Digoxin and Risk of Ventricular Tachyarrhythmia and Death in ICD Recipients.

BACKGROUND: Some studies have shown digoxin use to be associated with adverse outcomes, including increased mortality. There are limited data on whether digoxin use is associated with increased risk of ventricular tachycardia/ventricular fibrillation (VT/VF) in heart failure patients with an implantable cardioverter-defibrillator (ICD). OBJECTIVES: This study sought to assess whether digoxin use is associated with increased risk of VT/VF in patients with heart failure with reduced ejection fraction with a primary prevention ICD in landmark clinical trials. METHODS: The study cohort consisted of patients with an ICD or cardiac resynchronization therapy-defibrillator who were enrolled in 4 landmark MADIT trials (Multicenter Automatic Defibrillator Implantation Trials). We employed propensity score quintile stratification for treatment with digoxin as well as additional multivariable adjustment to assess the risk of digoxin vs no-digoxin therapy for the endpoints of first and recurrent VT/VF and all-cause mortality. The proportional hazards regression models for arrhythmia-specific endpoints incorporated adjustments for the competing risk of death. RESULTS: At baseline, 1,155 of 4,499 patients were on digoxin (26%). After propensity score quintile stratification, patients prescribed digoxin were shown to exhibit a statistically significant 48% increased risk of VT/VF (P < 0.001), 42% increased risk of the composite of VT/VF or death (P < 0.001), and a 37% increased risk of all-cause mortality (P = 0.006). Digoxin use was also associated with increased risk of appropriate ICD shocks (HR: 1.91; P < 0.001) and with increased burden of VT/VF events (HR: 1.46; P = 0.001). CONCLUSIONS: Our findings suggests that digoxin use is associated with ventricular tachyarrhythmia and death in heart failure with reduced ejection fraction patients with an ICD.

Atrial burst pacing with biphasic and monophasic waveforms for atrial fibrillation.

BACKGROUND: Biphasic pacing is a novel mode of pacing that was suggested to increase cardiac conduction velocity as compared with cathodal monophasic pacing. We aimed to evaluate the safety and efficacy of rapid atrial pacing to convert atrial fibrillation (AF) to normal sinus rhythm. METHODS: Multiple biphasic (anodal/cathodal), reverse biphasic (cathodal/anodal), and monophasic (cathodal) atrial pacing therapies were performed among 12 patients undergoing left atrial catheter ablation for AF. The efficacy end point was successful conversion of AF to sinus rhythm, and safety end point no induction of ventricular arrhythmias. Patients were paced at three cycle lengths (100, 200, and 333 msec) for 60 seconds at three locations (right and left atrial appendages and coronary sinus). RESULTS: Among the 66 biphasic (anodal/cathodal) pacing procedures one procedure in a patient with chronic AF, which involved pacing at the left atrial appendage with a cycle length of 200 msec, led to conversion of AF to sinus rhythm. None of the 66 monophasic pacing procedures or the 66 reverse biphasic (cathodal/anodal) pacing procedures was associated with AF termination. None of the biphasic pacing procedures was associated with induction of ventricular arrhythmias. CONCLUSIONS: Rapid atrial pacing using a variety of waveforms at the cycle length and output used in the current study was found to be safe. There was a single success in converting a chronic AF to sinus rhythm.

Assessment of facial video-based detection of atrial fibrillation across human complexion.

