Advanced Search

Study Preview



Study Title and Description

An evaluation of the change in electrocardiographic P-wave variables after acute caffeine ingestion in normal volunteers.



Key Questions Addressed
1 For [population], is caffeine intake above [exposure dose], compared to intakes [exposure dose] or less, associated with adverse effects on cardiovascular outcomes?
  • Comments Comments (
    0
    ) |

Primary Publication Information
  • Comments Comments (
    0
    ) |
TitleData
Title An evaluation of the change in electrocardiographic P-wave variables after acute caffeine ingestion in normal volunteers.
Author MF Caron,J Song,R Ammar,J Kluger,CM White,
Country
Year 2001
Numbers

Secondary Publication Information
There are currently no secondary publications defined for this study.


Extraction Form: Cardiovascular Design
Design Details
Question... Follow Up Answer Follow-up Answer
What outcome is being evaluated in this paper? Cardiovascular
  • Comments Comments (
    0
    ) |
What is the objective of the study (as reported by the authors)? We performed this study to evaluate the effects of higher doses of caffeine (mean 6.1 mg/kg; 400 mg) on maximum P-wave duration and P-wave dispersion in normal volunteers.
  • Comments Comments (
    0
    ) |
Provide a general description of the methods as reported by the authors. Information should be extracted based on relevance to the SR (i.e., caffeine related methods) Methods Study inclusion/exclusion Full- or part-time students at least 17 years of age at the University of Connecticut were eligible for inclusion in this randomized, double-blind, placebo-controlled, crossover trial. People with a history of ventricular or supraventricular dysrhythmias, hepatic or renal dysfunction, insomnia, lactose intolerance (due to the diluent of the placebo), caffeine allergy, or those without P-waves evaluable in at least eight electrocardiogram (ECG) leads were excluded. Ten healthy volunteers (five males, five females) met inclusion criteria without exclusion. Investigational Procedure All appointments for an individual were performed at the same time of day (within 2 h) to minimize any circadian variation in electrocardiographic variables. Participants abstained from caffeinated products for at least 2 days before study initiation and were randomly allocated to receive placebo (lactose monohydrate, lot 54101, Humco, Texarkana, TX, U.S.A.) or caffeine 400 mg (NoDoz, lot 911548, Bristol-Myers Products, New York, NY, U.S.A.) during phase 1. This dose is equivalent to approximately four to six cups of coffee. A baseline 12-lead ECG was performed during each study phase and a subsequent 12-lead ECG was taken 3 h after ingesting the study drug. A washout period of at least 2 days was employed between study phases. P-wave determination The 12-lead ECG recordings for each patient were grouped together and read by a blinded investigator. The precision ruler method (0.5 mm scale, Schlaedler Quinzel, Inc. Parsippany, NJ, U.S.A.) was employed to measure all the P-wave variables, as this method has been shown to be superior to the calliper and computer methods. Average P-wave duration (P-avg) is the mean P-wave duration of all those measured on the 12-lead ECG recording. Maximum P-wave duration (P-max) is the largest measurement of the P-wave duration among all those measured on the 12-lead ECG recording. P-wave dispersion (P-disp) was calculated by subtracting the shortest P-wave from the P-max measured on the 12-lead ECG. Study Endpoints/Statistical Analysis P-wave variables during the baseline period in each phase (either pre-caffeine or pre-placebo) were compared with their respective 3-h post-ingestion variables using a paired t-test. P-wave variable measurements while on caffeine were also compared with that of placebo (baseline vs. baseline and 3 h vs. 3 h) using an unpaired t-test. Delta-change was determined by subtracting the 3-h post-infusion P-wave variables from their respective baseline values. The delta-change was then compared between groups. If a variable was not normally distributed, within-group comparisons were made with a Wilcoxon Signed-Rank test, while between-group comparisons were made with a Mann±Whitney test. All data are presented as means +/- SD and a P-value < 0.05 is statistically significant.
  • Comments Comments (
    0
    ) |
How many outcome-specific endpoints are evaluated? 1
  • Comments Comments (
    0
    ) |
What is the (or one of the) endpoint(s) evaluated? (Each endpoint listed separately) Heart rhythm (Average P-wave duration [P-ave], maximum P-wave duration [P-max], and P-wave dispersion [P-disp])
  • Comments Comments (
    0
    ) |
List additional health endpoints (separately). 2
  • Comments Comments (
    0
    ) |
List additional health endpoints (separately).3
  • Comments Comments (
    0
    ) |
List additional health endpoints (separately).4
  • Comments Comments (
    0
    ) |
List additional health endpoints (separately).5
  • Comments Comments (
    0
    ) |
List additional health endpoints (separately).6
  • Comments Comments (
    0
    ) |
Clinical, physiological, other Physiological
  • Comments Comments (
    0
    ) |
What is the study design? Controlled Trial
  • Comments Comments (
    0
    ) |
Randomized or Non-Randomized? RCT
  • Comments Comments (
    0
    ) |
What were the diagnostics or methods used to measure the outcome? Objective
  • Comments Comments (
    0
    ) |
Optional: Name of Method or short description 12-lead ECG recordings read by a blinded investigator
  • Comments Comments (
    0
    ) |
Caffeine (general) Caffeine (general)
  • Comments Comments (
    0
    ) |
Coffee, Chocolate, energy drink, gum, medicine/supplement, soda, tea, other?
  • Comments Comments (
    0
    ) |
Measured or self reported? Measured
  • Comments Comments (
    0
    ) |
Children, adolescents, adults, or pregnant included? Adults
  • Comments Comments (
    0
    ) |
What was the reference, comparison, or control group(s)? (e.g. high vs low consumption, number of cups, etc.) Each subject served as their own control (intragroup comparison), plus comparisons were made between placebo vs. caffeine (intergroup comparison)
  • Comments Comments (
    0
    ) |
What were the listed confounders or modifying factors as stated by the authors? (e.g. multi-variable components of models.  Copy from methods) None
  • Comments Comments (
    0
    ) |
What conflicts of interest were reported? No information provided
  • Comments Comments (
    0
    ) |
Refid 11350538
  • Comments Comments (
    0
    ) |
What were the sources of funding? No information provided
  • Comments Comments (
    0
    ) |




Results & Comparisons

No Results found.