Intermittent versus Persistent Wolff-Parkinson-White Syndrome in Children: Electrophysiologic Properties and Clinical Outcomes.

BACKGROUND: Intermittent Wolff-Parkinson-White (WPW) syndrome is considered to have a lower risk of sudden death. Fewer data exist regarding electrophysiologic (EP) characteristics and the natural history of intermittent WPW in children. METHODS: All patients with WPW age 1-18 years at a single institution (1996-2013) were reviewed. Patients with intermittent preexcitation were compared to those with loss of preexcitation on Holter/exercise testing and those with persistent preexcitation. High-risk accessory pathway (AP) was defined as AP effective refractory period (APERP), block cycle length, or shortest preexcited RR interval during atrial fibrillation ≤250 ms. RESULTS: A total of 295 patients were included: 226 (76.6%) persistent, 39 (13.2%) intermittent, and 30 (10.2%) loss of preexcitation Holter/exercise. There were no differences in symptoms between groups. Median interquartile range APERP was significantly longer in intermittent WPW (380 [320, 488] ms vs 320 [300, 350] ms persistent, 310 [290, 330] ms loss of preexcitation Holter/exercise; P = 0.0008). At baseline, there was no difference between groups in frequency of high-risk pathways. However, when isoproterenol values were included, high-risk pathways were more frequent among patients with loss of preexcitation on Holter/exercise (54% vs 16% persistent, 11% intermittent; P = 0.005). There was one death in a patient with loss of preexcitation on exercise testing, no EP study, and prior drug use. A second patient with persistent WPW and APERP 270 ms required resuscitation following a methadone overdose. CONCLUSION: Intermittent preexcitation in children does not connote a lower risk AP by EP criteria or reduced symptoms. The low number of pediatric WPW patients who develop preexcited atrial fibrillation or sudden death warrants larger studies to investigate these outcomes.

Electrocardiographic Preexcitation and Risk of Cardiovascular Morbidity and Mortality: Results From the Copenhagen ECG Study.

BACKGROUND: The majority of available data on the clinical course of patients with ventricular preexcitation in the ECG originates from tertiary centers. We aimed to investigate long-term outcomes in individuals from a primary care population with electrocardiographic preexcitation. METHODS AND RESULTS: Digital ECGs from 328 638 primary care patients were collected during 2001 to 2011. We identified 310 individuals with preexcitation (age range, 8-85 years). Data on medication, comorbidity, and outcomes were collected from Danish nationwide registries. The median follow-up time was 7.4 years (quartiles, 4.6-10.3 years). Compared with the remainder of the population, patients with preexcitation had higher adjusted hazards of atrial fibrillation (hazard ratio [HR], 3.12; 95% confidence interval [CI], 2.07-4.70) and heart failure (HR, 2.11; 95% CI, 1.27-3.50). Subgroup analysis on accessory pathway location revealed a higher adjusted hazard of heart failure for a right anteroseptal accessory pathway (HR, 5.88; 95% CI, 2.63-13.1). There was no evidence of a higher hazard of death among individuals with preexcitation when looking across all age groups (HR, 1.07; 95% CI, 0.68-1.68). However, a statistically significant (P=0.01) interaction analysis (<65 versus ≥65 years) indicated a higher hazard of death for patients with preexcitation ≥65 years (HR, 1.85; 95% CI, 1.07-3.18). CONCLUSIONS: In this large ECG study, individuals with preexcitation had higher hazards of atrial fibrillation and heart failure. The higher hazard of heart failure seemed to be driven by a right anteroseptal accessory pathway. Among elderly people, we found a statistically significant association between preexcitation and a higher hazard of death.

QRS duration and mortality in patients with congestive heart failure.

BACKGROUND AND OBJECTIVES: It has been suggested that prolongation of the QRS duration (>120 ms) is an independent risk factor for mortality in patients with cardiomyopathy. The purpose of this study was to examine the association between QRS duration and survival in patients with heart failure. METHODS: We performed a retrospective analysis to examine the association between QRS prolongation (> or =120 ms) and mortality. The study population included 669 patients with heart failure. Two groups, on the basis of baseline QRS duration <120 milliseconds or > or =120 milliseconds, were identified. The groups were compared with respect to total mortality and sudden death. Subgroups were also stratified by right bundle branch block and left bundle branch block, ejection fraction (EF) <30% and > or =30% to 40%, ischemic and nonischemic cardiomyopathy, amiodarone and placebo. RESULTS: Prolonged QRS was associated with a significant increase in mortality (49.3% vs 34.0%, P =.0001) and sudden death (24.8% vs 17.4%, P =.0004). Left bundle branch block was associated with worse survival (P =.006) but not sudden death. In patients with an EF <30%, QRS prolongation continued to be associated with a significant increase in mortality (51.6% vs 41.1%, P =.01) and sudden death (28.8% vs 21.1%, P =.02). In those with an EF of 30% to 40%, QRS prolongation was associated with a significant increase in mortality (42.7% vs 23.3%, P =.0036) but not in sudden death (13.3% vs 12.0%, P =.625). After adjustment for baseline variables, independent predictors of mortality were found to be prolongation of QRS (P =.0028, risk ratio 1.46) and depressed EF (P =.0001, risk ratio 0.965). Age, type of cardiomyopathy, and drug treatment group were not predictive of mortality. CONCLUSION: QRS prolongation is an independent predictor of both increased total mortality and sudden death in patients with heart failure.

The natural history of electrocardiographic preexcitation in men. The Manitoba Follow-up Study.

OBJECTIVE: To examine the natural history of preexcitation occurring on the routine electrocardiogram (ECG). DESIGN: A longitudinal cohort study of 3983 originally healthy men followed prospectively for 40 years. SETTING: Free-living (community-dwelling) study members residing predominantly in Canada. PARTICIPANTS: Nineteen male study members with preexcitation occurring during routine examination in the 40-year follow-up of the Manitoba Follow-up Study. MEASUREMENTS: Routinely requested clinical examinations and ECGs, supplemented by information supplied by the study member or his physician. MAIN RESULTS: Ten study members were found to have preexcitation at enrollment, for a prevalence of 2.5 per 1000 (95% CI, 1.2 to 4.6). A delta wave was first detected during follow-up in an additional nine study members. Seventeen of 19 study members did not have the delta wave at some later time, and preexcitation was intermittently present in most of these members. Over time there was a loss of preexcitation, with 15 of 19 study members no longer exhibiting a delta wave by the end of follow-up. Five of 11 study members with symptoms had physician confirmation of an arrhythmia. Fourteen study members remain alive, and none of the five deaths was attributed to preexcitation. CONCLUSIONS: Preexcitation found on routine ECG in our originally healthy male study group did not confer excess morbidity or mortality, even in those study members who developed symptomatic arrhythmias. Most preexcitation was intermittent and disappeared over time.