Acute, reversible myocardial ischemia in a patient with an asthmatic attack

A 61-year-old woman with chronic asthma sustained an episode of dyspnea and chest heaviness and was brought to the emergency department. Her examination revealed tachypnea, tachycardia, hypotension, and diffuse prolonged respiratory wheezing. Arterial blood gas analysis showed severe hypoxemia and hypercapnia. A 12-lead electrocardiogram showed marked, downsloping ST-segment depression, with deep, negative T waves in leads I, II, III, and aVF and precordial leads V₃-V₆. After 15 minutes of therapy with oxygen, beta-agonists, and corticosteroids, the electrocardiographic abnormalities subsided and 2 hours later they had disappeared. Subsequent coronary angiography and ventriculography revealed normal coronary arteries and good left ventricular ejection fraction. It is concluded that an acute asthmatic paroxysm may produce transient myocardial ischemia even with angiographically documented normal coronary arteries.     

U Wave Variability in the Surface ECG

A 72‐year‐old man with heart failure, left ventricular dysfunction (ejection fraction 20%), prior ischemic stroke, COPD, and exacerbation of chronic renal failure was admitted in our unit. Serum potassium was 6.1 mmol/L, calcium concentration was at the lower normal range 2.15 mmol/L, and NT‐pro‐BNP was 28,900 pg/mL. The surface 12‐lead electrocardiogram (ECG) showed sinus rhythm at 60 bpm, PR interval 160 ms, QRS duration 115 ms, QT interval 460 ms, and left ventricular hypertrophy criteria. Negative T waves in leads I, II, aVL, and V₄–V₆ were also seen. In leads V₄–V₆, negative U waves were observed in concordance with negative T waves. In all precordial leads, beat‐to‐beat U‐wave polarity variability was observed as a polarity variation from negative to positive with associated and stable negative T waves, in a beat‐to‐beat alternate morphology.     

Preexcitation unmasks J waves: 2 cases

It is not known if J waves of early repolarization can be affected by depolarization or not. We report 2 cases in whom J waves were unmasked by preexcitation.A 59-year-old woman with Wolff-Parkinson-White syndrome who had frequent episodes of tachycardia underwent radiofrequency catheter ablation. The 12-lead electrocardiogram on admission showed delta waves and a notch in leads II, III, and aVF (J waves), which disappeared after the elimination of preexcitation. A 56-year-old man with Wolff-Parkinson-White syndrome was admitted for catheter ablation for supraventricular tachycardia. His electrocardiogram showed delta waves in I, II, aVL, V₂ to V₆, and J waves in the inferior leads and V₃ through V₆ with ST elevation and ST elevation in V₂. After ablation, J waves disappeared and were replaced by S waves. However, ST elevation remained in the precordial leads. The 2 cases suggest that J waves may be affected by the depolarization process: preexcitation.     

The resting surface electrocardiogram as a predictor of future hypertension

Resting supine and post-provocation (dynamic exercise, isometric exercise and cold pressor) levels of blood pressure were measured in 80 normotensive offspring of normotensive parents (control) and 55 normotensive offspring of parents with essential hypertension. The surface electrocardiogram (including conventional twelve leads, posterior chest leads, right-sided chest leads and bipolar precordial leads) was also recorded in all subjects. Twenty-eight offspring of parents with essential hypertension had their resting and/or post-provocation blood pressure above the upper limit of standard deviation in age- and sex-matched control group. Flat or upright T waves, with either S waves less than 0.2 mV, or S/R ratio less than 2, or T waves equal to or higher than the accompanying R waves in lead V₄R, could identify these potential hypertensives with nearly 90% specificity and nearly 75% sensitivity. The criterion had been derived, however, by analysis of the data achieved retrospectively. Therefore, the exact discriminating value of this criterion can be assessed only by a long-term prospective study.     

Ivabradine in the treatment of non-paroxysmal junctional tachycardia with interference atrioventricular dissociation: A case report

Ivabradine reduces the heart rate by selectively inhibiting the I_f current of the sinoatrial node, mainly for the treatment of chronic heart failure with decreased left ventricular systolic function and inappropriate sinus tachycardia, but the inhibitory effect on the atrioventricular node is rarely reported. The patient was admitted to hospital mainly because of intermittent chest pain for 7 years, which worsened for 10 days. Admission electrocardiogram (ECG) considered sinus tachycardia, with QS wave and T wave inversion in II, III, aVF, V₃R-V₅R, V₄–V₉ leads, and non-paroxysmal junctional tachycardia (NPJT) with interference atrioventricular dissociation. After treatment with ivabradine the ECG returned to normal conduction sequence. NPJT with interference atrioventricular dissociation is a fairly rare electrocardiographic phenomenon. This case reports for the first time that ivabradine is used in the treatment of NPJT with interference atrioventricular dissociation. It is speculated that ivabradine has a potential inhibitory effect on the atrioventricular node.     