Background: Early self-detection of atrial fibrillation (AF) can help delay and/or prevent significant associated complications, including embolic stroke and heart failure. We developed a facial video technology, videoplethysmography (VPG), to detect AF based on the analysis of facial pulsatile signals. Objective: The purpose of this study was to evaluate the accuracy of a video-based technology to detect AF on a smartphone and to test the performance of the technology in AF patients across the whole spectrum of skin complexion and under various recording conditions. Methods: The performance of video-based monitoring depends on a set of factors such as the angle and the distance between the camera and the patient's face, the strength of illumination, and the patient's skin tone. We conducted a clinical study involving 60 subjects with a confirmed diagnosis of AF. A continuous electrocardiogram was used as the gold standard for cardiac rhythm annotation. The VPG technology was fine-tuned on a smartphone for the first 15 subjects. Validation recordings were then done using 7053 measurements collected from the remaining 45 subjects. Results: The VPG technology detected the presence of AF using the video camera from a common smartphone with sensitivity and specificity ≥90%. The ambient level of illumination needs to be ≥100 lux for the technology to deliver consistent performance across all skin tones. Conclusion: We demonstrated that facial video-based detection of AF provides accurate outpatient cardiac monitoring including high pulse rate accuracy and medical-grade performance for AF detection.

Catheter ablation of atrial fibrillation in the elderly.

PURPOSE OF REVIEW: Atrial fibrillation is increasingly prevalent among older adults and is a major contributor to morbidity in this population due to associated strokes, heart failure, and quality of life impairment. Catheter ablation for atrial fibrillation is demonstrated to be superior to antiarrhythmic therapy for the control of symptomatic and medically refractory atrial fibrillation, but its safety and efficacy in the elderly are not well understood. Clinical trials to guide the optimal management strategy in this population are lacking. RECENT FINDINGS: Several nonrandomized clinical studies have recently addressed the issue of catheter ablation in the elderly and show favorable rates of success. Unfortunately, these studies are limited by the relatively small numbers of patients examined and often by their single-center and retrospective nature. SUMMARY: Before the results of these studies can be extrapolated, data from larger cohorts of elderly patients followed prospectively are desperately needed.

Predictive capability of left atrial size measured by CT, TEE, and TTE for recurrence of atrial fibrillation following radiofrequency catheter ablation.

BACKGROUND: Recurrence of atrial fibrillation (AF) after radiofrequency catheter ablation (RFCA) has been well established and is in part related to left atrial (LA) size. The purpose of this study was to assess the predictive capability of LA diameter (LAD) and LA volume (LAV) by echocardiography and computed tomography (CT) to determine success in patients undergoing RFCA of AF. METHODS: Eighty-eight patients with paroxysmal or persistent AF who had undergone RFCA and had a prior transthoracic echocardiogram (TTE), transesophageal echocardiogram (TEE), and CT were enrolled in the study. TTE LADs and LV ejection fraction as well as TEE LADs and LAVs in three views were recorded. CT LAVs were also recorded. Clinical parameters prior to ablation as well as at 1-year follow-up were assessed. RESULTS: A total of 40 (45%) patients with paroxysmal AF and 48 (55%) patients with persistent AF were analyzed. Paroxysmal AF patients had a RFCA success rate of 88% at 1 year with persistent AF patients having a 52% success rate (P < 0.001). A CT-derived LAV >or= 117 cc was associated with an odds ratio (OR) for recurrence of 4.8 (95% confidence interval [CI]=[1.4-16.4], P = 0.01) while a LAV >or=130 cc was associated with an OR for recurrence of 22.0 (95% CI =[2.5-191.0], P = 0.005) after adjustment for persistent AF. CONCLUSIONS: LA dimensions and AF type are highly predictive of AF recurrence following RFCA. LAV by CT has significant predictive benefit over standard LADs in severely enlarged atria even after adjustment for AF type.

Comparison of antiarrhythmic drug therapy and radiofrequency catheter ablation in patients with paroxysmal atrial fibrillation: a randomized controlled trial.

