The electrocardiographic changes in myocardial ischemia

Ligature of the ramus descendens of the left coronary artery in acute experiments on dogs caused no characteristic R-T deviations of the electrocardiogram provided the cardiac mechanism remained normal. However, a further impairment in the heart's blood supply induced by ligation of the inferior vena cava for five minutes, produced typical R-T deviations as seen in recent clinical coronary thrombosis, with a return to normal after the venous obstruction was removed.The appearance of a disturbance in the cardiac mechanism (extrasystoles and tachycardias) following coronary ligation alone produced R-T deviations.These experiments suggest that R-T deviation is a manifestation of myocardial ischemia in the production of which coronary occlusion is one factor.     

阵发性房颤患者心电图P波变化分析

目的分析阵发性心房颤动（PAF）患者心电图P波的变化。方法选择100例无器质性心脏病阵发性房颤患者（PAF组）,100例无房颤患者作为对照组（无PAF组）,采用体表心电图和超声心动图分别测量两组的V1导联P波时限（Pt）、V1导联P波终末负电势（Ptfv1）和左心房内径（LAD）、舒张末期左心室内径（LVD）、左心室射血分数（LVEF）等指标。结果 PAF组、无PAF组的Pt分别为（120±10）ms、（99±11）ms,Ptfv1分别为（0.051±0.023）mm·s、（0.026±0.010）mm·s,两组比较差异有统计学意义（P均〈0.01）;PAF组、无PAF组LAD分别为（33.6±3.9）mm、（32.7±4.2）mm,LVD分别为（44.6±4.1）mm、（42.7±4.3mm）,LVEF分别为（56.6±4.9）、（59.7±5.2）,两组比较差异无统计学意义（P均〉0.05）。结论阵发性房颤可引起心电图Pt及Ptfv1值增加,与左心房内径大小无相关。     

Acute electrocardiographic changes induced by amsacrine

The ECG effect of amsacrine (m-AMSA) was evaluated in 12 consecutive patients with leukemia. m-AMSA induced a significant prolongation of the Q-T interval (msecs, mean +/- SE) before (448 +/- 13) and 1 hour after (512 +/- 12) treatment (P . 0.0001, paired t test), without concomitant changes in the P-R interval, QRS duration, and heart rate. This selective cardiotoxic effect appeared to be transient and was noted towards the end of the iv drug administration, but was not present 24 hours later. No cardiac arrhythmias were noted during continuous monitoring. Nevertheless, it is assumed that the prolongation of the Q-T interval may represent a state of increased vulnerability to rhythm disturbances. Special care should be taken to avoid factors that may prolong the Q-T interval (hypokalemia, ischemia, or premedication with phenothiazine) during the administration of m-AMSA.     

子宫肌瘤患者的心电图分析

目的探讨子宫肌瘤患者的心电图表现。方法对200例子宫肌瘤患者心电图资料进行分析,200例健康体检女性作为对照组。结果子宫肌瘤患者心电图异常改变133例(66.5%),正常对照组心电图异常改变为46例(23%),二者差异有统计学意义。子宫肌瘤患者心电图异常以ST-T变化为主。结论子宫肌瘤患者心电图异常发生率较高,多表现为ST-T异常改变。     

甲状腺机能亢进患者的心电图分析

目的探讨甲状腺机能亢进（甲亢）患者的心电图表现。方法对85例甲亢患者心电图资料进行分析,85例性别、年龄匹配的健康体检者作为正常对照。结果甲亢患者心电图异常改变76例（89.41%）,正常对照组心电图异常改变为16例（18.82%）,二者差异有统计学意义（p〈0.001）。甲亢患者心电图改变以窦速、ST-T改变、房颤为主。结论甲亢患者心电图异常发生率较高,多表现为窦速、ST-T改变、房颤。     

Reversible electrocardiographic changes in hypothermia

A homeless man with accidental hypothermia showed massive ECG changes on hospital admission. Including sinus bradycardia, AV-block 1 degree, widened QRS complex with Osborne waves and QT prolongation. These changes were slowly but completely reversible after surface rewarming.     

