P-wave dispersion in panic disorder

Association between the early repolarization pattern and nocturnal suicide attempts

AIM

Numerous recent reports have highlighted the association between mental disorders and electrocardiographic findings. The early repolarization pattern (ERP) on electrocardiogram has been linked with a history of suicide attempts and attention deficit hyperactivity disorder, and associations with impulsivity have also been reported. It is known that suicidal intent is more common at night. Patients who have a mental disorder and ERP may have a higher likelihood of impulsivity, potentially increasing the risk of suicide at night.

METHODS

The subjects were 43 patients with a history of suicide attempts who had undergone electrocardiographic examination at Jikei University School of Medicine Kashiwa Hospital and received intervention from our department. Due to the diurnal variation in electrocardiographic findings, only patients who underwent the examination during the daytime were included. Patients' clinical backgrounds were compared according to the presence or absence of ERP, and the association between nocturnal suicide attempts and ERP was examined using multivariate analysis.

RESULTS

The frequency of nocturnal suicidal behavior was 76.2% in patients with ERP and 31.8% in those without ERP, but the difference was not significant after Bonferroni correction. In the multivariate analysis, there was a significant association of ERP with nocturnal suicide attempts (p = 0.018).

CONCLUSION

The finding of an association between ERP and nocturnal suicide attempts indicates that ERP is a biological indicator that can predict nocturnal suicide attempts.

Exploring the causal relationships and mediating factors between depression, anxiety, panic, and atrial fibrillation: A multivariable Mendelian randomization study

BACKGROUND

Atrial fibrillation is a significant cardiovascular disease, and the increased risk of its occurrence may be influenced by mental disorders. Currently, the causal relationship between them remains controversial. Our aim is to ascertain the relationship between atrial fibrillation and mental disorders including depression, anxiety, and panic, as well as the risk factors mediating this relationship, through the judgment of genetic susceptibility.

METHODS

We utilized the summarized statistics from nine large-scale genome-wide association studies (in European populations), including depression (PGC, N = 807,553), anxiety (FinnGen, N = 429,209), panic (PGC, N = 230,878), diabetes (UK Biobank, N = 655,666), smoking (IEU, 607,291), hypertension (UK biobank, N = 463,010), obstructive sleep apnea (IEU, N = 476,853), obesity (UK biobank, N = 463,010), and AF (IEU, N = 1,030,836). By applying bidirectional two-sample Mendelian randomization and multivariable Mendelian randomization to depression, anxiety, panic, and AF, we analyzed their causal relationships and the independent influence of specific risk factors. Furthermore, a two-step MR approach was used to assess the mediating effects of diabetes, smoking, hypertension, obstructive sleep apnea, and obesity.

RESULTS

Results from the Two-Sample Mendelian Randomization Inverse Variance Weighted Random Effects Model show: the occurrence of genetically predicted depression is related to an increased risk of atrial fibrillation (AF) (OR: 1.073; [95 % CI: 1.005-1.146] P < 0.05), and panic is more significantly associated than depression (OR: 1.017; [95 % CI: 1.008-1.027] P < 0.001), while anxiety has no causal relationship with the occurrence of AF (OR: 1.023; [95 % CI: 0.960-1.092], P > 0.05), and AF is not significantly related to the occurrence of depression, anxiety, or panic (P > 0.05). After correcting for the other two risk factors using multivariable Mendelian randomization, depression remains significantly related to the occurrence of AF (β: 0.075; 95 % CI: [0.006, 0.144], P < 0.05), while panic and anxiety are not related to the occurrence of AF. Among them, the risk factors for AF occurrence, hypertension and obesity, are mediators between depression and AF, with mediation proportions of 74.9 % and 14.3 %, respectively. The mediating effects of diabetes, smoking, and obstructive sleep apnea were found to be not statistically significant. The above results are robust after sensitivity analysis.

CONCLUSION

Our results identified that the genetic susceptibility to depression is an independent risk factor for the occurrence of AF, and that hypertension and obesity can mediate this process. Panic also poses some risk to the onset of AF. This demonstrates that controlling hypertension and obesity for emotional management is of great importance in preventing the occurrence of AF.

