Search

Risk for Permanent Pacemaker After Transcatheter Aortic Valve Implantation. Background: Permanent pacemaker (PM) requirement is a known complication after transcatheter aortic valve implantation (TAVI). There are, however, no systematic data concerning this complication. Objective: To determine the incidence and potential predictors of permanent PM requirement after TAVI based on published literature. Methods: We conducted a MEDLINE search to identify potentially relevant literature dealing with PM requirement after TAVI. Data were collected on paper extraction forms by 2 independent investigators. Results: There were 32 relevant published studies comprising data of 5,258 patients without an implanted PM before TAVI. An Edwards-Sapiens® prosthesis (ESP) was implanted in 2,887 patients, whereas 2,371 patients received a CoreValve® prosthesis (CVP). The crude incidence of PM implantation after TAVI was 15%. Six hundred and fourteen of 2,371 (25.8%) CVP patients and 189 of the 2,887 (6.5%) ESP patients had to receive a permanent PM (odds ratio [OR] 4.91, 95% confidence interval [CI] 4.12-5.86, P < 0.001). Presence of right bundle branch block (RBBB) before TAVI was a significant predictor for development of complete atrioventricular (AV) block and subsequent PM need (OR 1.358, 95% CI 1.001-1.841, P = 0.02). More than 90% of all AV-block requiring PM implantation occurred immediately or within 7 days after TAVI. Conclusion: Patients undergoing TAVI with implantation of CVP are at significantly higher risk for development of AV block and subsequent need for permanent PM, particularly if RBBB preexists. Since AV block occurs in >90% within the first week after the procedure, careful monitoring should be performed for at least 7 days after TAVI. [ABSTRACT FROM AUTHOR]

Introduction: The reuse of cardiac implantable electronic devices may help increase access to these therapies in low‐ and middle‐income countries (LMICs). No published data exist regarding the views of patients and family members in LMICs regarding this practice. Methods and Results: An article questionnaire eliciting attitudes regarding pacemaker reuse was administered to ambulatory adult patients and patients' family members at outpatient clinics at Centro Nacional Cardiologia in Managua, Nicaragua, Indus Hospital in Karachi, Pakistan, Hospital Carlos Andrade Marín, and Hospital Eugenio Espejo in Quito, Ecuador, and American University of Beirut Medical Center in Beirut, Lebanon. There were 945 responses (Nicaragua – 100; Pakistan – 493; Ecuador – 252; and Lebanon – 100). A majority of respondents agreed or strongly agreed that they would be willing to accept a reused pacemaker if risks were similar to a new device (707, 75%), if there were a higher risk of device failure compared with a new device (584, 70%), or if there were a higher risk of infection compared to a new device (458, 56%). A large majority would be willing to donate their own pacemaker at the time of their death (884, 96%) or the device of a family member (805, 93%). Respondents who were unable to afford a new device were more likely to be willing to accept a reused device (79% vs. 63%, p <.001). Conclusions: Patients and their family members support the concept of pacemaker reuse for patients who cannot afford new devices. [ABSTRACT FROM AUTHOR]

QT Interval Readings With a Smartphone Heart Monitor Introduction A variety of medications ranging from antiarrhythmics to psychotropics, as well as conditions such as bradycardia, can prolong the QT interval, increasing the risk for life-threatening arrhythmias. Monitoring the corrected QT interval (QTc) is therefore critical for patient safety. The recent development of smart phone heart monitors (SHM) may allow for easier QTc monitoring. We sought to evaluate the accuracy of an SHM for assessing the QTc, as compared to the standard 12-lead ECG. Methods and Results We compared the QTc interval in lead-I and lead-II between an SHM and 12-lead ECG. Healthy volunteers and hospitalized patients in sinus rhythm being loaded on dofetilide or sotalol were included. Manual and automatic measurements were studied. Across 99 healthy volunteers, the SHM QTc demonstrated good agreement (bias = 4 milliseconds, standard deviation of bias = 11 milliseconds) compared to the 12-lead ECG, using the Bland-Altman method of agreement. Across all hospitalized patients, the SHM was capable of demonstrating QTc prolongation. Between the 12-lead ECG and SHM, lead-I measurements had reasonable agreement (bias = 3 milliseconds, standard deviation of bias = 46 milliseconds). A QTc of > 500 milliseconds was associated with a higher likelihood (OR = 12.0; 95% CI 1.5-111.4; P = 0.02) to not achieve perfect agreement. Conclusion The SHM is accurate in measuring QTc interval in sinus rhythm when compared to 12-lead ECG in healthy volunteers. For patients receiving QT prolonging antiarrhythmics, SHM is capable of detecting QTc prolongation, and lead-I of the SHM is most accurate in measuring the QTc if < 500 milliseconds. [ABSTRACT FROM AUTHOR]

