Jaimie Manlucu

Risk of Arrhythmia and Sudden Death in Patients With Asymptomatic Preexcitation A Meta-Analysis

Background— The incidence of sudden cardiac death (SCD) and the management of this risk in patients with asymptomatic preexcitation remain controversial. The purpose of this meta-analysis was to define the incidence of SCD and supraventricular tachycardia in patients with asymptomatic Wolff-Parkinson-White ECG pattern. Methods and Results— We performed a systematic search of prospective, retrospective, randomized, or cohort English-language studies in EMBASE and Medline through February 2011. Studies reporting asymptomatic patients with preexcitation who did not undergo ablation were included. Twenty studies involving 1869 patients met our inclusion criteria. Participants were primarily male with a mean age ranging from 7 to 43 years. Ten SCDs were reported involving 11 722 person-years of follow-up. Seven studies originated from Italy and reported 9 SCDs. The risk of SCD is estimated at 1.25 per 1000 person-years (95% confidence interval [CI], 0.57–2.19). A total of 156 supraventricular tachycardias were reported involving 9884 person-years from 18 studies. The risk of supraventricular tachycardia was 16 (95% CI, 10–24) events per 1000 person-years of follow-up. Children had numerically higher SCD (1.93 [95% CI, 0.57–4.1] versus 0.86 [95% CI, 0.28–1.75]; P=0.07) and supraventricular tachycardia (20 [95% CI, 12–31] versus 14 [95% CI, 6–25]; P=0.38) event rates compared with adults. Conclusion— The low incidence of SCD and low risk of supraventricular tachycardia argue against routine invasive management in most asymptomatic patients with the Wolff-Parkinson-White ECG pattern.

Cryoablation Versus RF Ablation for AVNRT: A Meta‐Analysis and Systematic Review

Atrioventricular nodal reentrant tachycardia (AVNRT) is the most common supraventricular tachycardia referred for ablation. High success rates have been accompanied with a small risk of atrioventricular (AV) block. Cryoablation has been used as an alternative to radiofrequency (RF) ablation, but studies have been underpowered in comparing the 2 techniques.

Canadian Cardiovascular Society/Canadian Heart Rhythm Society 2016 Implantable Cardioverter-Defibrillator Guidelines

Sudden cardiac death is a major public health issue in Canada. However, despite the overwhelming evidence to support the use of implantable cardioverter defibrillators (ICDs) in the prevention of cardiac death there remains significant variability in implantation rates across Canada. Since the most recent Canadian Cardiovascular Society position statement on ICD use in Canada in 2005, there has been a plethora of new scientific information to assist physicians in their discussions with patients considered for ICD implantation to prevent sudden cardiac death due to ventricular arrhythmias. We have reviewed, critically appraised, and synthesized the pertinent evidence to develop recommendations regarding: (1) ICD implantation in the primary and secondary prevention of sudden cardiac death in patients with and without ischemic heart disease; (2) when it is reasonable to withhold ICD implantation on the basis of comorbidities; (3) ICD implantation in patients listed for heart transplantation; (4) implantation of a single- vs dual-chamber ICD; (5) implantation of single- vs dual-coil ICD leads; (6) the role of subcutaneous ICDs; and (7) ICD implantation infection prevention strategies. We expect that this document, in combination with the companion article that addresses the implementation of these guidelines, will assist all medical professionals with the care of patients who have had or at risk of sudden cardiac death.

