Electrocardiographic Variables Research Articles

Effect Of Levothyroxine Treatment On Qt Dispersion In Patients With Subclinical Hypothyroidism

To examine the effect of levothyroxine treatment in patients with subclinical hypothyroidism on electrocardiographic variables, especially on ventricular repolarization-related factors. Sixteen women (mean age, 48.2 years) with subclinical hypothyroidism were treated with levothyroxine for 16 weeks. All standard 12-lead electrocardiographic recordings were scanned and transferred to a computer, and the QT intervals were measured on 300 times magnified recordings. QT dispersion, which reflects the heterogeneity of the ventricular repolarization, was calculated by the difference between the QT maximum and the QT minimum. We found that, after 16 weeks of levothyroxine treatment, the QT interval decreased from 387.2 +/- 10.8 ms to 345.6 +/- 13.0 ms (P<0.0001). The study patients exhibited a significant reduction of QT dispersion from 46.5 +/- 5.3 ms to 30.7 +/- 5.8 ms (P<0.0001). On linear regression analysis, a positive relationship was found between QT dispersion and logarithmic serum TSH levels (r = 0.492; P<0.0001). We conclude that serum TSH concentration has a role in ventricular inhomogeneity and, therefore, that subclinical hypothyroidism may predispose to ventricular arrhythmias. A large-scale, multicenter, randomized trial should be undertaken to address the benefit-to-risk ratio of levothyroxine treatment on cardiac inhomogeneity in patients with subclinical hypothyroidism.

Abstract 744: Arrhythmogenesis in Heart Failure: Role of Interstitial Fibrosis

Background: Sudden cardiac death due to ventricular tachyarrhythmia (VT) accounts for a large number of deaths in patients with heart failure. Several cellular events which occur during pathological remodeling of the failing ventricle are implicated in the genesis of VT, including action potential prolongation, dysregulation of intercellular coupling, and fibrosis. Interestingly, transgenic mice over-expressing constitutively active PKD (caPKD) develop severe heart failure without interstitial fibrosis, an otherwise prominent feature of the disease. The goal here was to define the role of interstitial fibrosis in the proarrhythmic phenotype of failing myocardium. Methods and Results: We performed echocardiographic, electrocardiographic, and in vivo electrophysiologic studies in 8 –10 week old caPKD mice (n=12). Similar studies were performed in mice with load-induced heart failure induced by surgical pressure overload (sTAB, n=10), a model of heart failure with prominent interstitial fibrosis. caPKD and sTAB mice showed similar degrees of ventricular dilation (LV systolic dimension caPKD 2.4±0.8 mm vs 3.0±0.9 sTAB, p=0.18) and severe systolic dysfunction (% fractional shortening caPKD 25±11 vs 28±11 sTAB, p=0.62). Yet, caPKD mice showed minimal interstitial fibrosis, comparable to unoperated controls. With the exception of ventricular refractory period, which was higher in caPKD (48±11 msec vs 36±7 TAB and 40±8 WT, p&lt;0.05), other electrocardiographic and electrophysiologic variables were similar among the 3 groups (p=NS), including heart rate, QT duration, and mean VT threshold. As expected, VT (≥3beats) was readily inducible by programmed stimulation in sTAB mice (7/10). By contrast, VT was less inducible in caPKD mice (4/12; p=0.1 vs TAB and &lt;0.05 vs WT), and uninducible in unoperated controls (0/12). VT was polymorphic in both models, but episodes of VT were both slower (VT cycle length caPKD 58±4.0 msec vs 48±1 sTAB, p=0.016) and longer in caPKD mice (caPKD 1.8±0.7 sec vs 0.47±0.3 sTAB, p=0.038). Conclusion: Interstitial fibrosis contributes to the inducibility, maintenance, and rate of VT in heart failure. These findings highlight the importance of anti-remodeling therapies known to target fibrosis in heart disease.