Impact of Continuous Positive Airway Pressure Background Obesity-hypoventilation syndrome (OHS) is defined as daytime hypercapnia and hypoxemia in obese patients with sleep-disordered breathing. We evaluated the electrocardiographic P-wave duration and dispersion (PD) and echocardiographic noninvasive indicators of atrial conduction heterogeneity in OHS patients and the impact of CPAP on atrial conduction and atrial fibrillation incidence. Methods and Results We enrolled 50 OHS patients and 50 sex- and age-matched obese subjects as control. Study population underwent cardiologic evaluation and polysomnography before enrollment, at 1- and 6-month follow-ups after CPAP therapy. The OHS group showed a significant increase in inter-atrial (35.2 ± 8 milliseconds vs. 20.1 ± 2.7 milliseconds, P < 0.0001), intra-left (30.5 ± 7.2 milliseconds vs. 16.5 ± 2 milliseconds, P < 0.0001), and intra-right atrial electromechanical delays (AEMD)(24.8 ± 10 milliseconds vs. 15 ± 2.6 milliseconds, P < 0.0001) as well as in Pmax (130 ± 7.4 milliseconds vs. 97 ± 7.2 milliseconds, P = 0.002) and PD (56.5 ± 8.5 milliseconds vs. 31 ± 7.2 milliseconds, P = 0.002) compared to the control group. Significant improvement was noted after 6 months of CPAP therapy in inter-atrial (35.2 ± 8 milliseconds vs. 24.5 ± 6.3 milliseconds, P < 0.0001), intra-left (30.5 ± 7.2 milliseconds vs. 20.6 ± 5 milliseconds, P = 0.003), and intra-right AEMD (24.8 ± 10 milliseconds vs. 17 ± 7.5 milliseconds, P < 0.0001), as well as in Pmax (130 ± 7.4 milliseconds vs. 95 ± 10 milliseconds, P < 0.0001) and in PD (56.5 ± 8.5 milliseconds vs. 32.5 ± 6 milliseconds, P < 0.0001) in the OHS group. External loop recorder monitoring detected paroxysmal AF in 19 OHS patients (38%) with significant reduction in paroxysmal AF episodes (12 ± 6 vs. 47 ± 12, P < 0.0001) after 6-month CPAP therapy. Conclusion Our findings showed a significant increase of electrocardiographic and echocardiographic indexes of atrial conduction heterogeneity in OHS patients. The CPAP therapy, having a positive impact on atrial conduction time, seems to reduce AF incidence in OHS patients [ABSTRACT FROM AUTHOR]

Mapping of Scar-Related VT Background Substrate-based VT ablation is mostly based on maps acquired with ablation catheters. We hypothesized that multipolar mapping catheters are more effective for identification of scar and local abnormal ventricular activity (LAVA). Methods and results Phase1: In a sheep infarction model (2 months postinfarction), substrate mapping and LAVA tagging (CARTO®3) was performed, using a Navistar (NAV) versus a PentaRay (PR) catheter (Biosense Webster). Phase2: Consecutive VT ablation patients from a single center underwent NAV versus PR mapping. Point pairs were defined as a PR and a NAV point located within a 3D-distance of ≤3 mm. Agreement was defined as both points in a pair being manually tagged as normal or LAVA. Four sheep (4 years, 50 ± 4.8 kg) and 9 patients were included (53 ± 14 years, 8 male, 6 ischemic cardiomyopathy). Mapping density was higher within the scar with PR versus NAV (3.2 vs. 0.7 points/cm2, P = 0.001) with larger bipolar scar area (68 ± 55 cm2 vs. 58 ± 48 cm2, P = 0.001). In total, 818 point pairs were analyzed. Using PR, far-field voltages were smaller (PR vs. NAV; bipolar: 1.43 ± 1.84 mV vs. 1.64 ± 2.04 mV, P = 0.001; unipolar; 4.28 ± 3.02 mV vs. 4.59 ± 3.67 mV, P < 0.001). More LAVA were also detected with PR (PR vs. NAV; 126 ± 113 vs. 36 ± 29, P = 0.001). When agreement on LAVA was reached (overall: 72%; both LAVA, 40%; both normal, 82%) higher LAVA voltages were recorded on PR (0.48 ± 0.33 mV vs. 0.31 ± 0.21 mV, P = 0.0001). Conclusion Multipolar mapping catheters with small electrodes provide more accurate and higher density maps, with a higher sensitivity to near-field signals. Agreement between PR and NAV is low. [ABSTRACT FROM AUTHOR]

