QT dispersion and hypertensive heart disease in the elderly

Bariatric surgery mitigated electrocardiographic abnormalities in patients with morbid obesity

Obesity can lead to cardiovascular dysfunctions and cause electrocardiographic disruptions. Bariatric surgery plays a significant role in weight loss. To assess its benefits, this study investigated electrocardiographic changes before and after bariatric surgery. The present article describes a retrospective cohort study with a 6-month follow-up period. Electrocardiograms were interpreted and compared before and six months after surgery. The relationships between weight loss, type of surgery, and electrocardiographic alterations were analyzed. A total of 200 patients participated in the study, with 34 (17%) men and 166 (83%) women. The mean age of the participants was 44.6 ± 8.6, and their mean body mass index was 43.8 ± 5.5 kg/m2. The mean of QTc decreased after the surgery, while the Sokolow-Lyon scores increased. The statistical analysis showed that QTc dispersion (> 40) (P < 0.001), right ventricular hypertrophy (P < 0.001), abnormal R wave progression (P < 0.001), QTc (P < 0.001) and Sokolow-Lyon criteria (P < 0.001) significantly changed postoperatively. In conclusion, bariatric surgery can reduce QTc, correct poor R wave progression, and resolve right ventricular hypertrophy (RVH) in patients with morbid obesity.

Effects of Bariatric Surgery on Heart Rhythm Disorders: a Systematic Review and Meta-Analysis

The aim of this systematic review is to provide an overview of the literature on the effects of bariatric surgery on obesity-associated electrocardiogram (ECG) abnormalities and cardiac arrhythmias. Fourteen studies were included with a methodological quality ranging from poor to good. Majority of the studies showed a significant decrease of QT interval and related measures after bariatric surgery. Seven studies were included in the meta-analysis on effects of bariatric surgery on QTc interval and a significant decrease in QTc interval of - 33.6 ms, 95%CI [- 49.8 to - 17.4] was seen. Bariatric surgery results in significant decrease in QTc interval and P-wave dispersion, i.e., a normalization of initial pathology. The effects on atrial fibrillation are conflicting and not yet fully understood.

P-wave and QT dispersion in hypertensive disorders of pregnancy

Aim: To compare P-wave and QT dispersion values in hypertensive disorders of pregnancy and controls and also in preeclampsia, chronic hypertension, and gestational hypertension separately.Material and methods: We included 140 hypertensive pregnants and 110 healthy age-matched pregnants in this study. The hypertensive pregnants were divided into three subgroups: preeclampsia (n = 43), chronic hypertension (n = 51), and gestational hypertension (n = 46). P-wave and QT dispersion values were compared between groups.Results: Hypertensive pregnants had higher P-wave (41.74 ± 5.51 vs. 37.73 ± 5.62, p < .001) and QTc dispersion (45.44 ± 7.62 vs. 39.77 ± 8.34, p < .001) values. In subgroup analysis, P-wave dispersion and QTc dispersion were different between preeclamptic, chronic hypertensive, and gestational hypertensive patients. Also, they were significantly higher in chronic hypertension as compared to gestational hypertension and they were higher in preeclampsia than in gestational hypertension. No difference was found according to these parameters between preeclampsia and chronic hypertension. In correlation analysis, both P-wave dispersion and QTc dispersion were positively correlated with systolic (r = 0.409, p < .001 and r = 0.306, p < .001) and diastolic blood pressure (r = 0.390, p < .001 and r = 0.287, p < .001) which are main clinical determinants of hypertensive disorders.Conclusion: In clinical practice, chronic hypertensive pregnants are generally followed up in their future life for cardiovascular disorders. Also, we recommend that we must inform and follow preeclamptic patients for future cardiovascular diseases.

