*3.2. Study Population and Clinical Characteristics*

Figure 2 shows the diagnoses of the probands and relatives at baseline and at last follow-up. At baseline, the majority of probands had DCM (*n* = 17.81%), one (5%) HNDC, and three (14%) indeterminate CM, while among relatives, four (13%) had DCM, 18 (56%) had indeterminate CM, and ten (31%) had no signs of cardiomyopathy.

**Figure 2.** Diagnoses of probands and relatives at initial visit and last follow-up. Legend: CM: cardiomyopathy; DCM: dilated cardiomyopathy; HNDC: hypokinetic non-dilated cardiomyopathy.

Table 2 shows baseline clinical characteristics of 21 probands and 32 relatives. In the study group, relatives were a decade younger than probands (*p* = 0.002), allowing us to better understand the early phase of the disease. As expected, HF symptoms with advancement of left ventricular dysfunction were more frequent in probands as well as arrhythmias and ICD requirements. Of interest, while AVB was present in nearly half of the relatives (43.7%), LBBB was found in probands only. In line with the previous findings, the presence of elevated NT-proBNP was significantly more common in probands than in relatives (*p* = 0.003); however, the presence of elevated levels of hsTnT merely tended to be more common in probands versus relatives (*p* = 0.065), indicating that elevated hsTnT might be a useful biomarker of the onset of the disease. Of note, elevated hsTnT level tended to be more common than elevated creatine phosphokinase (CK) activity, a widely accepted marker of syndromic form of cardiolaminopathy (48% vs. 28% of *LMNA* mutation carriers respectively, *p* = 0.06).



Legend: Number of subjects is expressed as *n* (%). Continuous variables are shown as mean ± SD or median and quartiles (Q1:25th–Q2:75th percentiles). ACE-I: angiotensin converting enzyme inhibitor; ARB: angiotensin receptor blocker; AV block: atrioventricular block; CCD: cardiac conduction defect; CK: creatine phoshokinase; CRT-D: cardiac resynchronization therapy defibrillator; hs: high sensitive; ICD: implantable cardioverter defibrillator; LBBB: left bundle branch block; LVE: left ventricular enlargement; LVEDD: left ventricular end-diastolic dimension; LVEF: left ventricular ejection fraction; MRA: mineralocorticoid receptor antagonist; nsVT: non-sustained ventricular tachycardia; NT-proBNP: N-terminal pro-brain natriuretic peptide; NYHA class: New York Heart Association functional class; PPX: prophylaxis; SCA: sudden cardiac arrest; SCD: sudden cardiac death; sVT: sustained ventricular tachycardia.