Zoledronic Acid Alters Atrial Electrophysiology Introduction Our objective was to determine effects of zoledronic acid (ZA) on atrial electrophysiological parameters and electrocardiographic measurements. Methods and Results Ex vivo perfusion study: Isolated guinea pig hearts were perfused with modified Krebs-Henseleit (K-H) buffer with or without ZA 0.07 mg/kg/L (each n = 6). In ZA-perfused hearts, atrial action potential at 90% repolarization (APD90) decreased more from baseline than in controls (−23.2% ± −5.1% vs. −2.1% ± −8.1%, P < 0 .0001), as did APD30 (−28.8% ± −3.8% vs. −2.1% ± −2.1%, P < 0.0001). In vivo dose-response study: Guinea pigs underwent intraperitoneal injections every 2 weeks in 1 of 4 groups (each n = 8): ZA 0.007 mg/kg (low-dose), ZA 0.07 mg/kg (medium-dose), ZA 0.7 mg/kg (high-dose), or placebo. Hearts were excised at 8 weeks and perfused with modified K-H. Atrial effective refractory period (ERP) was lower with medium- and high-dose ZA versus placebo (P = 0.004). Atrial APD30 was lower with high-dose ZA versus placebo, low and medium doses (P < 0.001). Canine ECG study: Mature female beagles received intravenous ZA 0.067 mg/kg or saline (placebo; each n = 6) every 2 weeks for 12 weeks. P wave dispersion was greater in the ZA group (7.7 ± 3.7 vs. 3.4 ± 2.6 ms, P = 0.04). There were no significant differences in P wave index, maximum or minimum P wave duration, or PR interval. Conclusion ZA shortens left atrial APD and ERP and increases P wave dispersion. [ABSTRACT FROM AUTHOR]

QRS Fragmentation and QTc in Hypertrophic Cardiomyopathy Background QRS fragmentation (fQRS) and prolonged QTc interval on surface ECG are prognostic in various cardiomyopathies other than hypertrophic cardiomyopathy (HCM). The association between fQRS and prolonged QTc duration with occurrence of ventricular tachyarrhythmias or sudden cardiac death (VTA/SCD) in patients with HCM was explored. Methods and Results One hundred and ninety-five clinical HCM patients were studied. QTc duration was derived applying Bazett's formula; fQRS was defined as presence of various RSR' patterns, R or S notching and/or >1 additional R wave in any non-aVR lead in patients without pacing or (in)complete bundle branch block. The endpoints comprised SCD, ECG documented sustained VTA (tachycardia or fibrillation) or appropriate implantable cardioverter defibrillator (ICD) therapies (antitachycardia pacing [ATP] or shock) for VTA in ICD recipients (n = 58 [30%]). QT prolonging drugs recipients were excluded. After a median follow-up of 5.7 years (IQR 2.7-9.1), 26 (13%) patients experienced VTA or SCD. Patients with fQRS in ≥3 territories (inferior, lateral, septal, and/or anterior) (p = 0.004) or QTc ≥460 ms (p = 0.009) had worse cumulative survival free of VTA/SCD than patients with fQRS in <3 territories or QTc <460 ms. fQRS in ≥3 territories (ß 4.5, p = 0.020, 95%CI 1.41-14.1) and QTc ≥460 ms (ß 2.7, p = 0.037, 95%CI 1.12-6.33) were independently associated with VTA/SCD. Likelihood ratio test indicated assessment of fQRS and QTc on top of conventional SCD risk factors provides incremental predictive value for VTA/SCD (p = 0.035). Conclusions Both fQRS in ≥3 territories and QTc duration are associated with VTA/SCD in HCM patients, independently of and incremental to conventional SCD risk factors. [ABSTRACT FROM AUTHOR]

