Diabetes is a risk factor for heart failure and cardiovascular mortality with specific changes to myocardial metabolism, energetics, structure, and function. The gradual impairment of insulin production and signalling in diabetes is associated with elevated plasma fatty acids and increased myocardial free fatty acid uptake and activation of the transcription factor PPARα. The increased free fatty acid uptake results in accumulation of toxic metabolites, such as ceramide and diacylglycerol, activation of protein kinase C, and elevation of uncoupling protein-3. Insulin signalling and glucose uptake/oxidation become further impaired, and mitochondrial function and ATP production become compromised. Increased oxidative stress also impairs mitochondrial function and disrupts metabolic pathways. The diabetic heart relies on free fatty acids (FFA) as the major substrate for oxidative phosphorylation and is unable to increase glucose oxidation during ischaemia or hypoxia, thereby increasing myocardial injury, especially in ageing female diabetic animals. Pharmacological activation of PPARγ in adipose tissue may lower plasma FFA and improve recovery from myocardial ischaemic injury in diabetes. Not only is the diabetic heart energetically-impaired, it also has early diastolic dysfunction and concentric remodelling. The contractile function of the diabetic myocardium negatively correlates with epicardial adipose tissue, which secretes proinflammatory cytokines, resulting in interstitial fibrosis. Novel pharmacological strategies targeting oxidative stress seem promising in preventing progression of diabetic cardiomyopathy, although clinical evidence is lacking. Metabolic agents that lower plasma FFA or glucose, including PPARγ agonism and SGLT2 inhibition, may therefore be promising options.

Background: Takotsubo cardiomyopathy (TTC) is increasingly well‐recognized as a cause of chest‐pain syndromes, especially in aging females. The most common complications of TTC occur in the first 24 hours post onset of symptoms and include shock and/or arrhythmias.Hypothesis: We tested the hypothesis that the severity of early hypotension in TTC reflects the extent of myocardial involvement and dysfunction.Methods: In 80 consecutive TTC patients, correlates of blood pressure on the day of admission were sought via univariate followed by multivariate analysis.Results: Mean systolic blood pressure (SBP) on day 1 was 120 ± 24 (SD) mm Hg. During the first 3 days of admission, 39% of patients had SBP <90 mm Hg, and 9% died and/or required intra‐aortic balloon pump insertion. The extent of release of N‐terminal pro‐brain natriuretic peptide, with its potential correlate of associated vasodilator activity, varied inversely with pulmonary‐artery saturation, a measure of cardiac output. However, there was no significant relationship between normetanephrine release and SBP. On multivariate analyses there was no significant relationship between SBP and (1) wall‐motion score index (as an index of left‐ventricular systolic dysfunction) or (2) T₂ enhancement on cardiac magnetic resonance imaging and peak N‐terminal pro‐brain natriuretic peptide (as indices of myocardial inflammation).Conclusions: Although severe hypotension and shock occur commonly during acute stages of TTC, these complications are multifactorial in origin, probably representing a combination of impaired inotropic state and vasodilatation. Importantly, initial hypotension does not imply severe left ventricular inflammation or systolic dysfunction.