Electrocardiographic markers of structural heart disease and predictors of death in 2332 unselected patients undergoing outpatient Holter recording

To test the hypothesis that the QS interval of ventricular ectopic beats (VEBs) (ventricular ectopic QS interval, VEQSI) would provide a marker for the presence of structural heart disease and a predictor of mortality. We interviewed and examined 2332 patients undergoing Holter ECG monitoring for clinical indications. In persons with VEBs, the morphologies were counted and the QS interval was measured for each of these morphologies. The duration of the broadest VEB, measured from the QRS onset in the derivation showing the earliest onset to its end in the derivation showing the latest termination, was taken as that patient's VEQSI. Survival was ascertained from public health records. Of 15 electrocardiographic variables pre-selected as potential prognostic indicators, VEQSI demonstrated the strongest association with the presence of structural heart disease (P = 0.013). Thirty-four persons died in 16 +/- 4 months follow-up. Univariate predictors of mortality are age, history of myocardial infarction, maximum heart rate, QS interval, the number of VEB morphologies, and the VEQSI. On multivariate analysis, only age (P < 0.001) and the number of VEB morphologies (P = 0.02) predicted mortality. VEQSI predicts the presence of structural heart disease. The number of VEB morphologies in a Holter recording predicts all-cause mortality.

Single-Lead Electrocardiographic Variables in the Detection of Prior Myocardial Infarction with Respect to Q-Wave Status and Infarct Age

Objectives: Conventionally, the detection of prior myocardial infarction (MI) is based on QRS abnormalities, which may ignore non-Q-wave MI (NQMI). We aimed at finding automatically applicable quantitative ECG variables for diagnosing prior MI. Methods: Body surface potential mapping (BSPM) was registered and automatically analyzed in 144 patients with prior MI and in 75 healthy controls. The MI was defined according to its age as recent or old, and Q-wave status as Q-wave MI (QMI) or NQMI. Results: The QRSSTT integral, the STT integral and the T-wave apex amplitude applied in single, selected leads were found to be the optimal parameters in the detection of prior MI. The areas under the receiver-operating characteristic curves (AUC) were 89% for each, and detection was equal in old and recent MI (AUCs from 87 to 90%), and in QMI and NQMI (AUCs from 88 to 90%). Conclusions: The quantitative, automatically applicable single-lead variables comprising ventricular repolarization was effective in detecting prior MI, irrespective of the time elapsed from MI or the Q-wave status. These variables could be suitable for population studies and health screening purposes and are applicable to automatic ECG diagnostics of prior MI.

Role of Left Atrial Size in Risk Stratification and Prognosis of Patients Undergoing Stress Echocardiography

The purpose of this study was to evaluate the role of diastolic dysfunction as measured by left atrial (LA) size in patients undergoing stress echocardiography (SE). Left atrial size is a surrogate marker of diastolic function. However, its prognostic value in patients referred for SE is not well defined. We evaluated 2,705 patients (60 +/- 13 years, 47% men) undergoing SE (56% dobutamine). Patients with significant mitral valve disease (mitral stenosis or > or = moderate mitral regurgitation) were excluded. Enlarged LA was defined as a LA size indexed to body surface area > or =2.4 cm/m2. Follow-up (mean 2.7 +/- 1.0 years) for nonfatal myocardial infarction or cardiac death (n = 122) was obtained. A dilated LA was able to further risk-stratify both the normal and abnormal SE groups. In the presence of a dilated LA, an abnormal SE portends a worse prognosis compared with patients with normal LA size. Cox proportional modeling showed that a dilated LA added incremental value over traditional risk factors, stress electrocardiographic, rest echocardiographic, and SE variables for the prediction of hard events (global chi-square increased from 90.4 to 113.1 to 176.1 to 184.4 to 190.5; p < 0.05 all groups). Left atrial size was a significant predictor of events independent of left ventricular systolic dysfunction and ischemia (relative risk = 1.84, 95% confidence interval 1.19 to 2.85; p = 0.006). In patients referred for stress echocardiography, LA size provides independent and incremental value over standard risk factors including left ventricular systolic dysfunction and ischemia. Left atrial size is a powerful prognosticator and should be routinely used in the prognostic interpretation of stress echocardiography.