Effect of obesity and weight loss on ventricular repolarization: a systematic review and meta-analysis

We performed a systematic review and meta-analysis of the effects of obesity ± overweight and weight loss on the corrected QT interval (QTc) and QT or QTc dispersion (indices of ventricular repolarization). Mean difference for both QTc and QT or QTc dispersion with 95% confidence intervals (CIs) was calculated comparing obese ± overweight subjects and normal weight controls and QTc and QT or QTc dispersion before and after weight loss from diet ± exercise or bariatric surgery. A total of 22 studies fulfilled the selection criteria. Compared with normal weight controls, there was a significantly longer QTc in obese ± overweight subjects (mean difference of 21.74 msec, 95% CI: 18.76 to 22.32) and significantly longer QT or QTc dispersion (mean difference of 15.17 msec, 95% CI: 13.59 to 16.74). Weight loss was associated with a significant decrease in QTc (mean difference -25.77 msec, 95% CI: -28.33-23.21) and QT or QTc dispersion (mean difference of -13.46 msec, 95% CI: -15.60 to -11.32 in obese ± overweight subjects. Thus, obesity ± overweight is associated with significant prolongation of QTc and QT or QTC dispersion. Weight loss in obese ± overweight subjects produces significant decreases in these variables. © 2016 World Obesity.

Ventricular repolarization markers for predicting malignant arrhythmias in clinical practice

Malignant cardiac arrhythmias which result in sudden cardiac death may be present in individuals apparently healthy or be associated with other medical conditions. The way to predict their appearance represents a challenge for the medical community due to the tragic outcomes in most cases. In the last two decades some ventricular repolarization (VR) markers have been found to be useful to predict malignant cardiac arrhythmias in several clinical conditions. The corrected QT, QT dispersion, Tpeak-Tend, Tpeak-Tend dispersion and Tp-e/QT have been studied and implemented in clinical practice for this purpose. These markers are obtained from 12 lead surface electrocardiogram. In this review we discuss how these markers have demonstrated to be effective to predict malignant arrhythmias in medical conditions such as long and short QT syndromes, Brugada syndrome, early repolarization syndrome, acute myocardial ischemia, heart failure, hypertension, diabetes mellitus, obesity and highly trained athletes. Also the main pathophysiological mechanisms that explain the arrhythmogenic predisposition in these diseases and the basis for the VR markers are discussed. However, the same results have not been found in all conditions. Further studies are needed to reach a global consensus in order to incorporate these VR parameters in risk stratification of these patients.

Evaluation of ventricular repolarization in pregnant women with intrahepatic cholestasis

BACKGROUND

Bile acids can induce arrhythmia by altering cardiomyocyte contractility or electrical conduction. The aim of this study was to investigate, by means of QT dispersion parameter detected by simple standard electrocardiogram (ECG), ventricular repolarization changes in pregnant women with and without intrahepatic cholestasis of pregnancy (ICP).

METHODS

In this case-control study including 75 pregnant women with cholestasis and 35 healthy, uncomplicated pregnancy cases, electrocardiographic QT interval durations and QT dispersion (QT-disp) parameters, corrected for the patients' heart rate using the Hodges formula, were investigated.

RESULTS

Maximum corrected QT interval values were significantly higher in the severe ICP group than in the control group (p < 0.001) and significantly higher in the severe ICP group than in the mild ICP group (p = 0.01). The values of the mild ICP and control groups were similar. Corrected QT-disp values were also significantly higher in both ICP groups than in the control group and significantly higher in the severe ICP group than in the mild ICP group.

CONCLUSION

Cholestatic diseases predispose patients to cardiovascular complications. Our data clearly demonstrated that QT-disp values were significantly altered in pregnant women with cholestasis when compared to the normal ones. This simple ECG parameter can be used to screen high-risk women, in order to better target counseling regarding lifestyle modifications and to conduct closer follow up and management of women with a history of ICP.

Relation of left ventricular mass to QTc in normotensive severely obese patients

Prolongation of the corrected QT interval (QTc) has been described in obese subjects. This study assesses the relation of left ventricular (LV) mass to QTc in normotensive severely obese subjects. Fifty normotensive patients whose BMI was ≥40 kg/m(2) (mean age: 38 ± 7 years) were studied. QTc was derived using Bazett's formula. LV mass was calculated using the formula of Devereux et al. and was indexed to height(2.7). Mean QTc was 428.8 ± 19.0 ms and was significantly longer in those with than in those without LV hypertrophy (P < 0.01) QTc correlated positively and significantly with BMI (r = 0.392, P < 0.025), LV mass/height(2.7) (r = 0.793, P < 0.0005), systolic blood pressure (r = 0.742, P < 0.001), LV end - systolic wall stress (r = 0.746, P < 0.001) and LV internal dimension in diastole (r = 0.788, P < 0.0005). Among five variables tested, LV mass/height(2.7) was identified as the sole predictor of QTc by multivariate analysis. In conclusion, LV mass and loading conditions that may affect LV mass are important determinants of QTc in normotensive severely obese subjects.

