Cardiac involvement in inflammatory bowel disease: role of acylcarnitine esters.

OBJECTIVES: Cardiovascular complications have been frequently described in Inflammatory Bowel Disease (IBD). Both Crohn disease and Ulcerative Colitis are characterized by malabsorption of some micronutrients, such as carnitine, which is a very important element for myocardial metabolism, being demonstrated that its deficiency correlates with heart involvement in coeliac disease. Aims of this study are to evaluate cardiac function in IBD patients asymptomatic for cardiovascular diseases and to correlate the cardiac data with the profile of carnitine esters plasma levels. MATERIALS AND METHODS: The study was carried out on 20 IBD patients by comparison with 18 sex- and age-matched clinically healthy controls. Personal and familial history, physical examination, standard electrocardiogram and echocardiogram were performed in all subjects. Complete panel of nutritional status parameters and serum levels of free carnitine and its esters were evaluated both in IBD patients and control subjects. RESULTS: Isovaleryl-carnitine, Tiglyl-carnitine, Octenoylcarnitine and Decanoyl-carnitine, were found to be significantly lower in IBD patients. Significant correlations were found between some carnitine esters and echocardiographic parameters although total and free carnitine were meanly more elevated in IBD. No statistically significant differences in echocardiographic parameters were found between IBD patients and control subjects. CONCLUSIONS: Deficiency of some isoforms of carnitine, especially those esterified with short chain fatty acids, may play an important role in cardiac involvement in course of IBD and could lead, over time, to dilated cardiomiopathy.

Prediction of QTc length as function of BMI: a clinical tool to establish arrhythmias risk in obesity.

AIMS: Among the electrocardiographic alterations used for stratifying the cardiovascular risk of life threatening arrhythmias (LFA) and sudden death (SD) there is the increment of the corrected QT(QTc). This increment is usually observable in obese patients (OP). Therefore, a study has been planned to investigate the possibility to predict QTc values in OP simply by detecting the best fitting regression method that represents the relationship between QTc and Body Mass Index (BMI). MATERIALS AND METHODS: The study has been carried on 144 individuals classified as a function of their BMI in normoponderal subjects (NPS, No. 24; F/M=15/9; BMI=21.8± 1.7 kg/m(2)), Class I OP (No. 24; F/M=17/7; BMI=32.5± 1.1 kg/m(2)); Class II OP (No. 24; F/M=17/7; BMI=37.7± 1.5 kg/m(2)). Class IIIa (No. 24, F/M=15/9; BMI=44.4± 27 kg/m(2)), Class IIIb (No. 24; F/M=14/10; BMI 54.3± 2.7 kg/m(2)); Class IIIc (No. 24; F/M=14/10; BMI=63.3± 4.5 kg/m(2)). Both linear and non-linear fitting modes have been tested. RESULTS: While the BMI progressively increases in classified OP, the QTc shows an intergroup difference that is not only not constant but also declining in Class IIIc obesity. The optimal regressive model was found to be the following fourth order degree polynomial: QTc=317,15+(7,47xBMI)+(-0,28*BMI(2))+(0,005xBMI(3))+ (-0,00003xBMI(4)). CONCLUSION: By entering the BMI of a given OP into the above-cited formula, the QTc can be easily predicted and compared to that of NPS. Importantly, to have the possibility for a pre-electrocardiographic estimation of QTc allows all the medical and paramedical personnel, involved in the multidisciplinary treatment of obesity, to immediately establish the cardiovascular risk in the OP under observation.

Autonomic imbalance in celiac children.

AIM: Involvement of many organs and apparatus such as heart, central and peripheral nervous systems have been reported in celiac disease. Autonomic neuropathy has frequently been reported both in untreated and in gluten free diet (GFD) adult patients and, to our knowledge, has never been investigated in celiac children. The aim of the study was to evaluate autonomic function in children with celiac disease. METHODS: Fifteen children with untreated celiac disease were enrolled. Fifteen healthy children served as controls. None of the patients was diabetic. Central or peripheral neurological diseases, were absent. In all participants, at recruitment and after 24 months of GFD, serum anti-tTG and AEA levels, inflammatory markers, IgG, IgM and IgA anti-ganglioside antibodies, were performed. Heart rate variability indexes were employed to evaluate autonomic system balance. RESULTS: Our results indicate that also children with celiac disease may exhibit an imbalance of the neurovegetative system with a prevailing sympathetic tone, persisting on a GFD. All presented symptoms such as abdominal pain, diarrhea or constipation, vomiting, meteorism, regurgitation in whom autonomic dysfunction could be involved, but these symptoms disappeared on gluten free diet. This tend to exclude the prevailing sympathetic tone as a main factor underlying symptoms of celiac disease. CONCLUSION: Children affected by celiac disease exhibit an enhanced sympathetic tone, persisting after 24 months of GFD whereas gastrointestinal and systemic symptoms disappear. The pathogenesis of this phenomenon still remains unclear.

