Use of dabigatran for periprocedural anticoagulation in patients undergoing catheter ablation for atrial fibrillation

BACKGROUND

Pulmonary vein isolation (PVI) for atrial fibrillation is associated with a transient increased risk of thromboembolic and hemorrhagic events. We hypothesized that dabigatran can be safely used as an alternative to continuous warfarin for the periprocedural anticoagulation in PVI.

METHODS AND RESULTS

A total of 999 consecutive patients undergoing PVI were included; 376 patients were on dabigatran (150 mg), and 623 patients were on warfarin with therapeutic international normalized ratio. [corrected] Dabigatran was held 1 to 2 doses before PVI and restarted at the conclusion of the procedure or as soon as patients were transferred to the nursing floor. Propensity score matching was applied to generate a cohort of 344 patients in each group with balanced baseline data. Total hemorrhagic and thromboembolic complications were similar in both groups, before (3.2% versus 3.9%; P=0.59) and after (3.2% versus 4.1%; P=0.53) matching. Major hemorrhage occurred in 1.1% versus 1.6% (P=0.48) before and 1.2% versus 1.5% (P=0.74) after matching in the dabigatran versus warfarin group, respectively. A single thromboembolic event occurred in each of the dabigatran and warfarin groups. Despite higher doses of intraprocedural heparin, the mean activated clotting time was significantly lower in patients who held dabigatran for 1 or 2 doses than those on warfarin.

CONCLUSIONS

Our study found no evidence to suggest a higher risk of thromboembolic or hemorrhagic complications with use of dabigatran for periprocedural anticoagulation in patients undergoing PVI compared with uninterrupted warfarin therapy.

Endoscopic findings in upper gastrointestinal bleeding patients at Lacor hospital, northern Uganda

BACKGROUND

Upper gastrointestinal bleeding (UGIB) is a common emergency medical condition that may require hospitalization and resuscitation, and results in high patient morbidity. Upper gastrointestinal endoscopy is the preferred investigative procedure for UGIB because of its accuracy, low rate of complication, and its potential for therapeutic interventions.

OBJECTIVE

To determine the endoscopic findings in patients presenting with UGIB and its frequency among these patients according to gender and age in Lacor hospital, northern Uganda.

METHODS

The study was carried out at Lacor hospital, located at northern part of Uganda. The record of 224 patients who underwent endoscopy for upper gastrointestinal bleeding over a period of 5 years between January 2006 and December 2010 were retrospectively analyzed.

RESULTS

A total of 224 patients had endoscopy for UGIB which consisted of 113 (50.4%) males and 111 (49.6%) females, and the mean age was 42 years ± SD 15.88. The commonest cause of UGIB was esophagealvarices consisting of 40.6%, followed by esophagitis (14.7%), gastritis (12.6%) and peptic ulcer disease (duodenal and gastric ulcers) was 6.2%. The malignant conditions (gastric and esophageal cancers) contributed to 2.6%. Other less frequent causes of UGIB were hiatus hernia (1.8), duodenitis (0.9%), others-gastric polyp (0.4%). Normal endoscopic finding was 16.1% in patients who had UGIB.

CONCLUSIONS

Esophageal varices are the commonest cause of upper gastrointestinal bleeding in this environment as compared to the west which is mainly peptic ulcer disease.

Remote monitoring of cardiovascular devices: a time and activity analysis

BACKGROUND

Expanding indications for cardiovascular implantable electronic devices are accompanied by an increasing burden of device clinic follow-up. Remote monitoring (RM) may be less time-consuming compared to in-office follow-up; however, its effect on the device clinic workflow has not been clarified.

OBJECTIVE

To determine the impact of RM on device clinic workflow.

METHODS

Detailed workflow data were prospectively collected over a 2-week period in a busy device clinic.