Electrocardiographic Predictors of New-Onset Heart Failure in Men and in Women Free of Coronary Heart Disease (from the Atherosclerosis in Communities [ARIC] Study)

We compared the prognostic value of 12 electrocardiographic (ECG) variables in predicting risk of new-onset heart failure (HF) in a subgroup of 13,555 participants of the Atherosclerosis Risk in Communities (ARIC) study who were considered free of coronary heart disease at the onset of the study. Cox proportional hazards models were used to evaluate risk of HF for the highest decile of the distribution of each ECG variable (lowest decile for ST and T amplitudes in lead V(5)), with the remaining deciles as reference groups. Risk models were adjusted for demographic and clinical variables. In univariate Cox regression models, in men 11 and in women 8 of the 12 ECG variables were significant, strong predictors of risk of new-onset HF. Subsequently, 8 ECG variables with low mutual correlations were entered simultaneously into a multivariate Cox regression model. In men, large left ventricular mass by electrocardiogram, QT prolongation, and increased heart rate were the strongest independent predictors of new-onset HF, each with a twofold increased risk. Other independent predictors in men were ST depression in lead V(5), wide QRS/T angle, and old (silent) myocardial infarction, each with a >50% increased risk of incident HF. In women, QRS nondipolar voltage was associated with an 87% increased risk of incident HF, and other independent predictors, as in men, were wide QRS/T angle and increased heart rate. In conclusion, several ECG abnormalities are manifestations of evolving HF in men and women considered free of coronary heart disease.

Effects of echinacea on electrocardiographic and blood pressure measurements

The effects of Echinacea purpurea on electrocardiographic and blood pressure measurements in healthy volunteers were evaluated. Healthy volunteers were randomized to receive a single 350-mg dose of E. purpurea or placebo in a crossover fashion with a seven-day washout period between treatment phases. Twelve-lead electrocardiograms were acquired, and systolic and diastolic blood pressure measurements were taken immediately before (baseline) and at one, three, five, and eight hours after ingestion of the study drug. Electrocardiographic variables (P wave and QRS complex duration and PR, Q-T, Q-Tc, and RR intervals) were measured in lead II by one blinded study investigator. Duplicate blood pressure determinations were taken manually at each time point and then averaged. The maximum posttreatment values, irrespective of time point, for each electrocardiographic and blood pressure measurement were compared between groups. Of the 17 healthy adults initially screened for this study, 16 completed both phases. There was no difference in maximum posttreatment electrocardiographic or blood pressure (systolic or diastolic) variables noted between groups. Mild headache was reported by one patient receiving echinacea and one receiving placebo. One participant receiving echinacea experienced shortness of breath five hours posttreatment and mild flu-like symptoms after eight hours; symptoms completely resolved over the next several days. A single 350-mg dose of E. purpurea had no effect on electrocardiographic and blood pressure measurements of healthy volunteers.

Surface electrocardiography and biochemichal variables in patients with coronary artery disease: The ugly face of microalbuminuria

In their well designed longitudinal study, Yue et al. attempted to explore the relationship between ECG and biochemichal markers in patients with coronary artery disease (CAD) [ [1] Yue W. Schneider A. Ruckerl R. et al. Relationship between electrocardiographic and biochemical variables in coronary artery disease. Int J Cardiol. 2007; 119: 185-191 Abstract Full Text Full Text PDF PubMed Scopus (19) Google Scholar ]. They found a significant association between ECG parameters reflecting abnormal repolarization and elevated levels of C-reactive protein (CRP) and fibrinogen. Also, abnormal heart rate variability was associated with increased concentrations of soluble E-selectin. However they found no association between ECG markers and parameters reflecting increased procoagulation states.

Change in Atrial Flutter Wave Morphology—Insight into the Sources of Electrocardiographic Variants in Common Atrial Flutter

Whether the activation sequence of the right or left atrium plays a role in the morphology of the flutter wave in common atrial flutter is not completely understood. We present two patients with common counterclockwise atrial flutter in whom changes in the left atrial activation sequence produced significant changes in flutter wave polarity (+ to - and - to -/+ biphasic) without a change in the activation sequence within the right atrium. These cases highlight the possible role of alterations of the interatrial connections in the genesis of atypical manifestations of common atrial flutter.