[Diagnosing silent cardiac dysautonomia via ambulatory blood pressure monitoring: early diagnosis shown by the lack of heart rate circadian rhythm in type 1 diabetes mellitus]. / Studio della disautonomia cardiaca silente mediante monitoraggio ambulatorio della pressione arteriosa: diagnosi tramite la scomparsa del ritmo circadiano della frequenza cardiaca nei pazienti con diabete mellito tipo 1.

INTRODUCTION: Diabetes mellitus (DM) can be complicated by an involvement of Neurovegetative System (NVS), conventionally and non-invasively diagnosed by the means of Ewing's test and Heart Rate Variability (HRV) analysis. It is well known that the NVS is physiologically responsible, via biological clocks, for the regulation of Circadian Rhythms (CR) characterizing the majority of biological functions. Therefore, this study is aimed at investigating the CR of Heart Rate (HR) and Blood Pressure (BP) in DM, postulating that the diagnosis of Silent Cardiac Dysautonomia (SCD) could be facilitated by detecting anomalous rhythmometric changes, including the worse one, i.e., the lose of a CR. MATERIALS AND METHODS: The study has been performed on 30 clinically healthy subjects (CHS), 10 patients with DM1 and 30 patients with DM2, who underwent an ambulatory BP monitoring (ABPM) collecting data equidistantly every 30 minutes, under standardized conditions of lifestyle. The group specific monitored values of systolic (S), diastolic (D) BP, as well as HR have been analyzed via: 1. a conventional analysis of their intradiem variability; 2. a chronobiometric analysis (Cosinor method) of their CR. RESULTS: The conventional analysis disclosed that in CHS, DM1 and DM2, both the HR and BP show an intradiem variability that is significant (p less than 0.001). The chronobiological analysis showed that in CHS and DM2, both the HR and BP show a significant CR (p less than 0.001), viceversa in DM1 HR is characterized by a non significant CR (p=0.124), notwithstanding that the SBP and DBP maintain a significant CR (p less than 0.001). CONCLUSIONS: The disappearance of HR CR in DM1 reveals the involvement of neurovegetative biological clock that selectively controls the HR CR, as it is demonstrated by the pathophysiological finding of an internal desynchronization between the HR and BP CR. The selective lose of HR CR in DM1 leads to conclude that the ABPM, along with its Cosinor analysis, might be a practical, repeatable, low cost, low risk technique for diagnosing the SCD, at least in DM1.

Parathyroidectomy erase increased myocardial electrical vulnerability in patients with primary hyperparathyroidism.

BACKGROUND: Patients with primary hyperparathyroidism (pHPT) show an increased bioelectrical risk not related to cardiovascular complications, this risk seems to persist after surgery and this last finding is still controversial and probably related to follow-up length. METHODS: The aim of the study is to evaluate QT parameters in 11 patients with primary hyperparathyroidism (pHPT) 18 months after parathyroid surgery using computed standard 12-leads ECG compared to those of 29 healthy subjects (HS). RESULTS: In pHPT patients, 4 months after parathyroidectomy QT and QTc dispersion persist significantly higher than HS. 18 months after surgery, QT and QTc dispersion resulted comparable with HS. QT dispersion was found significantly higher in pHPT at 4 months respect 18 months after parathyroidectomy. CONCLUSIONS: ECG alteration after parathyroidectomy gradually return within normal limits and we can affirm that surgery erase bioelectrical risk in pHPT.

Analysis of the chaotic component of the sinusal R-R intervals as a tool for detecting a silent cardiac dysautonomia in type 2 diabetes mellitus.

