Normal atrial conduction in medically treated patients with bulimia nervosa.

BACKGROUND: Bulimia nervosa (BN) patients are characterized by binge eating followed by compensatory behaviors. Ingestion of emetic substances, characteristic to some BN patients, has been reported to be associated with supraventricular arrhythmias. AIMS: To evaluate atrial electrocardiographic markers for supraventricular arrhythmias in patients with BN. METHOD: The cohort included 31 patients with BN and sex- and age-matched controls. Twelve-lead electrocardiography was conducted on all participants under strict standards. P wave length and P wave dispersion in each patient were computed from a randomly selected beat and an averaged beat constructed from 7-12 beats, included in a 10-s ECG. RESULTS: No statistically significant differences were found between the groups for minimal, maximal, and average P wave duration and P wave dispersion, calculated either from a random beat or averaged beats. CONCLUSION: BN patients who are medically monitored and treated, have normal P wave parameters and P wave dispersion, and therefore do not appear to have an increased risk for developing supraventricular arrhythmias. Future research should focus on evaluating the effect of acute ingestion of emetic drugs on resting ECG of BN patients, as well as using signal averaging techniques and prolonged ECG-Holter monitoring.

Normal QT dispersion in colchicine-resistant familial Mediterranean fever (FMF).

The association between familial Mediterranean fever (FMF) and subclinical cardiac disease remains controversial. The aim of the current study was to evaluate whether FMF patients, who do not respond to colchicine treatment, and thereby endure persistent inflammation, have increased QT dispersion (QTd) values. Twenty-two FMF patients and 22 age- and sex-matched control subjects were included in the study. Repolarization and QT dispersion parameters were computed from 12-lead ECG recording using designated computer software, and results of five beats were subsequently averaged. Both FMF patients and controls had similar comorbidities, similar values of average QT, average corrected QT interval length, average QTd interval, average QT corrected dispersion, QT dispersion ratio, JT dispersion (JTd), and JT corrected dispersion. In conclusion, FMF patients who were unresponsive to colchicine treatment and did not develop amyloidosis had normal QTd and JTd parameters, indicating a non-increased risk for repolarization-associated ventricular arrhythmias.

Medically treated anorexia nervosa is associated with normal P wave parameters.

Anorexia nervosa (AN) is an increasingly common medical condition. Some studies have demonstrated an increased prevalence of atrial premature contractions and anatomical changes in AN patients. Our aim was to investigate P wave parameters and P wave dispersion, an electrocardiographic marker for supraventricular arrhythmias, and its effect on AN. The study group included 48 patients with AN, most hospitalized for a few weeks, and a matched control group. All participants underwent 12-lead electrocardiography (ECG) under strict standards. P wave length and P wave dispersion in each patient were computed from a randomly selected beat and an averaged beat, constructed from 7 to 12 beats, included in a 10-s ECG. There were no statistically significant differences found between the groups for minimal, maximal, average P wave duration and P wave dispersion, calculated either from a random beat or averaged beats. In conclusion, medically treated AN patients who have gained weight have normal P wave parameters, and therefore do not appear to have an increased electrocardiographic risk for atrial fibrillation compared with healthy controls. Further studies are required to evaluate the influence of different disease stages, electrolyte imbalance and other medical complications on P wave parameters and risk for supraventricular arrhythmias in AN patients.

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.

Normal late ventricular potentials in hospitalized patients with eating disorders.

OBJECTIVE: Eating disorders, in particular anorexia nervosa (AN), are associated with cardiovascular complications and risk of arrhythmias. In a recent published study, it was found that patients with eating disorders, especially those affected by bulimia nervosa (BN) and a history of AN have abnormal late ventricular potentials (LPs). LPs are electrocardiographic markers used in detecting abnormal depolarization and increased risk of arrhythmias. Given the paucity of knowledge regarding the affects of eating disorders on cardiac depolarization, our aim was to further explore LPs in patients with eating disorders. METHOD: The study group included 30 hospitalized patients with eating disorders (14 with AN, 10 with BN with no history of AN, and 6 with BN and history of AN). Signal averaged electrocardiography was conducted on all patients using the Frank corrected orthogonal lead system. RESULTS: No patient with either eating disorder tested positive for LPs. DISCUSSION: Hospitalized patients with eating disorders, medically monitored and treated for several weeks, had normal serum electrolytes, started to normalize their weight, and did not appear to be prone to arrhythmias associated with abnormal depolarization. The prognostic significance of LPs in risk stratification of patients with eating disorders should be further evaluated by large cohort studies and longer follow-up studies.

QT dispersion in amyloidosis due to familial Mediterranean fever.

