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BACKGROUND The list of medications linked to drug-induced long QT syndrome (LQTS) is diverse. It is possible that food products too have QT-prolonging potential.OBJECTIVE We tested the effects of grapefruit juice on the QT interval with the methodology used by the pharmaceutical industry to test new drugs. METHODSThis was an open-label, randomized, crossover study with blinded outcome evaluation, a thorough QT study of grapefruit juice performed according to the Guidelines for the Clinical Evaluation of QT/QTc for Non-antiarrhythmic Drugs. Thirty healthy volunteers and 10 patients with congenital LQTS were studied. Healthy volunteers drank 2 L of grapefruit juice (in divided doses), or received 400 mg oral moxifloxacin, in a randomized crossover study. Patients with LQTS were tested with only grapefruit. Repeated baseline, off-drug, and on-drug (grapefruit or moxifloxacin) electrocardiograms were scanned and coded. QT measurements were done with electronic calipers. RESULTSIn comparison to off-drug electrocardiograms, grapefruit juice led to significant rate-corrected QT (QTc) prolongation. The absolute net QTc prolongation from grapefruit was 14.0 ms (95% confidence interval 6.2-21.7 ms; P , .001). The QT-prolonging effects of grapefruit in healthy volunteers were comparable with those of moxifloxacin. The QT-prolonging effects of grapefruit juice were greater in female patients and particularly marked in patients with LQTS (net QTc prolongation 21.8 ms; 95% confidence interval 3.4-35.3 ms; P 5 .034).CONCLUSION Grapefruit juice, at doses tested, prolongs the QT interval. The effect is significant in healthy volunteers, greater in female patients, and more so in patients with LQTS.

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Objectives: To study the clinical characteristics and impact of bronchoscopy in children from developing countries, referred for cardiac surgery, through the "Save a Child's Heart" (SACH) organization. Methods:We performed a retrospective hospital-chart review of SACH children (0-18 years old) referred between 2006 and 2021 who underwent fiberoptic bronchoscopy. We examined demographics, congenital-heart-disease (CHD) types, bronchoscopy's indications and findings, subsequent recommendations, number of ventilation, and intensive-care-unit days. The primary outcome was percent changes in management and diagnosis, following the bronchoscopy. We included a control group matched-for-age and CHD type, who did not undergo bronchoscopy.Results: We performed 82 bronchoscopies in 68 children: 18 (26.5%) preoperatively; 46 (67.6%) postoperatively; and four (5.9%) both. The most prevalent CHDs were Tetralogy-of-Fallot (27.9%) and ventricular-septal-defect (19.1%). The main indications were persistent atelectasis (41%) and mechanical ventilation/weaning difficulties (27.9%). Bronchoscopic evaluations revealed at least one abnormality in 51/68 (75%) children. The most common findings were external airway compression (23.5%), bronchomalacia (19.1%), and mucus secretions (14.7%). Changes in management were made in 35 (51.4%) cases, with a major change made in 14/35 (40%) children. Compared to the control group, the children undergoing bronchoscopy were both ventilated longer (median 6 vs. 1.5 days, p < 0.0001) and stayed longer in the intensive care unit (median 1.5 vs. 18.5 days, p < 0.0001). Conclusion:A bronchoscopy is an important tool in the diagnosis and management of the unique group of children from developing countries with CHD referred for cardiac surgery. The results of our study, reveal a more complicated clinical course in children requiring bronchoscopy compared to controls.