T-Wave Predicts CRT Response in LBBB Patients Introduction Chronic heart failure patients with a left ventricular (LV) conduction delay, mostly due to left bundle branch block (LBBB), generally derive benefit from cardiac resynchronization therapy (CRT). However, 30-50% of patients do not show a clear response to CRT. We investigated whether T-wave analysis of the ECG can improve patient selection. Methods and Results The study population comprised 244 CRT recipients with baseline 12-lead electrocardiogram recordings. Echocardiographic response after 6-month CRT was defined as a ≥5% increase in LV ejection fraction (LVEF). Vectorcardiograms (VCGs) were constructed from the measured 12-lead ECGs using an adapted Kors algorithm on digitized ECGs. Logistic regression models indicated repolarization variables as good predictors of CRT response. The VCG-derived T-wave area predicted CRT response (odds ratio [OR] per 10 μVs increase 1.172 [P < 0.001]) even better than QRS-wave area (OR = 1.116 [P = 0.001]). T-wave area had especially predictive value in the LBBB patient group (OR = 2.77 in LBBB vs. 1.09 in non-LBBB). This predictive value persisted after adjustment of multiple covariates, such as gender, ischemia, age, hypertension, coronary artery bypass graft, and the usage of diuretics and β-blockers. In LBBB patients, the increase in LVEF was 6.1 ± 9.7% and 11.3 ± 9.1% in patients with T-wave area below and above the median value, respectively (P < 0.01). Conclusion In patients with LBBB morphology of the QRS complex, a larger baseline T-wave area is an important independent predictor of LVEF increase following CRT. [ABSTRACT FROM AUTHOR]

Brugada Syndrome in the Elderly Background The clinical course and prognosis of Brugada syndrome (BS) in the elderly is unknown. The purpose of this study was to investigate the clinical characteristics, management, and prognosis of BS in an elderly population. Methods and Results A total of 437 patients with BS were included in this study. Patients were categorized in 2 groups according to the age at the time of diagnosis: <60 years (N = 363) and ≥60 years (N = 74). Moreover, an elderly patients' subgroup analysis was performed between patients with an age between 60 and 70 years (N = 49) and subjects older than 70 years (N = 25). Among elderly patients (50% male, mean age: 67 ± 6 years), family history of sudden death (SD) and induction of sustained ventricular arrhythmias during programmed ventricular stimulation were less frequent as compared to younger patients. Two patients (3%) had a previous episode of aborted SD. Elderly patients with BS presented more frequently with ECG conduction disturbances or previous transient advanced atrioventricular block as compared to younger patients. Of the elderly patients, 42% underwent implantable cardioverter defibrillator implantation and 7% received a pacemaker. After a mean follow-up time of 54 ± 18 months, none of the elderly patients with BS older than 70 years experienced documented life-threating ventricular arrhythmias. Family screening was performed in 58 family members and a BS diagnosis was confirmed in 49%. Conclusion The clinical features and the benign prognosis of BS patients older than 70 years likely identify a lower risk category of patients as compared to younger individuals. The device-guided management in this setting remains individualized and sometimes controversial. Moreover, BS diagnosis in the elderly should not be missed, mainly due to the clinical impact on the family of elderly patients. [ABSTRACT FROM AUTHOR]

