Aysha Arshad

Superior vena cava defibrillator coils make transvenous lead extraction more challenging and riskier

To the Editor: Studies have demonstrated equivalent defibrillation efficacy and all-cause mortality in patients with single and dual coil implantable cardioverter-defibrillator (ICD) leads ([1,2][1]). Despite this equivalency, the vast majority of implanted ICD leads are dual coil ([3][2]). The

Cardiac resynchronization therapy is more effective in women than in men: the MADIT-CRT (Multicenter Automatic Defibrillator Implantation Trial with Cardiac Resynchronization Therapy) trial.

OBJECTIVES The purpose of this study was to investigate the factors related to sex-specific outcomes for death and heart failure events in the MADIT-CRT (Multicenter Automatic Defibrillator Implantation Trial With Cardiac Resynchronization Therapy) trial. BACKGROUND In the MADIT-CRT trial, women seemed to achieve a better result from resynchronization therapy than men. METHODS All 1,820 patients (453 female and 1,367 male) enrolled in the MADIT-CRT trial were included in this sex-specific outcome analysis that compared the effect of cardiac resynchronization therapy with defibrillator (CRT-D) relative to implanted cardioverter-defibrillator (ICD) on death or heart failure (whichever came first), heart failure only, and death at any time. RESULTS Female patients were more likely to have nonischemic cardiomyopathy and left bundle branch block and less likely to have renal dysfunction than male patients. Overall, female patients had a better result from CRT-D therapy than male patients, with a significant 69% reduction in death or heart failure (hazard ratio: 0.31, p < 0.001) and 70% reduction in heart failure alone (hazard ratio: 0.30, p < 0.001). Women had a significant 72% reduction in all-cause mortality in the total population (hazard ratio: 0.28, p = 0.02) and significant 82% and 78% reductions in mortality in those with QRS ≥ 150 ms and with left bundle branch block conduction disturbance, respectively, with sex-by-treatment interactions for mortality reduction significant at p < 0.05 in each of these 3 patient groups. These beneficial CRT-D effects among women were associated with consistently greater echocardiographic evidence of reverse cardiac remodeling in women than in men. CONCLUSIONS Women in the MADIT-CRT trial obtained significantly greater reductions in death or heart failure (whichever came first), heart failure alone, and all-cause mortality with CRT-D therapy than men, with consistently greater echocardiographic evidence of reverse cardiac remodeling in women than in men. (Multicenter Automatic Defibrillator Implantation Trial With Cardiac Resynchronization Therapy [MADIT-CRT]; NCT00180271).

Long‐Term Outcome Following Successful Pulmonary Vein Isolation: Pattern and Prediction of Very Late Recurrence

Background: Despite encouraging results of pulmonary vein isolation (PVI) ablation for atrial fibrillation (AF), it is unclear whether there is genuine cure or there is an important attrition rate. We sought to determine the long‐term outcome of the initial responders who experienced a prolonged AF‐free complete response.

The utility of 12-lead Holter monitoring in patients with permanent atrial fibrillation for the identification of nonresponders after cardiac resynchronization therapy.

OBJECTIVES This study sought to determine the incidence of ineffective capture using 12-lead Holter monitoring and to assess whether this affects response to cardiac resynchronization therapy (CRT). BACKGROUND Cardiac resynchronization therapy is used in patients with atrial fibrillation (AF), prolonged QRS duration, and heart failure in the setting of ventricular dysfunction. The percentage of ventricular pacing is used as an indicator of adequate biventricular (BiV) pacing. Although device counters show a high pacing percentage, there may be ineffective capture because of underlying fusion and pseudo-fusion beats. METHODS We identified 19 patients (age 72 +/- 8 years, ejection fraction 18 +/- 5%), with permanent AF who underwent CRT. All patients received digoxin, beta-blockers, and amiodarone for rate control; device interrogation showed >90% BiV pacing. Patients had a 12-lead Holter monitor to assess the presence of effective (>90% fully paced beats/24 h) pacing. At 12 months post-CRT, the New York Heart Association functional class was reassessed and an echocardiogram was obtained and compared with pre-CRT. RESULTS Only 9 (47%) patients had effective pacing. The other 10 (53%) patients had 16.4 +/- 4.6% fusion and 23.5 +/- 8.7% pseudo-fusion beats. Long-term responders (> or =1 New York Heart Association functional class improvement) to CRT had a significantly higher percentage of fully paced beats (86.4 +/- 17.1% vs. 66.8 +/- 19.1%; p = 0.03) than nonresponders. CONCLUSIONS Pacing counters overestimate the degree of effective BiV pacing in patients with permanent AF undergoing CRT therapy. Only patients with complete capture responded clinically to CRT. These findings have important implications for the application of CRT to patients with permanent AF and heart failure.

