Decreased prevalence of cardiac arrhythmias during and after vigorous and prolonged exercise in healthy male marathon runners.

BACKGROUND: Vigorous exercise such as marathon running results in an increased risk of sudden cardiac death. Malignant arrhythmias seem to be the primary cause. However, continuous electrocardiographic monitoring for detection of arrhythmias during a marathon race has not been performed yet. METHODS: Twenty male marathon runners (age 45 ± 8 years) free of cardiovascular disease underwent 24-hour Holter monitoring 5 weeks before a marathon race (baseline). Subsequently, wireless Holter monitoring started immediately before the race, recorded up to 70 hours postrace. Electrocardiograms were analyzed for the presence of arrhythmias. Additionally, cardiac troponin, interleukin-6 (IL-6), and electrolytes were assessed prerace and postrace. RESULTS: At baseline Holter recordings, runners showed a median of 9 (interquartile range 3-25) atrial premature complexes (APCs) and 4 (2-16) ventricular premature complexes (VPCs) per 100,000 beats. Compared to baseline, the number of APCs decreased significantly during and 1 hour after the marathon race (0 [0-3] and 0 [0-0], all P < .001) as well as the number of VPCs during the race (0 [0-0], P = .008). No malignant arrhythmias occurred. Mean postrace levels for troponin and IL-6 were significantly augmented after the race (prerace to postrace: troponin 4 times, IL-6 17 times, all P < .001); however, no significant influence of these biomarkers or electrolytes on the prevalence of arrhythmias was observed (all P > .05). CONCLUSIONS: In this cohort of male runners free of cardiovascular disease, the prevalence of arrhythmias during and after a marathon race was decreased. Arrhythmogenic risk was independent of changes in biomarkers assessing cardiac injury, inflammation, and changes in electrolytes.

Metronomic cyclophosphamide for bone marrow carcinomatosis in metastatic castration-resistant prostate cancer.

PURPOSE: In some patients with prostate cancer, bone marrow carcinomatosis develops later in the course of the disease, which has a poor prognosis. These are often heavily pretreated patients in the castration-resistant situation for whom there are no other therapeutic options, because either all available systemic therapies have already been used or the use of one is not possible due to the cytopenias associated with bone marrow carcinomatosis. In our literature search, there are no data on this treatment in the setting available, especially no clinical trial or even randomized data. This case series is to determine the clinical efficacy of metronomic cyclophosphamide in patients with metastatic castration-resistant prostate cancer and bone marrow carcinomatosis, particularly with regard to stabilization of the blood count (thrombocytopenias) and thus the possibility of further (more toxic) lines of therapy. METHODS: Retrospective unicenter analysis was performed on eleven patients between 54 and 84 years of age on metronomic cyclophosphamide for bone marrow carcinomatosis in metastatic castration-resistant prostate cancer treated at a Swiss cancer center between 2014 and 2023. RESULTS: Eleven patients received metronomic cyclophosphamide for varying periods of time; the majority had severe cytopenias (especially thrombocytopenias). Partially hematologic stabilization was achieved with administration of further systemic therapies. CONCLUSION: Our case series demonstrates that the use of metronomic cyclophosphamide allows hematologic stabilization for months, benefiting patients who had already received all available therapies for metastatic castration-resistant prostate cancer. Alternatively, it may act as bridging therapy to allow consecutive administration of more toxic therapies with proven survival benefit.