- Implantable Defibrillator Therapy in Cardiac Arrest Survivors With a Reversible Cause
- Clinical Outcome of Electrophysiologically Guided Ablation for Nonparoxysmal Atrial Fibrillation Using a Novel Real-Time 3-Dimensional Mapping Technique: Results From a Prospective Randomized Trial
- Electrocardiographic Repolarization Abnormalities and Electroanatomic Substrate in Arrhythmogenic Right Ventricular Cardiomyopathy
- Defining the Outcome of Ventricular Tachycardia Ablation: Timing and Value of Programmed Ventricular Stimulation
- Global ECG Measures and Cardiac Structure and Function: The ARIC Study (Atherosclerosis Risk in Communities)
- Idiopathic Ventricular Arrhythmias Originating From the Infundibular Muscles: Prevalence, Electrocardiographic and Electrophysiological Characteristics, and Outcome of Catheter Ablation
- Atrial Infarction-Induced Spontaneous Focal Discharges and Atrial Fibrillation in Sheep: Role of Dantrolene-Sensitive Aberrant Ryanodine Receptor Calcium Release
- Can We Use the Intrinsic Left Ventricular Delay (QLV) to Optimize the Pacing Configuration for Cardiac Resynchronization Therapy With a Quadripolar Left Ventricular Lead?
- Predictors of Zero X-Ray Ablation for Supraventricular Tachycardias in a Nationwide Multicenter Experience
- Left Septal Slow Pathway Ablation for Atrioventricular Nodal Reentrant Tachycardia
- Incidence and Clinical Significance of New-Onset Device-Detected Atrial Tachyarrhythmia: A Meta-Analysis
- Long-Term Outcome of Pulmonary Vein Isolation With and Without Focal Impulse and Rotor Modulation Mapping: Insights From a Meta-Analysis
- Figures & Tables
- Info & Metrics
Paul J. Wang, MD
Implantable Defibrillator Therapy in Cardiac Arrest Survivors With a Reversible Cause
Adetola Ladejobi, MD, MPH… Samir Saba, MD
Adetola Ladejobi and associates studied 1433 patients between 2000 and 2012 who were discharged alive after sudden cardiac arrest (SCA). A reversible and correctable cause was identified in 792 (55%) patients. Reversible SCA cause was defined as significant electrolyte or metabolic abnormality, evidence of acute myocardial infarction or ischemia, recent initiation of antiarrhythmic drug or illicit drug use, or other reversible circumstances. Of the 792 SCA survivors because of a reversible and correctable cause (age 61±15 years, 40% women), 207 (26%) patients received an implantable cardioverter-defibrillator after their index SCA. During a mean follow-up of 3.8±3.1 years, 319 (40%) patients died. Implantable cardioverter-defibrillator implantation was highly associated with lower all-cause mortality (P<0.001) even after correcting for unbalanced baseline characteristics (P<0.001). In subgroup analyses, only patients whose SCA was not associated with myocardial infarction extracted benefit from implantable cardioverter-defibrillator (P<0.001). The authors concluded that in survivors of SCA because of a reversible and correctable cause, implantable cardioverter-defibrillator therapy is associated with lower all-cause mortality except if the SCA was because of myocardial infarction. Further prospective multicenter randomized controlled trials will be needed to confirm this observation.
Clinical Outcome of Electrophysiologically Guided Ablation for Nonparoxysmal Atrial Fibrillation Using a Novel Real-Time 3-Dimensional Mapping Technique: Results From a Prospective Randomized Trial
Carlo Pappone, MD, PhD… Vincenzo Santinelli, MD
Carlo Pappone and associates studied 81 patients with persistent atrial fibrillation (PersAF) randomized to undergo high-density electrophysiological mapping to identify repetitive-regular activities (RRa) before modified circumferential pulmonary vein ablation (mCPVA) or modified circumferential pulmonary vein ablation alone. The primary end-point was freedom from arrhythmic recurrences at 1 year. In total, 81 PersAF patients (74% male, mean age 61.7±10.6 years) underwent mapping/ablation procedure. There were 479 regions exhibiting RRa in 81 patients (5.9±2.4 RRa per patient): 232 regions in the mapping group (n=41) and 247 in the control group (n=40). Overall, 185/479 (39%) RRa were identified within the pulmonary veins, whereas 294/479 (61%) in nonpulmonary vein regions. Mapping-guided ablation resulted in higher arrhythmia termination rate as compared with conventional strategy (25/41, 61% versus 12/40, 30%; P<0.007). Total radiofrequency duration (P=0.38), mapping (P=0.46), and fluoroscopy times (P=0.69) were not significantly different between the groups. No major procedure-related adverse events occurred. After 1 year, 73.2% of mapping group patients were free from recurrences versus 50% of control group (P=0.03). The authors concluded that targeted ablation of regions showing RRa provided an adjunctive benefit in terms of arrhythmia freedom at 1-year follow-up in the treatment of PersAF. These findings should be confirmed by additional larger, randomized, multicenter studies.