Morphology of Far-Field Electrograms and ATP Effectiveness Introduction Fast ventricular tachycardias (FVT) are less likely to be terminated by antitachycardia pacing (ATP). No information is available regarding the ability of far-field electrogram (Ff-EG) morphology (Ff-EGm) in predicting the result of the subsequent ATP. Our objective is to determine the relationship between Ff-EGm and ATP efficacy. Methods and Results In this multicenter study we analyzed 289 FVT (cycle length [CL]: 250-320 milliseconds) occurring consecutively in 52 ICD patients with Medtronic devices (LVEF: 37 ± 6; pacing site: right ventricular apex). FVT programming was standardized, including a single ATP burst as initial therapy. The configuration of Ff-EG was HVA versus HVB. FVTs were classified in QFVT or non-QFVT according to the presence or absence of a negative initial deflection in the Ff-EG. The mean CL was 291 ± 24 milliseconds. We observed 4 Ff-EGm: QS (n = 14, 5%), QR (n = 158, 55%), R (n = 93, 32%), and RS (n = 24, 8%). The ATP effectiveness was 80% (86% in QS, 85% in QR, 74% in R, 62% in RS). The frequency of successful ATP was higher in QFVT: 86 versus 71% (P = 0.002). By logistic regression analysis, a QFVT pattern (OR = 2.3; P = 0.015) remained as an independent predictor of effective ATP. ATP was safer in QFVTs, the frequencies of shock (14% vs 29%; P = 0.002), acceleration (5.1 vs 12.3%; P = 0.02), and syncope (4.6 vs 12.3%; P = 0.01) being lower. Conclusions Since ATP is less effective in non-QFVTs, they are less well tolerated. Therefore, the substrate of non-QFVTs may need a specific treatment. [ABSTRACT FROM AUTHOR]

Inappropriate Therapy in Single Versus Dual Chamber Background The majority of implantable cardioverter defibrillators (ICDs) are dual-chamber devices, but studies on the frequency of inappropriate therapy in dual- versus single-chamber devices have shown conflicting results. The aim of this study is to determine whether implantation of dual-chamber ICD devices decrease the incidence of inappropriate therapy without an unacceptable increase in complications. Methods In the ICD arm of the MADIT-CRT study (N = 704), comparisons of single- versus dual-chamber ICD devices were investigated on the endpoints of inappropriate therapy (antitachycardia pacing [ATP] and shocks) and device- and procedure-related complications by use of multivariate Cox proportional hazard regression analysis (hazard ratio dual:single chamber) adjusting for relevant covariates. Results The frequency of inappropriate therapies in single- and dual-chamber recipients was 41/294 (14%) and 50/410 (12%), respectively. There was no significant difference in overall inappropriate therapy (hazard ratio [HR] = 0.95 [CI: 0.63-1.45], P = 0.95) or inappropriate ATP (HR = 0.98 [CI: 0.61-1.58], P = 0.94), between single- and dual-chamber devices, using single-chamber as a reference (Dual:Single). However, there was a trend toward a decrease in inappropriate shocks (HR = 0.60 [CI: 0.34-1.08], P = 0.09) in the dual-chamber group. The same was evident when only analyzing inappropriate therapy for atrial tachyarrhythmias (HR = 0.88 [CI: 0.56-1.38], P = 0.58). There was no significant difference between the groups in device- or procedure-related complications (HR = 1.54 [CI: 0.82-2.90], P = 0.18). Conclusion No significant difference was found in inappropriate therapy or complications in patients treated with single- versus dual-chamber ICD devices. [ABSTRACT FROM AUTHOR]

Intrinsic QRS Narrowing with CRT. Background: Cardiac resynchronization therapy (CRT) improves left ventricular ejection fraction (LVEF) in patients with congestive heart failure, LV systolic dysfunction, and a wide QRS complex. Previous reports suggest that CRT may also induce electrical remodeling but the impact on clinical outcome remains unknown. Objective: We sought to determine (1) if chronic CRT induces a relevant shortening of the intrinsic QRS (iQRS), (2) whether changes in the native conduction system correlate with clinical or echocardiographic response to CRT, and (3) to identify predictors of iQRS width shortening. Methods: We prospectively included 85 consecutive patients with left bundle-branch block who received a CRT device in 3 French centers. NYHA class, iQRS duration, LVEF, and left ventricular volumes were assessed before and 1 year after CRT implantation. Clinical and echocardiographic CRT responders were defined respectively as NYHA class improvement >1 class without heart failure hospitalization and an increase of LVEF by ≥10% and/or a decrease in LVESV by ≥15%. Electrocardiographic responders were defined as a decrease in iQRS duration by ≥20 ms. Results: Baseline and 1-year follow-up mean iQRS durations were, respectively, 168.0 ± 19.7 ms and 149.6 ± 31.6 ms (P < 0.0001). Electrocardiographic response, observed in 43/85 patients (51%), was associated with a greater rate of clinical (P = 0.035) and echocardiographic (P = 0.023) response. Younger age, male gender, and longer baseline QRS width were independent predictors of electrocardiographic response. Conclusion: CRT decreases iQRS duration. A reduction of at least 20 ms in iQRS duration is associated with better clinical and echocardiographic response. (J Cardiovasc Electrophysiol, Vol. 23, pp. 1219-1227, November 2012) [ABSTRACT FROM AUTHOR]