Cardiac amyloid deposition in FMF may cause increased QT dispersion (QTd), a marker for cardiac arrhythmias. The aim of this study was to further evaluate repolarization dispersion in familial Mediterranean fever (FMF) with amyloidosis. Findings on 12-lead electrocardiography were compared between 18 patients with FMF-amyloidosis and 18 age- and sex-matched control subjects. Repolarization and dispersion parameters were computed with designated computer software, and results of the 5 beats were subsequently averaged. There were no statistically significant differences between the groups as to average corrected QT interval length, average QTd interval, average QT corrected dispersion, or QT dispersion ratio. JT dispersion and JT corrected dispersion were also similar in both groups. In conclusion, patients with FMF-amyloidosis seem to have QT and JT dispersion parameters similar to those of healthy subjects. Future research and longer follow-ups should be conducted in order to evaluate the prognostic importance of repolarization dispersion parameters in amyloidosis of FMF.

QT variability among weight-restored patients with anorexia nervosa.

OBJECTIVE: Anorexia nervosa (AN) may be complicated by cardiac arrhythmias and sudden death. A single study reported an increased QT variability index (QTVI), a marker for cardiac arrhythmogenicity, in AN patients. The aim of the current study was to further evaluate repolarization dynamics in a large cohort of patients with AN without electrolyte abnormalities and to evaluate previously unreported repolarization dynamics parameters. METHODS: Forty-three AN patients and 45 age- and sex-matched controls were included in the study. Twenty-nine AN patients were hospitalized for a mean time of 1.5±1.1 months. The rest were ambulatory AN patients. Electrocardiograms were conducted under strict standards. QT variability index, normalized QT variability (QTVN) and power spectral analysis of QT dynamics were conducted with designated computer software. RESULTS: None of the patients had an electrolyte imbalance. Although mean QT was higher in AN patients compared with controls, QTc results were similar following corrections for RR interval. There was no significant difference in QTVI, QTVN and power spectral analysis parameters among groups. The results of QTVI and QTVN were comparable to those previously published for healthy individuals. During 3 years of follow-up, no patient developed arrhythmias or suddenly died. CONCLUSIONS: Medically treated AN patients who gained weight and had normal serum electrolytes appeared to have normal QTc and QT variability indexes, reflecting a nonincreased risk for cardiac arrhythmias. We suggest that weight normalization, medical treatment and lack of electrolyte abnormalities are responsible in part for these results. Further evaluation of the prognostic significance of QTVI and QTVN in AN is warranted.

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.

The efficiency of 10-second resting heart rate for the evaluation of short-term heart rate variability indices.

BACKGROUND: High values of resting heart rate were found to be correlated with adverse outcomes in various patient groups. Heart rate variability (HRV) is a reliable technique in determining autonomic nervous system function. Our aim was to evaluate whether a 10-second resting heart rate obtained from a resting electrocardiogram (ECG), could be used as a reliable evaluation of short-term HRV. METHODS: Seventy-nine healthy volunteers were included in the study. All participants underwent a 10-second ECG, and 5-minute HRV measurement under strict criteria. RESULTS: A significantly negative correlation was found between resting heart rate and 5-minute max-RR, min-RR, standard deviation of normal RR intervals (SDNN), root mean square of successive differences of RR intervals (RMSSD), HRV triangular index, number of intervals differing by 50 milliseconds from the preceding interval (NN50), pNN50, standard deviation of the points perpendicular to the line of identity (SD1), standard deviation along the line of identity (SD2), and high frequency spectral component (HF). A significant positive correlation was found between resting heart rate and a 5-minute low frequency spectral component (LF) and LF/HF ratio. Specifically, max-RR and min-RR were found to have the best correlation with resting heart rate. CONCLUSIONS: Resting heart rate obtained from a 10-second ECG can be used for crude estimation of all HRV results in healthy individuals who do not take medications, with variable efficacy depending on the measured parameter. Resting heart rate was especially efficient in predicting max-RR and min-RR. Further research should focus on assessing the reliability of a resting heart rate for HRV evaluation, in patients with autonomic dysfunction and high-risk cardiac patients.

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 systemic AA amyloidosis of familial Mediterranean fever.

Familial Mediterranean fever (FMF) is a hereditary disease characterized by attacks of fever and polyserositis. Recent studies differ as to whether FMF is associated with 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 with amyloidosis. The study groups consisted of 16 patients with FMF and amyloidosis, and 16 age- and sex-matched control subjects. All participants underwent 12-lead electrocardiography under strict standards. P-wave length and P-wave dispersion in each individual patient were computed from a randomly selected beat and an averaged beat constructed from 7 to 12 beats, included in a 10-s electrocardiogram. No statistically significant differences were found between the groups for minimal, maximal, and average P-wave duration and P-wave dispersion, calculated either from a random beat or averaged beats. In conclusion, although a small difference cannot be excluded because of the small study groups, FMF patients with amyloidosis appear to have atrial conduction parameters similar to those of healthy controls, and therefore apparently do not have an increased electrocardiographic risk for developing supraventricular arrhythmias.