Electrocardiographic Repolarization Abnormalities and Electroanatomic Substrate in Arrhythmogenic Right Ventricular Cardiomyopathy
Maciej Kubala, MD… Francis E. Marchlinski, MD
Maciej Kubala and associates examined repolarization abnormalities in 40 patients (29 men, mean age 38 years) within arrhythmogenic right ventricular cardiomyopathy (ARVC), comparing the extent and location of abnormal T (NegT) waves ≥1 mm in depth (n=32) and downsloping elevated ST segment (D-ST) (n=13), in ≥2 adjacent leads, to area and location of endocardial (ENDO) bipolar (<1.5 mV) and unipolar (<5.5 mV) and epicardial (EPI) bipolar (<1.0 mV) voltage abnormalities. They found an abnormal unipolar RV ENDO area of 33.4±19.3% was present in 8 patients without NegT. Patients with NegT extending beyond lead V3 (n=20) had larger low bipolar (31.4±18.9% versus 16.5±14.6%, P=0.008) and unipolar ENDO areas (66.0±19.6% versus 47.4±25.1%, P=0.013) and larger EPI low bipolar area (56.0±19.3% versus 40.1±24.9%, P=0.030) compared with those with NegT limited to leads V1 through V3 (n=20). ECG location of NegT regionalized to location of substrate. Patients with D-ST, all localized to leads V1 and V2, had more unipolar ENDO abnormalities (71.8±18.1% versus 49.4±23.5%, P=0.005) involving outflow and mid-RV, compared with patients without D-ST. The authors concluded that in ARVC, abnormal electroanatomic mapping areas are proportional to the extent of T wave inversion on 12-lead ECG. Marked voltage abnormalities can exist without repolarization change. D-ST pattern in V1 and V2 occurs with more unipolar ENDO voltage abnormality, consistent with more advanced transmural disease.
Defining the Outcome of Ventricular Tachycardia Ablation: Timing and Value of Programmed Ventricular Stimulation
Teresa Oloriz, MD, PhD… Paolo Della Bella, MD
Teresa Oloriz and associates examined the timing and value of programmed ventricular stimulation (PVS) after catheter ablation for ventricular tachycardia (VT). They performed 218 PVS 6 days (5–7) after ablation (186 noninvasive programmed stimulations [NIPS] and 32 invasive PVS) in 210 consecutive patients (ischemic 48%, median left ventricular ejection fraction 37%, syncope 35% with trauma associated 6%). After ablation, implantable cardioverter-defibrillators were programmed according to NIPS results (class A—noninducible; class B—nondocumented inducible VT; and class C—documented inducible VT), with high and delayed VT detection intervals. Concordance between PVS-end procedure and PVS-day 6 was 67%. Positive and negative predictive values were higher for PVS-day 6 (53% and 88% versus 43% and 71%). Ischemic and patients with preserved ejection fraction showed the highest negative predictive value (91% and 96%). Among 46/174 (26%) noninducible patients at PVS-end procedure, but inducible at day 6, 59% had VT recurrence at 1-year follow-up; recurrences were 9% when both studies were noninducible. There were no inappropriate shocks; incidence of syncope was 3%, none was harmful. The rate of appropriate shocks per patient per month according to NIPS results was significantly reduced, comparing the month before and after ablation (class A: 2 (0.75–4) versus 0; class B: 2 (1–4) versus 0; class C: 2 (1–4) versus 0; P<0.001). The authors concluded that PVS at day 6 predicts VT recurrence.
