Heart rate variability in familial Mediterranean fever

Vagus nerve stimulation as a therapeutic option in inflammatory rheumatic diseases

The vagus nerve forms intricate neural connections with an extensive number of organs, particularly the digestive system. The vagus nerve has a pivotal role as a fundamental component of the autonomic nervous system, exhibiting an essential effect. It establishes a direct link with the parasympathetic system, consequently eliciting the synaptic release of acetylcholine. Recent studies have revealed the potential anti-inflammatory function of the vagus nerve. The activation of the hypothalamic system through the stimulation of vagal afferents is fundamentally involved in regulating inflammation. This activation process leads to the production of cortisol. The other mechanism, defined as the cholinergic anti-inflammatory pathway, is characterized by the involvement of vagal efferents. These fibers release the neurotransmitter acetylcholine at particular synaptic connections, involving interactions with macrophages and enteric neurons. The mechanism under consideration is ascribed to the α-7-nicotinic acetylcholine receptors. The fusion of acetylcholine receptors is responsible for the restricted secretion of inflammatory mediators by macrophages. A potential mechanism for anti-inflammatory effects involves the stimulation of the sympathetic system through the vagus nerve, leading to the control of immunological responses within the spleen. This article offers an extensive summary of the present knowledge regarding the therapeutic effectiveness of stimulating the vagus nerve in managing inflammatory rheumatic conditions based on the relationship of inflammation with the vagus nerve. Furthermore, the objective is to present alternatives that may be preferred while applying vagus nerve stimulation approaches.

Cardiovascular manifestations of monogenic periodic fever syndromes

Periodic fever syndromes (PFS) are a group of autoinflammatory diseases characterized by repeated febrile episodes and systemic inflammation. The most common monogenic periodic fever syndromes are familial Mediterranean fever, mevalonate kinase deficiency/hyper immunoglobulin D syndrome, cryopyrin-associated periodic syndrome, and tumor necrosis factor receptor-associated periodic syndrome. Although fever is the predominant feature of PFS, other systems, including the cardiovascular system, may be involved in the disease process. This review focuses on cardiovascular risks and issues in monogenic PFS. Cardiovascular involvement may occur as a disease manifestation, association, or result of complications or a drug's adverse effects in monogenic PFS. Pericarditis seems to be a feature of PFS. Patients with recurrent pericarditis or pericarditis resistant to conventional treatment should be evaluated for PFS. Amyloidosis is the most severe complication of PFS, increasing the risk of cardiac morbidity. Furthermore, ongoing inflammation may result in early atherosclerosis. Therefore, assessing cardiovascular risks in PFS patients should be considered a part of routine care. Key points • Pericarditis is the most common cardiac involvement of monogenic periodic fever syndromes (PFS), while some forms may present with myocarditis. • Amyloidosis, the most significant complication of PFS, may lead to deterioration in cardiac functions. • Ongoing inflammation in PFS may result in endothelial dysfunction and atherosclerosis. • Effective control of inflammation and reducing concomitant risk factors such as obesity, diabetes mellitus, and hypertension could improve cardiovascular outcomes in PFS patients.

Evaluation of peripheral nerve involvements in patients with familial Mediterranean fever

Objectives

The aim of this study was to evaluate possible peripheral and autonomic nerve involvement in familial Mediterranean fever (FMF) patients with nerve conduction studies, sympathetic skin response (SSR) and RR interval variability (RRIV).

Patients and methods

The comparative case series was conducted with 76 participants between November 2017 and December 2018. Forty-six FMF patients, [12 with amyloidosis (5 males, 7 females; mean age: 44.7±13.9 years) and 34 without amyloidosis (14 males, 20 females; mean age: 35.9±8.7 years)], and 30 healthy volunteers (11 males, 19 females; mean age: 38.4±10 years) were included in this study. Nerve conduction parameters, SSR latency and amplitude from palmar and plantar responses, and RRIV at rest and deep breathing were studied in all the subjects. Neuropathic symptoms of the patient group were evaluated using the survey of autonomic symptoms scale and the neuropathy disability score.