Postexercise electrocardiographic and clinical changes in patients with sick sinus syndrome

Forty patients with sick sinus syndrome, 15 women and 25 men with a mean age of 53.83 +/- 13.34 years, were studied using a maximal graded bicycle stress test. None of the patients were using a pacemaker or being treated with drugs that would interfere with the sinus node function; one patient had family myocardiopathy and eight suffered from essential hypertension. All patients, including those suffering from very marked bradycardia (less than 40 beats/min) responded to the increased effort with increased heart rate. The exercise test was stopped in 22 patients (55%) after the appearance of clinical signs and in 4 (10%) after ST-segment depression greater than 1 mm. Eight (20%) finished the stress test after reaching the maximal heart rate according to age, due to an increase in sinus rate. The exercise produced or increased extrasystoles in five patients (12.5%), but only one was forced to suspend the test. The Q-T interval, corrected for heart rate according to Bazett's formula (QTc), was measured on the resting ECG before the start of the test and on the ECG recorded immediately following the end of the exercise in all patients, except one with atrial fibrillation. In 24 patients (60%), a QTc mean increase of 0.040 +/- 0.022 sec was observed at the end of the stress test. Fourteen (35%) had the usual shortening due to the increase in heart rate. One patient showed no variation of the QTc. A lengthening of the QTc at the end of the exercise in more than half of the patients was the most intriguing electrocardiographic change.(ABSTRACT TRUNCATED AT 250 WORDS)     

Standard electrocardiographic and signal-averaged electrocardiographic changes in congestive heart failure

A 54-year-old man with congestive heart failure and peripheral edema was monitored during treatment with serial electrocardiograms (ECGs) and two signal-averaged ECGs. Weights and a host of ECG parameters were monitored. ECGs recorded in the 5 years before his index admission were also considered in the quantitative ECG analysis. Amelioration of his peripheral edema was associated with reduction of his weight and increase in the QRS and P-wave amplitudes, and duration in QRS complexes and QT intervals in the ECGs, but unchanged signal-averaged ECGs. This case report provides insight into the mechanism of the change in QRS duration in ECGs during changing edematous states resulting from clinical deterioration or improved compensation in patients with congestive heart failure.     

Evolution of the electrocardiographic changes in patients with hypertrophic cardiomyopathy.

In 75 patients with hypertrophic cardiomopathy (HCM) followed for a mean period of 5.5 years (range 2-20 years), evolution of the electrocardiographic (EKG) changes was assessed. Progression of EKG abnormalities occurred in 35 patients (47%). It was manifested by an increase in precordial QRS voltage in 33 patients, development of new P-wave mitral in 11 patients, and development or disappearance of pathologic Q waves in 14 patients. With follow-up times greater than 5 years, 5-8 years, and greater than 8 years, EKG progression was present in 27, 41, and 80% of patients, respectively. Age less than 30 years at the beginning of study and left ventricular outflow obstruction predisposed to EKG progression within 5-8 years. Patients with progressive EKG changes were more prone to experience clinical deterioration than those without EKG progression (63 vs. 15%, p less than 0.001). With chronic verapamil administration, progression of EKG abnormalities occurred insignificantly less often than with propranolol treatment (35 vs. 64%, p = 0.20). It is concluded that with long-term follow-up, HCM tends to progress in a significant proportion of adult patients.     

Long-term follow-up of electrocardiographic changes in patients with asymmetric apical hypertrophy

The serial electrocardiographic (ECG) changes of 20 patients with asymmetric apical hypertrophy (AAH) were retrospectively reviewed relative to their clinical symptoms, echocardiography and Doppler echocardiography, and thallium-201 perfusion scintigraphy. These patients were followed 4-18 years (mean 8 years). Patterns of the serial ECG changes were as follows: Seven patients (group Ia) had an increase of 10 mm or greater in the highest R wave amplitude in the precordial leads, with newly-developed giant T wave inversion. Five patients (group Ib) had relatively stable ECGs and the changes in the R wave amplitudes of less than 10 mm. Six patients (group IIa) had a decrease of 10 mm or greater in the highest R wave amplitude with mild decreases of negative T wave amplitudes. In the remaining two patients (group IIb) right bundle branch block developed. At the last follow-up study, group IIa had lower R wave amplitudes and longer QTc than did those in group I. The follow-up periods and their mean age did not differ among the groups. At the initial evaluation, exercise limitation was rare in group I; whereas, most of the patients in group II presented symptoms such as palpitation, chest pain or exertional dyspnea. These cardiac symptoms developed slowly but progressively during the follow-up period, and their incidence increased both in groups I and II at the final observation. Left ventricular (LV) wall thickness at the chordal level showed normal values and did not differ between the two groups, but apical wall thickness was greater in group II than in group I. Two-dimensional echocardiography showed a spade-like deformity of the LV in group II. In group I, the LV deformity was less marked and was not noted at the initial examination. Color Doppler echocardiography frequently revealed "paradoxical flow" expelled from the obliterated apex to the base in the early diastolic filling period in group II. Left ventriculography confirmed asynchronous contraction, hyperkinesis in the basal segment and dyskinesis at the apical segment, resulting in this abnormal intraventricular blood flow profiles. Serial studies by thallium-201 (TL) perfusion scintigraphy disclosed that four of the eight patients in group II developed localized hypoperfusion at the apex where a high and homogeneous uptake of TL was previously noted.(ABSTRACT TRUNCATED AT 400 WORDS)     