CONTEXT: Antiarrhythmic drugs are commonly used for prevention of recurrent atrial fibrillation (AF) despite inconsistent efficacy and frequent adverse effects. Catheter ablation has been proposed as an alternative treatment for paroxysmal AF. OBJECTIVE: To determine the efficacy of catheter ablation compared with antiarrhythmic drug therapy (ADT) in treating symptomatic paroxysmal AF. DESIGN, SETTING, AND PARTICIPANTS: A prospective, multicenter, randomized (2:1), unblinded, Bayesian-designed study conducted at 19 hospitals of 167 patients who did not respond to at least 1 antiarrhythmic drug and who experienced at least 3 AF episodes within 6 months before randomization. Enrollment occurred between October 25, 2004, and October 11, 2007, with the last follow-up on January 19, 2009. INTERVENTION: Catheter ablation (n = 106) or ADT (n = 61), with assessment for effectiveness in a comparable 9-month follow-up period. MAIN OUTCOME MEASURES: Time to protocol-defined treatment failure. The proportion of patients who experienced major treatment-related adverse events within 30 days of catheter ablation or ADT was also reported. RESULTS: At the end of the 9-month effectiveness evaluation period, 66% of patients in the catheter ablation group remained free from protocol-defined treatment failure compared with 16% of patients treated with ADT. The hazard ratio of catheter ablation to ADT was 0.30 (95% confidence interval, 0.19-0.47; P < .001). Major 30-day treatment-related adverse events occurred in 5 of 57 patients (8.8%) treated with ADT and 5 of 103 patients (4.9%) treated with catheter ablation. Mean quality of life scores improved significantly in patients treated by catheter ablation compared with ADT at 3 months; improvement was maintained during the course of the study. CONCLUSION: Among patients with paroxysmal AF who had not responded to at least 1 antiarrhythmic drug, the use of catheter ablation compared with ADT resulted in a longer time to treatment failure during the 9-month follow-up period. TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT00116428.

Right ventricular dysfunction and the incidence of implantable cardioverter-defibrillator therapies.

INTRODUCTION: Implantable cardioverter-defibrillator (ICD) therapy is well established in preventing sudden cardiac death in patients with left ventricular dysfunction. The influence of right ventricular (RV) function on ICD therapy for sudden cardiac death (SCD) is not known. METHODS: We retrospectively studied 222 patients receiving an ICD for primary prevention of SCD. Baseline clinical and echocardiographic data were gathered. RV systolic function was qualitatively assessed as normal or abnormal (described as mildly, moderately, or severely reduced). Primary endpoint was combined ICD therapy or death and secondary endpoint was ICD therapy alone. RESULTS: The mean follow-up was 940 +/- 522 days. The mean left ventricular ejection fraction was 0.23 +/- 0.07. By Kaplan-Meier analysis, RV dysfunction was predictive of combined ICD therapy or death when comparing between normal and abnormal RV function (P = 0.008) and among qualitative ranges of RV function (P = 0.012). RV dysfunction was not predictive of ICD therapy alone with either type of classification. After adjusting for clinical covariates, severe RV dysfunction was predictive of the combined endpoint of ICD therapy or death (HR 2.02, 95% CI 1.04-3.92, P = 0.037). CONCLUSION: Severe RV dysfunction appears to be an independent predictor of the combined endpoint of ICD therapy or death. RV dysfunction does not reliably predict the incidence of ICD therapy alone.

Brugada syndrome with marked conduction disease: dual implications of a SCN5A mutation.

A 51-year-old woman presented with an episode of syncope. Upon further review she was found to have a typical Brugada type pattern on her electrocardiogram. She did not have evidence for structural heart disease. At electrophysiological testing she was found to have marked infrahisian conduction disease and had easily inducible polymorphic ventricular tachycardia. She underwent implantation of a dual-chamber implantable cardioverter defibrillator (ICD) and family screening was recommended. Genetic analysis revealed a novel nonsense mutation in the gene encoding for the sodium channel (SCN5A). Five months after ICD implantation the patient had an episode of ventricular fibrillation documented on ICD interrogation. This case is unique as it is consistent with an overlap syndrome, namely both Brugada Syndrome and distal atrioventricular (AV) conduction disease secondary to a novel SCN5A mutation in a young female. This finding highlights the phenotypic heterogeneity of novel SCN5A mutations.

Detection of atrial fibrillation using an earlobe photoplethysmographic sensor.