Acute myocardial infarction and congestive heart failure following a blunt chest trauma

 A 42-year-old man experienced chest discomfort after being struck by a low-speed flying object. Two weeks after the accident, the patient complained of severe shortness of breath accompanied by ankle edema. Chest X-ray indicated acute pulmonary edema and left ventricular enlargement. There were Q waves and flat T waves in the precordial ECG leads. Echocardiography revealed dyskinesis in the interventricular septum, hypokinesis in the anterior left ventricular wall, and severe impairment of left ventricular function. A coronary angiogram showed 90% stenosis of the proximal left descending coronary artery. Subsequent medical therapy with diuretics and enalapril led to significant improvement in ventricular function and the patient's symptoms. We conclude that a mild blunt chest trauma can cause myocardial infarction and severe congestive heart failure. Careful investigations into myocardial ischemia or infarction and a close follow-up should be conducted in all patients presenting with a blunt chest trauma. Received: April 22, 2002 / Accepted: August 2, 2002 Correspondence to L. Wang     

Electrocardiogram mimics of acute ST-segment elevation myocardial infarction: insights from cardiac magnetic resonance imaging in patients with tako-tsubo (stress) cardiomyopathy

An important subset of patients (10%) with chest pain and ST-segment elevation on initial electrocardiogram (ECG) do not have acute coronary occlusion. In our experience, 5% of women presenting with chest pain and ST-segment elevation are proven to have the newly recognized syndrome of tako-tsubo (stress) cardiomyopathy (TC). Patients with TC present with clinical and electrocardiographic features mimicking ST-segment elevation anterior myocardial infarction due to left anterior descending (LAD) occlusion. The initial and subsequent ECG findings in TC are therefore of clinical importance. Thirty-three consecutive patients with TC were identified from within a single institution community-based cardiology practice. All were female aged 32 to 90 years (mean, 68 years) with acute chest pain associated with an emotional or physical stressful event, and akinesia of the mid-distal left ventricle but without significant atherosclerotic coronary artery obstruction. All patients with TC presented with anterior ST-segment elevation most marked in leads V₁ to V₅, maximal in leads V₂ and V₃. Distribution of ST-segment elevation was similar to 44 female control patients with acute (LAD) occlusion. ST-segment elevation magnitude was less in patients with TC (1.4 ± 1.5 mm) than in patients with LAD occlusion (2.4 ± 2.2 mm) (P < .001) but with considerable overlap. Left ventricular ejection fraction (LVEF) was significantly lower in TC patients (29% ± 9%) than in patients with LAD occlusion (42% ± 13%) (P < .05). Peak troponin T was significantly lower in patients with TC (0.64 ± 0.86 ng/mL) than in patients with LAD occlusion (3.88 ± 4.9 ng/mL) (P < .0001). Cardiovascular magnetic resonance imaging detected myocardial necrosis in 1 patient with TC. At follow-up, LVEF returned to normal (> 50%) in all patients with TC. In patients with TC, ECG evolution was characterized by resolution of ST-segment elevation, appearance of T-wave inversion (most marked in precordial leads V₃-V₆ and limb leads aVL, I, and −aVR), QTc interval prolongation (378 ± 60 milliseconds [initial] vs 470 ± 72 milliseconds [follow-up], P < .05), and reappearance of precordial R waves. In conclusion, patients with TC frequently present with anterior ST-segment elevation, which cannot be reliably distinguished from that of acute LAD occlusion. In TC, the combination of minimal troponin release, absent delayed hyperenhancement on cardiac magnetic resonance imaging (in most of patients), and return to normal LVEF is consistent with the presence of significant myocardial stunning. The ECG evolution of progressive T-wave inversion, QTc interval lengthening, and R-wave reappearance could be the electrophysiologic manifestation of an underlying stunned myocardium in this condition.     

Persistent Thebesian Vessels Involving the Right and Left Ventricles Leading to Coronary Steal Phenomena and Ischemia

We report an extremely rare case of thebesian vein microfistulae to both ventricles. A 65‐year‐old woman, with no major cardiovascular risk factors, presented with multiple episodes of chest pain. The resting electrocardiogram showed T‐wave inversion in leads V₁–V₄. A Dipyridamole myocardial perfusion imaging revealed large and severe inferior defect with complete reversibility. Coronary angiography showed no coronary artery disease. On contrast injection, an exaggerated capillary blush from the distal portions of the right and left coronary artery systems was seen in both ventricles, mimicking the image of ventriculography. This appearance suggests prominent thebesian vessels, a congenital communication between the coronaries and the two ventricles. The clinical relevance of these myocardial sinusoids is still not well established. Although the majority of these fistulas are small in size and with no clinical significance, they can rarely present with chest pain, cardiac arrhythmia, syncope, myocardial infarction, and/or pulmonary hypertension. These fistulae when excessive can cause significant shunting of blood to the ventricles, leading to coronary steal phenomena and ischemia. This phenomenon is facilitated by the low resistance in these microfistulae as opposed to the higher resistance in the normal coronary circulation. Due to the diffuse nature of these microfistulae, neither surgery nor transcatheter therapy is feasible. This condition can only be managed medically; however, it should be noted that vasodilator agents, such as nitrates, can worsen the coronary steal phenomenon. Our patient was treated with ranolazine with significant improvement in her symptoms, which was not reported previously. Multiple coronary artery microfistulae could be an underestimated condition of angina in patient with normal coronaries.     