RESULTS

Five hundred remote transmissions were received from 434 patients between March 1 and March 16, 2011--346 implantable cardioverter-defibrillator, 84 pacemaker, and 70 implantable loop recorder transmissions--on 4 RM platforms (CareLink 56.4%, Merlin.net 21.4%, LATITUDE 17.8%, and Home Monitoring 4.4%). The mean time spent per transmission was 11.5 ± 7.7 minutes, which was less than in-person interrogations (27.7 ± 9.9 minutes; P <.01). Of 500 transmissions, 135 (27.0%) demonstrated clinically important findings; however, only 41 (8.2%) were forwarded for physician review. Of 500 transmissions, 138 (27.6%) were unscheduled, and these were more likely to contain a clinically important event (56 of 138 [40.6%] vs 79 of 362 [21.8%]; P = .0001). A total of 5.8% of the transmissions were duplicate. Transmissions that revealed clinically important findings took longer to process than those that did not (21.0 ± 7.4 minutes vs 10.1 ± 2.1 minutes; P <.05). A total of 49.2% of the scheduled remote transmissions were missed because of patient noncompliance. Telephone follow-up of patients (mean 21 patients/d) who missed scheduled remote transmissions took a mean of 55.1 (range 20-98) min/d.

CONCLUSIONS

Analysis of RM transmissions has significant implications for the device clinic workflow. Nonactionable transmissions are rapidly processed, allowing clinicians to focus on clinically important findings. However, poor patient compliance complicates the workflow efficiency of currently available systems.

Investigation of a novel algorithm for synchronized left-ventricular pacing and ambulatory optimization of cardiac resynchronization therapy: results of the adaptive CRT trial

BACKGROUND

In patients with sinus rhythm and normal atrioventricular conduction, pacing only the left ventricle with appropriate atrioventricular delays can result in superior left ventricular and right ventricular function compared with standard biventricular (BiV) pacing.

OBJECTIVE

To evaluate a novel adaptive cardiac resynchronization therapy ((aCRT) algorithm for CRT pacing that provides automatic ambulatory selection between synchronized left ventricular or BiV pacing with dynamic optimization of atrioventricular and interventricular delays.

METHODS

Patients (n = 522) indicated for a CRT-defibrillator were randomized to aCRT vs echo-optimized BiV pacing (Echo) in a 2:1 ratio and followed at 1-, 3-, and 6-month postrandomization.

RESULTS

The study met all 3 noninferiority primary objectives: (1) the percentage of aCRT patients who improved in their clinical composite score at 6 months was at least as high in the aCRT arm as in the Echo arm (73.6% vs 72.5%, with a noninferiority margin of 12%; P = .0007); (2) aCRT and echo-optimized settings resulted in similar cardiac performance, as demonstrated by a high concordance correlation coefficient between aortic velocity time integrals at aCRT and Echo settings at randomization (concordance correlation coefficient = 0.93; 95% confidence interval 0.91-0.94) and at 6-month postrandomization (concordance correlation coefficient = 0.90; 95% confidence interval 0.87-0.92); and (3) aCRT did not result in inappropriate device settings. There were no significant differences between the arms with respect to heart failure events or ventricular arrhythmia episodes. Secondary end points showed similar benefit, and right-ventricular pacing was reduced by 44% in the aCRT arm.

CONCLUSIONS

The aCRT algorithm is safe and at least as effective as BiV pacing with comprehensive echocardiographic optimization.

Implantable cardioverter-defibrillator FDA safety advisories: Impact on patient mortality and morbidity

BACKGROUND

A significant proportion of implantable cardioverter-defibrillators (ICDs) have been subject to Food and Drug Administration (FDA) advisories. The impact of device advisories on mortality or patient care is poorly understood. Although estimated risks of ICD generators under advisory are low, dependency on ICD therapies to prevent sudden death justifies the assessment of long-term mortality.

OBJECTIVE

To test the association of FDA advisory status with long-term mortality.

METHODS

The study was a retrospective, single-center review of clinical outcomes, including device malfunctions, in patients from implantation to either explant or death. Patients with ICDs first implanted at Cleveland Clinic between August 1996 and May 2004 who became subject to FDA advisories on ICD generators were identified. Mortality was determined by using the Social Security Death Index.

RESULTS

In 1644 consecutive patients receiving first ICD implants, 704 (43%) became subject to an FDA advisory, of which 172 (10.5%) were class I and 532 (32.3%) were class II. ICDs were explanted before advisory notifications in 14.0% of class I and 10.1% of class II advisories. Among ICDs under advisory, 28 (4.0%) advisory-related and 15 non-advisory- related malfunctions were documented. Over a median follow-up of 70 months, 814 patients died. Kaplan-Meier 5-year survival rate was 65.6% overall, and 64.2, 61.1, and 69.3% in patients with no, class I, and class II advisories, respectively (P = .17).