Would corrected QT dispersion predict left ventricular hypertrophy in hypertensive patients?

AIMS

We explored whether QT corrected dispersion (QTcD) can identify left ventricular hypertrophy (LVH) in hypertensives.

METHODS

We enrolled 100 hypertensive patients (study group) and 30 normotensive subjects (control group). Echocardiography was performed to measure left ventricular mass and left ventricular mass index. Electrocardiogram was performed to measure QTcD.

RESULTS

LVH was present in 42 patients (42%) of the study group, none among controls. Hypertensive patients had significantly greater indices of LVH and QTcD compared with controls (p <0.001 for all). Similarly, among hypertensive patients, those with LVH had a significantly greater QTcD compared with those without (p <0.001). Pearson's correlation coefficient test demonstrated strongly positive correlations between QTcD and the indices of LVH (p <0.001 for all). Analysis of the receiver operating characteristic curves identified 60 ms as the optimal cut-off value of QTcD that best predicts LVH in hypertensives. Using this value, QTcD was able to predict LVH with a sensitivity of 92.9% and specificity 98.2%.

CONCLUSIONS

QTcD is significantly increased in hypertensive patients with LVH compared with those without, being strongly correlated with the indices of LVH. A QTcD cut-off value of 60 ms predicted LVH in hypertensive patients with a high sensitivity and specificity.

Prognostic evaluation of QT-dispersion in elderly hypertensive and normotensive patients

BACKGROUND

QT-corrected interval dispersion (QTcD) is an indirect index of increased heterogeneity of ventricular repolarization. However, the prognostic value of (QTcD) in elderly hypertensive and normotensive patients has not been thoroughly investigated yet.

METHODS

The study population consisted of 60 consecutive patients (34 males/26 females; mean age: 63+/-11 years) with mild to moderate essential arterial hypertension and 48 consecutive age-matched healthy subjects (24 males/24 females; 65+/-16 years). QTcD was measured by a 12-lead electrocardiogram (ECG) as the difference between maximum and minimum QT-interval, corrected for heart rate. Ventricular arrhythmias were recorded by a 24-hour Holter ECG and classified by a modified Lown's score (range: 0-6). Left ventricular mass was measured echocardiographically and indexed by body surface area [left ventricular mass index (LVMI)]. Nine patients were lost during the follow-up period. Patients were followed up for 54+/-9 months, and the primary end-point was the major cardiovascular events (including cardiac mortality).

RESULTS

Major cardiovascular events occurred in 22 patients (22%). Patients with QTcD>or=45 ms (n=35) had a higher rate of major cardiovascular events (43% vs 11%; log rank: 14.8; P<0.001), a higher LVMI (146+/-29 vs 104+/-21 g/m2; P<0.001), greater values of systolic and diastolic blood pressure (154+/-16 vs 144+/-18 mmHg; P<0.01 and 92+/-10 vs 88+/-8 mmHg; P<0.05, respectively), a higher number of premature ventricular beats (354+/-870 vs 113+/-301; P<0.05), and a greater Lown's score (3.7+/-1.9 vs 1.4+/-1.8; P<0.05) than patients with QTcD<45 ms. QTcD (>or=or<45 ms) was an independent predictor of major cardiovascular events (odds ratio: 4.9; 95% confidence interval: 2.0-12.1; P=0.001) after adjustment for LVMI, Lown's score (>or=or<3), age (>or=or<65 years), and QTc max (>or=or<437 ms).

CONCLUSIONS

QTcD is an independent predictor of major cardiovascular events in elderly hypertensive and normotensive patients and might be used in their risk stratification.