Assessment of age, gender, and anxiety on ECG waveform morphology in a large population of domestic dogs

Cardiovascular diseases are major causes of death in the western world and this incidence increases in the elderly population. With aging, there are physiologic changes to the cardiac structure secondary to adipose tissue deposition, calcification of valve leaflets and changes in the structure of the heart including atrial remodeling. Such changes can make the myocardium more susceptible to stress leading to a higher prevalence of cardiovascular diseases in the aging population. Studies in healthy humans have shown that these structural and molecular changes in the heart are manifested as changes on an electrocardiogram (ECG). Using animal models, similar ECG changes have been found in guinea pigs, rabbits, and mice. No veterinary study has specifically evaluated if comparable aging changes occur in canine species. In this cross-sectional retrospective study, 12,026 ECGs from apparently healthy dogs were obtained and evaluated. Age was observed to have both linear and non-linear associations with multiple ECG variables, including P wave amplitude and duration, R amplitude and QRS duration. This study confirmed that, like humans, there may be ECG changes secondary to normal physiological cardiac aging. Further studies are warranted to confirm and elaborate on these findings as canines may be a useful model for cardiac aging in humans.

Relationship between the early repolarization pattern and a history of suicide attempts among drug-free psychiatric patients

Aim

Suicide attempts are an important severe psychiatric symptom and a clear outcome for mental disorders. Although the relationship between the early repolarization pattern in electrocardiogram and psychiatric disorders has recently been reported, these reports have not been able to exclude the influence of psychiatric drugs. This study aimed to investigate the relationship between the early repolarization pattern and a history of suicide attempts among patients not receiving psychiatric medication.

Methods

A total of 71 patients with a history of suicide attempts were investigated, 38 of whom were analyzed for this study. We compared the frequency of the early repolarization pattern between a suicide attempt group and a control group. Then, we investigated the association between the early repolarization pattern and the suicide attempt group by logistic regression analysis, including electrocardiographic findings associated with psychiatric disorders.

Results

The findings indicated that the frequency of the early repolarization pattern was significantly higher in the suicide attempt group (n = 20; 52.6%) than in the control group (n = 4; 10.5%) (P < 0.001), and the results of the logistic regression analysis indicated that the early repolarization pattern was associated with suicide attempts.

Conclusions

These findings suggest that the early repolarization pattern is associated with a history of suicide attempts.

Death of a child and the risk of atrial fibrillation: a nationwide cohort study in Sweden

Aims

The role of psychological stress in the aetiology of atrial fibrillation (AF) is unclear. The death of a child is one of the most severe sources of stress. We aimed to investigate whether the death of a child is associated with an increased risk of AF.

Methods and results

We studied parents with children born during 1973–2014 included the Swedish Medical Birth Register (n = 3 924 237). Information on death of a child, AF and socioeconomic, lifestyle and health-related covariates was obtained through linkage to nationwide population and health registers. We examined the link between death of a child and AF risk using Poisson regression. Parents who lost a child had a 15% higher risk of AF than unexposed parents [incidence rate ratio (IRR) and 95% confidence intervals (CI): 1.15 (1.10–1.20)]. An increased risk of AF was observed not only if the child died due to cardiovascular causes [IRR (95% CI): 1.35 (1.17–1.56)], but also in case of deaths due to other natural [IRR (95% CI): 1.15 (1.09–1.21)] or unnatural [IRR (95% CI): 1.10 (1.02–1.19)] causes. The risk of AF was highest in the 1st week after the loss [IRR (95% CI): 2.87 (1.44–5.75)] and remained 10–40% elevated on the long term.

Conclusions

Death of a child was associated with a modestly increased risk of AF. Our finding that an increased risk was observed also after loss of a child due to unnatural deaths suggests that stress-related mechanisms may also be implicated in the development of AF.

Examination of ECG characteristics of patients admitted to emergency department with conversive attack

OBJECTIVE

Conversion disorder is defined as a disorder with one or more neurological symptoms that accompany psychological conflict, suggesting a physical disorder. It has been shown that patients with conversion disorder have an imbalance in the autonomic nervous system. There are only a limited number of studies that have examined how conversion disorder is related with surface ECG parameters. The present study aimed to investigate the effects of conversion disorder on the surface ECG parameters of patients with conversion disorder admitted to the emergency department.

METHODS

This cross-sectional case-control study included 98 patients who were admitted to the emergency department and diagnosed with conversion disorder and 56 healthy volunteers. All patients underwent 12-derivation ECG. PR interval, P wave dispersion, duration of QRS complex, QT interval, QTc interval, frontal QRS-T angle values were calculated for all individuals.