Early repolarization is associated with symptoms in patients with type 1 and type 2 long QT syndrome

BACKGROUND Early repolarization (ER) is associated with an increased risk for death from cardiac causes. Recent evidence supports ERs role as a modifier and/or predictor of risk in many cardiac conditions. OBJECTIVE The purpose of this study was to determine the prevalence of ER among genotype-positive patients with long QT syndrome (LQTS) and evaluate its utility in predicting the risk of symptoms. METHODS ER was defined as QRS slurring and/or notching associated with ≥1-mV QRS-ST junction (J-point) elevation in at least 2 contiguous leads, excluding the anterior precordial leads. The ECG with the most prominent ER was used for analysis. Major ER was defined as ≥ 2-mm J-point elevation. Symptoms of LQTS included cardiac syncope, documented polymorphic ventricular tachycardia (VT), and resuscitated cardiac arrest. RESULTS One hundred thirteen patients (mean age 41 ± 19 years; 63 female) were reviewed, among whom 414 (mean 3.7 ± 1.5) ECGs were analyzed. Of these, 30 patients (27%) with a history of symptoms. Fifty patients (44%) had ER, and 19 patients (17%) had major ER. Patients with major ER were not different from patients without major ER with respect to age, sex, long QT type, longest QTc recorded, number of patients with QTc >500 ms, or use of beta-blockade. Univariate and independent predictors of symptom status included the presence of major ER, longest QTc recorded >500 ms, and female sex. CONCLUSION ER ≥2 mm was the strongest independent predictor of symptom status related to LQTS, along with female sex and QTc >500 ms.

A novel algorithm to assess risk of heart failure exacerbation using ICD diagnostics: validation from RAFT.

BACKGROUND The integrated diagnostics (ID) algorithm is an implantable device-based tool that collates data pertaining to heart rhythm, heart rate, intrathoracic fluid status, and activity, producing a risk score that correlates with 30-day risk of heart failure (HF) hospitalization. OBJECTIVE We sought to validate the ID algorithm using the Resynchronization-Defibrillation for Ambulatory Heart Failure Trial. METHODS Diagnostic measures of the algorithm include OptiVol fluid index, nighttime heart rate, minutes of patient activity, heart rate variability, and combined measure of cardiac rhythm and biventricular pacing. Monthly evaluations of ID parameters were assessed for the development of HF symptoms and hospitalization for HF. RESULTS A total of 1224 patients were included: 741 (61%) with cardiac resynchronization therapy with defibrillator devices and 483 (39%) with implanted cardioverter-defibrillator only. The mean age was 66 ± 9 years, and 1013 (83%) were men. A total of 37,861 months of follow-up data were available, with 258 HF hospitalizations (event rate 0.68% per month). There were 33 HF hospitalizations during low-risk months (0.21% per month), 123 during medium-risk months (0.66% per month), and 102 during high-risk months (2.61% per month). Compared with low-risk months, and 95% confidence intervals) of HF hospitalizations during medium-risk months was 2.9 (2.0-4.4) and during high-risk months was 10.7 (6.9-16.6). Multivariable analysis demonstrated that each ID variable had independent association with HF hospitalization. CONCLUSION The risk of HF as determined by the ID algorithm correlated with HF hospitalization and several HF signs and symptoms among patients in the Resynchronization-Defibrillation for Ambulatory Heart Failure Trial. This may present a useful adjunct to detect early signs of HF and adjust therapy to reduce morbidity and costs involved with hospital admission.

Extensive Thrombosis Following Lead Extraction: Further Justification for Routine Post-operative Anticoagulation

Lead extraction is becoming increasingly common as indications for pacing and ICD insertion expand. Periop management varies between extraction centers, and no clinical guidelines have addressed the need for perioperative anticoagulation. We report a case of massive thrombosis which occurred shortly after laser lead extraction and is undoubtedly related to the trauma of the extraction and ensuing hypercoagulabiilty. Routine post-operative anticoagulation has been advocated as a means to prevent access vein (subclavian) stenosis, but many centres do not employ a routine post-extraction anticoagulation strategy. Pulmonary embolism following lead extraction is a known complication of this procedure and late mortality following lead extraction is a significant and underappreciated problem. We propose that further research attention should be directed at addressing the issue of routine post-extraction anticoagulation.