ICD Electrograms and Origin of Impulses. Introduction: The implantable cardioverter-defibrillator (ICD) electrogram (EG) is a documentation of ventricular tachycardia. We prospectively analyzed EGs from ICD electrodes located at the right ventricle apex to establish (1) ability to regionalize origin of left ventricle (LV) impulses, and (2) spatial resolution to distinguish between paced sites. Methods and Results: LV electro-anatomic maps were generated in 15 patients. ICD-EGs were recorded during pacing from 22 ± 10 LV sites. Voltage of far-field EG deflections (initial, peak, final) and time intervals between far-field and bipolar EGs were measured. Blinded visual analysis was used for spatial resolution. Initial deflections were more negative and initial/peak ratios were larger for lateral versus septal and superior versus inferior sites. Time intervals were shorter for apical versus basal and septal versus lateral sites. Best predictive cutoff values were voltage of initial deflection <-1.24 mV, and initial/peak ratio >0.45 for a lateral site, voltage of final deflection <-0.30 for an inferior site, and time interval <80 milliseconds for an apical site. In a subsequent group of 9 patients, these values predicted correctly paced site location in 54-75% and tachycardia exit site in 60-100%. Recognition of paced sites as different by EG inspection was 91% accurate. Sensitivity increased with distance (0.96 if ≥ 2 cm vs 0.84 if < 2 cm, P < 0.001) and with presence of low-voltage tissue between sites (0.94 vs 0.88, P < 0.001). Conclusions: Standard ICD-EG analysis can help regionalize LV sites of impulse formation. It can accurately distinguish between 2 sites of impulse formation if they are ≥2 cm apart. (J Cardiovasc Electrophysiol, Vol. 23, pp. 506-514, May 2012) [ABSTRACT FROM AUTHOR]

Toward MR-Guided Electroanatomical Voltage Mapping for Catheter Ablation. Introduction: Integration of preprocedural delayed enhanced magnetic resonance imaging (DE-MRI) with electroanatomical voltage mapping (EAVM) may provide additional high-resolution substrate information for catheter ablation of scar-related ventricular tachycardias (VT). Accurate and fast image integration of DE-MRI with EAVM is desirable for MR-guided ablation. Methods and Results: Twenty-six VT patients with large transmural scar underwent catheter ablation and preprocedural DE-MRI. With different registration models and EAVM input, 3 image integration methods were evaluated and compared to the commercial registration module CartoMerge. The performance was evaluated both in terms of distance measure that describes surface matching, and correlation measure that describes actual scar correspondence. Compared to CartoMerge, the method that uses the translation-and-rotation model and high-density EAVM input resulted in a registration error of 4.32±0.69 mm as compared to 4.84 ± 1.07 (P <0.05); the method that uses the translation model and high-density EAVM input resulted in a registration error of 4.60 ± 0.65 mm (P = NS); and the method that uses the translation model and a single anatomical landmark input resulted in a registration error of 6.58 ± 1.63 mm (P < 0.05). No significant difference in scar correlation was observed between all 3 methods and CartoMerge (P = NS). Conclusions: During VT ablation procedures, accurate integration of EAVM and DE-MRI can be achieved using a translation registration model and a single anatomical landmark. This model allows for image integration in minimal mapping time and is likely to reduce fluoroscopy time and increase procedure efficacy. (J Cardiovasc Electrophysiol, Vol. 23, pp. 74-80, January 2012) [ABSTRACT FROM AUTHOR]