Resumo Fundamento: A fragmentação do QRS (fQRS) é classicamente definida como a presença de morfologia empastada do QRS em pelo menos duas derivações contíguas e sua importância prognóstica tem sido demonstrada no infarto do miocárdio com elevação do ST (STEMI). No entanto, nenhum estudo investigou a significância do fQRS de derivação única (sl-fQRS) no eletrocardiograma (ECG). Objetivos: Avaliar se o sl-fQRS é tão valioso quanto o fQRS clássico em pacientes com STEMI aguda que tiveram sucesso na revascularização com intervenção coronariana percutânea primária (ICPp). Métodos: Incluímos 330 pacientes com um primeiro STEMI que tinham sido revascularizados com sucesso com ICPp. O eletrocardiograma do paciente foi obtido nas primeiras 48 horas, e os pacientes foram divididos em três grupos de acordo com a ausência de fQRS (não-fQRS); presença de fQRS numa única derivação (sl-fQRS); e ≥ 2 derivações com fQRS (fQRS clássico). Resultados: A mortalidade intrahospitalar foi significativamente maior tanto em pacientes com sl-fQRS como em pacientes com ≥ 2 derivações com fQRS em comparação com pacientes com não-fQRS. Na análise da curva ROC, ≥ 1 derivação com fQRS produziu uma sensibilidade de 75% e especificidade de 57,4% para a predição de mortalidade intrahospitalar. A análise multivariada mostrou que sl-fQRS é um preditor independente de mortalidade intrahospitalar (OR: 3,989, IC 95%: 1,237-12,869, p = 0,021). Conclusões: Embora o conceito de pelo menos duas derivações seja mencionado para a definição clássica de fQRS, nosso estudo mostrou que fQRS em apenas uma derivação também está associado com maus resultados. Portanto, ≥ 1 derivação com fQRS pode ser útil ao descrever os pacientes sob risco cardíaco alto em STEMI agudo.

Abstract Background: QRS fragmentation (fQRS) is classically defined as the presence of slurred QRS morphology in at least two contiguous leads, and its prognostic importance has been shown in ST elevation myocardial infarction (STEMI). However, no study has investigated the significance of single lead fQRS (sl-fQRS) in surface electrocardiography (ECG). Objectives: To evaluate whether sl-fQRS is as valuable as classical fQRS in patients with acute STEMI who had successful revascularization with primary percutaneous coronary intervention (pPCI). Methods: We included 330 patients with a first STEMI who had been successfully revascularized with pPCI. The patient’s electrocardiography was obtained in the first 48 hours, and the patients were divided into three groups according to the absence of fQRS (no-fQRS); fQRS presence in a single lead (sl-fQRS); and ≥2 leads with fQRS (classical fQRS). Results: In-hospital mortality was significantly higher both in patients with sl-fQRS and in patients with ≥ 2 leads with fQRS compared to patients with no-fQRS. In ROC curve analysis, ≥ 1 leads with fQRS yielded a sensitivity of 75% and specificity of 57.4% for the prediction of in-hospital mortality. Multivariate analysis showed that sl-fQRS is an independent predictor of in-hospital mortality (OR: 3.989, 95% CI: 1.237-12.869, p = 0.021). Conclusions: Although the concept of at least two derivations is mentioned for the classical definition of fQRS, our study showed that fQRS in only one lead is also associated with poor outcomes. Therefore, ≥1 leads with fQRS can be useful when describing the patients under high cardiac risk in acute STEMI.

OBJECTIVE: Fibromyalgia is characterized by diffuse musculoskeletal pain and discomfort. There are several reports regarding autonomic nervous system dysfunction in patients with fibromyalgia. Heart rate turbulence is expressed as ventriculophasic sinus arrhythmia and has been considered to reflect cardiac autonomic activity. Heart rate turbulence has been shown to be an independent and powerful predictor of sudden cardiac death in various cardiac abnormalities. The aim of this study is to determine whether heart rate turbulence is changed in female patients with fibromyalgia compared with healthy controls. METHODS: Thirty-seven female patients (mean age, 40±11 years) with fibromyalgia, and 35 age- and sex-matched healthy female control subjects (mean age, 42±9 years) were included. Twenty-four hours of ambulatory electrocardiography recordings were collected for all subjects, and turbulence onset and turbulence slope values were automatically calculated. RESULTS: The baseline clinical characteristics of the two groups were similar. There were no significant differences in turbulence onset and turbulence slope measures between patients and control subjects (turbulence onset: −1.648±1.568% vs. −1.582±1.436%, p ϝ 0.853; turbulence slope: 12.933±5.693 ms/RR vs. 13.639±2.505 ms/RR, p ϝ 0.508). Although body mass index was negatively correlated with turbulence slope (r ϝ −0.258, p ϝ 0.046), no significant correlation was found between body mass index and turbulence onset (r ϝ 0.228, p ϝ 0.054). CONCLUSION: To the best of our knowledge, this is the first study to evaluate heart rate turbulence in patients with fibromyalgia. It appears that heart rate turbulence parameters reflecting cardiac autonomic activity are not changed in female patients with fibromyalgia.

OBJECTIVES: Subclinical atherosclerosis has been recently detected in adolescents with a family history of premature atherosclerosis. However, no studies in the literature have assessed the cardiac autonomic functions of these adolescents. The aim of this study was to evaluate the cardiac autonomic functions of adolescents with a family history of premature atherosclerosis compared with those of age- and gender-matched adolescents without a family history of atherosclerosis. METHOD: We evaluated the cardiac autonomic functions of 36 adolescents with a family history of premature atherosclerosis (Group 1) and compared them with those of 31 age- and gender-matched adolescents whose parents did not have premature atherosclerosis (Group 2). Twenty-four-hour time domain (standard deviation of all normal sinus RR intervals [SDNN], standard deviation of the mean of normal RR intervals in each 5-minute segment [SDANN], root-mean-square differences in successive RR intervals) and frequency domain (very low frequency, low frequency, high frequency, low frequency/high frequency) parameters of heart rate variability were used for the evaluation of cardiac autonomic functions. RESULTS: There were no differences in the time and frequency domain parameters of heart rate variability between the two groups. Heart rate was negatively correlated with SDNN (r = -0.278, p = 0.035), while age was significantly correlated with root-mean-square differences in successive RR intervals, high frequency, low frequency and low frequency/high frequency (r = -0.264, -0.370, 0.265 and 0.374, respectively; p<0.05 for all). CONCLUSION: We found that the cardiac autonomic functions of adolescents with a family history of premature atherosclerosis were not different compared with those of adolescents without a positive family history of premature atherosclerosis. It appears that subclinical atherosclerosis does not reach a critical value such that it can alter cardiac autonomic functions in adolescence.