Comparison of the Prognostic Significance of the Electrocardiographic QRS/T Angles in Predicting Incident Coronary Heart Disease and Total Mortality (from the Atherosclerosis Risk In Communities Study)

Spatial QRS/T angle and spatial T-wave axis were shown to be strong independent predictors of incident coronary heart disease (CHD) and total mortality, but they are not routinely available. We evaluated whether frontal plane QRS/T angle, easily obtained as the difference between frontal plane axes of QRS and T, provides a suitable substitute for spatial QRS/T angle as a risk predictor. Our study consisted of 13,973 participants from the ARIC Study. Outcome variables were incident CHD and total mortality during a median follow-up of 14 years. Electrocardiographic variables were categorized as abnormal (>/=95th percentile), borderline (>/=75th and <95th percentile), and normal (<75th percentile) separately for men and women. Cox regression was used to assess the effect of electrocardiographic variables on risk of each outcome. The normal category was considered the reference cell. With adjustment for demographic and clinical characteristics, both QRS/T angles were approximately equally strong predictors of total mortality with >50% increased risk. Spatial QRS/T angle was a stronger predictor of incident CHD in women, with a 114% increased risk, but it was not significantly associated with risk of incident CHD in men. Similarly, frontal plane QRS/T angle was statistically significant for only women with a 74% increased risk of incident CHD. In conclusion, frontal plane QRS/T angle as an easily derived risk measure is a suitable clinical substitute for spatial QRS/T angle for risk prediction.

The normal electrocardiogram of four species of conscious raptors

The aim of this study was to describe normal ECG patterns and values in four species of conscious raptors (Eurasian kestrel, Griffon vulture, Little owl, and Eurasian Eagle owl). Electrocardiograms were carried out in 75 conscious birds belonging to four species of raptors. Lead II waveforms were analysed to determine amplitudes and durations of waves and intervals. Morphologic patterns of P-QRS-T deflections were analysed in the six limb leads. Rhythm, heart rate, mean electrical axis, presence of Ta wave, ST slurring, and P-on-T phenomenon were also studied. The influence of species, body weight and heart rate in electrocardiographic variables were statistically analysed ( P < 0.05). Sinus rhythm was present in all tracings, showing sinus arrhythmia in four cases. Ta wave was present in six tracings and P-on-T phenomenon in four. ST segment could be identified in all tracings, being mainly high above baseline. Significant differences between species were found for all the electrocardiographic parameters. The heart rate and body weight were also found to be a significant influence in most parameters. This study provides electrocardiographic data for four species of raptors that can be used to establish comparisons for clinical purposes.

Localization of prior myocardial infarction by repolarization variables

Background To find quantitative, automatically applicable electrocardiographic (ECG) variables for detecting prior myocardial infarction (MI) in different myocardial regions. Methods Observational study. Body surface potential mapping (BSPM) was recorded at rest, and automatically analyzed with regard to ECG parameters, blinded to the clinical characteristics of the study subjects, 144 patients with prior MI and 75 healthy controls. MI location was determined by cine angiography or echocardiography as anterior (66 patients), inferoposterior (89 patients), and lateral (15 patients). Patients' 12-lead ECG was interpreted according to Minnesota code (Q-wave MI in 97 patients). The QRSSTT, QRS, and STT integrals, and the T-apex amplitude in detecting prior anterior and inferoposterior MI were analyzed. Results The T-apex amplitude, QRSSTT integral, and STT integral were functional in detecting MI in all tested locations on a single-lead basis, with areas under receiver operating characteristic curves (AUC) of over 90% ( p < 0.001) in optimal sites. In the best leads AUC for the QRSSTT integral in anterior MI was 93% (CI 87–99%) and for the inferoposterior MI 92% (CI 88–97%). These repolarization variables outperformed the Minnesota code in all tested MI locations. They were also able to distinguish between anterior and inferoposterior MI with an AUC of > 85% ( p < 0.001). Conclusions Quantitative, automatically applicable single-lead repolarization variables detect prior MI irrespective of its location. They may simplify the screening for and localization of old infarctions as compared to the conventional ECG methods.

