When arterial blood pressure rises, we have what is known as high blood pressure and the heart becomes overloaded, as it were: it pumps blood against the greater resistance created by this extra pressure. During most of the XX century doctors believed that the growth of cardiac muscle (left ventricular hypertrophy or LVH) presented by patients with high blood pressure was beneficial for the heart. It was thought that this change enabled the pumping of blood with greater force, compensating for the greater resistance due to higher blood pressure. However, clinical and epidemiological studies at the end of the last century revealed that high blood pressure patients with LVH showed more frequent and more severe cardiac complications than high blood pressure individuals without LVH. This led a number of clinical and basic research groups to the hypothesis that not everything was quite right with the idea that hypertrophy of the cardiac muscle was the answer to high blood pressure. They also believed that, masked by the hypertrophy, they might find decisive alterations which, in the long term, might suggest a prognosis of high blood pressure cases with LVH worse than those without. It was now thought that the heart in high blood pressure cases may suffer structural changes thus producing massive scarring (myocardial fibrosis). Method for diagnosis and treatments 20 years ago it was thought that a progressive substitution of the heart muscle cells by inert fibres played a critical role in the deterioration of the heart and the appearance of clinical complications in high blood pressure patients. Over this period, the research team has provided evidence, from both animals and high blood pressure human patients that this hypothesis was, indeed, correct and proceeded to explore some possible mechanisms for this deterioration. Researchers at CIMA and the Navarre University Hospital have developed a method for the bloodless diagnosis of myocardial fibrosis and have shown that certain pharmacological treatments not only prevent damage to the tissue, but also repair the tissue damaged. 30% of the adult world population has high blood pressure and half of these shows LVH and are, thus, prone to the consequences of myocardial fibrosis. This data means that, of the 8 million people with high blood pressure currently in Spain, 4 million have LVH and fibrosis. As outlined in Nature, doctors now have diagnostic means and pharmacological measures to prevent fibrosis of the heart in these 4 million citizens. Thus, this medical research offers a "message of hope to the public at large.