A Detailed Description and Assessment of Outcomes of Patients With Hospital Recorded QTc Prolongation

Corrected QT (QTc) interval prolongation has been shown to be an independent predictor of mortality in many clinical settings and is a common finding in hospitalized patients. The causes and outcomes of patients with extreme QTc interval prolongation during a hospital admission are poorly described. The aim of this study was to prospectively identify patients with automated readings of QTc intervals >550 ms at 1 academic tertiary hospital. One hundred seventy-two patients with dramatic QTc interval prolongation (574 ± 53 ms) were identified (mean age 67.6 ± 15.1 years, 48% women). Most patients had underlying heart disease (60%), predominantly ischemic cardiomyopathy (43%). At lease 1 credible and presumed reversible cause associated with QTc interval prolongation was identified in 98% of patients. The most common culprits were QTc interval-prolonging medications, which were deemed most responsible in 48% of patients, with 25% of these patients taking ≥2 offending drugs. Two patients were diagnosed with congenital long-QT syndrome. Patients with electrocardiograms available before and after hospital admission demonstrated significantly lower preadmission and postdischarge QTc intervals compared with the QTc intervals recorded in the hospital. In conclusion, in-hospital mortality was high in the study population (29%), with only 4% of patients experiencing arrhythmic deaths, all of which were attributed to secondary causes.

Loss-of-Function KCNE2 Variants: True Monogenic Culprits of Long-QT Syndrome or Proarrhythmic Variants Requiring Secondary Provocation?

Background— Insight into type 6 long-QT syndrome (LQT6), stemming from mutations in the KCNE2-encoded voltage-gated channel &bgr;-subunit, is limited. We sought to further characterize its clinical phenotype. Methods and Results— Individuals with reported pathogenic KCNE2 mutations identified during arrhythmia evaluation were collected from inherited arrhythmia clinics and the Rochester long-QT syndrome (LQTS) registry. Previously reported LQT6 cases were identified through a search of the MEDLINE database. Clinical features were assessed, while reported KCNE2 mutations were evaluated for genotype–phenotype segregation and classified according to the contemporary American College of Medical Genetics guidelines. Twenty-seven probands possessed reported pathogenic KCNE2 mutations, while a MEDLINE search identified 17 additional LQT6 cases providing clinical and genetic data. Sixteen probands had normal resting QTc values and only developed QT prolongation and malignant arrhythmias after exposure to QT-prolonging stressors, 10 had other LQTS pathogenic mutations, and 10 did not have an LQTS phenotype. Although the remaining 8 subjects had an LQTS phenotype, evidence suggested that the KCNE2 variant was not the underlying culprit. The collective frequency of KCNE2 variants implicated in LQT6 in the Exome Aggregation Consortium database was 1.4%, in comparison with a 0.0005% estimated clinical prevalence for LQT6. Conclusions— On the basis of clinical phenotype, the high allelic frequencies of LQT6 mutations in the Exome Aggregation Consortium database, and absence of previous documentation of genotype–phenotype segregation, our findings suggest that many KCNE2 variants, and perhaps all, have been erroneously designated as LQTS-causative mutations. Instead, KCNE2 variants may confer proarrhythmic susceptibility when provoked by additional environmental/acquired or genetic factors, or both.

Atrial flutter and atrial fibrillation ablation – sequential or combined? A cost-benefit and risk analysis of primary prevention pulmonary vein ablation

BACKGROUND Recent studies have tested the hypothesis that preventive pulmonary vein isolation (PVI) at time of atrial flutter ablation in patients who have not had atrial fibrillation (AF) will reduce future incidence of AF. OBJECTIVE To model relative procedural costs, risks, and benefits of sequential versus combined ablation strategies. METHODS The decision model compares a sequential ablation strategy of atrial flutter ablation, followed by future PVI if necessary, with an initial combined flutter and preventive PVI ablation strategy. Assumptions are AF incidence 20% per year, PVI success rate 70%, PVI complication rate 4%, atrial flutter complication rate 1%, and costs

Intravascular Hemolysis Secondary to Aorto-atrial Fistula Presenting as Red Urine

13,056 for PVI and