Results

Nerve conduction studies of the patient group revealed polyneuropathy in seven (15.21%) patients and carpal tunnel syndrome in six (13.04%) patients. The mean amplitudes of SSR measured from the soles were significantly lower than the control group (p=0.041). The mean values of RRIV during rest and hyperventilation were lower in the patient group compared to the control group, but no statistically significant difference was found (p=0.484, p=0.341).

Conclusion

We detected that the prevalence of carpal tunnel syndrome in our patient population (13.04%) was higher than in the general population. Most of the changes in the range of parameters of SSR and RRIV determined in the patient group did not reach statistical significance, suggesting subclinical dysautonomia in FMF patients.

Acute Pediatric Colchicine Toxicity is Associated with Marked Bradydysrhythmias

BACKGROUND

Colchicine ingestion is rare but highly lethal. Patients usually die of multiorgan failure and cardiogenic shock. Colchicine is not only associated with depressed myocardial function but also with fatal heart rhythm disturbances, such as complete heart block, ventricular tachycardia, and asystole. While histologic changes of myocytes are well known, the mechanism by which colchicine affects cardiac impulse generation and conduction is not fully understood.

CASE REPORT

We present a case of colchicine ingestion with sinus bradycardia, marked sinus arrhythmia, and first- and second-degree heart block. A 10-year-old previously healthy boy was brought to the emergency department for the sudden onset of dizziness, abdominal pain, and vomiting after ingesting his grandfather's colchicine and furosemide. His symptoms improved with ondansetron and intravenous normal saline. However, because of the colchicine ingestion, he was admitted to the pediatric intensive care unit for observation. He first developed PR prolongation (∼4-30 h postingestion) followed by marked sinus bradycardia and sinus arrhythmia along with second-degree heart block (∼48-60 hours postingestion). The minimum heart rate was 40 beats/min. Marked sinus arrhythmia was observed, suggesting an increase in parasympathetic activity. His heart rhythm improved initially with less sinus arrhythmia followed by resolution of heart block. He was discharged home without any sequelae. Holter monitoring 1 week after discharge showed normal heart rate variability for age. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: This case provides novel insights into how colchicine may affect the heart's electrophysiology. Colchicine may increase the parasympathetic tone enough to cause sinus bradycardia and different degrees of heart block.

Late ventricular potentials in familial Mediterranean fever with and without AA amyloidosis

Objective

Familial Mediterranean fever (FMF) is an autosomal recessive disease characterized by episodic and chronic inflammation that may lead to both accelerated coronary atherosclerosis and cardiac AA amyloidosis. We hypothesized that late ventricular potentials (LPs), an established electrocardiographic susceptibility marker of ventricular arrhythmias, will be more common in FMF than in the adjusted normal population due to these two types of inflammation-associated cardiac effects. Therefore, we aimed to evaluate the occurrence of LPs in FMF patients with and without amyloidosis.

Material and Methods

Signal-averaged electrocardiography was performed in consecutive patients with FMF using the Frank corrected orthogonal lead system. At least 200 consecutive beats were digitally recorded and averaged, and the presence of LPs was determined according to acceptable thresholds.

Results

There were 54 patients with colchicine-treated FMF, of whom 14 had biopsy-proven AA amyloidosis. None of the uncomplicated FMF patients and 2 of the 14 FMF amyloidosis patients had abnormal or borderline LPs.

Conclusion

Based on LPs as a susceptibility marker for arrhythmia, FMF patients, including the large majority of FMF patients with amyloidosis, are seemingly not at an increased risk to develop arrhythmias.

