Effects of Acute Triiodothyronine Treatment in Patients with Anterior Myocardial Infarction Undergoing Primary Angioplasty: Evidence from a Pilot Randomized Clinical Trial (ThyRepair Study).

Background: Thyroid hormone has a differential action on healthy and ischemic heart. Triiodothyronine (T3) administration improved postischemic cardiac function while it limited apoptosis in experimentally induced ischemia. Thus, the present study investigated the potential effects of acute liothyronine (LT3) treatment in patients with anterior myocardial infarction. Methods: This study is a pilot, randomized, double-blind, placebo-controlled trial (ThyRepair study). We randomized 52 patients and analyzed data from 37 patients (n = 16 placebo and n = 21 LT3), per prespecified per protocol analysis. We excluded three patients who had died of cardiovascular causes (one in placebo and two in LT3 arm), four with small infarct size below a pre-specified threshold (in the placebo arm), and the rest, who lacked follow-up data. LT3 treatment started after stenting as an intravenous (i.v.) bolus injection of 0.8 µg/kg of LT3 followed by a constant infusion of 0.113 µg/kg/h i.v. for 48 hours. All patients had cardiac magnetic resonance (CMR) at hospital discharge and 6 months follow-up. The primary end point was CMR left ventricular (LV) ejection fraction (LVEF) and secondary endpoints were LV volumes, infarct volume (IV), and safety. Results: The CMR LVEF% at 6 months was 53.6 ± 9.5 for the LT3-treated group and 48.6 ± 11 for placebo, p = 0.15. Acute LT3 treatment resulted in a significantly lower LV end-diastolic volume index (92.2 ± 16.8 mL/m2 vs. 107.5 ± 22.2, p = 0.022) and LV systolic volume index (47.5 ± 13.9 mL/m2 vs. 61.3 ± 21.7, p = 0.024) at hospital discharge, but not at 6 months. There was no statistically significant difference in CMR IV at hospital discharge between the groups (p = 0.24). CMR IV tended to be lower in the LT3-treated group at 6 months (18.7 ± 9.5 vs. 25.9 ± 11.7, in placebo, p = 0.05). Serious, life-threatening events related to LT3 treatment were not observed. A tendency for an increased incidence of atrial fibrillation (AF) was found in the LT3 group during the first 48 hours (19% for T3 group vs. 5% for placebo, p = 0.13). Conclusion: This pilot randomized, placebo-controlled trial study suggests potential favorable effects (acute cardiac dilatation and 6-month IV) as well as potential concerns regarding a higher risk of AF after LT3 administration early after myocardial infarction, which should be tested in a larger scale study.

Effects of Thyroid Hormone on Tissue Hypoxia: Relevance to Sepsis Therapy.

Tissue hypoxia occurs in various conditions such as myocardial or brain ischemia and infarction, sepsis, and trauma, and induces cellular damage and tissue remodeling with recapitulation of fetal-like reprogramming, which eventually results in organ failure. Analogies seem to exist between the damaged hypoxic and developing organs, indicating that a regulatory network which drives embryonic organ development may control aspects of heart (or tissue) repair. In this context, thyroid hormone (TH), which is a critical regulator of organ maturation, physiologic angiogenesis, and mitochondrial biogenesis during fetal development, may be of important physiological relevance upon stress (hypoxia)-induced fetal reprogramming. TH signaling has been implicated in hypoxic tissue remodeling after myocardial infarction and T3 prevents remodeling of the postinfarcted heart. Similarly, preliminary experimental evidence suggests that T3 can prevent early tissue hypoxia during sepsis with important physiological consequences. Thus, based on common pathways between different paradigms, we propose a possible role of TH in tissue hypoxia after sepsis with the potential to reduce secondary organ failure.

A giant, free-floating mass in the left atrium in a patient with atrial fibrillation.

A large intracardiac mass is a rare condition and one with an extremely high risk of haemodynamic and embolic complications. Urgent surgical excision is the treatment of choice, and the histological examination reveals the exact nature of the mass, usually a myxoma or a thrombus. We present the case of an 80-year-old woman, with a history of atrial fibrillation, who was admitted because of a seriously impaired level of consciousness, and fever. A large cerebral infarct and a urinary tract infarction were diagnosed. On the transthoracic echocardiogram a giant, free-floating mass was detected in the left atrium, transiently obstructing the mitral valve orifice. Based on the features of the mass and patient's history, it was considered more likely to be a thrombus rather than a tumour. Given the patient's extremely unfavourable neurological status, cardiac surgery was considered to be contraindicated and the patient was administered unfractionated heparin intravenously. Unfortunately, after a few hours the patient suffered a cardiac arrest and died.

Incidental diagnosis of a large coronary fistula: angiographic and cardiac MRI findings.

Coronary artery fistulas are rare anomalies of the coronary arteries that may sometimes be totally asymptomatic and can be found incidentally during coronary arteriography later in adult life. We report the case of a 75-year-old man with such a fistula and describe our diagnostic approach. In addition, we review the literature on the etiology, epidemiology, the diagnostic modalities and treatment of coronary fistulas.