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.

Heart rate variability in familial Mediterranean fever.

Familial Mediterranean fever (FMF) is a hereditary disease, characterized by recurrent episodes of fever and polyserositis. Heart rate variability (HRV) is a powerful, simple and reliable technique to evaluate autonomic nervous system function. Previous studies of physiologic parameters during tilt-test have suggested that patients with FMF have abnormal cardiovascular reactivity and occult dysautonomia. Prompted by these findings, the present study sought to evaluate HRV in patients with FMF, at rest and in the standing position. The study sample included 34 patients with FMF and 34 sex- and age-matched control subjects. All underwent electrocardiography according to strict criteria. HRV parameters were computed with custom-made software. There was no significant difference in HRV parameters, in either the supine or standing position, between the FMF and control groups. In both groups, the upright position was associated with a significant decrease, when compared with the supine position, in maximal RR interval, minimal RR, average RR, root square of successive differences in RR interval, number of intervals differing by >50 ms from preceding interval (NN50), NN50 divided by total number of intervals (pNN50) and high-frequency components as well as a significant increase in average heart rate, very low frequency or low-frequency components, low-frequency/high-frequency components ratio and total power. In conclusion, patients with FMF who are continuously treated with low-dose colchicine have not developed amyloidosis and have normal HRV parameters in the supine and upright position. Further investigation of occult dysautonomia in FMF is needed.

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.

Pattern of cerebrospinal fluid lactic dehydrogenase during treatment of bacterial meningitis.

Bacterial and aseptic meningitis are characterized by distinctive lactic dehydrogenase isoenzyme patterns. No studies have quantified the dynamics of lactic dehydrogenase isoenzyme distribution during treated bacterial meningitis. We used a retrospective case-series design, and reviewed files of all neonates with bacterial meningitis who attended our pediatric tertiary medical center for 8 years period. We identified neonates in whom a repeated lumbar puncture was indicated. Findings of cerebrospinal fluid analysis, including levels of lactic dehydrogenase isoenzymes, were compared with an age-matched reference group. In two patients with meningitis, lumbar puncture with cerebrospinal fluid analysis was repeated because of inadequate response to treatment or initially obscure etiologic pathogens. Both patients had initially low levels of lactic dehydrogenase-1 and lactic dehydrogenase-2 and high levels of lactic dehydrogenase-4 and lactic dehydrogenase-5, similar to other patients with bacterial meningitis. The distribution pattern of lactic dehydrogenase isoenzyme normalized after adequate antibiotic treatment. In light of the encouraging results in these two patients, further studies are warranted regarding the value of lactic dehydrogenase isoenzyme measurements for follow-up purposes and for evaluations of response to treatment.

QT dispersion in uncomplicated familial Mediterranean fever.

The aim of the study was to further evaluate repolarization dispersion in familial Mediterranean fever (FMF). Findings on 12-lead electrocardiography were compared with 32 patients with uncomplicated FMF and age- and sex-matched control subjects. All procedures followed stringent standards. Repolarization and dispersion parameters were computed with designated computer software, and results of the five beats were subsequently averaged. There were no statistically significant differences between the groups in average QT and average corrected QT interval length, average QT interval dispersion, average QT corrected dispersion, or QT dispersion ratio. During 6 months of follow-up, no cases of sudden death or arrhythmia were documented in either group. Patients with FMF who are continuously treated with low-dose colchicine and have not developed amyloidosis seem to have QT dispersion parameters similar to those of healthy subjects and therefore apparently have no increased risk of adverse cardiac events associated with abnormal repolarization.

P-wave dispersion in familial dysautonomia.

BACKGROUND: Familial dysautonomia is a hereditary disease characterized by dysfunction of the sensory and autonomic nervous systems. Studies in patients with familial dysautonomia have shown that abnormal cardiac autonomic denervation might influence repolarization. Autonomic tone also affects atrial conduction parameters and P-wave dispersion, which are predictive of atrial fibrillation. OBJECTIVES: To examine the possible association of familial dysautonomia with abnormal atrial conduction and P-wave dispersion. METHODS: The study population included 12 patients with familial dysautonomia and age and gender-matched control subjects. All participants underwent a 12-lead electrocardiogram under strict conditions. P-wave lengths and P-wave dispersion were computed from a randomly selected beat and an averaged beat using designated computer software. RESULTS: There were no statistically significant differences between the groups in minimal, maximal and average P-wave duration or P-wave dispersion for a randomly selected beat. P-wave dispersion for an averaged beat was also similar. During 6 months follow-up, no supraventricular arrhythmias were documented in either group. CONCLUSIONS: We found that patients with familial dysautonomia had P-wave dispersion parameters not significantly different from those of controls. Further research is required to clarify the effects of dysautonomia on atrial conduction in familial dysautonomia.