This study explores the heart rate (HR) variability (V) in order to detect whether the chaotic component of the sinusal R-R intervals (SRRI) can be interpreted as an early indicator of a silent cardiac neurovegetative dysautonomia in apparently uncomplicated Type 2 diabetic patients (DP). The SRRI were provided by the 24-h Holter ECG of 10 Type 2 DP (5 M and 5 F, mean age = 41 +/- 5 years). Control data were obtained by the 24-h Holter ECG of 10 clinically healthy subjects (CHS, 5 M and 5 F, mean age = 38 +/- 6 years). The chaotic component of HRV was investigated via the correlation dimension (CD) analysis (A) of the SRRI, performed per each hour of the ECG recording. The hourly-qualified series of SRRI, HR and CD index (I) were, in turn, analyzed via methods of conventional statistics and chronobiology, the latter ones for assessing the circadian rhythm (CR). The CDI CR was found to peak during the night in CHS, and to be unphysiologically rotated to the diurnal hours of the day in Type 2 DP. The diurnal inversion of the CDI CR in Type 2 DP suggests that the chaotic component of HRV shows an abnormal rhythnic pattern over the day-night period. Considering that the investigated Type 2 DP were lacking of documentable signs of cardiac neuropathy, it is hypothesized that the diurnal phase of shift CDI CR might be a potential indicator of a silent autonomic cardiac dysfunction in Type 2 DP. Such a hypothesis waits for further confirmations.

A lower level of entropy in circadian rhythm of the sinus R-R intervals suggests a prevalence of the cardiac sympathetic regulation in early physiological pregnancy.

The study estimates the unpredictable disorder (chaos) within the 24 h pattern of sinus R-R intervals (SRRI) in clinically healthy pregnant women (CHPW) and clinically healthy non-pregnant women (CHNPW), in order to evaluate the early gestational changes in neurovegetative cardiac pacing. SRRI were provided by the 24-h Holter ECG of 10 CHPW and 10 CHNPW. SRRI were investigated by descriptive conventional statistics by means of the Time and Frequency Domain Analysis, and subsequently, in their chaotic component by means of entropy analysis. Both the SRRI and entropy were tested via the Cosinor method to better decipher whether or not the periodic disorder in heart rate variability is modified in pregnancy as a result of a gestational tonic resetting of the cardiac sympatho-vagal regulation. Cosinor analysis documented that the circadian rhythm of both the SRRI and entropy were preserved in CHNPW and CHPW. However, the circadian rhythm of SRRI and entropy in CHPW exhibited a significantly decreased 24 h mean. Via the analysis of the rhythmicity of entropy, this study has documented that the chaos in the 24 h pattern of SRRI is less prominent in CHPW than in CHNPW. Such a reduction of level in the deterministic periodic chaos of heart rate variability provides evidence that, in early pregnancy, a tonic elevation of the sympathetic activity regulates cardiac pacing.

Carnitine deficiency in patients with coeliac disease and idiopathic dilated cardiomyopathy.

BACKGROUND AND AIMS: Idiopathic dilated cardiomyopathy (IDCM) and coeliac disease (CD) are two pathological conditions which may lead, by different mechanisms, to malabsorption of various micronutrients, including carnitine, active in cardiac metabolism. The aim of the present investigation was primarily to evaluate differences in serum concentrations of total carnitine between IDCM patients and patients with IDCM associated with CD and then also to evaluate, in the latter, the effect of a gluten-free diet on serum concentrations of total carnitine. METHOD AND RESULTS: Serum carnitine was determined by enzymatic spectrophotometric assay in three groups of individuals: group A, 10 patients (5 males, 5 females), mean age 46.5+/-10.8 years, presenting isolated IDCM; group B, 3 patients (2 males, 1 female), mean age 34+/-8 years, with IDCM+CD; and group C, 10 healthy subjects (5 males, 5 females), mean age 38.6+/-11.1 years. All patients with IDCM belonged to class NYHA I-II. Mean concentrations of total serum carnitine in the group of patients with isolated IDCM (group A) were found to be lower than in the controls (group C). The concentrations in patients with IDCM associated with CD (group B) were lower than in the control group and also lower than in the isolated IDCM (group A). After 2 years on a gluten-free diet, patients presenting IDCM associated with CD showed a progressive increase in mean serum carnitine levels compared to values observed prior to the diet. CONCLUSIONS: Patients presenting IDCM associated with CD show a greater decrease in serum total carnitine levels than patients presenting the isolated form of IDCM. A gluten-free diet, in these patients, leads to a progressive increase in serum levels of this substance.

