Normal limits of the spatial QRS-T angle and ventricular gradient in 12-lead electrocardiograms of young adults: dependence on sex and heart rate

Background and purpose

Normal limits of the spatial QRS-T angle and spatial ventricular gradient (SVG) are only available from Frank vectorcardiograms (VCGs) of male subjects. We determined normal limits for these variables derived from standard 12-lead electrocardiograms (ECGs) of 660 male and female students aged 18 to 29 years.

Methods

A computer algorithm was used that constructed approximated VCG leads by inverse Dower matrix transformation of the 12-lead ECG and subsequently calculated the spatial QRS-T angle, SVG magnitude, and orientation.

Results

In female subjects, the QRS-T angle was more acute (females, 66° ± 23°; normal, 20°-116°; males, 80° ± 24°; normal, 30°-130°; P < .001), and the SVG magnitude was smaller (females, 81 ± 23 mV·ms; normal, 39-143 mV·ms; males, 110 ± 29 mV·ms; normal, 59-187 mV·ms; P < .001) than in male subjects. The male SVG magnitude in our study was larger than that computed in Frank VCGs (79 ± 28 mV·ms; P < .001).

Conclusions

The spatial QRS-T angle and SVG depend strongly on sex. Furthermore, normal limits of SVG derived from Frank VCGs differ markedly from those derived from VCGs synthesized from the standard ECG. As nowadays, VCGs are usually synthesized from the 12-lead ECG; normal limits derived from the standard ECG should preferably be used.     

Assessment of the Spatial QRS-T Angle by Vectorcardiography: Current Data and Perspectives

The concept of the ventricular gradient (VG) was conceived in the 1930s and its calculation yielded information that was not otherwise obtainable. The VG was not utilized by clinicians at large because it was not easy to understand and its computation time-consuming. Spatial vectorcardiography is based on the concept of the VG. Its current major clinical use is to identify primary [heterogeneity of ventricular action potential (VAP) morphology] in the presence of secondary [heterogeneity in ventricular depolarization instants] T-wave abnormalities in an ECG. Nowadays, the calculation of the spatial VG can be computed on the basis of a regular routine ECG and contributes to localization of arrhythmogenic areas in the heart by assessing overall and local VAP duration heterogeneity. Recent population-based studies suggest that the spatial VG is a dominant ECG predictor of future cardiovascular events and death and it is superior to more conventional ECG parameters. Its assessment warrants consideration for intensified primary and secondary prevention efforts and can be included in everyday clinical practice. This review addresses the nature and diagnostic potential of the spatial VG. The main focus is the role of the spatial VG in ECG assessment of dispersion of repolarization, a key factor in arrhythmogeneity.     

Influence of the vectorcardiogram synthesis matrix on the power of the electrocardiogram-derived spatial QRS-T angle to predict arrhythmias in patients with ischemic heart disease and systolic left ventricular dysfunction

Background and Purpose

Several studies have demonstrated that the spatial mean QRS-T angle (SA) predicts cardiac events and mortality. Spatial mean QRS-T angle is a vectorcardiographic variable. Because in clinical practice, 12-lead standard electrocardiograms (ECGs) are recorded rather than vectorcardiograms (VCGs) according to Frank, VCGs are commonly obtained by synthesizing them from 12-lead ECGs, by using a VCG synthesis matrix. Hence, the thus computed SA is an estimate of the real SA measured in the Frank VCG. Recent studies have shown that Kors VCG synthesis matrix yields better estimates of SA than the inverse Dower VCG synthesis matrix. Our current study aims to compare the predictive power of these SA variants for the occurrence of potentially lethal arrhythmias.

Methods

The study group consisted of patients with ischemic heart disease and left ventricular systolic dysfunction who received an implantable cardioverter-defibrillator (ICD) for primary prevention. During follow-up, the occurrence of appropriate device therapy (occurrence of ventricular arrhythmia) was noted. Alternative SAs were computed in VCGs synthesized from standard 12-lead ECGs by using either the inverse Dower matrix (SA-Dower) or the Kors matrix (SA-Kors). Comparison of the predictive power of SA-Dower and SA- Kors was performed by receiver operating characteristic analysis, by Kaplan-Meier analysis, and by univariate and multivariate Cox regression analysis, using every 10th percentile of SA as a cutoff value.

