Cardiovascular diseases are the leading cause of death worldwide, and a health problem in low- and middle-income as well as high-income countries. They also constitute the main cause of death in Latin America, with ischemic heart disease as the principal cause in most countries of the region. In Cuba, heart disease is the first cause of death, followed by cancer and stroke. In its 2030 Agenda for Sustainable Development, the UN recognizes the importance of chronic non-communicable diseases, including cardiovascular diseases.

Cuba has participated actively as lead partner in design and implementation of the two regional technical cooperation projects conducted over the last six years by the International Atomic Energy Agency to address cardiovascular diseases in Latin American and Caribbean member states. These projects have generated greater interest among participating countries in the use of myocardial perfusion for dilated cardiomyopathy and coronary artery disease compared to other imaging techniques; disseminated knowledge about nuclear cardiology techniques and clinical applications in heart failure and coronary artery disease; and made important contributions to implementing harmonized, appropriate and safe clinical protocols. Cuba’s contribution to the International Atomic Energy Agency’s regional cardiology projects has fostered development of human resources and harmonized protocols both nationally and regionally, and demonstrated the importance of region-based scientific cooperation that ensures greater opportunities and more equitable access to resources. This participation has also accrued important benefits to Cuba’s own nuclear cardiology program.

KEYWORDS Cardiovascular disease, myocardial perfusion imaging, nuclear cardiology, scientific cooperation, low-income populations, Latin America, Caribbean region, Cuba

INTRODUCTION Heart failure, primarily in the elderly, is a growing epidemic in today’s world. It leads to high rates of disability and mortality, as well as significant health care expenditures, making it important to assess possible predictors of adverse cardiac events. In Cuba, heart failure mortality is 19.1/100,000 population.

OBJECTIVES Assess the value of stress–rest protocol gated-SPECT for identifying patients with symptomatic heart failure likely to suffer adverse cardiac events.

METHODS A study was conducted of 52 patients (mean age 59 years, SD 9; 62% women) with functional capacity II/III (New York Heart Association scale) and left ventricular ejection fraction <40%. Patients were divided into two groups based on coronary heart disease diagnosis: those with coronary heart disease (41), labeled ischemic; and those without (11), labeled nonischemic. All underwent gated SPECT myocardial perfusion scintigraphy with technetium-99m-labeled methoxyisobutyl isonitrile, using a two-day stress–rest protocol, including evaluation of intraventricular synchrony by phase analysis. Patients were followed over 36 months for adverse cardiac effects.

RESULTS No significant differences were observed between the two groups during the stress test with regard to exercise time, metabolic equivalents or percentage of maximal heart rate during maximal stress. Summed stress, rest and difference scores, however, were significantly different between the ischemic and nonischemic groups: 16.82 (SD 6.37) vs. 7.54 (SD 5.8), p <0.001; 14.43 (SD 6.28) vs. 6.45 (SD 3.77), p = 0.001; and 2.39 (SD 4.89) vs. 1.09 (SD 3.7), p = 0.034. No differences were found in ventricular function, although stress-minus-rest left ventricular ejection fraction was slightly lower in patients with ischemic heart disease (-1.29, SD 5.8) than in patients without ischemic heart disease (1.27, SD 4.31). Dyssynchrony was greater in patients with ischemic heart disease than in those without, primarily during stress (p <0.01). The only variable that showed a possible association with the occurrence of adverse events was <5 metabolic equivalents on the stress test (p = 0.03), while resting phase SD showed only a tendency toward association (p = 0.05).

CONCLUSIONS Information on myocardial perfusion, functional capacity and intraventricular synchrony obtained from stress–rest gated SPECT may help identify patients with symptomatic heart failure who are likely to develop adverse cardiac events, enabling better management of higher-risk cases and improved allocation of resources.

KEYWORDS Heart failure, congestive heart failure, myocardial ischemia, ischemic heart disease, coronary artery disease, gated SPECT, perfusion, ventricular function, intraventricular synchrony, phase analysis, Cuba

Cardiovascular disease is the main cause of death for diabetics, and in many cases its presence is silent due to cardiac autonomic neuropathy. Thus, early diagnosis of coronary disease is essential, permitting proper risk stratification and appropriate therapy. This paper examines the usefulness of several noninvasive imaging techniques to study cardiovascular diseases in individuals with diabetes mellitus, with emphasis on nuclear cardiology, and proposes a diagnostic algorithm for detection of silent ischemia.

Keywords Myocardial perfusion scintigraphy, myocardial perfusion imaging, radionuclide imaging, diabetes mellitus, silent myocardial ischemia, Cuba