QT dispersion and left ventricular hypertrophy in elderly hypertensive and normotensive patients

Inhomogeneity of ventricular repolarization as detected by QT dispersion may be a potential leading mechanism of sudden death in hypertensive and normotensive (age related) left ventricular hypertrophy. Aim of this study was to investigate QT dispersion, ventricular arrhythmias, and left ventricular mass index in elderly hypertensive and normotensive patients. Study population consisted of 60 consecutive patients (sex: 34 men/26 women; age: 63 +/- 11 years) with essential arterial hypertension and 48 age and sex-matched control subjects (24 men/24 women; 64 +/- 16 years). Measurements included QTc dispersion, ventricular arrhythmias, and left ventricular hypertrophy. Hypertensive patients had greater left ventricular mass index (P = .006) and higher QTc dispersion (P = .004) than controls. Left ventricular hypertrophy was diagnosed in 57 (31 men/26 women) of all subjects. These patients had higher blood pressure (P < .05), Lown's score (P < .001), and QTc dispersion (P < .001). QTc dispersion and Lown's score were independent predictors of left ventricular mass index (P < .001). Conclusively, QTc dispersion is a strong indicator of left ventricular mass index and might be used in risk stratification of hypertensive and normotensive elderly patients.

Effect of obesity on P-wave dispersion and QT dispersion in women

OBJECTIVE

The aim of this study was to investigate the effect of obesity on dispersion of P-wave duration and QTc interval in obese women.

METHODS

Forty-two obese women (Body mass index (BMI)=40+/-3 kg/m(2), mean age 45+/-9 years) and compared age-matched (BMI=22+/-1 kg/m(2), mean age 41+/-6 years) twenty-five non-obese women were included in our study. Maximum and minimum P-wave duration, P-wave dispersion (difference between the maximum and the minimum P-wave duration), maximum and minimum QTc interval, and QTc dispersion (the difference between the maximum and the minimum QTc interval) were measured from 12-lead ECG. ECG's were transferred to a personal computer via a scanner and then used for magnification of 400 times by Adobe Photoshop software.

RESULTS

There was significant difference in BMI (40+/-3 vs 22+/-1 kg/m(2), P<0.001, respectively) between obese and non-obese women. Obese women had higher Max. P-wave duration (116+/-11 vs 94+/-14 ms, P<0.001), P-wave dispersion (51+/-15 vs 26+/-11 ms, P<0.001), Max. QTc interval (449+/-38 vs 419+/-30 ms, P<0.001) and QTc dispersion (57+/-23 vs 38+/-15 ms, P<0.001) compared to non-obese women. A significant correlation was found between BMI and Max. P-wave duration (r=0.584, P<0.001), P-wave dispersion (r=0.621, P<0.001), Max. QTc interval (r=0.410, P<0.001), and QTc dispersion (r=0.429, P<0.001). In the linear regression analysis, compared to co-morbidity factors such as age, hypertension, diabetes mellitus and smoking, there was significant association between only BMI and electrocardiographic values (P-wave and QTc dispersion).

CONCLUSION

We concluded that obesity caused significant increase in P-wave and QTc dispersion. Therefore, obese women may not only be under the risk of ventricular arrhythmias, but also they may under the risk of atrial arrhythmias.

Lack of Correlation Between QTc Dispersion and Morning Blood Pressure Surge in Recently Diagnosed Essential Hypertensive Patients

BACKGROUND

Cardiovascular events are known to occur more frequently in patients with a high morning surge in blood pressure (BP), but the correlation between a morning BP surge and corrected QT dispersion (QTc) has not been confirmed to date.

METHODS AND RESULTS

The correlation between the morning BP surge and QTc was studied in 82 patients recently diagnosed with high BP (47 males, 35 females). Twenty-four-hours BP monitoring was conducted to classify patients into dipper (n=45) or nondipper (n=37) groups according to the degree of nocturnal BP reduction. QTc was found to be significantly longer in the nondippers compared with the dippers (36.1+/-17.2 vs 47.6+/-20.7, p<0.001). In addition, there was a significant increase in the end-diastolic interventricular septum thickness (IVSd), left ventricular posterior wall thickness in diastole (PWT) and left ventricular mass index (LVMI) in the nondippers vs the dippers (respectively, 0.93+/-0.09 vs 1.03+/-0.05, p<0.001, 0.94+/-0.09 vs 1.01+/-0.04, p<0.01, 109.7+/-12.8 vs 129.1+/-20.9, p<0.001). QTc had a significant positive correlation with nighttime BP, IVSd, PWT, and LVMI, but negatively correlated with the nocturnal BP reduction rate. These results were maintained even after adjusting for age and gender. However, a significant correlation between the morning BP surge and QTc was not confirmed.