Results

The study group consisted of 412 patients (361 men; mean ± SD age 63 ± 11 years), in which 56 patients had appropriate ICD therapy during follow-up. Receiver operating characteristic analysis revealed that the area under the curve of SA-Kors was significantly larger than area under the curve of SA-Dower (0.646 vs 0.607, P = .043). The discriminative power of SA-Kors for the absence/presence of appropriate ICD therapy in patients during follow-up was generally superior to SA-Dower over a wide range of cutoff values in the Kaplan-Meier analysis and generally yielded stronger hazard ratios in the univariate and multivariate Cox regression analyses.

Conclusion

If there is no specific reason to use the inverse Dower matrix, VCG synthesis from standard 12-lead ECGs should preferably be done by using the Kors matrix. It is likely to assume that already published studies in which the predictive value of SA-Dower was demonstrated would yield stronger results if the SA-Dower angles were substituted by SA-Kors angles.     

体表心电图鉴别心室流出道特发性室性心动过速的起源部位

目的 :评价 12导联心电图在鉴别左室和右室流出道室性心动过速 (VT)及鉴别左室流出道VT中主动脉瓣上起源的VT和主动脉瓣下起源的VT中的价值。方法 :回顾性分析了射频消融术获得成功的 5 6例流出道特发性VT患者体表心电图特点 ,右室流出道VT组 (RVOT VT)组 4 0例 ,左室流出道VT(LVOT VT)组 16例 ,其中主动脉瓣上组 (左冠窦内 ) 10例 ,主动脉瓣下组 6例。结果 :LVOT VT组胸前导联R波移行均早于V4导联 ,87.5 %(14 / 16 )在V1或V2 导联 ,RVOT VT组 82 .5 % (33/ 4 0 )胸前导联R波移行≥V4导联 ,无一例在V3 导联前移行 ;RVOT VT组V1和V2 导联R波时限指数和R/S波幅指数明显小于LVOT VT组 [(30 .4± 12 .6 ) %∶(5 7.4± 14 .2 ) %和 (13.8± 7.5 ) %∶(5 8.2± 11.4 ) % ,均P <0 .0 1]。主动脉瓣上LVOT VT组下壁导联 (Ⅱ ,Ⅲ ,aVF)R波振幅明显高于主动脉瓣下组 ;V5和V6导联或单独V6导联有s波对确定主动脉瓣下起源的LVOT VT敏感性 10 0 % (6 / 6 ) ,V5和V6导联均无s波对确定主动脉瓣上起源的LVOT VT特异性 90 % (9/ 10 )。结论 :体表心电图对初步确定心室流出道VT的起源部位可以提供很大的帮助。     

Normal limits of the electrocardiogram in Nigerians

Background

There has been no large study of ECG measures derived by automated methods in an apparently healthy indigenous West African population.

Methods

ECGs were recorded from apparently healthy Nigerians and analysed using automated methods. Age and sex based normal ranges were then established.

Results

A total of 782 males and 479 females aged between 20 and 87 years were studied. Mean QRS duration in males was 87.9 ± 9.4 ms and 83.4 ± 7.6 ms in females (P < .0001). Mean QTc (Hodges) was 393 ± 16 ms in males and 406 ± 16 ms in females (P < .0001). The Cornell index (SV3 + RaVL) was higher in males and decreased with increasing age in males though the reverse was true in females (P < .0001). STj amplitude was lower in older compared to younger males and higher in males.

Conclusion

This is the first large study of automated ECG measurements from healthy blacks living in West Africa which allows the determination of ECG normal limits in such a population.     

平面QRS-T夹角对陈旧性心肌梗死患者心功能不全的评估价值

目的通过分析体表心电图平面QRS-T夹角,从而探索一种陈旧性心肌梗死(简称心梗)心功能不全的心电图评估方法。方法回顾性分析本院住院的陈旧性心梗患者,心电图机自测QRS波向量与T波向量,计算出平面QRS-T夹角,测量各患者的左室射血分数(LVEF),分析两者之间的联系。结果 1000例陈旧性心梗患者,平面QRS-T夹角为88.5±50.6°。平面QRS-T夹角与LVEF负相关(r=-0.406,P(0.01),LVEF越低,相关越密切。分别以平面QRS-T夹角(80°、(90°、(100°为界定点进行分析,其中平面QRS-T夹角(90°诊断心功能不全的灵敏度和特异度最强(76%,74%)。结论平面QRS-T夹角与陈旧性心梗患者的LVEF呈负相关。     

