The current issue of our journal includes several studies on left ventricular function and heart failure. In heart diseases, investigating whether a new treatment method or drug is effective requires large randomized trials. Once the effectiveness of a method or drug has been adequately demonstrated through large studies, it will usually receive approval. The patients included in studies used for drug approval may have a wide range of characteristics. In this context, a new method or drug may be more effective in certain patient groups, and less so in other groups. It is evident that identifying the patients who will or will not benefit from a new treatment method is important. Subgroup analyses are performed to determine the patient groups who will benefit from a treatment. However, the power of a study may sometimes be insufficient to properly evaluate treatment effectiveness or lack of effectiveness in different subgroups, and if subgroup analysis is performed under such circumstances, the results will most likely be unreliable.

Identifying the patient groups who will or will not benefit from a new treatment method becomes even more important in interventional treatments. Use of an invasive treatment \-- for example, placement of an implantable cardioverter defibrillator or biventricular pacemaker \-- in a patient who will not benefit from it may result in more harm than good, since these methods can also lead to complications. In fact, the same stand is true for medications as well, due to their associated side effects.

Cardiac resynchronization therapy (CRT) is a well established therapy for patients with heart failure with a reduced ejection fraction. While this treatment is effective in certain patient groups, the majority of patients who receive a biventricular pacemaker for CRT do not benefit from it, making it crucial to identify these patients beforehand. For this reason, once a new treatment method enters clinical use, the method in question should continue to be investigated with studies working to identify the patient groups who may or may not benefit from the treatment, as well as those who may actually be harmed.

A lack of effectiveness in CRT treatment may also be related to placement technique, as poor placement of the left ventricular electrode leads to treatment failure. The study conducted by Şipal et al. titled "Surface Electrogram-Guided Left Ventricular Lead Placement Improves Response to Cardiac Resynchronization Therapy," published in the current issue of our journal, investigates the benefit of using a surface electrocardiogram to determine where the left ventricular lead will be placed. This type of study is important to ensure the proper application of invasive treatment methods, and for patients to get the maximum benefit from the treatment.

Unfortunately, the importance given to anamnesis and physical examination is gradually decreasing, despite the fact that the most important information for the diagnosis of coronary artery disease and acute coronary syndromes can be retrieved from the anamnesis. Physical examination is also very important for the diagnosis of cardiac diseases. I would like to highlight that the case report titled "Worth listening to the kidney: An uncommon cause of congestive heart failure" in the current issue of our journal is an interesting and instructive case demonstrating the importance of a physical examination.