CONCLUSION

In the present nondipper hypertensive patients, QTc, nighttime BP, LVMI, and wall thickness were significantly greater than in the dipper patients. However, there was no significant correlation between the morning BP surge and QTc.

Prolonged recovery time in the left precordial leads reflects increased left ventricular mass in the hypertensive patients

Hypertensive left ventricular hypertrophy (LVH) is considered to be a risk for arrhythmogenicity, but the quantification of the changes in T-wave morphology, as the reflection of repolarization abnormality, has not been fully established. The purpose of this study was to quantify the T-wave changes in the hypertensive patients and to investigate the relationship with the increased left ventricular mass. Standard 12-lead electrocardiogram and echocardiogram were recorded in 90 hypertensive patients. Activation time (AT), activation recovery interval (ARI), and recovery time (RT) were measured in the precordial lead and QT interval in the 12 leads. To compare the left precordial T-wave changes among patients, measurements of ARI and RT in the right precordial negative T wave were excluded. Each parameter excluding AT was corrected with Bazett formula, and then the dispersion was calculated. Left ventricular mass index was determined echocardiographically to select non-LVH group (n=31) and LVH group (n=59). In both groups, AT, ARI, and RT in the left precordial leads were larger compared with those in the right precordial leads. Dispersion of AT was not different between the 2 groups. However, the dispersion of ARI and RT in LVH group was significantly greater than that in non-LVH group. There were correlations between left ventricular mass index and the dispersion of RT (r=0.66, P<.001), ARI (r=0.61, P<.001), and 12-lead QT (r=0.42, P<.001). In patients with LVH, significant prolongation of RT in the left precordial leads was observed, suggesting that this RT change resulted from the nonuniformity of epicardial action potential duration.

Multivariate associates of QT interval parameters in diabetic patients with arterial hypertension: importance of left ventricular mass and geometric patterns

The aim of the study was to assess the determinants of increased QT interval parameters in diabetic patients with arterial hypertension and, in particular, the strength of their relationships to echocardiographically derived left ventricular mass (LVM) and geometric patterns. In a cross-sectional study with 289 hypertensive type 2 diabetic outpatients, maximal QT and QTc (heart rate-corrected) intervals, and QT, QTc, and number-of-leads-adjusted QT interval dispersions were manually measured from standard baseline 12-lead ECGs. Electrocardiographic criteria for left ventricular hypertrophy (LVH) were either Sokolow-Lyon or Cornell sex-specific voltages. LVM and geometric patterns were determined by 2D echocardiography. Statistical analyses involved bivariate tests (Mann-Whitney, chi2, Spearman's correlation coefficients, ANOVA and receiver-operating-characteristic (ROC) curve analyses) and multivariate tests (multiple linear and logistic regressions). QT dispersion measurements showed significant correlations with echocardiographic LVM (r=0.26-0.27). ROC curves demonstrated a poor isolated predictive performance of all QT parameters for detection of LVH (areas under curve: 0.58-0.59), comparable to that of electrocardiographic voltage criteria. Only patients with concentric hypertrophy had significantly increased QT dispersion (QTd) when compared to those with normal geometries (64.24+/-21.09 vs 53.20+/-15.35, P<0.05). In multivariate analyses, both electrocardiographic and echocardiographic LVH were independent predictors of increased QTd, as well as only QTd and gender were determinants of LVM. In conclusion, increased QT interval dispersion is associated with LVM and concentric hypertrophy geometric pattern in diabetic hypertensive patients, although in isolation neither QTd nor any QT parameter presents enough predictive performance to be recommended as screening procedures for detection of LVH.