Atrial fibrillation (AF) is the most common cardiac arrhythmia in the world, associated with increased risk of thromboembolic events and an increased mortality rate. In addition, a significant portion of AF patients are asymptomatic. Current AF diagnostic methods, often including a body surface electrocardiogram or implantable loop recorder, are both expensive and invasive and offer limited access within the general community. OBJECTIVE: We tested the feasibility of the detection of AF using a photoplethysmographic signal acquired from an inexpensive, non-invasive earlobe photoplethysmographic sensor. This technology can be implemented into wearable devices and would enable continuous cardiac monitoring capabilities, greatly improving the rate of asymptomatic AF detection. APPROACH: We conducted a clinical study of patients going through electrical cardioversion for AF treatment. Photoplethysmographic recordings were taken from these AF patients before and after their cardioversion procedure, along with recordings from a healthy control group. Using these recordings, cardiac beats were identified and the inter-systolic interval was calculated. The inter-systolic interval was used to calculate four parameters to quantify the heart rate variability indicative of AF. Receiver operating characteristic curves were used to calculate discriminant thresholds between the AF and non-AF cohorts. MAIN RESULTS: The parameter with the greatest discriminant capability resulted in a sensitivity and specificity of 90.9%. These results are comparable to expensive ECG-based and invasive implantable loop recorder AF detection methods. SIGNIFICANCE: These results demonstrate that using a non-invasive earlobe photoplethysmographic signal is a viable and inexpensive alternative to ECG-based AF detection methods, and an alternative that could be invaluable in detecting subclinical AF.

Variation in left atrial transmural wall thickness at sites commonly targeted for ablation of atrial fibrillation.

BACKGROUND: The number of catheter ablations performed for atrial fibrillation (AF) has increased dramatically over the past several years. Regional variation in left atrial (LA) wall thickness is known to exist but have not been described in detail. AF ablation success and complication rates may be related to regional differences in LA wall thickness. OBJECTIVE: To evaluate differences in transmural wall thickness in five pre-defined anatomic areas within the LA which are commonly targeted for AF ablation. MATERIALS AND METHODS: We measured LA wall transmural thickness in 34 human heart specimens using calipers in five anatomic areas frequently targeted during AF ablation (anterior wall, septum, mitral isthmus, posterior wall and roof). RESULTS: The autopsied individuals were 53% female, 67.7% had CAD, 14.7% had atrial fibrillation, 61.8% had hypertension, and 21.6% had congestive heart failure. The roof was the thinnest region with mean thickness measuring significantly less than each other area (p 0.005 for the posterior wall and <0.001 for all other areas). The septum was the thickest region with mean thickness measuring significantly greater than each other area (p = 0.05, 0.001, <0.001, <0.001 measured against the anterior wall, isthmus, posterior wall and roof, respectively). CONCLUSIONS: Significant regional differences exist for mean left atrial wall thickness among the different anatomic areas within the left atrium which are often targeted during catheter ablation of AF. These differences may have significant implications in determining the ideal intensity and total duration of radiofrequency energy required to achieve a safe and successful ablation.

Noninducibility of atrial fibrillation as an end point of left atrial circumferential ablation for paroxysmal atrial fibrillation: a randomized study.

BACKGROUND: An anatomic approach of left atrial radiofrequency circumferential ablation (LACA) to encircle the pulmonary veins is often effective in eliminating paroxysmal atrial fibrillation (AF). However, no electrophysiological end points other than voltage abatement and/or conduction slowing or block across ablation lines have been used. It has been unclear whether noninducibility of AF is a clinically useful end point. METHODS AND RESULTS: In 100 patients with paroxysmal AF (mean age, 55+/-10 years), LACA to encircle the left- and right-sided pulmonary veins was performed during AF, with additional ablation lines in the posterior left atrium and mitral isthmus, with an 8-mm-tip catheter. After completion of this lesion set, sinus rhythm was present, and AF lasting >60 seconds was not inducible in 40 patients (40%; group 1). The 60 patients in whom AF was still present or who still had inducible AF were randomly assigned to no further ablation (group 2; 30 patients) or to additional ablation lines along the left atrial septum, roof, and/or anterior wall where there were fractionated electrograms (group 3; 30 patients). In group 3, AF was rendered noninducible in 27 of 30 patients (90%). At a 6-month follow-up, 67% of patients in group 2 were free of AF without drug therapy compared with 86% of patients in group 3. (P=0.05, log-rank test). Left atrial flutter occurred in 17% and 27% of patients in each group, respectively (P=0.3). CONCLUSIONS: After LACA in patients with paroxysmal AF, AF usually can be rendered noninducible by additional ablation at sites of fractionated electrograms. Noninducibility of AF attained by additional electrogram-guided left atrial ablation may be associated with a better midterm clinical outcome than when AF is still inducible after LACA alone.