Cardiac autonomic functions in children with familial Mediterranean fever

Familial Mediterranean fever (FMF) is the most common inherited autoinflammatory disease in the world. The long-term effects of subclinical inflammation in FMF are not well recognized. Some studies have suggested that FMF is associated with cardiac autonomic dysfunction in adult FMF patients. The objective of this study was to investigate the cardiac autonomic functions in pediatric FMF patients by using several autonomic tests. Thirty-five patients with FMF and 35 healthy controls were enrolled in this cross-sectional study. Demographic data, disease-specific data, and orthostatic symptoms were recorded. In all participants, 12-lead electrocardiography (ECG), 24 h ambulatory electrocardiographic monitoring, transthoracic echocardiography, treadmill exercise test, and head upright tilt-table (HUTT) test were performed. The heart rate recovery (HRR) indices of the two groups were similar. Also, chronotropic response was similar in both groups. The time-domain parameters of heart rate variability (HRV) were similar in both groups, except mean RR (p = 0.024). Frequencies of ventricular and supraventricular ectopic stimuli were similar in both groups. There were no statistically significant differences between the groups in average QT and average corrected QT interval length, average QT interval dispersion, and average QT corrected dispersion. There was no significant difference between the two groups regarding the ratio of clinical dysautonomic reactions on HUTT. However, we observed a significantly higher rate of dysautonomic reactions on HUTT in patients with exertional leg pain than that in patients without (p = 0.013). When the fractal dimension of time curves were compared, FMF patients exhibited significantly lower diastolic blood pressure parameters than controls in response to HUTT. Cardiovascular autonomic dysfunction in children with FMF is not prominent. Particularly, patients with exertional leg pain are more prone to have dysautonomic features. Further studies are needed to elucidate the exact mechanisms leading to impaired cardiac autonomic functions in FMF.

Heart rate variability in familial Mediterranean fever patients

OBJECTIVE

Familial Mediterranean fever (FMF) is an autosomal recessive autoimmune disease, presenting with the attacks of fever and inflammation of serous membranes. One of the leading causes of death in autoimmune rheumatologic diseases is cardiovascular events. The purpose of this study is to evaluate the effects of FMF on the autonomic nerve and cardiovascular systems by measuring the indices of heart rate variability (HRV).

MATERIAL AND METHODS

Thirty FMF patients and the same number of healthy volunteers were enrolled to the study. Standard deviation of all R-R intervals (SDNN), the square root of the sum of the square of the differences between successive R-R intervals (RMSSD), standard deviation of 5-minute mean values of R-R interval (SDANN), low frequency (LF), and high frequency (HF) were measured.

RESULTS

Time domain indices (SDNN, SDANN, and RMSSD) were: 124.67±40.79, 129.87±36.43 (p=0.605); 11.43±38.41, 11.23±38.98 (p=0.984); and 33.43±17.39, 38.17±12.8 (p=0.235) for FMF patients and controls, respectively, and similar in both groups. Frequency domain indices (HF, LF, and LF/HF) were: 290.41±290.25, 322.20±222.54 (p=0.639); 596.16±334.07, 805.80±471.00 (p=0.051); and 3.57±2.57, 3.05±1.40 (p=0.338) for FMF patients and controls, respectively, and similar in both groups.

CONCLUSION

The HRV parameters were similar in both groups. However, studies including larger populations and using different methods are required to clarify if autonomic dysfunction exists in patients with FMF.

Assessment of autonomic functions in children with familial Mediterranean fever by using heart rate variability measurements

AIM

The aim of this study is to analyze possible autonomic nerve system alterations and assess the efficacy of heart rate variability (HRV) analysis in anticipation of cardiovascular risks in pediatric patients with familial Mediterranean fever (FMF).

METHOD

In this study, cardiac autonomic functions were investigated in children with FMF by analyzing HRV and its other probable cardiac effects by echocardiography. We studied 70 pediatric patients with FMF and 50 healthy controls.

RESULTS

The time-domain parameters of HRV were compared between the FMF and control groups. SDNN (standard deviation of all NN intervals) was significantly decreased in patients with FMF as compared to control subjects. The other time-domain parameters of HRV and the frequency-domain parameters of HRV were similar in both groups. Frequency-dependent HRV parameters were similar in both groups, as were conventional echocardiographic parameters.

CONCLUSION

HRV is a convenient and reliable technique for evaluation of autonomic functions. There are only a few studies on the assessment of autonomic functions by means of HRV in adult FMF patients but not in pediatric patients. Further studies are required to assess whether there is autonomic dysfunction in children with FMF.