Idiopathic dilated cardiomyopathy associated with coeliac disease: the effect of a gluten-free diet on cardiac performance.

An increased incidence of coeliac disease has recently been reported in patients with idiopathic dilated cardiomyopathy. This report deals with three patients with idiopathic dilated cardiomyopathy and coeliac disease who underwent clinical and laboratory evaluation to establish the effect of a gluten-free diet on cardiac performance. Two patients observed the gluten-free diet regimen very strictly, and, after a 28-month follow-up period, showed an improvement in echocardiographic parameters as well as in cardiological features and quality of life, as evaluated by the Minnesota Living with Heart Failure questionnaire and the Gastrointestinal Symptom Rating Scale questionnaire. The third patient did not observe the gluten-free diet and presented a worsening in the echocardiographic parameters and cardiological symptoms which required supplementary drug therapy. These preliminary data appear to suggest that the gluten-free diet may have a beneficial effect on cardiac performance in patients with idiopathic dilated cardiomyopathy.

[Circadian periodicity in human heart rate daily variability disorders: subsequent demonstrations through a chronobiological approach to the values of estimated alpha exponent on sinusal R-R intervals]. / Periodicità circadiana del disordine nella variabilità giornaliera della frequenza cardiaca umana: ulteriore dimostrazione tramite approccio cronobiologico ai valori dell'esponente alfa stimato sugli intervalli sinusali R-R.

OBJECTIVE: The present study is aimed at giving a further demonstration that the disorder in human heart rate variability is characterized by a circadian periodicity. Such an evidence has been provided by estimating the alpha exponent of the Lévy's stable distribution approximated to the histogram of the differences between the durations of two adjacent sinusal R-R intervals. MATERIALS AND METHODS: The purpose has been pursued by estimating the alpha exponent on fragments of one hour of the Holter electrocardiogram executed in 10 clinically healthy subjects (5 males and 5 females, ranging in age from 23 to 30 years). RESULTS: The chronobiological analysis of the hourly-qualified values of the alpha exponent has demonstrated a significant circadian rhythm for this coefficient. CONCLUSIONS: The significant circadian periodicity of the alpha exponent is a further evidence that the disorder in human heart rate variability, herein represented by the extreme variability of the differences between the durations of two consecutive sinusal R-R intervals, is characterized by a periodic recursivity.

Prevalence of coeliac disease in idiopathic dilated cardiomyopathy.

We examined 52 patients with idiopathic cardiomyopathy (IDCM) for coeliac disease. Three of them had coeliac disease, suggesting that prevalence of coeliac disease in IDCM patients is increased.

The chaotic component of human heart rate variability shows a circadian periodicity as documented by the correlation dimension of the time-qualified sinusal R-R intervals.

OBJECTIVE: This study investigates the hypothesis that the nonlinear component of human heart rate (HR) variability might show a periodic structure over the 24-h span. Such a postulate could explain how the chaotic component might coexist with the deterministic periodic variability of instantaneous HR in beat per minute. MATERIALS AND METHODS: The sinusal R-R intervals (sRRi) of the Holter EKG of 10 clinically healthy subjects (5 M, 5 F, 23-30 years) were analyzed per each hour of the day-night span according to two methods for the nonlinear chaotic variability, i.e., the correlation dimension method, and the linear periodic variability, i.e., periodic regression analysis. RESULTS: The hourly-qualified correlation integrals were found to show a significant circadian rhythm, with an acrophase located during the night in coincidence with the longest duration of the sRRi and the lowest rate of cardiac pulse. CONCLUSIONS: The rhythmic structure of the chaotic component of the human HR variability let us to think that a deterministic periodic chaos of fractal type regulates the nonlinear cardiac dynamics. Such a periodic structure allows the chaos to be compatible with the deterministic linear periodicity of circadian type which characterizes the within-day variability of human HR.

[The heart rate variability indices and the circadian rhythm of the hourly heart rate: 2 prognostic indicators of mortality and malignant ventricular arrhythmias in patients with a myocardial infarct]. / Indici di variabilità della frequenza cardiaca e ritmo circadiano della frequenza cardiaca oraria: due indicatori prognostici di mortalità e di aritmie ventricolari maligne nei pazienti con infarto miocardico.

