Abstract
Objective To investigate the characteristics of dynamic electrocardiogram and their clinical implications in elderly patients with nonvalvular atrial fibrillation combined with long R-R intervals. Methods Elderly patients diagnosed with nonvalvular atrial fibrillation who were admitted as an inpatient or attended the outpatient department from January 2015 to January 2020 were selected. Patients were divided into two groups based on the presence of a long R-R interval. The characteristics and therapeutic significance of dynamic electrocardiogram between the two groups were compared. Results A total of 532 patients were included in our analyses. Of these, 399 patients were in the long R-R interval group and 133 in the nonlong R-R interval group. In 399 patients, there were 48,840 long R-R intervals manifested within 24 hours. The average, slowest, and fastest ventricular rates during sleep time were higher than those in nonsleep time, while the number of long R-R intervals in sleep time was significantly smaller than that in nonsleep time (P < 0.05). Clinical parameters including dizziness/syncope, cerebral infarction, ST-segment changes, platelet count, average hematocrit, prothrombin time (PT), left ventricular systolic function, end-diastolic diameter, pulmonary artery pressure, and left ventricular ejection fraction were comparable between the groups (P > 0.05). When compared with the nonlong R-R interval group, the level of C-reactive protein was slightly lower in the long R-R interval group (P < 0.05). In addition, the long R-R interval group had a higher incidence of atrial premature beats but a lower incidence of ventricular premature beats. Furthermore, the probability of long R-R interval combined with paroxysmal atrial tachycardia, transient ventricular arrest, second-degree atrioventricular block, and complete or incomplete right bundle branch block was higher than that of nonlong R-R interval (P < 0.05). In patients with long R-R interval >3 s, the risk of having second-degree atrioventricular block and complete or incomplete right bundle branch block was significantly lower, while the risk of having transient ventricular arrest was higher when compared to patients with long R-R intervals of 2-3 s (P < 0.05P). Conclusions Long R-R interval is a common electrocardiographic phenomenon among the elderly with nonvalvular atrial fibrillation. The long R-R interval mostly occurs in nonsleeping time. The average ventricular rate, slowest ventricular rate, and fastest ventricular rate of sleep time are higher than nonsleeping time. Analysis of the characteristics of the dynamic electrocardiogram of these patients may shed light on the mechanisms for long R-R intervals, including the likelihood of concealed conduction and physiological interference in the atrioventricular node, overspeed inhibition, increased vagus nerve tension, or pathological atrioventricular block.
Highlights
As one of the most common cardiovascular diseases, atrial fibrillation is widely observed among the elderly with the incidence of 2–4% and 8% in those aged over 60 and 80 years, respectively [1, 2]
Removal of triggers and factors causing persistent AF is key for successful treatment. erefore, in this study, the characteristics of dynamic electrocardiogram and their clinical implications in elderly patients with nonvalvular atrial fibrillation combined with long R-R intervals were analyzed ad compared with those without long R-R intervals
E inclusion criteria of this study were as follows: (1) patient with a confirmed diagnosis of nonvalvular atrial fibrillation based on comprehensive examinations including clinical manifestation and dynamic electrocardiogram, and all patients had clinical symptoms such as dizziness, shortness of breath, and palpitations; (2) an R-R interval exceeded 2.0 s on continuous monitoring by dynamic electrocardiogram; (3) not consuming any medications that might affect the characteristics of electrocardiogram within 4 weeks prior to the inclusion in this study
Summary
As one of the most common cardiovascular diseases, atrial fibrillation is widely observed among the elderly with the incidence of 2–4% and 8% in those aged over 60 and 80 years, respectively [1, 2]. Long R-R interval, defined as > 1.5 s, is commonly observed in the dynamic electrocardiogram of patients with atrial fibrillation. Atrial fibrillation is more likely to occur with a significantly prolonged R-R interval when compared with sinus rhythm, for which a standard of >2.0 s is widely applied in clinical practice [4, 5]. Erefore, in this study, the characteristics of dynamic electrocardiogram and their clinical implications in elderly patients with nonvalvular atrial fibrillation combined with long R-R intervals were analyzed ad compared with those without long R-R intervals Removal of triggers and factors causing persistent AF is key for successful treatment. erefore, in this study, the characteristics of dynamic electrocardiogram and their clinical implications in elderly patients with nonvalvular atrial fibrillation combined with long R-R intervals were analyzed ad compared with those without long R-R intervals
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