Cardiac implantable electronic device infections: Incidence, risk factors, and the effect of the AigisRx antibacterial envelope

BACKGROUND Cardiac implantable electronic device (CIED) infection is associated with morbidity and mortality. OBJECTIVES To determine the incidence and risk factors for CIED infection, to develop a scoring index for risk stratification, and to analyze the effect of the AIGISRx envelope on infection rates. METHODS Consecutive patients who underwent a CIED procedure were identified and surveyed for 6 months for the development of an infection necessitating removal of all implanted hardware. RESULTS In the pre-envelope era, an infection occurred in 25 (1.5%) of 1651 patients. After its availability, an envelope was used in 275 (22%) of 1240 patients; an infection occurred in 8 (0.6%) patients in this era (P = .029 vs pre-envelope). In the overall cohort of 2891 patients, the infection rate was 1.2% and 3.5% in patients with an implantable cardioverter-defibrillator device and those with a cardiac resynchronization therapy defibrillator device, respectively (P = .018); in these patients, 7 independent risk factors predicted infection: early pocket re-exploration, male sex, diabetes, upgrade procedure, heart failure, hypertension, and glomerular filtration rate < 60 mL/min. A composite risk score (0-25; C index 0.72; 95% confidence interval 0.61-0.83) was created by weight, adjusting these 7 factors: 3 groups emerged-low risk (score 0-7; 1% infection), medium risk (score 8-14; 3.4% infection), and high risk (score ≥15; 11.1% infection). The envelope reduced infections by 79% and 100% in the medium- and high-risk groups, respectively. CONCLUSIONS CIED infection most commonly occurred in patients with an implantable cardioverter-defibrillator device and those with a cardiac resynchronization therapy defibrillator device. A composite score based on clinical variables appeared feasible for infection risk stratification. The AIGISRx envelope significantly lowered the risk of CIED infection. Randomized clinical data are warranted.

Long-term ECG monitoring using an implantable loop recorder for the detection of atrial fibrillation after cavotricuspid isthmus ablation in patients with atrial flutter

BACKGROUND In patients with atrial flutter who undergo cavotricuspid isthmus ablation, long-term electrocardiographic (ECG) monitoring may identify new onset of atrial fibrillation (AF). OBJECTIVES To ascertain, through the use of an implantable loop recorder (ILR) with a dedicated AF detection algorithm, the incidence, duration, and burden of new AF in these patients and to develop an optimal postablation ECG monitoring strategy. METHODS We enrolled 20 patients with flutter, a CHADS2 score of 2-3, and no prior episode of AF. After cavotricuspid isthmus ablation, we implanted an ILR, which was interrogated routinely; all stored ECGs were adjudicated. RESULTS During a mean follow-up of 382 ± 218 days, 3 patterns were observed. First, in 11 (55%) patients, stored ECGs confirmed AF at 62 ± 38 days after ablation. Second, in 4 (20%) patients, although the ILR suggested AF, episodes actually represented sinus rhythm with frequent premature atrial contractions and/or oversensing. Third, in 5 (25%) patients, no AF was observed. Episodes <4 hours were associated with low AF burden (<1%) or false detections. The 1-year freedom from any episode of AF >4 and >12 hours was 52% and 83%, respectively. CONCLUSIONS Our data show that many (but not all) patients develop new AF within the first 4 months of flutter ablation. Since external ECG monitoring for this duration is impractical, the ILR has an important role for long-term AF surveillance. Future research should be directed toward identifying the relationship between duration/burden of AF and stroke and improving existing ILR technology.

Very long-term outcome after initially successful catheter ablation of atrial fibrillation