The aim of this study was to investigate the circadian variability of heart rate in acute myocardial infarction (AMI) in identifying patients at high risk for malignant ventricular arrhythmias (MVA) and sudden death within 1 year of the acute event. The investigation was carried out in 43 patients, who underwent 24-hour Holter monitoring within 3 months of AMI. Besides the time domain indexes of heart rate variability (SDNN, SDNN index, pNN50, rMSSD), the circadian rhythm of hourly total beats (HTB) and hourly qualified beats (HQB) has been analyzed by the Cosinor method. The AMI patients with MVA and those with MVA who died within 1 year the acute event showed SDNN, SDNN index and pNN50 values lower than subjects without MVA and survived patients with MVA, respectively; the individuals with AMI at high risk for MVA and for sudden death had an SDNN value < 105 ms and 50 ms, respectively. The circadian rhythm of HTB and HQB was statistically validated only in the group without MVA; patients without the circadian rhythm of HTB and HQB showed a higher mortality rate within 1 year of AMI, and the majority was in the group with MVA. The contemporary evidence of an SDNN value < 105 ms and the lack of HTB and HQB circadian rhythm increased sensitivity for identifying patients with MVA to 75%. On the other hand, the contemporary evidence of an SDNN value < 50 ms and the lack of HTB and HQB circadian rhythm increased sensitivity for identifying patients who died within 1 year of AMI to 100%. In conclusion, the assayed methods seem to be both useful and complementary in identifying patients at high risk for MVA and sudden death within 1 year of AMI.

[Cigarette smoking and acute myocardial infarct]. / Fumo di sigaretta e infarto acuto del miocardio.

UNLABELLED: Cigarette smoking is commonly considered as a major risk factor for Acute Myocardial Infarction (AMI). Although AMI has a high incidence in smokers, it doesn't seem to correlate with a worse in hospital prognosis. In order to investigate if cigarette smoking does affect the in-hospital prognosis in patients with AMI, 590 consecutive patients (451 males and 139 females; mean age 63.4 years) admitted to the Coronary Care Unit (CCU) with definite AMI have been studied. Patients were divided in two groups: Group A (303 patients, 269 males and 34 females) smokers till AMI and Group B (287 patients, 182 males and 105 females) nonsmokers or smokers till a month before AMI. RESULTS: The mean age of nonsmokers was higher than smokers (68.4 years vs 58.8 years; p < 0.001). In addition they showed more frequently hypertension (48.8% vs 38%; p < 0.001), diabetes (31.3% vs 16.3%; p < 0.001), and healed infarction or angina (45.6% vs 37.5%). Among Group B higher global mortality rate was observed (22.6% vs 7.6%; p < 0.001) either among thrombolysed patients (10.1% vs 4.4%; p < 0.001) either among not thrombolysed (26.9% vs 4.4%; p < 0.001). The grading in age classes confirmed a higher mortality in nonsmokers patients (6.7% vs 4.9% age > or = 40 and < or = 65 years; 32.5% vs 13.3% > 65 years). They also presented more frequently arrhythmias (15.3% vs 12.2%), ischemic complications (25.4% vs 18.7%), and congestive heart failure (46% vs 34.2%). CONCLUSIONS: According to other authors the results of this study confirm a better prognosis in smokers with AMI. Up to authors hypothesis this outcome could be related either to the younger age, a to a different pathogenetic mechanism of coronaric occlusion to raised thrombosis.

[The peak of creatine phosphokinase level in the acute phase of myocardial infarction in patients with and without ischemic precedents]. / Il picco della creatinfosfochinasi nella fase acuta dell'infarto miocardico nei pazienti con e senza precedenti ischemici.

Two hundred and one patients admitted to Coronary Care Unit with documented acute myocardial infarction, whose chest pain had occurred within 12 hours of hospital admission non thrombolised, were studied. The peak of creatine kinase (CK) was examined and compared between patients without previous manifestations of myocardial ischemia (group A, 106 patients) and patients with/history angina pector or healed myocardial infarction (group B, 95 patients). The mean peak creatine kinase level in the negative history group was higher (2261 +/- 226 U/L vs 1779 +/- 97 U/L p < 0.001), especially in patients aged less than 65. No significant difference was observed in patients aged more than 64 of the two groups. Patients with a positive history presented more frequently ischemic complications (p < 0.05) while the frequency of hemodynamic disturbances and arrhythmias was not significantly different. Total mortality was similar in the two groups (22.6% vs 21%) and more frequently occurred in older patients with congestive heart failure. The authors form the hypothesis that the higher mean peak creatine level in patients without previous myocardial ischemia is the result of absence of coronary collateral circulation. The presence of collateral vessels permits less extensive myocardial infarction but it does not change the prognosis.