RESULTS

When compared with the control group, the conversion disorder group revealed a significant difference in terms of PWD [60 (40-80) vs. 40 (40-60) P = 0.01], QT [385 (364-410) vs. 378 (354-394), P = 0.048], QTc [420 (405-430) vs. 406 (397-429), P = 0.039], and frontal QRS-T angle [25 (15-33) vs. 20 (8-35), P = 0.018]. In the multivariate linear regression analysis, conversion disorder was found to be an independent predictor for both PWD (β = 0.196, P = 0.014) and frontal QRS-T angle (β = 0.258, P = 0.011).

CONCLUSION

This study is the first to show that conversion disorder significantly increases QT, QTc, P wave dispersion, and frontal QRS-T angle.

Is panic disorder a disorder of physical fitness? A heuristic proposal

Currently, panic disorder (PD) is considered a mental disorder based on the assumptions that panic attacks (PAs) are “false alarms” that arise from abnormally sensitive defense systems in the central nervous system and that PD is treated with therapies specifically acting on anxiety or fear mechanisms. This article aims to propose an alternative perspective based on the results of some experimental studies. Our heuristic proposal suggests not only that PD may be a mental disorder but also that patients with PD have real abnormal body functioning, mainly involving cardiorespiratory and balance systems, leading to a decline in global physical fitness. PAs, as well as physical symptoms or discomfort in some environmental situations, may be “real alarms” signaling that the adaptability resources of an organism are insufficient to respond appropriately to some internal or external changes, thus representing the transient conscious awareness of an imbalance in body functioning. The antipanic properties of several modern treatments for PD may include their beneficial effects on body functions. Although anxiety or fear mechanisms are evidently involved in PD, we hypothesize that a reduction of physical fitness is the “primum movens” of PD, while anxiety or fear is induced and sustained by repeated signals of impaired body functioning. We propose considering panic in a broader perspective that offers a central role to the body and to contemplate the possible role of somatic treatments in PD.

Depression in Cardiovascular Patients in Middle Eastern Populations: A Literature Review

Cardiovascular disease (CVD) is increasing in Middle Eastern countries. Depression is associated with increased morbidity and mortality rates among cardiovascular (CV) patients. Early detection of and intervention for depression among CV patients can reduce morbidity and mortality and save health care costs. Public information on mental health care needs of Arab CV patients living in Middle East regions is scattered and limited. This literature review surveyed and summarized research studies to learn what is known about the relationship between depression and CVD in Middle Eastern populations. The information will raise awareness among health care professionals and policy makers regarding the clinical significance of depression in Arab CV patients. It might contribute to development of culturally appropriate and effective mental health care services. Multiple databases were searched and 60 articles were assessed, including studies that investigated depression in Arab CV patient populations, physiological mechanisms of depression-CVD comorbidity, and intervention strategies that affect CV risk in depressed Arab patients. We discuss the extent to which this issue has been explored in Arab populations living in Middle East regions and Arab populations living abroad. We recommend that more comprehensive and in-depth research studies be conducted with Arab cardiac patients to enable implementation of culturally appropriate and effective mental health care interventions.

Is there cardiac risk in panic disorder? An updated systematic review

BACKGROUND

The recognized relationship between panic disorder (PD) and cardiac disorders (CDs) is not unequivocal. We reviewed the association between PD and coronary artery disease (CAD), arrhythmias, cardiomyopathies, and sudden cardiac death.

METHODS

We undertook an updated systematic review, according to PRISMA guidelines. Relevant studies dating from January 1, 2000, to December 31, 2014, were identified using the PubMed database and a review of bibliographies. The psychiatric and cardiac diagnostic methodology used in each study was then to very selective inclusion criteria.

RESULTS

Of 3044 studies, 14 on CAD, 2 on cardiomyopathies, and 1 on arrhythmias were included. Overall, the studies supported a panic-CAD association. Furthermore, in some of the studies finding no association between current full-blown PD and CAD, a broader susceptibility to panic, manifesting as past PD, current agoraphobia, or subthreshold panic symptoms, appeared to be relevant to the development of CAD. Preliminary data indicated associations between panic, arrhythmias, and cardiomyopathies.