正常变异心电图ST段及T波改变与心向量图横面T环顺钟向运行的关系

目的了解正常变异心电图(ECG)ST段及T波(ST－T)改变与心向量图(VCG)横面T环顺钟向运行(顺转)的关系。方法对122例VCG横面T环顺转及可转向并有ECGST－T改变者进行4种状态下的ECG检测。结果VCG横面T环顺转及可转向者的ECGST－T改变,可通过口服普萘洛尔、变换体位或运动试验,使之恢复正常,与对照组相比,差异有非常显著性意义(P＜0.01)。结论ECGST－T改变通过矫正而恢复正常者,部分考虑与心脏发育欠成熟、心脏神经功能调节不良有关。VCG检查可帮助正常变异ECGST－T改变的诊断。     

The spatial QRS-T angle in the Frank vectorcardiogram: accuracy of estimates derived from the 12-lead electrocardiogram

Background and Purpose

The spatial QRS-T angle (SA), a predictor of sudden cardiac death, is a vectorcardiographic variable. Gold standard vertorcardiograms (VCGs) are recorded by using the Frank electrode positions. However, with the commonly available 12-lead ECG, VCGs must be synthesized by matrix multiplication (inverse Dower matrix/Kors matrix). Alternatively, Rautaharju proposed a method to calculate SA directly from the 12-lead ECG. Neither spatial angles computed by using the inverse Dower matrix (SA-D) nor by using the Kors matrix (SA-K) or by using Rautaharju's method (SA-R) have been validated with regard to the spatial angles as directly measured in the Frank VCG (SA-F). Our present study aimed to perform this essential validation.

Methods

We analyzed SAs in 1220 simultaneously recorded 12-lead ECGs and VCGs, in all data, in SA-F-based tertiles, and after stratification according to pathology or sex.

Results

Linear regression of SA-K, SA-D, and SA-R on SA-F yielded offsets of 0.01°, 20.3°, and 28.3° and slopes of 0.96, 0.86, and 0.79, respectively. The bias of SA-K with respect to SA-F (mean ± SD, −3.2° ± 13.9°) was significantly (P < .001) smaller than the bias of both SA-D and SA-R with respect to SA-F (8.0° ± 18.6° and 9.8° ± 24.6°, respectively); tertile analysis showed a much more homogeneous behavior of the bias in SA-K than of both the bias in SA-D and in SA-R. In pathologic ECGs, there was no significant bias in SA-K; bias in men and women did not differ.

Conclusion

SA-K resembled SA-F best. In general, when there is no specific reason either to synthesize VCGs with the inverse Dower matrix or to calculate the spatial QRS-T angle with Rautaharju's method, it seems prudent to use the Kors matrix.     

Predictive power of T-wave alternans and of ventricular gradient hysteresis for the occurrence of ventricular arrhythmias in primary prevention cardioverter-defibrillator patients

Background and purpose

Left ventricular ejection fraction lacks specificity to predict sudden cardiac death in heart failure. T-wave alternans (TWA; beat-to-beat T-wave instability, often measured during exercise) is deemed a promising noninvasive predictor of major cardiac arrhythmic event. Recently, it was demonstrated that TWA during recovery from exercise has additional predictive value. Another mechanism that potentially contributes to arrhythmogeneity is exercise-recovery hysteresis in action potential morphology distribution, which becomes apparent in the spatial ventricular gradient (SVG). In the current study, we investigated the performance of TWA amplitude (TWAA) during a complete exercise test and of exercise-recovery SVG hysteresis (SVGH) as predictors for lethal arrhythmias in a population of heart failure patients with cardioverter-defibrillators (ICDs) implanted for primary prevention.

Methods

We performed a case-control study with 34 primary prevention ICD patients, wherein 17 patients (cases) and 17 patients (controls) had no ventricular arrhythmia during follow-up. We computed, in electrocardiograms recorded during exercise tests, TWAA (maximum over the complete test) and the exercise-recovery hysteresis in the SVG. Statistical analyses were done by using the Student t test, Spearman rank correlation analysis, receiver operating characteristics analysis, and Kaplan-Meier analysis. Significant level was set at 5%.