CONCLUSIONS

ICD advisories impacted 43% of the patients. Advisory-related malfunctions affected 4% within the combined advisory group. Based on a conservative management strategy, ICDs under advisory were not associated with increased mortality over a background of significant disease-related mortality.

Predictors of response to cardiac resynchronization therapy in patients with a non-left bundle branch block morphology

Patients with non-left bundle branch block (LBBB) morphologies are thought to derive less benefit from cardiac resynchronization therapy (CRT) than those with LBBB. However, some patients do exhibit improvement. The characteristics associated with a response to CRT in patients with non-LBBB morphologies are unknown. Clinical, electrocardiographic, and echocardiographic data were collected from 850 consecutive patients presenting for a new CRT device. For inclusion, all patients had a left ventricular ejection fraction of ≤35%, a QRS duration of ≥120 ms, and baseline and follow-up echocardiograms available. Patients with a paced rhythm or LBBB were excluded. The response was defined as an absolute decrease in left ventricular end-systolic volume of ≥10% from baseline. Multivariate models were constructed to identify variables significantly associated with the response and long-term outcomes. A total of 99 patients met the inclusion criteria. Of these 99 patients, 22 had right bundle branch block and 77 had nonspecific intraventricular conduction delay; 52.5% met the criteria for response. On multivariate analysis, the QRS duration was the only variable significantly associated with the response (odds ratio per 10-ms increase 1.23, 95% confidence interval 1.01 to 1.52, p = 0.048). During a mean follow-up of 5.4 ± 0.9 years, 65 patients died or underwent heart transplant or left ventricular assist device placement. On multivariate analysis, the QRS duration was inversely associated with poor long-term outcomes (hazard ratio per 10-ms increase 0.79, 95% confidence interval 0.66 to 0.94, p = 0.005). In patients with advanced heart failure and non-LBBB morphologies, a wider baseline QRS duration is an important determinant of enhanced reverse ventricular remodeling and improved long-term outcomes after CRT.

The impact of left ventricular size on response to cardiac resynchronization therapy

Patients with nondilated (NDCM) or severely dilated cardiomyopathies (SDCM) have been underrepresented in clinical trials of cardiac resynchronization therapy (CRT). We examined changes in left ventricular ejection fraction (LVEF) and survival in patients with NDCM or SDCM compared with those with traditionally studied moderately dilated cardiomyopathy.

METHODS

We evaluated 800 consecutive patients undergoing the original implantation of a biventricular pacemaker between January 2004 and August 2007. For inclusion, patients had a baseline and pre-CRT echocardiogram, an LVEF ≤40%, a US social security number, and New York Heart Association class II to IV symptoms on standard medical therapy. Patients with a follow-up echocardiogram >2 months after device implantation were included in an analysis of remodeling. Using multivariate models, the impact of baseline left ventricular end-diastolic diameter (LVEDD) on change in LVEF and all-cause mortality was assessed.

RESULTS

A total of 668 patients met inclusion criteria and were included in the assessment of mortality. Four hundred seventy-one had an appropriately timed follow-up echocardiogram and were included in the analysis of remodeling. Patients in all 3 groups realized improvements in LVEF (%) after CRT as follows: NDCM (n = 137; LVEDD ≤5.5 cm) 10.0 ± 12.7, P < .001; moderately dilated cardiomyopathy (n = 233; LVEDD 5.6-6.9 cm) 8.2 ± 11.3, P < .001; and SDCM (n = 101; LVEDD ≥7.0 cm) 5.4 ± 9.4, P < .001. In multivariate analysis, baseline LVEDD was inversely associated with change in LVEF (parameter estimate -3.13 ± 0.56, P < .001) and directly associated with increased all-cause mortality (hazard ratio 1.25 [1.05-1.47] P = .01).

CONCLUSION

Patients with NDCM and SDCM experience significant improvements in LVEF after CRT. The degree of baseline left ventricular dilatation before CRT is an important predictor of subsequent changes in LVEF and survival.

QRS fragmentation is not associated with poor response to cardiac resynchronization therapy

BACKGROUND

QRS fragmentation (fQRS) has been shown to be a marker of scar in patients with left ventricular dysfunction. Whether fQRS is associated with progressive left ventricular remodeling and increased mortality in patients receiving cardiac resynchronization therapy (CRT) is unclear.

