Carbon monoxide poisoning increases Tpeak-Tend dispersion and QTc dispersion

Objective

Carbon monoxide (CO) poisoning leads to cardiac dysrhythmia. Increased heterogeneity in ventricular repolarisation on electrocardiogram (ECG) shows an increased risk of arrhythmia. A number of parameters are used to evaluate ventricular repolarisation heterogeneity on ECG. The aim of our study is to investigate the effect of acute CO poisoning on indirect parameters of ventricular repolarisation on ECG.

Methods

Sixty-seven patients were included in this case–control study. Thirty patients with acute CO poisoning were assigned to group 1 (19 females, mean age: 30.8 ± 11.3 years). A control group was formed with patients without known cardiac disease (group 2, n = 37; 25 females, mean age: 26.0 ± 5.2 years). Twelve-lead ECG and serum electrolyte levels were recorded in all patients. Also, carboxyhaemoglobin (COHb) levels were recorded in group 1. T_peak–T_end (T_pT_e) interval, T_pT_e dispersion, T_pT_e/QT ratio, QT interval and QT_d durations were measured as parameters of ventricular repolarisation. Corrected QT (QT_c) and QT_c dispersion (QT_cd) intervals were determined with the Bazett’s formula.

Results

The mean COHb level in group 1 was 27.6 ± 7.4% and mean duration of CO exposure was 163.5 ± 110.9 min. No statistically significant difference was found in age, gender, serum electrolytes or blood pressure levels between the groups. QRS, QT, QT_c, T_pT_e interval and T_pT_e/QT ratio were similar between the groups (p > 0.05). QTcd (65.7 ± 64.4 vs 42.1 ± 14.2 ms, p = 0.003) and T_pT_e dispersion (40.5 ± 14.8 vs 33.2 ± 4.9 ms, p = 0.006) were significantly longer in group 1 than group 2. COHb level was moderately correlated with TpTe dispersion (r = 0.29; p = 0.01).

Conclusion

To our knowledge, this is the first study to investigate T_pT_e interval and dispersion in CO poisoning. Our results showed that T_pT_e dispersion and QTc dispersion increased after CO poisoning.

Hypercholesterolemia is Accounted for Atherosclerosis at the Proximal Arterial Segments of Myocardial Bridging

Arterial shear stress was generally implicated in the development of atherosclerotic plaque (AP). Atherosclerotic plaque may be associated with myocardial bridging (MB). We evaluated the metabolic abnormalities which could determine the localization of AP at the proximal coronary segment of MB. We analyzed the patients with MB, AP&MB, and AP on left anterior descending (LAD) artery who were diagnosed by multislice computed tomography coronary angiography. Serum levels of metabolic parameters were compared among study groups. Patients with MB&AP and AP were significantly older than those in the MB group. Patients with MB&AP had AP and MB at the proximal and middle segments of LAD artery, respectively. Total cholesterol, low-density lipoprotein (LDL) cholesterol and very LDL, and triglyceride levels were significantly higher in patients with MB&AP and AP compared to only MB. Low-density lipoprotein cholesterol was significantly correlated with the type of coronary artery disease in multiple regression analysis. Myocardial bridging may be an anatomical determinant for the localization of AP proximal to itself in the presence of hypercholesterolemia.

Increased frequency of mitral valve prolapse in patients with deviated nasal septum

Any abnormality of collagen may affect the tissues with higher collagen content, e.g., joints, heart valves, and great arteries. Mitral valve prolapse (MVP) is a characteristic of generalized collagen abnormality. Nasal septum (NS) is constituted by osseous and cartilaginous septums that are highly rich in collagen. We evaluated the co-existence of deviation of NS (DNS) in patients with MVP. We retrospectively evaluated the recordings of echocardiographic and nasal examinations of subjects with MVP and DNS. We analyzed the features of MVP and anatomical classification of DNS among subjects. Totally, 74 patients with DNS and 38 subjects with normal nasal passage were enrolled to the study. Presence of MVP was significantly higher in patients with DNS compared to normal subjects (63 vs 26%, p < 0.001). Prolapse of anterior, posterior and both leaflets was higher in patients with DNS. Thickness of anterior mitral leaflet was significantly increased in patients with DNS (3.57 ± 0.68 vs 4.59 ± 1.1 mm, p < 0.001) compared to normal subjects. Type I, II, and III, IV DNS were higher in frequency in patients with MVP while type V and VI were higher in normal subjects. DNS is highly co-existent with MVP and increased thickness of mitral anterior leaflet. Generalized abnormality of collagen which is the main component of mitral valves and nasal septum may be accounted for co-existence of MVP and DNS. Also co-existence of them may exaggerate the symptoms of patients with MVP due to limited airflow through the nasal passage.

The CHA2DS2-VASc score as a predictor of left atrial thrombus in patients with non-valvular atrial fibrillation

OBJECTIVE

To investigate whether or not the CHA2DS2-VASc score predicts left atrial (LA) thrombus detected on pre-cardioversion transoesophageal echocardiography (TEE).

MATERIALS AND METHODS

The medical records of patients who had undergone TEE were reviewed to assess the presence of LA thrombus prior to direct-current cardioversion for atrial fibrillation (AF). The CHA2DS2-VASc score was calculated for each patient. Clinical TEE reports were reviewed for the presence of LA thrombus. Patients with a valve prosthesis or rheumatic mitral valve disease were excluded from this study.

RESULTS

A total of 309 patients were identified. The mean age was 70.1 ± 9.8 years and 151 (49%) patients were males and 158 (51%) were females. LA thrombus was seen in 32 (10.3%) of the 309 patients. Fifty (16.2%) patients had a low CHA2DS2-VASc score (0-1), 230 (74.4%) had an intermediate score (2-4) and 29 (9.4%) had a high score (5-9). The incidence of LA thrombus in the low, intermediate and high CHA2DS2-VASc score groups was 0, 4.4 and 68.7%, respectively. The LA thrombus risk increased with increasing CHA2DS2-VASc scores. On multivariate logistic analysis, the CHA2DS2-VASc score (OR 3.26, 95% CI 2.3-4.65; p = 0.001) and age (OR 0.93, 95% CI 0.88-0.98; p = 0.004) were independent risk factors for LA thrombus in patients with non-valvular AF.

CONCLUSION

A high CHA2DS2-VASc score was independently associated with the presence of LA thrombus in patients with non-valvular AF.