Catheter ablation for paroxysmal atrial fibrillation: segmental pulmonary vein ostial ablation versus left atrial ablation.

BACKGROUND: Segmental ostial catheter ablation (SOCA) to isolate the pulmonary veins (PVs) and left atrial catheter ablation (LACA) to encircle the PVs both may eliminate paroxysmal atrial fibrillation (PAF). The relative efficacy of these 2 techniques has not been directly compared. METHODS AND RESULTS: Of 80 consecutive patients with symptomatic PAF (age, 52+/-10 years), 40 patients underwent PV isolation by SOCA and 40 patients underwent LACA to encircle the PVs. During SOCA, ostial PV potentials recorded with a ring catheter were targeted. LACA was performed by encircling the left- and right-sided PVs 1 to 2 cm from the ostia and was guided by an electroanatomic mapping system; ablation lines also were created in the mitral isthmus and posterior left atrium. The mean procedure and fluoroscopy times were 156+/-45 and 50+/-17 minutes for SOCA and 149+/-33 and 39+/-12 minutes for LACA, respectively. At 6 months, 67% of patients who underwent SOCA and 88% of patients who underwent LACA were free of symptomatic PAF when not taking antiarrhythmic drug therapy (P=0.02). Among the variables of age, sex, duration and frequency of PAF, ejection fraction, left atrial size, structural heart disease, and the ablation technique, only an increased left atrial size and the SOCA technique were independent predictors of recurrent PAF. The only complication was left atrial flutter in a patient who underwent LACA. CONCLUSIONS: In patients undergoing catheter ablation for PAF, LACA to encircle the PVs is more effective than SOCA.

Atrio-esophageal fistula as a complication of percutaneous transcatheter ablation of atrial fibrillation.

BACKGROUND: Radiofrequency ablation for atrial fibrillation is becoming widely practiced. METHODS AND RESULTS: Two patients undergoing circumferential pulmonary vein ablation for atrial fibrillation in different centers developed symptoms compatible with endocarditis 3 to 5 days after the procedure. Their clinical condition deteriorated rapidly, and both suffered multiple gaseous and/or septic embolic events causing cerebral and myocardial damage. One patient survived after emergency cardiac and esophageal surgery; the other died of extensive systemic embolization. An atrio-esophageal fistula was identified in both patients. CONCLUSIONS: Atrio-esophageal fistulas can occur after catheter ablation in the posterior wall of the left atrium. This diagnosis should be excluded in any patient with symptoms or signs of endocarditis after left atrial ablation, and expeditious cardiac surgery is critical if the diagnosis is confirmed. Lower power and temperature settings for applications of radiofrequency energy along the posterior left atrial wall may prevent further cases of fistula formation.

Clinical significance of inducible atrial flutter during pulmonary vein isolation in patients with atrial fibrillation.

