow gradient and the sudden death risk. Institution of aggressive medical therapy early in the course of the disease may help improve quality of life and provide survival benefit.

Defibrillation threshold testing fails to show clinical benefit during long-term follow-up of patients undergoing cardiac resynchronization therapy defibrillator implantation

BACKGROUND

The utility of defibrillation threshold testing in patients undergoing implantable cardioverter-defibrillator (ICD) implantation is controversial. Higher defibrillation thresholds have been noted in patients undergoing implantation of cardiac resynchronization therapy defibrillators (CRT-D). Since the risks and potential benefits of testing may be higher in this population, we sought to assess the impact of defibrillation safety margin or vulnerability safety margin testing in CRT-D recipients.

METHODS AND RESULTS

A total of 256 consecutive subjects who underwent CRT-D implantation between January 2003 and December 2007 were retrospectively reviewed. Subjects were divided into two groups based on whether (n= 204) or not (n= 52) safety margin testing was performed. Patient characteristics, tachyarrhythmia therapies, procedural results, and clinical outcomes were recorded. Baseline characteristics, including heart failure (HF) severity, were comparable between the groups. Four cases of HF exacerbation (2%), including one leading to one death, were recorded in the tested group immediately post-implantation. No complications were observed in the untested group. After a mean follow-up of 32 ± 20 months, the proportion of appropriate shocks in the two groups was similar (31 vs. 25%, P = 0.49). There were three cases of failed appropriate shocks in the tested group, despite adequate safety margins at implantation, whereas no failed shocks were noted in the untested group. Survival was similar in the two groups.

CONCLUSION

Defibrillation efficacy testing during implant of CRT-D was associated with increased morbidity and did not predict the success of future device therapy or improve survival during long-term follow-up.

Electrophysiological differences between the epicardium and the endocardium of the left atrium

BACKGROUND

Electrophysiological properties of the atrial endocardium compared to epicardium are not well understood. The purpose of this study was to compare the electrophysiological properties and vulnerability to arrhythmia induction from these regions.

METHODS AND RESULTS

Transseptal endocardial and percutaneous epicardial mapping were performed in a porcine model (n = 7). Two opposing 4-mm electrophysiological catheters were positioned endocardially and epicardially. A circular mapping catheter (CMC) was positioned at the ostium of the common inferior pulmonary vein (CIPV) recording left atrial (LA)-PV potentials. Endocardial and epicardial effective refractory periods (ERPs) at two basic cycle lengths (CLs) of 600 and 400 ms were recorded from four anatomic locations (CIPV, LA appendage, right superior PV, and LA posterior wall). Atrial repetitive response (ARR) induction was also tested from endocardial and epicardial sites. Overall, 254 ERP measurements (mean 36.3 per animal) and 84 induction attempts (mean 12 per animal) were performed. The ERP was significantly shorter in the epicardium compared to the endocardium at basic CL of 400 ms (P = 0.006) but not at CL of 600 ms (P = 0.2). In addition, only the epicardium demonstrated ERP shortening when the CL of the basic drive was shortened (P = 0.03). ARR could be induced more often from the epicardium (P = 0.002) and fibrillatory activity with epicardial/endocardial dissociation was recorded (n = 3). Also, the earliest PV activation site on the CMC was noted to be different in 16.5% of cases during epicardial and endocardial pacing.

CONCLUSION

The electrophysiological characteristics of the atrial epicardium are different from the endocardium with a shorter ERP and more frequent ARR induction by programed stimulation.

Neuraxial modulation for refractory ventricular arrhythmias: value of thoracic epidural anesthesia and surgical left cardiac sympathetic denervation

BACKGROUND

Reducing sympathetic output to the heart from the neuraxis can protect against ventricular arrhythmias. The purpose of this study was to assess the value of thoracic epidural anesthesia (TEA) and left cardiac sympathetic denervation (LCSD) in the management of ventricular arrhythmias in patients with structural heart disease.

METHODS AND RESULTS

Clinical data of 14 patients (25 to 75 years old, mean+/-SD of 54.2+/-16.6 years; 13 men) who underwent TEA, LCSD, or both to control ventricular tachycardia (VT) refractory to medical therapy and catheter ablation were reviewed. Twelve patients were in VT storm, and 2 experienced recurrent VT despite maximal medical therapy and catheter ablation procedures. The total number of therapies per patient before either procedure ranged from 5 to 202 (median of 24; 25th and 75th percentile, 5 and 56). Eight patients underwent TEA, and 9 underwent LCSD (3 patients had both procedures). No major procedural complications occurred. After initiation of TEA, 6 patients had a large (> or =80%) decrease in VT burden. After LCSD, 3 patients had no further VT, 2 had recurrent VT that either resolved within 24 hours or responded to catheter ablation, and 4 continued to have recurrent VT. Nine of 14 patients survived to hospital discharge (2 TEA alone, 3 TEA/LCSD combined, and 4 LCSD alone), 1 of the TEA alone patients underwent an urgent cardiac transplantation.

CONCLUSIONS

Initiation of TEA and LCSD in patients with refractory VT was associated with a subsequent decrease in arrhythmia burden in 6 (75%) of 8 patients (68% confidence interval 51% to 91%) and 5 (56%) of 9 patients (68% confidence interval 34% to 75%), respectively. These data suggest that TEA and LCSD may be effective additions to the management of refractory ventricular arrhythmias in structural heart disease when other treatment modalities have failed or may serve as a bridge to more definitive therapy.

Atrial fibrillation and congestive heart failure

Atrial fibrillation (AF) and congestive heart failure (CHF) are commonly encountered together, either condition predisposing to the other. The presence of each condition increases the morbidity and mortality associated with the other and their coexistence complicates patient management. Common risk factors include age, hypertension, diabetes mellitus and coronary artery disease. This article addresses the complex interplay between AF and CHF with regards to shared mechanisms, effects on prognosis, management issues and available, pharmacological and non-pharmacological therapeutic options.

Accuracy of sonography in transient synovitis

The presence of acute transient synovitis (TS, irritable hip) often warrants hospital admission not only to exclude underlying sepsis but also to aspirate when the intraarticular pressure might induce ischemia in the femoral head. Diagnostic doubt may affect this admission. We evaluated 68 patients in a prospective study comparing sonography with diagnostic aspiration and clinical examination. Sonography proved to be relatively accurate (81%) but was inferior to careful clinical evaluation in diagnosing hip effusions. Sonography may be helpful if diagnostic doubt exists. Aspiration under sonographic control will improve this accuracy.