Evaluating reliability of ultra-short ECG indices of heart rate variability in diabetes mellitus patients

Our aim was to investigate the reliability of ultra-short HRV in patients with DM. A good correlation was found between the 1 minute and 5 minute parameters for maximal-RR, minimal-RR, average-RR, SDNN, RMSSD, pNN50, and total power. Also, a good correlation between 10 second and 5 minute parameters was found for maximal-RR, minimal-RR, average-RR, and RMSSD. We suggest that certain ultra-short HRV parameters can be used efficiently in DM patients for autonomic evaluation.

QT dispersion and cardiac involvement in children with Familial Mediterranean fever

Familial Mediterranean fever is a hereditary disease characterised by recurrent and self-terminated attacks of fever and polyserositis. An earlier study found that adult patients of Familial Mediterranean fever had an abnormally longer QT dispersion and corrected QT dispersion, markers for ventricular arrhythmogenicity. QT dispersion is a simple non-invasive arrhythmogenic marker that can be used to assess homogeneity of cardiac repolarisation; however, it has not been studied in children with Familial Mediterranean fever before. The aim of this study was to assess QT dispersion and corrected QT dispersion, and their relationship with systolic and diastolic function of the left ventricle in a group of children with Familial Mediterranean fever. We performed electrocardiography and Doppler echocardiography on patients and controls. Maximum QT, minimum QT, QT dispersion, corrected QT, maximum corrected QT, minimum corrected QT, and corrected QT dispersion intervals were measured from standard 12-lead electrocardiography. No statistically significant differences were found between the groups in QT dispersion, corrected QT dispersion, and systolic-diastolic function of the left ventricle parameters. During the 12 months of follow-up, no ventricular arrhythmias were documented in either group.

QT interval variability in familial Mediterranean fever: a study in colchicine-responsive and colchicine-resistant patients

The association between familial Mediterranean fever (FMF), early atherosclerosis, and electrocardiographic markers for arrhythmias remains controversial. There are conflicting results as to the occurrence of high QT dispersion in FMF. The aim of the present study was to further investigate repolarization dynamics and other repolarization-associated pro-arrhythmogenic markers in FMF patients. To explore repolarization in FMF, patients who responded well to colchicine and patients who had not responded to colchicine, yet were amyloidosis-free, were included. We aimed to evaluate whether increased inflammatory burden, a characteristic of non-responsive patients, was specifically associated with abnormal repolarization. Included in the study were 53 FMF patients (27 colchicine non-responders) and 53 age- and sex-matched control subjects. Electrocardiograms were performed under strict standards. QT variability parameters were computed with custom-made computer software. No significant difference in any of the QT dynamic parameters was found in either FMF group compared with the healthy controls. Mean values of QT variability index, regardless of colchicine response, were similar to previously published results for healthy persons. In conclusion, patients with FMF who are continuously treated with colchicine and have not developed amyloidosis, regardless of their clinical response, have normal QT variability parameters, indicating normal repolarization dynamics and suggesting no increased risk of repolarization-associated cardiac arrhythmias.

Abnormal heart rate variability in AA amyloidosis of familial Mediterranean fever

BACKGROUND

A scarcity of data exists relating to the effect of amyloidosis of Familial Mediterranean fever (FMF) on the autonomic nervous system. Our aim was to further investigate the presence of dysautonomia in FMF-AA amyloidosis, using a comparative case series design.

MATERIAL AND METHODS

The study group consisted of 40 patients with FMF: 20 without co-morbidities or amyloidosis and 20 in various stages of renal amyloidosis. Time domain and power spectral analyses of heart rate dynamics were performed according to accepted procedures. Findings were compared with 20 healthy control subjects.