Blood pressure and cardiac autonomic function in relation to risk factors and treatment perspectives in Type 1 diabetes

The cumulative incidence of diabetic nephropathy in Type 1 diabetes mellitus is in the order of 25 30%. The recognition that elevated blood pressure (BP) is a major factor in the progression of these patients to end-stage renal failure has led to the widespread use of antihypertensive therapy in order to preserve glomerular filtration rate and ultimately to reduce mortality. The routine measurement of microalbuminuria allows early identification of the subgroup of patients at increased risk of developing clinical nephropathy. Microalbuminuric Type 1 diabetic patients show a number of characteristic pathological abnormalities. In addition to elevated BP and abnormal circadian rhythm, there are also associated abnormalities of vagal function, lipid profile and endothelial function, as well as an increased prevalence of retinopathy. The first section of this two-part review focusses on the early changes associated with renal involvement in Type 1 diabetes. It addresses the associations between urinary albumin excretion, glycaemic control, smoking, BP, circadian BP variation, QT interval abnormalities and autonomic function in three groups of patients; those with normoalbuminuria, those progressing towards microalbuminuria and those with established low-grade microalbuminuria.

Lack of association between QT dispersion and blood pressure response during dental surgery

1. It is well known that dental surgery induces increases in blood pressure. However, the factors influencing this increase are not yet fully understood. We have determined the relationship between QTc (= QT/RR(1/2), with RR being the R-R interval in seconds) dispersion, measured with a 12-lead surface electrocardiogram, and changes in blood pressure during tooth extraction. 2. Both QTc dispersion and the power spectrum of R-R variability were determined before the dental surgery was undertaken. The low-frequency (LF; 0.041-0.140 Hz), high- frequency (HF; 0.140-0.500 Hz) and total spectral powers (TF; 0.000-4.000 Hz) were calculated and the ratio of LF to HF and the percentage of HF relative to TF (%HF; HF/TF x 100) were used as indices of sympathovagal balance and parasympathetic activities, respectively. 3. In the present study, QTc dispersion failed to correlate with LF/HF and %HF. Systolic blood pressure and pulse rate increased significantly during tooth extraction; however, changes in these variables failed to correlate with QTc dispersion. 4. These results suggest that QTc dispersion is not associated with the power spectrum of R-R variability and that it does not affect the blood pressure response during tooth extraction.

Increased QTc dispersion is related to blunted circadian blood pressure variation in normoalbuminuric type 1 diabetic patients

A reduced nocturnal fall in blood pressure (BP) and increased QT dispersion both predict an increased risk of cardiovascular events in diabetic as well as nondiabetic subjects. The relationship between these two parameters remains unclear. The role of diabetic autonomic neuropathy in both QT dispersion and circadian BP variation has been proposed, but data have been conflicting. The aim of the present study was to describe associations between QT dispersion and circadian BP variation as well as autonomic function in type 1 diabetic patients. In 106 normoalbuminuric (urinary albumin excretion <20 microg/min) normotensive patients, we performed 24-h ambulatory BP (Spacelabs 90207) and short-term (three times in 5 min) power spectral analysis of RR interval oscillations, as well as cardiovascular reflex tests (deep breathing test, postural heart rate, and BP response). No patient had received (or had earlier received) antihypertensive or other medical treatment apart from insulin. In a resting 12-lead electrocardiogram, the QT interval was measured by the tangent method in all leads with well-defined T-waves. The measurement was made by one observer blinded to other data. The QT interval was corrected for heart rate using Bazett's formula. The QTc dispersion was defined as the difference between the maximum and the minimum QTc interval in any of the 12 leads. When comparing patients with QTc dispersion below and above the median (43 ms), the latter had significantly higher night BP (114/67 vs. 109/62 mmHg, P < 0.003/P < 0.001), whereas day BP was comparable (129/81 vs. 127/79 mmHg). Diurnal BP variation was blunted in the group with QTc dispersion >43 ms with significantly higher night/day ratio, both for systolic (88.8 vs. 86.2%, P < 0.01) and diastolic (83.1 vs. 79.5%, P < 0.01) BP. The association between QTc dispersion and diastolic night BP persisted after controlling for potential confounders such as sex, age, duration of diabetes, urinary albumin excretion, and HbA1c. Power spectral analysis suggested an altered sympathovagal balance in patients with QTc dispersion above the median (ratio of low-frequency/high-frequency power: 1.0 vs. 0.85, P < 0.01). In normoalbuminuric type 1 diabetic patients, increased QTc dispersion is associated with reduced nocturnal fall in BP and an altered sympathovagal balance. This coexistence may be operative in the ability of these parameters to predict cardiovascular events.