Cross‐sectional study of electrocardiographic pattern in healthy children resident at high altitude

Electrocardiographic studies have reported persistent right ventricle predominance in high altitude children as an adaptive response. No information was provided on ethnicity and environmental factors in those studies. We assessed the electrocardiographic characteristics in healthy high altitude children with mixed ancestry and relatively high mobility to lower altitudes. A cross-sectional study of 321 children aged 2 months through 19 years old and living at high altitude (Tintaya, Peru, 4,100 m) was conducted. Standard 12-lead electrocardiography was performed. Information was obtained on ethnicity, medical history, place and altitude of pregnancy and birth, mobility of children and their parents and grandparents to lower altitudes, and housing conditions. A medical examination, echocardiography, hemoglobin, oxygen saturation, and anthropometric measurements were performed. Means between sexes were compared through Mann-Whitney test for independent samples not normally distributed. Potentially influential variables on electrocardiographic values were controlled through a general linear model. Electrocardiographic parameters including QRS axis, RV1, RSV1, RV1SV5, RSV5, RSV6, and SV1RV5 did not show a right predominance pattern at any age. Values were within sea level norms. None of the genetic or environmental factors controlled showed a consistent influence on the electrocardiographic variables. Our study showed an electrocardiographic pattern similar to that of sea level in high altitude children with some degree of high-altitude ancestry, comparatively well-nourished and with relatively high mobility to low altitudes.

Risk Stratification Using Stress Echocardiography: Incremental Prognostic Value over Historic, Clinical, and Stress Electrocardiographic Variables Across a Wide Spectrum of Bayesian Pretest Probabilities for Coronary Artery Disease

We sought to evaluate the risk stratification ability and incremental prognostic value of stress echocardiography over historic, clinical, and stress electrocardiographic (ECG) variables, over a wide spectrum of bayesian pretest probabilities of coronary artery disease (CAD). Stress echocardiography is an established technique for the diagnosis of CAD. However, data on incremental prognostic value of stress echocardiography over historic, clinical, and stress ECG variables in patients with known or suggested CAD is limited. We evaluated 3259 patients (60 +/- 13 years, 48% men) undergoing stress echocardiography. Patients were grouped into low (<15%), intermediate (15-85%), and high (>85%) pretest CAD likelihood subgroups using standard software. The historical, clinical, stress ECG, and stress echocardiographic variables were recorded for the entire cohort. Follow-up (2.7 +/- 1.1 years) for confirmed myocardial infarction (n = 66) and cardiac death (n = 105) was obtained. For the entire cohort, an ischemic stress echocardiography study confers a 5.0 times higher cardiac event rate than the normal stress echocardiography group (4.0% vs 0.8%/y, P < .0001). Furthermore, Cox proportional hazard regression model showed incremental prognostic value of stress echocardiography variables over historic, clinical, and stress ECG variables across all pretest probability subgroups (global chi2 increased from 5.1 to 8.5 to 20.1 in the low pretest group, P = .44 and P = .01; from 20.9 to 28.2 to 116 in the intermediate pretest group, P = .47 and P < .0001; and from 17.5 to 36.6 to 61.4 in the high pretest group, P < .0001 for both groups). A normal stress echocardiography portends a benign prognosis (<1% event rate/y) in all pretest probability subgroups and even in patients with high pretest probability and yields incremental prognostic value over historic, clinical, and stress ECG variables across all pretest probability subgroups. The best incremental value is, however, in the intermediate pretest probability subgroup.

Electrocardiographic and Hemodynamic Effects of Coenzyme Q10 in Healthy Individuals: A Double-Blind, Randomized Controlled Trial

Coenzyme Q10 (CoQ10) is an endogenous cofactor required for mitochondrial energy production and touted to treat heart failure and prevent statin-induced myopathy. In guinea pig ventricular myocytes, CoQ10 prolongs action potential duration, an effect that might prolong the QTc interval in humans. Additionally, CoQ10 reduced blood pressure in patients with essential hypertension. To determine the electrocardiographic (ECG) and hemodynamic impact of CoQ10 in healthy individuals. Healthy volunteers (N = 26; 62% male, age 24 +/- 3 y) were randomized to receive a single dose of CoQ10 50 mg and matching placebo in a crossover fashion with a 7 day washout period between treatments. Twelve-lead ECGs, systolic and diastolic blood pressure, and other hemodynamic parameters (cardiac index and systemic vascular resistance index) were evaluated immediately before (baseline) and 1, 3, 5, and 8 hours after ingestion of the study drug. ECG parameters (P wave and QRS complex duration; PR, QT, QTc, and RR intervals) were measured in lead II by one blinded investigator. For each time point, duplicate blood pressure levels were taken manually and then averaged. Hemodynamic parameters were measured using bioelectrical impedance cardiography. CoQ10 had no effect on any of the evaluated ECG parameters. The maximum postdosing systolic blood pressure showed a statistically significant increase with CoQ10 (117 +/- 10 vs 119 +/- 10 mm Hg; p = 0.037), an effect driven by increases in cardiac index (3.09 vs 2.95 L/min/m(2); p = 0.017). However, blood pressure elevation was most evident at the 5 hour timepoint (116 +/- 10 vs 113 +/- 11 mm Hg; p = 0.049) and was only transient. There were no differences between groups for maximum postdosing diastolic blood pressure. One dose of CoQ10 does not have any effect on ECG variables and exhibits only mild and transient effect on systolic blood pressure in young, healthy people.