METHODS

We reviewed the preimplant and follow-up echocardiograms in 233 patients undergoing the new implantation of a CRT device between December 2001 and November 2006. Patients were included if they had a pre-CRT ECG with appropriate filter settings (filter 0.16-100 or 0.16-150 Hz, 25 mm/s, 10 mm/mV), a left ventricular ejection fraction (LVEF) ≤40%, and New York Heart Association class II-IV symptoms on standard medical therapy. The 12-lead electrocardiogram (ECG) was interpreted by two blinded reviewers for the presence of fQRS. Remodeling end points, including changes in LVEF and left ventricular end-diastolic (LVEDV) and systolic (LVESV) volumes, were compared between patients with and without contiguous fQRS, and an assessment of all-cause mortality was made.

RESULTS

Two hundred thirty-two patients met inclusion criteria, of which 50 demonstrated fQRS in contiguous leads. There was no difference in improvement in LVEF (%) (7.9 ± 12.9 vs 6.8 ± 11.0, P = 0.60) or reduction in LVEDV (mL) (-30.1 ± 57.2 vs -15.7 ± 47.6) or LVESV (mL) (-33.7 ± 58.1 vs -22.7 ± 50.6, P = 0.40) between patients with and without contiguous fQRS. At a mean follow-up of 4.4 ± 1.9 years, there were a total of 89 deaths, 22 (44.0%) in patients with contiguous fQRS and 67 (36.8%) without (log rank P = 0.31).

CONCLUSIONS

QRS fragmentation is not a predictor of progressive ventricular remodeling or mortality in heart failure patients undergoing CRT.

Utility of a novel watch-based pulse detection system to detect pulselessness in human subjects

BACKGROUND

The Wriskwatch is a novel, watch-based pulse detection device that detects the loss of a radial pulse via advanced pulse detection technology and immediately contacts emergency medical systems.

OBJECTIVE

The purpose of this first-in-man, prospective, single-blinded, phase 1 study was to evaluate the ability of this device to detect motionlessness and pulselessness in human subjects as a simulation of sudden cardiac death.

METHODS

The study cohort consisted of 34 patients: 24 hospitalized patients and 10 presenting for implantable cardioverter-defibrillator (ICD) testing. We simulated loss of pulse in our hospitalized patients via blood pressure cuff inflation to occlude the brachial arterial pulse at random times in 20 subjects with no inflations in 4 while the patients were instructed to keep perfectly still. Of the 10 patients undergoing ventricular fibrillation (VF) induction during ICD testing, the exact times of VF induction were recorded. A blinded reviewer determined if and when motion and pulse were lost in all patients using only data from the device.

RESULTS

Of the 34 patients, 2 had an unusable signal, 1 had device ejection during ICD testing, and 2 had too much motion artifact and were excluded (5/34 patients, or 14.7% of the total cohort). Of the 29 remaining subjects, 4 had no loss of pulse of which the device correctly identified 3. In the remaining 25 patients, the device correctly identified the time of pulselessness in 23 of 25 (16/17 hospitalized patients and 7/8 ICD patients). Overall, the Wriskwatch was worn for a total of 561.2 minutes. Pulselessness was present for 5.8 minutes. The sensitivity of the watch to detect pulse status (based on 15-second intervals) was 99.9%, and the specificity was 90.3%.

CONCLUSION

The Wriskwatch is a novel device that shows promise as a tool to hasten activation of emergency medical systems and facilitate early defibrillation in patients with cardiac arrest.

Natural History and Long-Term Outcomes of Ablated Atrial Fibrillation

Background—

Atrial fibrillation (AF) ablation is increasingly used in clinical practice. We aimed to study the natural history and long-term outcomes of ablated AF.

Methods and Results—

We followed 831 patients after pulmonary vein isolation (PVI) performed in 2005. We documented clinical outcomes using our prospective AF registry with most recent update on this group of patients in October 2009. In the first year after ablation, 23.8% had early recurrence. Over long-term follow-up (55 months), only 8.9% had late arrhythmia recurrence defined as occurring beyond the first year after ablation. Repeat ablations in patients with late recurrence revealed conduction recovery in at least 1 of the previously isolated PVs in all of them and right-sided triggers with isoproterenol testing in 55.6%. At last follow-up, clinical improvement was 89.9% (79.4% arrhythmia-free off antiarrhythmic drugs and 10.5% with AF controlled with antiarrhythmic drugs). Only 4.6% continued to have drug-resistant AF. It was possible to safely discontinue anticoagulation in a substantial proportion of patients with no recurrence in the year after ablation (CHADS score ≤2, stroke incidence of 0.06% per year). The procedure-related complication rate was very low.