[The "natural" history of ischemic cardiopathy, Incidence of coronary events in the follow-up of 114 ambulatory patients]. / La storia "naturale" della cardiopatia ischemica. Incidenza di eventi coronarici nel follow-up di 114 pazienti ambulatoriali.

In the last decade advances in cardiovascular research improved remarkably our understanding of coronary heart disease. However many important problems are so far unresolved. In the present study we focused on the "natural" history of ischemic heart disease in a group of 114 patients. One hundred-seven patients had recent myocardial infarction, and seven suffered from angina. They were observed for a mean period of five years (one to 168 months). Forty-nine patients (42.9%) had no coronary events; sixty-five had angina, myocardial infarction or both. The myocardial infarction was however rare (five cases). The most frequent presentation of angina was stable and effort angina, which sometimes subsided after a period of presence. The classification of angina was often very difficult in cases of effort angina with very low threshold. No relevant differences were found between patients with and without coronary events according to age, sex, duration of follow-up, location of previous myocardial infarction. A significant difference was found in the prevalence of risk factors only for hypertension, which was more frequent in patients with coronary events. Smokers were more frequent in group without coronary events. In our opinion, the most interesting conclusion is that, almost half of these patients remained completely asymptomatic for a very long period.

Treatment of myocardial infarction: hypotensive effect of different thrombolytic agents.

The incidence of hypotension in patients treated with thrombolytic agents for myocardial infarction was investigated in a series of 71 patients, 17 treated with urokinase, 35 with rtPA and 19 with APSAC. Hypotension was observed in 23.5% of the first group, in 5.5% of the second, and in 42.10% of the third (p < 0.002 between rtPA and APSAC). In the inferior location hypotensive reaction was much more frequent than in anterior one (p < 007) especially if a right ventricular involvement was associated. Even if hypotension is a minor and generally harmless complication, it poses many practical problems, and its occurrence must be taken into account when choosing a fibrinolytic treatment.

[Effects of carbamazepine on heart conduction in young patients: a serial study using ambulatory ECG]. / Effetti della carbamazepina sull'eccitoconduzione cardiaca in soggetti giovani: studio seriato con ECG-dinamico.

BACKGROUND: Carbamazepine (CBZ) is a first-line drug in the treatment of epileptic seizures and neuralgia. CBZ is also a cardioactive drug and sometimes induces sinusal dysfunction or AV conduction defects. METHODS: In order to investigate the effect of CBZ on sinus node function and AV conduction, long-term ECG recording (24 hours) and determination of plasma concentration of CBZ were carried out in 10 epileptic patients without heart disorders (5 males and 5 females, mean age 31 years), in the basal state, during steady-state (7th day) and after 30th day of CBZ treatment. The number of total cardiac beats, mean heart rate, P-Q and Q-T interval, sinus-atrial node and atrioventricular dysfunction and intraventricular conduction delay were evaluated. RESULTS: Plasma CBZ concentration was always in the therapeutic range (5-12 micrograms/ml): 9.5 micrograms/ml in the 7th day and 7.8 micrograms/ml in the 30th day. No significant differences in the number of cardiac beats, or P-Q and Q-T intervals were found; there was no depression of sinus node function nor delay of AV conduction. In the basal state, ectopic supraventricular beats (105 +/- 20/24 hours) were observed in 7 patients and repetitive in five of them. In the first Holter ECG recording during CBZ treatment, a strong reduction of ectopic supraventricular beats (6 +/- 3/24 hours) and disappearance of the bursts was observed. In the second control, when the CBZ concentration was lower, the number of ectopic supraventricular beats were moderately increased (30 +/- 8/24 hours) and in one patient supraventricular tachycardia reappeared. CONCLUSIONS: In young epileptic subjects without signs of heart disease, CBZ seems to have no significant effect on conduction, yet has a possible antiarrhythmic effect.