BACKGROUND The ablation of atrial fibrillation (AF) using pulmonary vein isolation is indicated when patients do not respond favorably to medical therapy. Successful procedures are accomplished in the majority of patients, but the outcome after many years of follow-up after ablation is unknown. OBJECTIVE To describe the long-term recurrence rate and pattern of AF after successful ablation. METHODS A prospectively identified cohort of 445 patients who demonstrated freedom from AF for at least 1 year postablation (single procedure in 391 [87.9%]) was followed for 66.0 ± 34.0 months. Patients were seen at least annually as outpatients and underwent regular electrocardiographic monitoring. RESULTS At 40.7 ± 27.0 months postablation, 97 (21.8%) patients experienced at least 1 episode of recurrent AF. The vast majority of events were symptomatic, and no serious clinical events were associated with AF recurrence (eg, stroke). There was a steady attrition rate reaching 16.3% and 29.8% at 5 and 10 years, respectively. In 29 patients (29.5%) of the patients, recurrences were self-limited; the remainder required either medical therapy or repeat ablation. By multivariate analysis, persistent AF (hazard ratio 3.08; P < .0001) and hypertension (hazard ratio 1.08; P = .009) were independent risk factors for the recurrence of AF. The presence of both factors placed the patient at high risk of recurrence: 37.6% at 5 years and 68.8% at 10 years. CONCLUSIONS Over the decade after a successful ablation of AF, most patients continue to demonstrate freedom from AF. At the highest risk of very late recurrence is the subset of patients with hypertension and prior persistent AF.

Multicenter experience with extraction of the Riata/Riata ST ICD lead

BACKGROUND In November 2011, the Food and Drug Administration issued a class I recall of Riata and Riata ST implantable cardioverter-defibrillator leads. Management recommendations regarding the recall have remained controversial. OBJECTIVE Data regarding the safety and feasibility of extraction of Riata implantable cardioverter-defibrillator leads are limited. METHODS We performed a retrospective study of patients undergoing extraction of Riata/Riata ST leads at 11 centers. RESULTS Between July 2003 and April 2013, 577 Riata/Riata ST leads were extracted from 577 patients (Riata 467, [84%]; Riata ST 89, [16%]). Complete procedural success achieved in 99.1%. The cohort was 78% men, with a mean age of 60 years and a mean left ventricular ejection fraction of 34% ± 14%. The mean implant duration was 44.7 months (range 0-124.6 months). The majority of leads extracted were for infection (305 [53.0%]) and 220 (35.7%) for lead malfunction. Evaluation for lead integrity was performed in 295 cases. Of these, 34.9% were found to have externalized cables. Implant duration was significantly longer in leads with externalized cables (P < .0001). No difference in lead integrity was noted between Riata and Riata ST leads (11.7% vs. 17.7% failure; P = .23). Among leads in which cable externalization was noted, laser sheaths were used more frequently (P = .01). Major complications included 3 superior vena cava/right ventricular perforations requiring surgical intervention with 1 death 12 days after the procedure and 1 pericardial effusion requiring percutaneous drainage (0.87%). CONCLUSION Extraction of the Riata/Riata ST leads can be challenging, and leads with externalized cables may require specific extraction techniques. Extraction of the Riata/Riata ST leads can be performed safely by experienced operators at high-volume centers with a complication rate comparable to published data.

Acute conversion of persistent atrial fibrillation during dofetilide initiation.

Background: Dofetilide (D) is a highly selective blocker of the rapid component of the delayed rectifier potassium current and was approved for the treatment of atrial fibrillation (AF) based on a satisfactory safety/efficacy profile from trials in patients with left ventricle (LV) dysfunction or heart failure. The dose‐dependant acute conversion rates (<72 hours) were reported to be in the range of 6–30%. We hypothesized that the acute pharmacological conversion rate of D is higher than previously reported if used in a healthier cohort of patients with persistent AF.

Comparison of endovascular versus epicardial lead placement for resynchronization therapy.

Cardiac resynchronization therapy (CRT) has been shown to improve survival and symptoms in patients with severe left ventricular (LV) dysfunction, congestive heart failure, and prolonged QRS duration. LV lead placement is achieved by placing the lead in the coronary sinus, an endovascular approach, or by a minimally invasive robotic-assisted thoracoscopic epicardial approach. There are no data directly comparing the 2 methods. Patients eligible for CRT were randomized to the endovascular and epicardial arms. Coronary sinus lead placement was achieved using the standard technique, and epicardial leads were placed using a minimally invasive robotic-assisted thoracoscopic approach. The primary end point was a decrease in LV end-systolic volume index at 6 months. The secondary end points included 30-day mortality rate, measures of clinical improvement, 1-year electrical lead performance, and 1-year survival rate. The relative improvement of LV end-systolic volume index from baseline to 6 months was similar between the arms (28.8% for the transvenous [n = 12] vs 30.5% for the epicardial (n = 9) arm, p = 0.93). There were no significant differences in the secondary end points between the 2 groups. In conclusion, there were no differences in echocardiographic and clinical outcomes comparing a conventional endovascular approach versus robotic-assisted surgical epicardial LV lead placement for CRT in patients with heart failure. Surgical approaches are still a viable alternative when a transvenous procedure has failed or is not technically feasible.