Conclusions—

Pulmonary vein isolation is safe and efficacious for long-term maintenance of sinus rhythm and control of symptoms in patients with drug-resistant AF. It obviates the need for antiarrhythmic drugs, negative dromotropic agents, and anticoagulants in a substantial proportion of patients.

A randomized controlled trial of the efficacy and safety of electroanatomic circumferential pulmonary vein ablation supplemented by ablation of complex fractionated atrial electrograms versus potential-guided pulmonary vein antrum isolation guided by intracardiac ultrasound

BACKGROUND

The study was conducted to compare relative safety and efficacy of pulmonary vein antrum isolation (PVAI) using intracardiac echocardiographic guidance and circumferential pulmonary vein ablation (CPVA) for atrial fibrillation (AF) using radiofrequency energy.

METHODS AND RESULTS

Sixty patients (81% men; 81% paroxysmal; age, 56+/-8 years) failing 2+/-1 antiarrhythmic drugs were randomly assigned to undergo CPVA (n=30) or PVAI (n=30) at 5 centers between December 2004 and October 2007. CPVA patients had circular lesions placed at least 1 cm outside of the veins. Ipsilateral veins were ablated en block with the end point of disappearance of potentials within the circular lesion. Left atrial roof line and mitral isthmus line were ablated without verification of block. For patients in AF postablation or with AF induced with programmed stimulation, complex fractionated electrograms were mapped and ablated to the end point of AF termination or disappearance of complex fractionated electrograms. PVAI did not include complex fractionated electrogram ablation. Esophageal temperature was monitored and kept within 2 degrees C of baseline or under 39 degrees C. Success was defined as absence of atrial tachyarrhythmias (AF/AT) off antiarrhythmic drugs. There was no difference between CPVA and PVAI regarding to baseline variables, catheter used, duration of the procedure, or RF delivery. Fluoroscopy time was longer with PVAI (54+/-17 minutes versus 77+/-18 minutes, P=0.0001). No significant complications occurred in either arm. PVAI was more likely to achieve control of AF/AT off antiarrhythmic drugs (57% versus 27%, P=0.02) at 2+/-1 years of follow-up.

CONCLUSIONS

A single PVAI procedure is more likely to result in freedom from AF/AT off antiarrhythmic drugs than CPVA supplemented by complex fractionated electrogram ablation in select patients.

Microvolt T-wave alternans, peak oxygen consumption, and outcome in patients with severely impaired left ventricular systolic function

BACKGROUND

Abnormal microvolt T-wave alternans (MTWA) and low peak oxygen consumption (VO2) both predict poor outcome in heart failure. However, their independent predictive properties have not been assessed in large-scale cohorts.

METHODS

This was an observational prospective cohort study of 303 consecutive patients referred for metabolic stress testing. All had an ejection fraction < or = 40% and were considered candidates for transplantation. The exercise laboratory did not collect MTWA data from patients with implanted pacemakers or defibrillators. The primary end point was a composite of all-cause death or United Network for Organ Sharing status 1 transplantation.

RESULTS

During a 2.8-year period, there were 34 deaths and 17 transplantations. Patients with abnormal MTWA had a higher event rate of 23% (31 of 136) vs 12% (20 of 167), with an unadjusted hazard ratio (HR) of 1.90 (95% confidence interval [CI], 1.90-3.33; p = 0.03). The association remained significant after adjustment for 3 clinical variables (HR, 1.89; 95% CI, 1.05-3.39; p = 0.03). After adding peak VO2 to the model, the association was no longer significant (adjusted HR, 1.18; 95% CI, 0.64-2.17, p = 0.60). After accounting for peak VO2 and 28 other confounders in a matched propensity analysis, MTWA was not predictive (propensity-matched HR, 0.79; 95% CI, 0.37-1.66; p = 0.53).

CONCLUSIONS

These results confirm the association of abnormal MTWA with poor outcome amongst patients with impaired left ventricular systolic function. However, this association is markedly attenuated after accounting for peak VO2.