Can Submaximal Exercise Variables Predict Peak Exercise Performance in Women with Chronic Fatigue Syndrome?

This study aimed at examining whether physiological exercise variables at the submaximal level, defined as 75% of the age-predicted target heart rate, are able to predict peak exercise performance in women with chronic fatigue syndrome (CFS) (n=222). Subjects performed a bicycle ergometric test against a graded increase in workload until exhaustion with continuous monitoring of electrocardiographic and ventilatory variables. Oxygen uptake at the submaximal level (VO2SUBMAX) correlated strongly with peak oxygen uptake (VO2PEAK) (r=0.70). For the prediction of VO2PEAK, linear regression analysis determined the line of best fit as: VO2PEAK=0.95xVO2SUBMAX+372.3. Using this equation, the mean error in the prediction was 14.6+/-11.2% (range 0.1-63.7%). It is concluded that the prediction of VO2PEAK based on VO2SUBMAX might be useful for analyzing group differences or treatment effects but not for individual (clinical) purposes.

Genome-wide association study of electrocardiographic and heart rate variability traits: the Framingham Heart Study.

BackgroundHeritable electrocardiographic (ECG) and heart rate variability (HRV) measures, reflecting pacemaking, conduction, repolarization and autonomic function in the heart have been associated with risks for cardiac arrhythmias. Whereas several rare monogenic conditions with extreme phenotypes have been noted, few common genetic factors contributing to interindividual variability in ECG and HRV measures have been identified. We report the results of a community-based genomewide association study of six ECG and HRV intermediate traits.MethodsGenotyping using Affymetrix 100K GeneChip was conducted on 1345 related Framingham Heart Study Original and Offspring cohort participants. We analyzed 1175 Original and Offspring participants with ECG data (mean age 52 years, 52% women) and 548 Offspring participants with HRV data (mean age 48 years, 51% women), in relation to 70,987 SNPs with minor allele frequency ≥ 0.10, call rate ≥ 80%, Hardy-Weinberg p-value ≥ 0.001. We used generalized estimating equations to test association of SNP alleles with multivariable-adjusted residuals for QT, RR, and PR intervals, the ratio of low frequency to high frequency power (LF/HFP), total power (TP) and the standard deviation of normal RR intervals (SDNN).ResultsAssociations at p < 10-3 were found for 117 (QT), 105 (RR), 111 (PR), 102 (LF/HF), 121 (TP), and 102 (SDNN) SNPs. Several common variants in NOS1AP (4 SNPs with p-values < 10-3; lowest p-value, rs6683968, p = 1 × 10-4) were associated with adjusted QT residuals, consistent with our previously reported finding for NOS1AP in an unrelated sample of FHS Offspring and other cohorts. All results are publicly available at NCBI's dbGaP at .ConclusionIn the community-based Framingham Heart Study none of the ECG and HRV results individually attained genomewide significance. However, the presence of bona fide QT-associated SNPs among the top 117 results for QT duration supports the importance of efforts to validate top results from the reported scans. Finding genetic variants associated with ECG and HRV quantitative traits may identify novel genes and pathways implicated in arrhythmogenesis and allow for improved recognition of individuals at high risk for arrhythmias in the general population.