RESULTS

No statistically significant differences were found in any of the studied heart rate variability (HRV) parameters between patients with uncomplicated FMF and controls. In contrast, patients with progressive amyloidosis (post renal transplantation or on dialysis) had significantly lower HRV parameters compared to control subjects (i.e. mean low frequency power spectral components 104.30 ms² vs. 172.09 ms², p <0.05, mean standard deviation of all normal RR intervals 32.27 ms vs. 51.51 ms, p <0.05, mean HRV triangular index 9.08 vs. 15.82, p <0.05). The adjusted odds ratio was 14.5 (95%CI 1.21-165.03, p = 0.04) for HRV triangular index lower than 12.2 in the progressive amyloidosis group, 41.24 (95%CI 1.81-938.68, p = 0.02) for low frequency power spectral components values lower than 142.35 ms², and 12.67 (95%CI 1.04-153.96, p = 0.04) for standard deviation of all normal RR intervals values lower than 40.15?ms.

CONCLUSION

Amyloidosis of FMF, particularly at a progressive stage, is associated with HRV abnormalities suggestive of the presence of autonomic nervous system dysfunction.

Reliability of Ultra-Short ECG Indices for Heart Rate Variability

BACKGROUND

Heart rate variability (HRV) is an accepted and reliable means for assessing autonomic nervous system dysfunction. A 5-minute measurement of HRV is considered methodologically adequate. Several studies have attempted to use shorter recordings of 1-2 minutes or 10 seconds. The aim of this study was to determine the reliability of HRV parameters calculated from ultra-short electrocardiogram recordings.

METHODS

Seventy healthy volunteers were recruited for the study. HRV was evaluated for 5 minutes according to accepted procedures. Thereafter, HRV parameters were recalculated from randomly selected 1-minute and 10-second intervals. The standard and ultra-short measurements were correlated using intraclass correlation coefficients.

RESULTS

Good correlations between the 5-minute electrocardiograms (ECGs) and both the 1-minute and 10-second ECGs were noted for average RR interval, and root mean square of successive differences in RR intervals (RMSSD). No correlation was noted for standard deviation of the RR interval (SDNN) and several other HRV parameters.

CONCLUSIONS

RMSSD, but not SDNN, seem a reliable parameter for assessing HRV from ultra-short (1 minute or 10 seconds) resting electrocardiographic recordings. Power spectral analysis and evaluation of other HRV parameters require longer recording periods. Further research is required to evaluate the importance of ultra-short RMSSD for cardiovascular risk stratification.

Normal autonomic nervous system responses in uncomplicated familial Mediterranean fever: a comparative case-control study

There is a paucity of knowledge regarding the autonomic nervous system function in patients with familial Mediterranean fever (FMF). Therefore, our aim was to evaluate autonomic responses in patients with FMF using complementary tests. The study groups included 33 patients with uncomplicated FMF and 39 control subjects. Autonomic function was evaluated by measuring responses to metronomic breathing, the Valsalva maneuver, and the Ewing maneuver. Autonomic parameters were computed from electrocardiograms with designated computer software. There were no statistically significant differences in any of the measured parameters of autonomic function between the patient and control group. The measured autonomic parameters of both groups were similar to those previously reported in healthy individuals. In conclusion, patients with FMF who did not develop amyloidosis due to continuous colchicine treatment appeared to have normal autonomic function, as reflected by the normal response to physiological autonomic stimuli.

P wave dispersion in familial Mediterranean fever

Familial Mediterranean fever (FMF) is a hereditary disease characterized by recurrent and self-terminated attacks of fever and polyserositis. A recent study found that FMF patients had an abnormally high P wave duration and P wave dispersion, markers for supraventricular arrhythmogenicity. The aim of our study was to further evaluate atrial dispersion in FMF patients. The study group consisted of 26 patients with uncomplicated FMF and age- and sex-matched control subjects. All participants underwent 12-lead electrocardiography under strict standards. P wave length and P wave dispersion were computed from a randomly selected beat and from an averaged beat constructed from 7 to 12 beats, included in a 10-s ECG. No statistically significant differences were found between the groups in minimal, maximal, and average P wave duration and P wave dispersion calculated either from a random beat or averaged beats. During 6 months of follow-up, no supraventricular arrhythmias were documented in either group. FMF patients who are continuously treated with colchicine and do not develop amyloidosis have normal atrial conduction parameters and therefore seemingly do not have an increased electrocardiographic risk of atrial fibrillation.