title: Prevalence and prognostic significance of exercise-induced nonsustained ventricular tachycardia in asymptomatic volunteers: BLSA (Baltimore Longitudinal Study of Aging).
abstract: OBJECTIVE
  This study sought to determine the clinical predictors and prognostic significance of exercise-induced nonsustained ventricular tachycardia (NSVT) in a large population of asymptomatic volunteers.
  
  
  BACKGROUND
  Prior studies have reported variable risk associated with exercise-induced ventricular arrhythmia.
  
  
  METHODS
  Subjects in the BLSA (Baltimore Longitudinal Study of Aging) free of known cardiovascular disease who completed at least 1 symptom-limited exercise treadmill test between 1977 and 2001 were included. NSVT episodes were characterized by QRS morphology, duration, and rate. Subjects underwent follow-up clinical evaluation every 2 years.
  
  
  RESULTS
  The 2,099 subjects (mean age: 52 years; 52.2% male) underwent a mean of 2.7 exercise tests, in which 79 (3.7%) developed NSVT with exercise on at least 1 test. The median duration of NSVT was 3 beats (≤5 beats in 84%), and the median rate was 175 beats/min. Subjects with (vs. without) NSVT were older (67 ± 12 years vs. 51 ± 17 years, p < 0.0001) and more likely to be male (80% vs. 51%, p < 0.0001) and to have baseline electrocardiographic abnormalities (50% vs. 17%, p < 0.0001) or ischemic ST-segment changes with exercise (20% vs. 10%, p = 0.004). Over a mean follow-up of 13.5 ± 7.7 years, 518 deaths (24.6%) occurred. After multivariable adjustment for age, sex, and coronary risk factors, exercise-induced NSVT was not significantly associated with total mortality (hazard ratio: 1.30; 95% confidence interval: 0.89 to 1.90; p = 0.17).
  
  
  CONCLUSIONS
  Exercise-induced NSVT occurred in nearly 4% of this asymptomatic adult cohort. This finding increased with age and was more common in men. After adjustment for clinical variables, exercise-induced NSVT did not independently increase the risk of total mortality.
authors.affiliation: Division of Cardiology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland 20892, USA.
authors.forename: Joseph E
authors.initials: JE
authors.lastname: Marine
authors.forename: Veena
authors.initials: V
authors.lastname: Shetty
authors.forename: Grant V
authors.initials: GV
authors.lastname: Chow
authors.forename: Jeanette G
authors.initials: JG
authors.lastname: Wright
authors.forename: Gary
authors.initials: G
authors.lastname: Gerstenblith
authors.forename: Samer S
authors.initials: SS
authors.lastname: Najjar
authors.forename: Edward G
authors.initials: EG
authors.lastname: Lakatta
authors.forename: Jerome L
authors.initials: JL
authors.lastname: Fleg
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D000375:Aging / Q000502:physiology*; D015142:Baltimore; D016001:Confidence Intervals; D004562:Electrocardiography / Q000379:methods; D005080:Exercise Test / Q000009:adverse effects*; D005260:Female; D015577:Geriatric Assessment / Q000379:methods; D006805:Human Experimentation; D006801:Humans; D053208:Kaplan-Meier Estimate; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D015995:Prevalence; D016016:Proportional Hazards Models; D011446:Prospective Studies; D012016:Reference Values; D012720:Severity of Illness Index; D012737:Sex Factors; D015996:Survival Rate; D017180:Tachycardia, Ventricular / Q000175:diagnosis / Q000453:epidemiology* / Q000209:etiology*
keywords: BLSA; Baltimore Longitudinal Study of Aging; CI; ECG; HR; NSVT; VPD; VT; aging; confidence interval; electrocardiogram; exercise testing; hazard ratio; nonsustained ventricular tachycardia; ventricular premature depolarization; ventricular tachycardia