OBJECTIVES: This study was designed to determine the prevalence and clinical significance of atrial flutter (AFL) that occurs during catheter ablation for atrial fibrillation (AF). BACKGROUND: Atrial flutter frequently occurs in patients with AF. METHODS: Pulmonary vein isolation was performed in 133 consecutive patients (age 52 +/- 11 years) for paroxysmal (n = 112) or persistent (n = 21) AF. A clinical episode of AFL was documented in 40 of the 133 patients (30%). During the ablation procedure, AFL occurred in 86 patients (65%), either spontaneously (n = 36) or by rapid atrial pacing (n = 50), with AFL being typical in the majority (80%). Cavo-tricuspid isthmus ablation was performed in 28 of the 133 patients. RESULTS: Among the 105 patients who did not undergo isthmus ablation, 25 patients (24%) were documented to have symptomatic AFL during a mean follow-up of 609 +/- 252 days. Among the clinical variables of age, gender, history of clinical AFL, ejection fraction, left atrial diameter, duration of AF, and occurrence of AFL during ablation, only a history of clinical AFL (p = 0.05) and occurrence of typical AFL during the ablation (p = 0.01) were independent predictors of symptomatic AFL during follow-up. The incidence of symptomatic AFL during follow-up was similar among patients who did and did not have long-term freedom from recurrent AF. CONCLUSIONS: In patients with AF who have either a history of AFL or an episode of typical AFL during an electrophysiologic study, symptomatic AFL is common after pulmonary vein isolation. Therefore, cavo-tricuspid isthmus ablation is appropriate during pulmonary vein isolation if AFL has been observed clinically or in the electrophysiology laboratory.

Prevalence, mechanisms, and clinical significance of macroreentrant atrial tachycardia during and following left atrial ablation for atrial fibrillation.

OBJECTIVES: The purpose of this study was to determine the prevalence and clinical significance of macroreentrant atrial tachycardia (AT) after left atrial (LA) circumferential ablation for atrial fibrillation (AF). BACKGROUND: Linear ablation for AF may result in macroreentrant AT. METHODS: Three hundred forty-nine patients (age 54 +/- 11 years) underwent LA circumferential ablation for AF (paroxysmal in 227). Ablation lines were created around the left-sided and right-sided pulmonary veins, with additional ablation lines in the posterior LA and mitral isthmus. If macroreentrant AT was observed acutely in the electrophysiology laboratory, it was not ablated. If an organized AT occurred during follow-up, the initial strategy was rate control. If AT persisted for > 3 to 4 months, catheter ablation was performed. RESULTS: Seventy-one patients (20%) had spontaneous or induced macroreentrant AT (cycle length 244 +/- 31 ms) in the electrophysiology laboratory following LA circumferential ablation. During follow-up, 85 patients (24%) experienced spontaneous AT (cycle length 238 +/- 35 ms) at a mean of 44 +/- 62 days following LA circumferential ablation. Among the 71 patients with macroreentrant AT acutely following LA circumferential ablation, 39 (55%) developed AT during follow-up. Among the 85 patients with AT during follow-up, the tachycardia remitted without a repeat ablation procedure in 28 patients (33%), most commonly within 5 months. Twenty-eight of the 349 patients (8%) underwent a repeat ablation procedure for AT. The critical isthmus was localized to the mitral isthmus in 17 of 28 patients (61%). CONCLUSIONS: Macroreentrant AT is a common form of proarrhythmia after LA circumferential ablation for AF. Because it may resolve spontaneously, ablation of AT should be deferred for several months.

Venous thrombosis and stenosis after implantation of pacemakers and defibrillators.

Venous complications of pacemaker/ implantable cardioverter defibrillator (ICD) system implantation rarely cause immediate clinical problems. The challenge starts when patients come for system revision or upgrade. Numerous reports of venous complications such as stenosis, occlusions, and superior vena cava syndrome have been published. We reviewed current knowledge of these complications, management, and their impact on upgrade/revision procedures. One study has suggested that intravenous lead infection promotes local vein stenosis. Another found that the presence of a temporary wire before implantation is associated with an increased risk of stenosis. Although data for ICD leads is based only on three studies-it suggests that the rate of venous complications is very similar to that of pacing systems, and probably data from pacing leads can be extrapolated to ICD leads. Despite 40 years of experience with transcutaneous implanted intravenous pacing systems and dozens of studies, we were unable to identify clear risk factors (confirmed by independent studies) that lead to venous stenosis. Neither the hardware (lead size, number and material) nor the access site choice (cephalic cut down, subclavian or axillary puncture) appears to affect rate of venous complications. A few factors were proposed as predictors of severe venous stenosis/occlusion: presence of multiple pacemaker leads (compared to a single lead), use of hormone therapy, personal history of venous thrombosis, the presence of temporary wire before implantation, previous presence of a pacemaker (ICD as an upgrade) and the use of dual-coil leads. Anticoagulant therapy (for other reasons than pacemaker lead) seemed to have protective antithrombotic effect.