LIMITATIONS

The studies were largely cross-sectional and conducted in cardiological settings. Only a few included blind settings. The clinical conditions of patients with CDs and the qualifications of raters of psychiatric diagnoses were highly heterogeneous. CDs other than CAD had been insufficiently investigated.

CONCLUSIONS

Our review supported a relationship between PD and CDs. Given the available findings and the involvement of the cardiorespiratory system in the pathophysiology of PD, an in-depth investigation into the panic-CDs association is highly recommended. This should contribute to improved treatment and prevention of cardiac events and/or mortality, linked to PD.

The Effect of Synthetic Cannabinoids on P-Wave Dispersion: An Observational Study

OBJECTIVE

The aim of this study was to investigate the effect of synthetic cannabinoids (SC) on P-wave dispersion (PD) in patients who consume SC.

MATERIALS AND METHODS

The study population included 72 patients who consumed SC and 36 age- and sex-matched healthy controls. The severity of addiction was detected using the addiction profile index (BAPI). The PD was measured by 12-lead ECG obtained upon admission to hospital. Statistical analyses were performed using the SPSS v20.0 statistical software package.

RESULTS

The mean age of the patients and controls was 26.9 ± 7.0 and 26.3 ± 6.5 years, respectively. Mean duration of SC consumption was 1.7 ± 0.7 years. Mean BAPI score of patients who consumed SC was 12.8 ± 3.4. Patients who consumed SC had a significantly higher PD value than controls (37.7 ± 11.5 vs. 30.6 ± 6.4 ms, p < 0.001). The BAPI score was significantly correlated with PD value (r = 0.675, p < 0.001). In the linear regression model that included PD value, age and heart rate, PD value was significantly and independently correlated with BAPI score (r2 of the model = 0.339; p < 0.001).

CONCLUSIONS

In this study, patients who consumed SC had significantly higher PD values than controls, and the BAPI score correlated with the PD value. Hence SC consumption could lead to an increased risk of cardiovascular disease through prolonged PD. We recommend the use of the simple and inexpensive ECG to assess cardiovascular risk in patients who consume SC.

P wave dispersion in obsessive-compulsive disorder

BACKGROUND

P wave dispersion (Pd) is defined as the difference between the maximum and the minimum P wave duration. It has recently been associated with increased anxiety levels, thereby predisposing affected individuals to fatal heart disease. Despite of evidence of this autonomous nervous system (ANS) relationship, there are no electrocardiography (ECG) studies in the patients with obsessive-compulsive disorder (OCD). Thus, in this study, we aimed to evaluate the Pd in OCD patients.

MATERIALS AND METHODS

The study consisted of a total of 25 patients with OCD and same number of physically and mentally healthy age- and gender-matched controls. For psychological testing, Yale-Brown Obsession and Compulsion (Y-BOCS) was administered.

RESULTS

Pmax was found to be significantly higher in the patients compared to controls. Pmin did not differ between groups. Left atrium sizes were not different between groups. As for the main parameter investigated in the present study, it was found that Pd was significantly increased in the OCD patients than the controls. Y-BOCS scores for the patient group was positively correlated with Pd (r = 0.73, P < 0.01).

CONCLUSIONS

In conclusion, our results suggest that Pd may be associated with OCD though our sample is too small to allow us to obtain a clear conclusion. Future studies with larger sample evaluating the effects of treatment are required.

P-wave and QT dispersion in patients with conversion disorder

OBJECTIVE

The aim of this study was to investigate QT dispersion (QTd), which is the noninvasive marker of ventricular arrhythmia and sudden cardiac death, and P-wave dispersion, which is the noninvasive marker of atrial arrhythmia, in patients with conversion disorder (CD).

PATIENTS AND METHODS

A total of 60 patients with no known organic disease who were admitted to outpatient emergency clinic and were diagnosed with CD after psychiatric consultation were included in this study along with 60 healthy control subjects. Beck Anxiety Inventory and Beck Depression Scale were administered to patients and 12-lead electrocardiogram measurements were obtained. Pd and QTd were calculated by a single blinded cardiologist.

RESULTS

There was no statistically significant difference in terms of age, sex, education level, socioeconomic status, weight, height, and body mass index between CD patients and controls. Beck Anxiety Inventory scores (25.2±10.8 and 3.8±3.2, respectively, P<0.001) and Beck Depression Scale scores (11.24±6.15 and 6.58±5.69, respectively, P<0.01) were significantly higher in CD patients. P-wave dispersion measurements did not show any significant differences between conversion patients and control group (46±5.7 vs 44±5.5, respectively, P=0.156). Regarding QTc and QTd, there was a statistically significant increase in all intervals in conversion patients (416±10 vs 398±12, P<0.001, and 47±4.8 vs 20±6.1, P<0.001, respectively).