72例肥厚性梗阻型心肌病心电图分析

目的　探讨肥厚性梗阻型心肌病与心电图异常的关系。方法　对 72例肥厚性梗阻型心肌病患者心电图资料进行分析。结果　本组合并心电图异常改变 6 9例 (95 8% ) ;伴ST段压低 4 4例(6 1 1% ) ,T波异常倒置 36例 (5 0 % ) ;左室大和高电压 30例 (41 7% ) ;心电轴左偏 2 7例 (37 5 % ) ;异常Q波 2 1例 (2 9 2 % ) ;P波时限增宽 18例 (2 5 2 % ) ;右侧胸前导联r波递增序列异常 18例 (2 5 % ) ;合并心房纤颤 4例 (5 5 % ) ;QRS时限 >0 12秒 ,伴束支阻滞或室内阻滞 2例 (2 7% ) ;心电图正常 3例。结论　肥厚性梗阻型心肌病与心电图异常具有相关性     

The prognostic significance of electrocardiographic changes in Chagas disease

IntroductionThe meaning of electrocardiographic changes appearing during the clinical follow-up of Chagas disease (ChD) is unknown. In this study, a patient cohort with ChD was followed to describe the electrocardiographic changes that may make it possible to identify patients whose left ventricular function has deteriorated.MethodsThe study sample consisted of a prospective cohort followed since 1998 to 1999, involving 220 patients aged 15 to 55 years, 30 controls, and 190 with ChD, without other comorbidities. The group was reexamined between 2004 and 2006, and new electrocardiograms were obtained for 153 patients, 25 (83%) of 30 in the control group and 128 (72%) of 177 in the ChD group. Electrocardiographic variables associated with a significant decrease in ejection fraction (5% or more) were identified.ResultsA significant decrease in ejection fraction was observed in 21 patients in the ChD group (18.7%) but in none of the non-ChD group (P = .024). Only the presence of a new electrocardiographic abnormality and an increase in QRS duration correlated with a decrease in an ejection fraction of 5% or more. QRS duration was correlated with both an increase in left ventricle diastolic diameter and a deterioration in the ejection fraction (r_s = 0.225, P = .017, and r_s = ?0.300, P < .001). A QRS increase of 5 milliseconds had 77.8% sensitivity and 62.2% specificity for identifying patients with significant decrease in ejection fraction.ConclusionThe increase in the duration of the QRS complex and the appearance of new electrocardiographic alterations may help in identifying patients with a significant decrease (of 5% or more) in left ventricle ejection fraction.     

Serial electrocardiographic and angiographic changes of patients with hypertrophic cardiomyopathy

The characteristics of ECG findings as they relate to myocardial changes during long-term course of hypertrophic cardiomyopathy (HCM) were studied. Serial changes in ECG were compared with changes left ventriculogram and bi-ventriculogram in 15 patients with HCM without intraventricular conduction disturbance. Serial changes in ECG findings, with special reference to the negative T wave, were categorized in three groups; 1) 5 patients with increase or appearance of the negative T wave (A-1 group). 2) 4 patients with decrease or disappearance of the negative T wave (A-2 group). 3) 6 patients without significant changes in the T wave (B-group). A-1 group presented a marked increase in SV1 + RV5, and of the thickness of anterior and apical wall, and a decrease of the peak dV/dt/EDV (end diastolic volume-normalized peak filling rate), serially. End diastolic volume (EDV) and ejection fraction (EF) did not change significantly. The configuration of left ventriculogram changed from a round form to a spade-like form. A-2 group presented a marked decrease in SV1 + RV5, the thickness of anterior and apical wall, peak dV/dt/EDV and peak dV/dt/V (left ventricular volume of the time of peak filling-normalized peak filling rote). EF decreased serially, 2 cases of A-2 group presented the clinical picture of dilated cardiomyopathy in the end stage. In B group, SV1 + RV5, the wall thickness and left ventricular function did not change, serially. In conclusion, serial observations of ECG are useful for assessing alterations in wall thickness, LV-form and LV-function.     

Unusual electrocardiographic changes in intrathoracic conditions

Electrocardiographic, roentgenographic and clinical findings from 5 patients with intrathoracic conditions were studied. Three patients suffering from left spontaneous pneumothorax and one from eventration of the left diaphragm were found to have an unusual phasic voltage alternation in their electrocardiograms. These changes were appearing during the course of the disease and disappearing with the correction of the condition. Respiratory variation of intrathoracic anatomy or amplitude and swinging of the heart seems a possible explanation.