Detection of atrial fibrillation using contactless facial video monitoring.

BACKGROUND: It is estimated that 33.5 million people in the world have developed atrial fibrillation (AF), and an estimated 30% of patients with AF are unaware of their diagnosis (silent AF). OBJECTIVE: The purpose of this study was to test a new technology for contactless detection of AF based on facial video recordings. METHODS: The proposed technique uses a camera to record an individual's face and extract the subtle beat-to-beat variations of skin color reflecting the cardiac pulsatile signal. In a group of adults referred for electrical cardioversion, we recorded the ECG and the video of the subjects' face before and after electrical cardioversion. We extracted the beat-to-beat pulse rates expressed as pulses per minute (ppm) from the videoplethysmographic (VPG) signal acquired using a standard web camera. We introduce a novel quantifier of pulse variability called the pulse harmonic strength (PHS) and report its ability to detect the presence of AF. RESULTS: Eleven subjects (8 male; age 65 ± 6 years) were included in the study. The VPG and ECG-based rates were statistically different between the AF and sinus rhythm periods: 72 ± 9 ppm vs 57 ± 7 ppm (P < .0001) for VPG and 80 ± 17 bpm vs 56 ± 7 bpm (P < .0001) for ECG signals. Among the 407 epochs of 15 seconds of synchronized ECG and VPG signals, PHS was associated with a 20% detection error rate, and the error rates of the automatic ECG-based measurements ranged between 17% and 29%. CONCLUSION: Our preliminary results support the concept that contactless video-based monitoring of the human face for detection of abnormal pulse variability due to AF is feasible.

Randomized comparison of anatomical versus voltage guided ablation of the cavotricuspid isthmus for atrial flutter.

OBJECTIVES: The purpose of this prospective study was to compare radiofrequency catheter ablation of the cavotricuspid isthmus using a strictly anatomic approach to an approach guided by a bipolar voltage map to avoid high voltage zones in the cavotricuspid isthmus. BACKGROUND: It is not clear whether local atrial electrogram amplitude influences the achievement of complete cavotricuspid isthmus block during radiofrequency catheter ablation for atrial flutter. METHODS: Thirty-two patients with atrial flutter were randomized to cavotricuspid isthmus ablation using an anatomical approach (group I, 16 patients) or guided by a bipolar voltage map (group II, 16 patients). A 3-dimensional electroanatomic mapping system and an 8-mm-tip ablation catheter were used in all patients. With the anatomical approach, an ablation line was created in the cavotricuspid isthmus at a 6 o'clock position in the 45 degree left anterior oblique projection. During voltage-guided ablation, a high-density bipolar voltage map of the cavotricuspid isthmus was created, and then contiguous applications of radiofrequency energy were delivered to create an ablation line through the cavotricuspid isthmus sites with the lowest bipolar voltage. RESULTS: Complete cavotricuspid isthmus conduction block was achieved in 100% of patients in each group. The mean maximum voltages along the line were 3.6 +/- 1.5 mV in group I, and 1.2 +/- 0.9 mV in group II (P < .01). Creating a high-density voltage map was associated with approximately 15-minute increase in the total procedure time (P = .2). During a mean follow-up of 177 +/- 40 days, there were no recurrences of atrial flutter in either group. There were no complications in either group. CONCLUSIONS: When cavotricuspid isthmus ablation for atrial flutter is performed with an 8-mm-tip catheter, complete block can be achieved in all patients regardless of local voltage. Ablation of high voltage zones is not associated with a higher recurrence rate. Therefore, anatomic ablation without voltage mapping is the preferred initial approach for cavotricuspid isthmus ablation.