CONCLUSION

A similar relation to that in literature between QTd and anxiety and somatoform disorders was also observed in CD patients. QTc and QTd were significantly increased compared to the control group in patients with CD. These results suggest a possibility of increased risk of ventricular arrhythmia resulting from QTd in CD patients. Larger samples are needed to evaluate the clinical course and prognosis in terms of arrhythmia risk in CD patients.

QT wave dispersion in patients with panic disorder

OBJECTIVE

QT dispersion (QTd), defined as the maximal inter-lead difference in QT intervals on 12 leads of the surface electrocardiogram (ECG), reflects the regional heterogeneity of ventricular repolarization and has been suggested as an important marker for risk of arrhythmia in addition to the QT interval. Some investigators proposed that it might be a predisposing factor for arrhythmic events and sudden death. Thus, we aimed to investigate whether QTd differs in patients with panic disorder from that in healthy controls.

METHODS

In 40 panic disorder patients and 40 healthy controls, Q(max), Q(min), and QTd values were measured. In addition, the Hamilton depression rating scale and the panic agoraphobia scale were scored for both patients and healthy volunteers.

RESULTS

Q(max) and Q(min) values in the panic disorder patients were significantly higher than those in healthy controls. The mean corrected QTd was significantly greater in the patients than in the controls. One-way analysis of covariance (ANCOVA; using left atrial size, age and heart rate as covariates) also corrected the significant difference. In addition, ANCOVA revealed a significant main effect for the diagnosis, indicating a significantly higher QTd for patients compared with controls.

CONCLUSION

QTd might be associated with panic disorder. Future studies in larger samples evaluating the effects of treatment are required.

Association between panic disorder and risk of atrial fibrillation:a nationwide study

OBJECTIVE

The aim of the present study was to investigate the association between panic disorder (PD) and atrial fibrillation (AF).

METHODS

We used a nationwide population-based data set from Taiwan. A total of 3888 patients with PD and without a diagnosis of AF from a sampled cohort data set of 1,000,000 were included in the study group. Ten people without PD and AF were selected for every 1 patient in the study group, matched by propensity score matching according to time of enrollment, age, sex, and comorbidities. We performed log-rank tests to analyze differences in accumulated AF-free survival rates between the two groups. Cox proportional hazard regressions were performed to evaluate the independent factors determining the longitudinal hazard of AF.

RESULTS

During a maximal 7-year follow-up, 48 patients from the study group (1.2% of the patients with PD) and 358 from the control group (0.9% of the patients without PD) were newly diagnosed as having AF. Patients with PD had a significantly higher incidence of AF (hazard ratio [HR] = 1.54 [1.14-2.09]; log-rank test, p = .004). After Cox model adjustment for risk factors and comorbidities, PD (HR = 1.73, 95% confidence interval [CI] = 1.26-2.37), age (HR = 1.07, 95% CI = 1.06-1.08), male sex (HR = 1.26, 95% CI = 1.03-1.55), hypertension (HR = 2.00, 95% CI = 1.55-2.56), history of coronary artery disease (HR = 1.45, 95% CI = 1.15-1.82), congestive heart failure (HR = 2.46; 95% CI, 1.84-3.30), and valvular heart disease (HR = 2.83, 95% CI = 1.85-4.42) were independently associated with increased risk of AF.

CONCLUSIONS

PD is independently associated with higher incidence of AF to be diagnosed in the future. Larger prospective studies or meta-analysis are suggested to confirm the findings.

Meta-analysis of p-wave dispersion values in healthy individuals: the influence of clinical characteristics

BACKGROUND

P-wave dispersion (Pd) is an appealing marker for predicting the risk of developing atrial fibrillation. At present, no definitive cutoff value has been determined as to the diagnosis of high-risk patients. Our aims were to evaluate P-wave parameters of healthy subjects published in the literature, determine normal range and weighted means of Pd and P-wave parameters, and investigate the influences of gender, age, and BMI on the weighted results.

METHODS

A systematic search of studies published in PubMed was conducted. Only studies which included control groups of healthy individuals were included.