Global ECG Measures and Cardiac Structure and Function: The ARIC Study (Atherosclerosis Risk in Communities)
Tor Biering-Sørensen, MD, PhD… Larisa G. Tereshchenko, MD, PhD
Tor Biering-Sørensen and associates examined ECG global electric heterogeneity (GEH) and its longitudinal changes are associated with cardiac structure and function in the ARIC study (Atherosclerosis Risk in Communities; N=5114; 58% female; 22% Blacks) using resting 12-lead ECGs (visits 1–5) and echocardiographic assessment of left ventricular (LV) ejection fraction, LV global longitudinal strain, LV mass index (LVMi), LV end-diastolic (LVEDVi), and end-systolic volume index (LVESVi) at visit 5. Longitudinal analysis included ARIC participants (N=14 609) with measured GEH at visits 1 to 4. GEH was quantified by spatial ventricular gradient, QRS-T angle, and sum absolute QRS-T integral. Cross-sectional and longitudinal regressions were adjusted for manifest and subclinical cardiovascular disease (CVD). Having 4 abnormal GEH parameters was associated with a 6.4% (95% confidence interval [CI], 5.5%–7.3%) left ventricular ejection fraction decline, a 24.2 (95% CI, 21.5–26.9) g/m2 increase in LVMi, a 10.3 (95% CI, 8.9–11.7) mL/m2 increase in LVEDVi, and a 7.8 (95% CI, 6.9–8.6) mL/m2 increase in LVESVi. Altogether, clinical and ECG parameters accounted for approximately one-third of LV volume and 20% of systolic function variability. The associations were significantly stronger in CVD. Sum absolute QRS-T integral increased by 20 mV*ms for each 3-year period in participants who demonstrated LV dilatation at visit 5. Sudden cardiac death victims demonstrated rapid GEH worsening, whereas those with LV dysfunction demonstrated slow GEH worsening. Healthy aging was associated with a distinct pattern of spatial ventricular gradient azimuth decrement. The authors concluded that GEH is a marker of subclinical abnormalities in cardiac structure and function.
Idiopathic Ventricular Arrhythmias Originating From the Infundibular Muscles: Prevalence, Electrocardiographic and Electrophysiological Characteristics, and Outcome of Catheter Ablation
Takumi Yamada, MD… G. Neal Kay, MD
Takumi Yamada and associates studied 19 patients with idiopathic ventricular arrhythmia (VA) origins in the parietal band (PB) in 14 and septal band (SB) in 5 among 294 consecutive patients with right ventricle VA origins. PB and SB VAs exhibited left bundle branch block with a left inferior (n=12) or superior (n=2) axis, and left (n=4) or right inferior (n=1) axis pattern, respectively. In the lead I, all PB VAs exhibited R waves, whereas SB VAs often exhibited S waves. A QS pattern in lead aVr and the presence of a notch in the mid-QRS were common in all infundibular muscle (IFM) VAs. During IFM VAs, a far-field ventricular electrogram with an early activation was always recorded in the His bundle region regardless of the location of the VA origins. With 9.2+6.9 radiofrequency applications and a duration of 972+946 seconds, catheter ablation was successful in 15 patients. VAs recurred in 4 during a follow-up period of 43+24 months.
Atrial Infarction-Induced Spontaneous Focal Discharges and Atrial Fibrillation in Sheep: Role of Dantrolene-Sensitive Aberrant Ryanodine Receptor Calcium Release
Uma Mahesh R. Avula, MD… Jérôme Kalifa, MD, PhD
Uma Mahesh R. Avula and associates examined the mechanisms underlying spontaneous atrial fibrillation (AF) in an ovine model of left atrial myocardial infarction (LAMI). LAMI was created by ligating the atrial branch of the left anterior descending coronary artery. ECG loop recorders were implanted to monitor AF episodes. In 7 sheep, dantrolene, a RyR2 (ryanodine receptor) blocker, was administered in vivo during the 8-day observation period (LAMI-D, 2.5 mg/kg, IV, BID). LAMI-animals experienced numerous spontaneous AF episodes over the 8-day monitoring period that were suppressed by dantrolene (LAMI, 26.1±5.1; sham, 4.3±1.1; LAMI-D, 2.8±0.8; mean±SEM episodes per sheep; P<0.01). Optical mapping showed spontaneous focal discharges (SFDs) originating from the ischemic/normal-zone border. SFDs were calcium-driven, rate-dependent, and enhanced by isoproterenol (0.03 µmol/L, from 210±87 to 3816±1450, SFDs per sheep), but suppressed by dantrolene (to 55.8±32.8, SFDs per sheep, mean±SEM). SFDs initiated AF-maintaining reentrant rotors anchored by marked conduction delays at the ischemic/normal-zone border. Nitric-oxide synthase-1 protein expression decreased in ischemic zone myocytes, whereas NADPH-oxidase and xanthine-oxidase enzyme activities and reactive oxygen species (ROS; DCFfluorescence) increased. Calmodulin aberrantly increased [3H] ryanodine binding to cardiac RyR2 in the ischemic zone. Dantrolene restored the physiological binding of calmodulin to RyR2. The authors concluded that atrial ischemia causes spontaneous AF episodes in sheep caused by SFDs that initiate reentry. Nitroso–redox imbalance in the ischemic zone is associated with intense ROS production and altered RyR2 responses to calmodulin. Dantrolene administration normalizes the calmodulin response, prevents LAMI-related SFDs and AF initiation.