Mechanisms of recurrent atrial fibrillation after pulmonary vein isolation by segmental ostial ablation.

OBJECTIVES: The aim of this study was to determine the mechanisms responsible for recurrent atrial fibrillation (AF) after pulmonary vein isolation (PV) by segmental ostial ablation. BACKGROUND: Recovery of conduction into a previously isolated PV is a common observation when there is recurrent AF soon after segmental ostial ablation. However, the mechanisms of recurrent AF have been unclear. METHODS: A repeat ablation procedure was performed in 50 patients who had recurrent paroxysmal AF at a mean of 7 +/- 6 months after segmental ostial ablation to isolate the PVs. During the repeat procedure, a ring catheter was inserted into each PV during sinus rhythm and AF to determine whether the veins were still isolated and, if not, whether there were PV tachycardias with a cycle length shorter than in the adjacent left atrium during AF. RESULTS: There was recovery of conduction over a previously ablated muscle fascicle in >/=1 PV in 49 patients (98%). There were 10 +/- 2 episodes of PV tachycardia per minute in 36 (72%) of the 50 patients during AF. Repeat ablation was performed by segmental ostial ablation (23 patients) or by left atrial catheter ablation to encircle the left- and right-sided PVs 1 to 2 cm from the ostia, with additional ablation lines in the posterior left atrium and mitral isthmus (27 patients). At 6-month follow-up, among 23 patients who underwent repeat ablation by segmental ostial ablation, AF recurred in 4 (21%) of the 19 patients who had PV tachycardias and in 3 (75%) of the 4 patients who did not (P = .03). Among the 27 patients who underwent left atrial ablation, AF recurred in 2 (12%) of the 17 patients who had PV tachycardias and in 1 (10%) of the 10 patients who did not (P = 0.7). CONCLUSIONS: Recovery of conduction in previously ablated muscle fascicles is a common finding in patients with recurrent AF after segmental ostial ablation. The efficacy of repeat segmental ostial ablation depends on the presence of PV tachycardias, whereas left atrial ablation is effective regardless of whether PV tachycardias are present or not during AF.

Effects of left atrial ablation of atrial fibrillation on size of the left atrium and pulmonary veins.

OBJECTIVES: The purpose of this study was to determine the effect of left atrial circumferential ablation on the size of the left atrium and pulmonary veins (PVs). BACKGROUND: The long-term effects of left atrial circumferential ablation on left atrial and PV size and anatomy have not been analyzed in quantitative fashion. METHODS: PV and left atrial sizes were analyzed in 41 consecutive patients (mean age 54 +/- 12 years) with paroxysmal (n = 25) or chronic (n = 16) atrial fibrillation. Computed tomography of the chest with three-dimensional reconstruction was performed before and 4 +/- 2 months after left atrial circumferential ablation. Left atrial circumferential ablation was performed to encircle the PVs 1 to 2 cm from the ostia, using a power output of 70 W. Additional ablation lines were created in the posterior left atrium and mitral isthmus. Radiofrequency energy also was delivered within the circles and at the PV ostia in 51% of patients at a reduced power output of 35 W. RESULTS: At 6 months, 36 patients (88%) were in sinus rhythm without antiarrhythmic drug therapy, including 3 patients (7%) who developed persistent left atrial flutter and underwent subsequent successful ablation of atrial flutter. There was a 15 +/- 16% decrease in left atrial volume (P < .01) and 10 +/- 35% decrease in PV ostial area (P < .01), without focal narrowing, in patients with a successful outcome. Focal PV stenosis did not occur in any of the 41 patients. CONCLUSIONS: Maintenance of sinus rhythm after left atrial circumferential ablation is associated with reduced left atrial and PV ostial size. Left atrial circumferential ablation for atrial fibrillation does not cause PV stenosis.