Results

Both SVGH and TWAA differed significantly (P < .05) between cases (mean ± SD, SVGH: −18% ± 26%, TWAA: 80 ± 46 μV) and controls (SVGH: 5% ± 26%, TWAA: 49 ± 20 μV). Values of TWAA and SVGH showed no significant correlation in cases (r = −0.16, P = .56) and in controls (r = −0.28, P = .27). Receiver operating characteristics of SVGH (area under the curve = 0.734, P = .020) revealed that SVGH less than 14.8% discriminated cases and controls with 94.1% sensitivity and 41.2% specificity; hazard ratio was 3.34 (1.17-9.55). Receiver operating characteristics of TWA (area under the curve = 0.699, P = .048) revealed that TWAA greater than 32.5 μV discriminated cases and controls with 93.8% sensitivity and 23.5% specificity; hazard ratio was 2.07 (0.54-7.91).

Discussion and conclusion

Spatial ventricular gradient hysteresis bears predictive potential for arrhythmias in heart failure patients with an ICD for primary prevention, whereas TWA analysis seems to have lesser predictive value in our pilot group. Spatial ventricular gradient hysteresis is relatively robust for noise, and, as it rests on different electrophysiologic properties than TWA, it may convey additional information. Hence, joint analysis of TWA and SVGH may, possibly, improve the noninvasive identification of high-risk patients. Further research, in a large group of patients, is required and currently carried out by our group.     

右心室间隔部希氏束附近室性期前收缩心电图与射频消融

目的 报道右心室流入道间隔部希氏束附近起源室性期前收缩体表心电图特征及射频消融效果。方法 无器质性心脏病频发性室性期前收缩5例,分析其12导联体表心电图室性期前收缩特点;病人接受心内电生理检查,于右心室流入道行激动与起搏标测,以心室激动较体表QRS波提早、消融导管远端起搏图形与体表心电图室性期前收缩相似部位为消融靶点。结果 室性期前收缩QRS波形态：5例病人Ⅰ导联和Ⅱ导联QRS波均呈R型,Ⅲ导联、aVF导联以低振幅波为主,V1导联均呈QS型,胸导联较早转变成qR或R型（发生于V2或V3）,V5、V6均呈高R型;室性期前收缩QRS波时限为110～120ms。5例病人分别于前间隔（2例）、中间隔（1例）、后间隔（2例）标测到消融靶点,放电后前间隔部、后间隔部病人室性期前收缩均消失,中间隔病人消融失败。无房室传导阻滞并发症。随访8～30个月,成功病例未应用抗心律失常药物,无室性期前收缩发作。结论 右心室流入道间隔部希氏束附近起源室性期前收缩体表心电图具有明显的特征,认识这些特征有助于导管标测与射频消融,消融此部位室性期前收缩安全、有效。     

Normal values and reproducibility of left ventricular filling parameters by radionuclide angiography

Background. In physiologic situations age, heart rate (HR) and left ventricular ejection fraction (EF) may influence left ventricular filling rate. In this study, we determined normal values for radionuclide angiography (RNA) derived diastolic filling parameters, the correlations with age, HR and EF and their reproducibility. Methods. The study was performed in 20 patients, 40–76 years old (mean 57), with normal findings at coronary angiography and left ventriculography. The first RNA was performed at rest (RNA1). Then, five minutes bicycle ergometry was performed and the patients were allowed five minutes rest before RNA was repeated (RNA2). From the left ventricular time activity curve we determined peak filling rate (PFR), time to peak filling rate (TPFR) and atrial contribution (AC) to ventricular filling. Results. Values for PFR1 were 2.2 ± 0.6 EDV/sec (PFR2 2.4 ± 0.7 EDV/sec, r = 0.82), for TPFR1 198 ± 22 msec (TPFR2 203 ± 24 msec, r = 0.45) and for AC1 31 ± 11% (AC2 31 ± 10%, r = 0.72). The correlations of PFR and TPFR with age were statistically significant (respectively r = - 0.68 and r = 0.48, P < 0.05). PFR was also influenced by HR and EF (resp. r = 0.51 and r = 0.50, P < 0.05). TPFR however was not influenced by HR and EF, whereas AC was positively correlated with HR (r = 0.79, P < 0.01). Conclusions. Radionuclide angiography is a reliable and reproducible method to assess parameters of diastolic left ventricular filling in individual patients. It may therefore be used to serially follow diastolic function. When used for interindividual comparison the dependency of RNA derived left ventricular filling parameters on age, HR and EF should however be considered.     