Beat-to-beat QT interval dynamics and variability in familial dysautonomia.

Familial dysautonomia (FD) is a disease characterized by dysfunction of the autonomic and sensory nervous systems. During the last five decades, the average life span of patients with FD has increased substantially. Nevertheless, sudden or unexplained death remains the most common cause of death in FD. Recently, our group reported that cardiac remodeling and hypertrophy are common in FD patients. We also described asymptomatic contractile dysfunction in some FD patients. It was speculated that repolarization abnormalities increases the risk of sudden death in patients with FD. However, data regarding repolarization dynamics in FD patients are limited. Twelve patients with FD and 12 healthy individuals (age and sex matched) underwent 5-min electrocardiograms. Time domain analysis of QT dynamics, power spectral analysis, QT variability index (QTVI), and normalized QT variance (QTVN) were computed. There was no difference in the time domain analysis of QT dynamics parameters between the two groups. QTVI((RR)) was also not statistically different. QTVI((HR)) was lower in the FD group compared to controls, but both values were low (therefore not considered pro-arrythmogenic) compared to published data. QTVN, not influenced by heart rate variability, was significantly higher in the FD group (0.39 +/- 0.1% vs. 0.3 +/- 0.05%, p = 0.032). In conclusion, most QT dynamics parameters in patients with FD are similar to that of normal controls. Nevertheless, FD patients have significantly higher QTVN, which might indicate higher risk for ventricular arrhythmias.

Recognizing malingering hypertension in young adults.

OBJECTIVE: Hypertension is unusual in young adults. Malingering hypertension is clinically suspected when there is a potential external secondary gain, absence of patient cooperation during diagnostic evaluation and a lack of response to antihypertensive treatment. The aim of this study was to investigate the possibility that abnormal ambulatory blood pressure patterns may be indicative of malingering hypertension rather than hypertension itself. METHODS: Young adults aged 19-20 years, referred for evaluation of high ambulatory blood pressure, underwent a detailed clinical interview, physical examination, and both in-clinic and 24-h ambulatory blood pressure monitoring. Blood pressure patterns were compared in patients with normal blood pressure values, essential hypertension, or suspected malingering hypertension (20 in each group). RESULTS: Both the suspected malingering hypertension and the essential hypertension group had higher blood pressure values during day and night than the normotensive group. Compared with essential hypertension subjects, the malingering hypertension group showed a greater fluctuation of blood pressure values, lower total percentage of time of abnormally high systolic blood pressure values during the day (41.9+/-16 vs. 65.9+/-12.4, P<0.001) and night (41.8+/-25 vs. 69+/-22.4, P=0.001), and higher maximum heart rate values during the day (132.8+/-15.2 vs. 115.1+/-11.6, P<0.001) and night (93.4+/-19.2 vs. 80.5+/-13.2, P=0.028). CONCLUSION: Patients with malingering hypertension form a distinct clinical group. We suggest that the diagnostician rely on clinical suspicion, fulfillment of our proposed criteria, and distinguishable characteristics of blood pressure patterns. Successful recognition of malingering hypertension can spare patients from unnecessary medical and surgical treatments.

Lactic dehydrogenase isoenzymes in adolescents with multiple sclerosis.

Multiple sclerosis is an immune-mediated demyelinating disease with high morbidity and major mortality. To determine the potential use of lactic dehydrogenase activity and lactic dehydrogenase isoenzyme concentrations in cerebrospinal fluid as biomarkers of multiple sclerosis, we reviewed the files of all patients with multiple sclerosis who attended our tertiary pediatric medical facility from 1999-2005. The study group included three adolescent patients with multiple sclerosis (cerebrospinal fluid analysis at diagnosis) and one patient with recurrent optic neuritis (cerebrospinal fluid analysis during a disease episode). The isoenzyme pattern was abnormal in all patients with multiple sclerosis, with higher-than-normal levels of lactic dehydrogenase-2, lactic dehydrogenase-3, and lactic dehydrogenase-5 in two patients, and lower-than-normal levels of lactic dehydrogenase-4 in one patient. It was not necessarily, however, the same two patients who had the abnormally high levels of lactic dehydrogenase-2, -3, and -5. The patient with optic neuritis also exhibited an abnormal lactic dehydrogenase isoenzyme pattern that shared common features with the others. Multiple sclerosis appears to be characterized by an abnormal lactic dehydrogenase isoenzyme pattern in cerebrospinal fluid. The importance of this finding and its diagnostic potential use warrant further investigation.