Electrocardiographic and hemodynamic effects of coenzyme Q10 in healthy individuals: a double-blind, randomized controlled trial.

BACKGROUND: Coenzyme Q10 (CoQ10) is an endogenous cofactor required for mitochondrial energy production and touted to treat heart failure and prevent statin-induced myopathy. In guinea pig ventricular myocytes, CoQ10 prolongs action potential duration, an effect that might prolong the QTc interval in humans. Additionally, CoQ10 reduced blood pressure in patients with essential hypertension. OBJECTIVE: To determine the electrocardiographic (ECG) and hemodynamic impact of CoQ10 in healthy individuals. METHODS: Healthy volunteers (N = 26; 62% male, age 24 +/- 3 y) were randomized to receive a single dose of CoQ10 50 mg and matching placebo in a crossover fashion with a 7 day washout period between treatments. Twelve-lead ECGs, systolic and diastolic blood pressure, and other hemodynamic parameters (cardiac index and systemic vascular resistance index) were evaluated immediately before (baseline) and 1, 3, 5, and 8 hours after ingestion of the study drug. ECG parameters (P wave and QRS complex duration; PR, QT, QTc, and RR intervals) were measured in lead II by one blinded investigator. For each time point, duplicate blood pressure levels were taken manually and then averaged. Hemodynamic parameters were measured using bioelectrical impedance cardiography. RESULTS: CoQ10 had no effect on any of the evaluated ECG parameters. The maximum postdosing systolic blood pressure showed a statistically significant increase with CoQ10 (117 +/- 10 vs 119 +/- 10 mm Hg; p = 0.037), an effect driven by increases in cardiac index (3.09 vs 2.95 L/min/m(2); p = 0.017). However, blood pressure elevation was most evident at the 5 hour timepoint (116 +/- 10 vs 113 +/- 11 mm Hg; p = 0.049) and was only transient. There were no differences between groups for maximum postdosing diastolic blood pressure. CONCLUSIONS: One dose of CoQ10 does not have any effect on ECG variables and exhibits only mild and transient effect on systolic blood pressure in young, healthy people.

Absence of QTc-interval-prolonging or hemodynamic effects of a single dose of bitter-orange extract in healthy subjects.

STUDY OBJECTIVE: To evaluate the hemodynamic and electrocardiographic effects of a single dose of commercially available bitter-orange dried-fruit extract, which is increasingly being used in dietary supplements. DESIGN: Randomized, double-blind, placebo-controlled, crossover study. SETTING: University of Connecticut, Storrs Campus. SUBJECTS: Eighteen healthy volunteers aged 18 years or older. INTERVENTION: Subjects were given either placebo or bitter-orange dried-fruit extract (450 mg standardized to 27 mg of m- or p-synephrine) in phase 1. The opposite treatment was given during phase 2 after a washout period of at least 7 days. MEASUREMENTS AND MAIN RESULTS: The rate-corrected QT (QTc) interval and blood pressure were measured before dosing and at 1, 3, 5, and 8 hours after dosing. Mean+/-SD values of the maximum postdose values were compared between groups. Subjects receiving bitter-orange extract versus those receiving placebo had similar postdose QTc intervals (402+/-29 vs 403+/-24 msec, p=0.653), systolic blood pressure (114+/-10 vs 115+/-8 mm Hg, p=0.686) and diastolic blood pressure (68+/-9 vs 68+/-8, p=0.879). CONCLUSION: Bitter-orange dried-fruit extract standardized to m- or p-synephrine 27 mg did not significantly alter the QTc interval or blood pressure after a single dose was administered. Future studies are necessary to ensure the safety of this herbal product with multiple doses.