Detection of elevated pulmonary pressures by the ECG-derived ventricular gradient: A comparison of conversion matrices in patients with suspected pulmonary hypertension

Background

The aim was to assess the diagnostic value of the Inverse Dower (INVD)-derived vectorcardiogram (VCG) and the Kors-derived VCG to detect elevated systolic pulmonary artery pressure (SPAP) in suspected pulmonary hypertension (PH).

Failure in short-term prediction of ventricular tachycardia and ventricular fibrillation from continuous electrocardiogram in intensive care unit patients

Background

Patients in the intensive care unit (ICU) setting are prone to malignant ventricular arrhythmias. We sought to test whether electrocardiographic (ECG) markers of autonomic tone, ventricular irritability, and repolarization lability could be used in short-term prediction of ventricular arrhythmias in this patient population.

Methods

We studied 38 patients with sustained (>30 seconds) monomorphic ventricular tachycardia, polymorphic ventricular tachycardia, or ventricular fibrillation while monitored in the ICU and 30 patients without arrhythmia in the ICU who served as controls. All patients had at least 12 hours of continuously recorded multilead ECG before arrhythmic event. Mean heart rate and measures of heart rate variability, QT variability, and ventricular ectopy were quantified in 1-hour epochs for the 12 hours before the arrhythmic event and in 5-minute epochs for the last hour preevent (and using a random termination time point in controls).

Results

A modest downward trend in QT variability and a rise in heart rate were observed hours before polymorphic ventricular tachycardia and ventricular fibrillation events, although no significant changes heralded monomorphic ventricular tachycardia and no changes in any parameter predicted imminent ventricular arrhythmia of any type. There were no significant differences in ECG parameters between arrhythmia patients and controls.

Conclusions

In ICU patients, sustained ventricular arrhythmias are not preceded by change in ECG measures of autonomic tone, repolarization variability, and ventricular ectopy. Short-term arrhythmia prediction may be difficult or impossible in this patient population based on ECG measures alone.     

体表心电图特征对特发性右心室流出道室性心动过速和室性早搏起源点的定位价值

目的 起源于右心室流出道(RVOT)不同位点的室性心动过速(VT)具有相应的心电图表现,本研究旨在摸索一种相对简单的根据体表心电图进行定位的方法 .方法 将RVOT分为游离壁和间隔而两大区,其中间隔面又分为9个区域.共320例RVOT-VT患者中,对213例既往消融成功患者的靶点与体表12导联心电图中QRS波形态之间的关系进行分析,并在消融前前瞻性地对另外107例患者的消融靶点进行预测,以检验其定位价值.结果 I导联对RVOT起源的VT有特殊的定位价值.在间隔面前部起源时,I导联以负向波为主,多为QS、Qr及rS型,随着起源点从前向后、从上向下,R波逐渐升高,其中起源于间隔侧中带(2、5、8区)时,以"M"型居多,在后壁时则表现为R波且有切迹.游离壁起源者的QRS时限明显延长,I和aVL导联的R波较间隔起源者高,而下壁导联的R波均较间隔的低(P<0.05).在前瞻性分析中,这些参数的敏感度、特异度、阳性和阴性预测值均较高.结论 RV-OT不同部位起源的VT有相应的心电图特征,其中I导联形态尤其具有定位价值,为RVOT心律失常起源提供了简便的定位标准.     

Value of the electrocardiogram in predicting left ventricular enlargement and dysfunction after myocardial infarction

To identify electrocardiographic predictors of left ventricular enlargement or persistent dysfunction following a myocardial infarction.Baseline and predischarge 12-lead electrocardiograms (ECGs) from 272 patients with anterior myocardial infarction who were enrolled in the Healing and Early Afterload Reducing Therapy trial were evaluated and related to echocardiographic data obtained at baseline and day 90. ST-segment elevation, QRS score, and number of negative T waves were assessed at both time points. The majority of patients (87%; n = 237) received reperfusion therapy. Multivariate models were used to adjust for potential confounders, including maximal creatine kinase level and ejection fraction at baseline.None of the baseline electrocardiographic variables independently predicted ventricular enlargement or recovery of function. In contrast, the sum of ST- and maximum ST-segment elevation, and the number of leads with ST-segment elevation > or =1 mm in the predischarge ECG, were independent predictors of ventricular enlargement from baseline to day 90. Each lead with ST-segment elevation > or =1 mm was associated with 3.5 mL of ventricular enlargement (95% confidence interval [CI]: 1.6 to 5.5 mL; P <0.0001). Similarly, the sum of ST-segment elevation (odds ratio [OR] = 0.78; 95% CI: 0.69 to 0.89; P <0.0001), the maximum ST-segment elevation (OR = 0.25; 95% CI: 0.13 to 0.45; P <0.0001), and the number of leads with ST-segment elevation > or =1 mm (OR = 0.58; 95% CI: 0.45 to 0.74; P <0.0001) were independently associated with a lower likelihood of recovery of function at day 90.Predischarge ECG may be a useful tool for early identification of patients at risk of ventricular enlargement and persistent dysfunction following myocardial infarction.     

