**1. Introduction**

Cardiovascular diseases (CVDs) remain a plight to modern-day humans, accounting for over one-third of all deaths worldwide, according to recent World Health Organization (WHO) estimates [1]. In the US alone, one person dies of CVD-related complications every 40 s, mostly ischemic attacks [2]. To this day, catheter-based or surgical interventions, e.g., coronary bypass and implantation of assist devices, are by far the most widely applied clinical measures—albeit with several complications [3,4]. Despite great improvements, most surgical interventions available are mere preservatives, i.e., attempts to sustain the functionally intact heart tissue for as long as possible without structural compensation. Howbeit, due to the progressive nature of CVDs, heart failure (HF) is, in most cases, inevitable [5]. Regardless of etiology and severity, many end-stage HF patients will eventually need cardiac transplantation [6]. With very few treatment options, not to mention the paucity of available donor hearts, the need for alternative therapeutic measures is indispensable.

In recent decades, stem cell (SC) technologies have emerged with a great promise that could be envisaged for almost all human ailments, most importantly for noncommunicable diseases characterized by organ dysfunction and/or degeneration. In this regard, CVDs are certainly the most attractive target for SC-based therapeutic approaches [7–10]. From a mere improvement of cardiac microenvironment, to partial regeneration and/or compensation of lost functional tissue, and ending with a complete fabrication of a surrogate heart, SCs have set the hopes high. Moreover, SC-based technologies have enabled great in-depth understanding of the pathogenesis of CVD entities and served as a platform to test novel therapeutic approaches at minimal risk of adverse events to patients and much lower costs. This article aims at reviewing the available knowledge on SCs and their applications for cardiovascular research, highlighting milestone achievements in both basic and translational research, and expanding in particular on pluripotent SCs.