Can We Use the Intrinsic Left Ventricular Delay (QLV) to Optimize the Pacing Configuration for Cardiac Resynchronization Therapy With a Quadripolar Left Ventricular Lead?
Wouter M. van Everdingen, MD, PhD… Mathias Meine, MD, PhD
Wouter M. van Everdingen and associates examined the use of LV sensing delay (QLV) for achieving optimal acute hemodynamic response to cardiac resynchronization therapy (CRT) with a quadripolar left ventricular (LV) lead. Forty-eight heart failure patients with a left bundle branch block were studied (31 male; age: 66±10 years; LV ejection fraction: 28±8%; QRS duration: 176±14 ms). Immediately after CRT implantation, invasive LV pressure–volume loops were recorded during biventricular pacing with each separate electrode at 4 atrioventricular delays. Acute CRT response, measured as a change in stroke work (Δ%SW) compared with intrinsic conduction, was related to intrinsic interval between Q on the ECG and QLV, normalized for QRS duration (QLV/QRSd), and electrode position. QLV/QRSd was 84±9% and variation between the 4 electrodes 9±5%. Δ%SW was 89±64% and varied by 39±36% between the electrodes. In univariate analysis, an anterolateral or lateral electrode position and a high QLV/QRSd had a significant association with a large Δ%SW (all P<0.01). In a combined model, only QLV/QRSd remained significantly associated with Δ%SW (P<0.05). However, a direct relation between QLV/QRSd and Δ%SW was only seen in 24 patients, whereas 24 patients showed an inverse relation. The authors concluded that the large variation in acute hemodynamic response indicates that the choice of the stimulated electrode on a quadripolar lead is important. Although QLV/QRSd was associated with acute hemodynamic response at group level, it cannot be used to select the optimal electrode in the individual patient.
Predictors of Zero X-Ray Ablation for Supraventricular Tachycardias in a Nationwide Multicenter Experience
Antonio Pani, MD… Pasquale Vergara, MD, PhD
Antonio Pani and associates conducted a multicenter, prospective study evaluating the determinants of zero fluoroscopy (ZFL) ablation of supraventricular tachycardias. They studied 430 patients (215 male, 55.4±22.1 years) with an indication to electrophysiological study and ablation of supraventricular tachycardias were enrolled. A procedure was defined as ZFL when no fluoroscopy was used. The total fluoroscopy time inversely correlated to the number of procedures previously performed by each operator since study start (r=−0.112, P=0.02). Two hundred eighty-nine procedures (67.2%) were ZFL; multivariable analysis identified as predictors of ZFL: procedure after the 30th for each operator, as compared for procedures up to the 9th (P=0.011, hazard ratio [HR], 3.49; 95% confidence interval [CI], 1.79–6.80); the type of arrhythmia (P=0.031; electrophysiological study and atrioventricular nodal reentry tachycardia ablation having the highest probability of ZFL; HR, 6.87; 95% CI, 2.08–22.7; and HR, 2.02; 95% CI, 1.04–3.91; respectively); the operator (P=0.002) and patient’s age (P=0.009). Among operators, achievement of ZFL varied from 0% to 100%; 8 (22.8%) operators achieved ZFL in 75% of their procedures. The probability of ZFL increased by 2.8% (HR, 0.98, 95% CI, 0.97–0.99) as patient’s age decreased by 1 year. Acute procedural success was obtained in all cases. The authors concluded that use of 3-dimensional mapping system completely avoided the use of fluoroscopy in most cases, with very low fluoroscopy time in the remaining and high safety and effectiveness profiles.