Idiopathic ventricular arrhythmias originating from the tricuspid annulus: Prevalence, electrocardiographic characteristics, and results of radiofrequency catheter ablation

BACKGROUND: Idiopathic ventricular tachycardias (VTs) and premature ventricular contractions (PVCs) arising from the tricuspid annulus have been reported. OBJECTIVE: The purpose of this study was to clarify the prevalence and characteristics of VT/PVCs originating from the tricuspid annulus. METHODS: The ECG characteristics and results of radiofrequency (RF) catheter ablation were analyzed in 454 patients with idiopathic VT/PVCs. RESULTS: Thirty-eight (8%) patients had VT/PVCs arising from the tricuspid annulus: 28 VT/PVCs (74%) originated from the septal portion of the tricuspid annulus and the remaining 10 (26%) from the free wall of the tricuspid annulus. QRS duration and Q-wave amplitude in each of leads V1-V3 were greater in VT/PVCs arising from the free wall of the tricuspid annulus than those from the septum of the tricuspid annulus (all P < .01). "Notching" of the QRS complex was observed more often in VT/PVCs arising from the free wall of the tricuspid annulus than those from the septum of the tricuspid annulus (P < .01). A Q wave in lead V1 was observed more often in VT/PVCs arising from the septum of the tricuspid annulus than those from the free wall of the tricuspid annulus (P < .005). R-wave transition occurred beyond lead V3 more often in VT/PVCs arising from the free wall of the tricuspid annulus than those from the septum of the tricuspid annulus (P < .005). RF catheter ablation eliminated 90% of the VT/PVCs arising from the free wall of the tricuspid annulus but only 57% of the VT/PVCs arising from septum of the tricuspid annulus. CONCLUSION: Idiopathic VT/PVCs arising from tricuspid annulus are not rare, and the detailed origin can be determined by ECG analysis. The preferential site of origin was the septum but also could be the free wall of the tricuspid annulus.     

起源点邻近房室瓣环的特发性室性心律失常体表心电图特点及射频消融治疗

目的 评估起源点邻近房室瓣环附近的室性心动过速和室性早搏(室速/室早)的体表心电图特点及射频消融治疗效果.方法 共19例特发性室速/室早患者接受常规电生理检查及射频消融治疗,对所有病例12导联体表心电图进行分析.结果 19例室速/室早术中均消融成功.10例起源于二尖瓣环附近,包括前侧壁(5例)、后侧壁(3例)、后间隔(2例).9例起源于三尖瓣环附近,包括游离壁侧5例、间隔侧4例.对各组瓣环室速/室早心电图做进一步分析,可概括出系列心电图判断指标用以估计消融靶点的部位.结论 起源点邻近房窜瓣环附近的室速/窒早是特发件室速/室早的一个亚组,射频消融治疗可取得良好效果,掌握其体表心电图特点有助于判定室速/室早的起源部位.     

新疆和田地区775例维吾尔族老年人心电图明尼苏达编码分析

目的 观察维吾尔族老人心电图异常编码的分布及其相关特点。方法 采用ＷＨＯ推荐的明尼苏达心电图编码分类法,对新疆和田地区非选择性的连续检查了７７５例维吾尔族老年人的静息状态心电图并行编码分析。结果 Ｑ／ＱＳ型检出率为４．８％,电轴左偏在－３以左为９．９％,左室最检出率为１８．１％,ＳＴ－Ｔ改变为１４．５％,束支传导阻滞为１０．７％,心律失常检出率为１１．１％,心电图符合冠心病和可颖冠心病的占１５．