Clinical Characteristics and Prognostic Factors of Patients with Severe Pulmonary Hypertension

Background and Objectives:The aim of this study was to investigate the clinical characteristics and predictors of the prognosis for patients with severe pulmonary hypertension (PHT). Subjects and Methods:A total of 169 patients with severe PHT (systolic pulmonary arterial pressure ≥70 mmHg by Doppler echocardiogram) were divided into two groups according to the mortality during 2.8±2.2 year clinical follow-up period: group I (moribund group, 34 patients, 60.0±15.7 years, 18 males) and group II (survived group, 135 patients, 57.2±16.9 years, 65 males). The clinical, electrocardiographic and echocardiographic variables were analyzed. Results:The three most common etiologies were valvular heart disease (VHD)(n=55: 32.9%), pulmonary thromboembolism (n= 29: 17.2%) and ischemic cardiomyopathy (n=17: 10.1%). The common presenting clinical symptoms were dyspnea on exertion, leg edema, cough and chest discomfort. Among the variables, the WHO functional classification at presentation [95% confidence interval (CI) 2.065-221.168, p=0.010], atrial fibrillation (AF)(95% CI 1.01410.161, p=0.041) and the left ventricular ejection fraction (LVEF)(95% CI 1.011-4.545, p=0.047) were significantly associated with the prognosis. Conclusion:VHD was the most common cause of severe PHT. The WHO functional classification at presentation, the presence of AF and low LVEF at presentation were the significant predictors of mortality for patients with severe PHT. (Korean Circulation J 2007;37:265-270)

Relationship between electrocardiographic and biochemical variables in coronary artery disease

Background ECG (electrocardiogram) markers reflecting abnormal heart rate variability and abnormal repolarization as well as several biochemical markers reflecting inflammation, endothelial dysfunction, and procoagulation states were reported to show an association with increased cardiovascular mortality. ECG and biochemical markers could operate independently or they could interrelate in pathogenetic pathways of coronary disease. In this study, we aimed to explore the relationship between ECG and biochemical markers in a longitudinal study of coronary patients. Methods A total of 499 observations from 52 patients with up to 12 repeated measurements were collected providing data on series of ECG (heart rate variability and repolarization) parameters and biochemical parameters. Generalized estimating equation models adjusting for repeated measurements were used for the analyses. Results There was a significant association between ECG parameters reflecting abnormal repolarization (prolonged QT interval, lower T wave amplitude) and elevated levels of C-reactive protein and fibrinogen. Abnormal heart rate variability, increased sympathetic tone (low-frequency power) was associated with increased concentrations of soluble E-selectin, a marker of endothelial cell activation. There was no association between ECG markers and parameters reflecting increased procoagulation states. Conclusion These results indicate that there is an association between ECG parameters and blood markers reflecting endothelial function and inflammation in coronary artery disease patients. The pathophysiologic mechanisms of these associations remain to be elucidated.

Evolução da onda P do eletrocardiograma após valvoplastia mitral em pacientes portadores de sobrecarga atrial esquerda

To investigate potential clinical, echocardiographic and/or hemodynamic predictors of the regression of electrocardiographic (ECG) signs of left atrial enlargement (LAE) after successful percutaneous mitral valvuloplasty (PMV).We studied 24 patients (75% female, mean age =37.1 +/- 11.9 years) with moderate to severe mitral stenosis (MS), sinus rhythm (SR) and ECG signs of LAE who underwent successful PMV between 2002 and 2004. At least 6 months after the procedure (388.2 +/- 192.9 days), the patients returned for clinical, ECG and echocardiographic follow-up. They were then divided in 2 groups: patients of group 1 (n = 8; 33.3%) still had ECG signs of LAE, and patients of group 2 (n = 16; 66.6%), had normal P wave. A multivariate analysis of clinical, ECG, echocardiographic and hemodynamic variables was performed.The mitral valve area (MVA) increased from 1.12 +/- 0.15 cm2 to 1.9 +/- 0.35 cm2 immediately after the procedure (p < 0.0001) and decreased to 1.89 +/- 0.41 cm2 at follow-up (p = NS). Left atrium diameter decreased from 48 +/- 2.9 mm pre-procedure to 43 +/- 4.8 mm at follow-up (p = 0.0001). P-wave duration decreased from 0.12 +/- 0.01 sec pre-PMV to 0.09 +/- 0.02 sec at follow-up (p = 0.0001). An MVA > or = 1.7 cm2 at follow-up was the only independent predictor of a normal P-wave after PMV (p=0.02).ECG changes suggestive of LAE regress in the majority of patients with MS and sinus rhythm that undergo a successful PMV. An MVA > or = 1.7 cm2 at late follow-up was found to be an independent predictor of such normalization.