Left Septal Slow Pathway Ablation for Atrioventricular Nodal Reentrant Tachycardia
Demosthenes G. Katritsis, MD, PhD… Fred Morady, MD
Demosthenes G. Katritsis and associated examined the role of slow pathway ablation from the left septum an alternative to right-sided ablation. Retrospectively, 1342 patients undergoing right septal slow pathway ablation for atrioventricular nodal reentrant tachycardia (AVNRT) were studied. Of these 15 patients, 11 with typical and 4 with atypical AVNRT, had a left septal approach after unsuccessful right-sided ablation (R+L group). In addition, 11 patients were subjected prospectively to a left septal only approach for slow pathway ablation without a previous right septal attempt (L group). Fluoroscopy times in the R+L and L groups were 30.5 (21.0–44.0) minutes, and 20.0 (17.0–25.0) minutes, respectively (P=0.061), and radiofrequency current delivery times were 11.3 (5.0–19.1) minutes, and 10.0 (7.0–12.0) minutes, respectively (P=0.897). There was no need for additional ablation lesions at other anatomic sites in either group, and no cases of atrioventricular block were encountered. Recurrence rates of the arrhythmia for the R+L and L groups were 6.7% and 0%, respectively, in the 3 months after ablation (P=1.000). The authors concluded that left septal ablation at the anatomic site of the left inferior nodal extension is an alternative for ablation of both typical and atypical AVNRT when ablation at the right posterior septum is ineffective.
Incidence and Clinical Significance of New-Onset Device-Detected Atrial Tachyarrhythmia: A Meta-Analysis
Mark N. Belkin, MD… Gaurav A. Upadhyay, MD
Mark N. Belkin and associates examined prior reports of with new-onset device-detected atrial tachyarrhythmia (DDAT). Despite the clear association between atrial fibrillation and risk for thromboembolic events (TE), the clinical significance of new-onset DDAT and TE remains disputed. We aimed to determine the risk of TE in patients using the OVID Medline, Cochrane, and Scopus databases to identify 4893 reports of randomized controlled trials, prospective, or retrospective studies of pacemaker or defibrillator patients reporting incidence of DDAT, the authors examined 28 studies following 24 984 patients. They had an average age of 69.9 years, 34.7% female, mean study duration 21.8±18.6 months. New-onset DDAT was observed in 23% of patients. Among 9 studies (n=8181) reporting TE, the absolute incidence was 2.1%. TE risk was significantly greater among patients with new-onset DDAT (relative risk, 2.88; confidence interval [CI], 1.79–4.64; P<0.001), compared with <1 minute (relative risk, 1.77; CI, 1.15–2.74; P=0.01). The authors concluded that new-onset DDAT is common, affecting close to one-quarter of all patients with implanted pacemakers or defibrillators.
Long-Term Outcome of Pulmonary Vein Isolation With and Without Focal Impulse and Rotor Modulation Mapping: Insights From a Meta-Analysis
Sanghamitra Mohanty, MD, MS… Andrea Natale, MD
Sanghamitra Mohanty and associates performed a meta-analysis systematically evaluating the outcome of pulmonary vein isolation (PVI) with and without focal impulse and rotor modulation (FIRM) ablation in patients with atrial fibrillation (AF). Extensive literature search was performed for studies reporting outcomes of PVI alone and PVI+FIRM procedures. For PVI alone, only randomized trials conducted in the last 3 years reporting single-procedure success rate off-antiarrhythmic drugs (AAD) at ≥12-months follow-up were included. In PVI+FIRM group, all published studies reporting single-procedure AAD success rate with at least 1-year follow-up were identified. Meta-analytic estimates were derived using DerSimonian and Laird random-effects models and pooled estimates of success rate (95% confidence interval [CI]) were computed. Statistical heterogeneity was assessed using Cochran Q test and I 2. Study quality was assessed using Newcastle–Ottawa Scale. Fifteen trials were included; 10 with PVI+FIRM (n=511, nonrandomized prospective design), 5 PVI-only trials (n=295, randomized trials). All patients in PVI-only trials had 100% nonparoxysmal AF excepting one study and no prior ablations. About 24% of PVI+FIRM population had paroxysmal AF. After 15.9±5.5 (median 12) months follow-up, the off-antiarrhythmic drugs pooled success rate was 50% FIRM+PVI (95% CI, 28%–72%) and 58% in PVI (95% CI, 46%–71%). Difference in effect size between groups was not statistically significant (P=0.21). No significant heterogeneity (total or within the group) was observed in this meta-analysis (negative I 2 values considered equal to zero). The authors concluded that the overall pooled estimate did not show any therapeutic benefit of PVI+FIRM approach over PVI alone.
- © 2018 American Heart Association, Inc.
- Implantable Defibrillator Therapy in Cardiac Arrest Survivors With a Reversible Cause
- Left Septal Slow Pathway Ablation for Atrioventricular Nodal Reentrant Tachycardia
- Figures & Tables
- Info & Metrics