RESULTS

Of the 657 studies initially identified, 80 were eligible for inclusion. The total number of participants was 6,827. The highest reported Pd values were 58.56 ± 16.24 ms; the lowest were 7 ± 2.7 ms. The weighted mean was 33.46 ± 9.65 ms; weighted median was 32.2 ms. Gender and age were not found to be associated with significant influences on P-wave parameter values. High-normal BMI was not found to be associated with increased P-wave parameter values.

CONCLUSIONS

Pd, Pmax, and Pmin span a wide range of values in healthy individuals. Seemingly, abnormal values were often reported in healthy adults. The high variability of P-wave parameters in healthy individuals, and overlapping of the results with those reported for patients with increased risk for atrial fibrillation, might suggest that this technique has limited sensitivity and specificity. The variability between studies may stem from methodological issues and, therefore, there is a definite need for methodological standardization of Pd measurements.

Comparison of P-wave dispersion in healthy dogs, dogs with chronic valvular disease and dogs with disturbances of supraventricular conduction

BACKGROUND

P-wave dispersion (Pd) is a new ECG index used in human cardiology and veterinary medicine. It is defined as the difference between the maximum and the minimum P-wave duration recorded from multiple different ECG leads. So far no studies were performed assessing the importance of P-wave dispersion in dogs.

METHODS

The current study was aimed at determining proper value of Pd in healthy dogs (group I), dogs with chronic valvular disease (group II) and dogs with disturbances of supraventricular conduction (group III). The tests were carried out in 53 healthy dogs, 23 dogs with chronic valvular disease and 12 dogs with disturbances of supraventricular conduction of various breeds, sexes and body weight from 1,5 to 80 kg, aged between 0,5 and 17 years, submitted to the ECG examination. ECG was acquired in dogs in a standing position with BTL SD-8 electrocardiographic device and analyzed once the recording was enlarged. P-wave duration was calculated in 9 ECG leads (I, II, III, aVR, aVL, aVF, V1, V2, V4) from 5 cardiac cycles.

RESULTS

The proper P-wave dispersion in healthy dogs was determined at up to 24 ms. P-wave dispersion was statistically significant increased (p<0.01) in dogs with chronic valvular disease and dogs with disturbances of supraventricular conduction. In dogs with the atrial enlargement the P-wave dispersion is also higher than in healthy dogs, although no significant correlation between the size of left atria and Pd was noticed (p=0.1, r=0,17).

CONCLUSIONS

The P-wave dispersion is a constant index in healthy dogs, that is why it can be used for evaluating P wave change in dogs with chronic valvular disease and in dogs with disturbances of supraventricular conduction.

Effect of anaesthetic agents on p-wave dispersion on the electrocardiogram: comparison of propofol and desflurane

Anaesthetics influence cardiac electrical activity by various mechanisms; thus, they may have pro-arrhythmic or anti-arrhythmic actions. Increased P-wave dispersion is associated with a risk of paroxysmal atrial fibrillation. The aim of the present study was to analyse the impact of propofol and desflurane on changes in P wave dispersion, which may reflect the anti-arrhythmic effects of these drugs. Fifty patients undergoing scheduled surgery were included in the study. Patients were divided into two equal groups: a propofol group and a desflurane group. Patients in the propofol group were initially administered 2.5 mg/kg propofol, followed by infusion of 6 mg/kg per h propofol. Anaesthesia in the desflurane group was achieved using inhalation induction, with concentrations up to 8-12.5 vol%. When signs of adequate anaesthesia were observed, the concentration of desflurane was reduced to 6 vol%. An electrocardiogram (ECG) was obtained before induction and then again 1, 3 and 5 min after the initiation of propofol infusion or the induction of anaesthesia in the desflurane group; additional measurements were performed after tracheal intubation. P-wave dispersion was assessed by differences in maximal and minimal P-wave duration on a 12-lead ECG. P-wave dispersion did not change over time in the desflurane group. In the propofol group, there was a significant decrease in P-wave dispersion after 3 and 5 min of anaesthesia. Significant differences were observed between study groups after 1, 3 and 5 min of anaesthesia, and disappeared after tracheal intubation. Mean and maximal P-wave duration did not change in either group. In conclusion, propofol decreases P-wave dispersion and this seems to be connected with the anti-arrhythmic properties of the drug.