Electroconvulsive therapy-induced transient T-wave inversions on ECG

Electroconvulsive therapy (ECT), regarded as safe, well tolerated, and one of the most effective treatments for depression, is used frequently in patients with underlying coronary artery disease. ECT has been associated with ST depression and arrhythmias probably due to increased myocardial demand in patients with coronary artery disease. This report describes a case of transient new T-wave inversions in precordial leads V² and V³ and flattening of T waves in leads III, V³, V⁴, V⁵, and a VF after two courses of ECT in a patient with minimal cardiac risk factors, normal echocardiogram, and normal pre-ECT electrocardiogram (ECG). These T-wave changes may represent increased sympathetic activity induced by ECT. Previous prospective studies of 26 and 21 patients undergoing serial ECT found only one new T-wave inversion and no pathologic Q waves on serial ECGs, suggesting that this is a rare finding.     

Wide band recording of the electrocardiogram and coronary heart disease

Wide band, high frequency electrocardiography employing an expanded time scale and both greater amplitude and a greater frequency response than conventional electrocardiographs reveals small notches in the QRS complex which are obscured in the conventional electrocardiogram. A total of more than three high frequency notches in Leads V₄, V₅, and V₆ plus the notches in the three largest limb leads suggests a high probability of coronary heart disease. This criterion is a modification of one we previously reported in that now fewer leads need be examined and slurs are not counted. In a control group of 100 normal subjects and 76 subjects with coronary artery disease used to develop this new criterion, there were 8 false positives (8 per cent) and 5 false negatives (7 percent). The Health Evaluation Center group provided 966 new subjects who were studied using the high frequency technique; 875 were classified as normal; 11 per cent had an abnormal number of notches. Of 24 patients with histories of myocardial infarction, 79 per cent showed excess notching. Of 12 subjects with angina pectoris, 7 showed excess notching. Notching in the 35 patients with uncomplicated hypertension and in 20 subjects with hypercholesterolemia was within the normal range. Twenty-four additional Provident Mutual Life Insurance Company employees were added to our long term study. Of these, two developed coronary artery disease. Both exhibited serial changes in the high frequency electrocardiogram.Wide band electrocardiography using the sum of the notches in the three largest limb leads and the notches in V₄, V₅, and V₆ is a useful adjunct for the detection of coronary heart disease especially when the conventional electrocardiogram is normal.     

Ventricular tachycardia in a Brugada syndrome patient caused by a novel deletion in SCN5A

The aim of the present study was to identify the molecular mechanism behind ventricular tachycardia in a patient with Brugada syndrome. Arrhythmias in patients with Brugada syndrome often occur during sleep. However, a 28-year-old man with no previously documented arrhythmia or syncope who experienced shortness of breath and chest pain during agitation is described. An electrocardiogram revealed monomorphic ventricular tachycardia; after he was converted to nodal rhythm, he spontaneously went into sinus rhythm, and showed classic Brugada changes with coved ST elevation in leads V₁ to V₂. Mutation analysis of SCN5A revealed a novel mutation, 3480 deletion T frame shift mutation, resulting in premature truncation of the protein. Heterologous expression of this truncated protein in human embryonic kidney 293 cells showed a markedly reduced protein expression level. By performing whole-cell patch clamp experiments using human embryonic kidney 293 cells transfected with the mutated SCN5A, no current could be recorded. Hence, the results suggest that the patient suffered from haploinsufficiency of Na_v1.5, and that this mutation was the cause of his Brugada syndrome.     

Left atrial rhythm in man: An experimental study

Ten patients with atrial septal defect of the secondum variety undergoing diagnostic haemodynamic study were subjected to electrical stimulation of the endocardium of the left atrium using a bipolar pacing electrode catheter. The polarity, frontal plane P wave axis and P wave configuration were analysed from ten scalar 12 lead electrocardiogram (ECG), recorded at 25–50 mm/sec during sinus rhythm and left atrial stimulation. While four patients demonstrated the “dome and dart” appearance of P waves in V₁, nine out of ten patients revealed upright P waves in V₁ during left atrial pacing; one patient showed inverted P waves in V₁–V₆. Four patients had negative ‘P’ waves in L₁ and only five of ten patients had inverted ‘P’ waves in L₁ and V₆. All the criteria of left atrial rhythm were present in only one patient. It appears that the ‘P’ wave changes during left atrial pacing are variable and that the typical findings of left atrial rhythm are not obtained in all cases. This study was planned because trans-septal left atrial stimulation in the genesis of left atrial rhythm has not been widely reported.     

A study of precordial leads in subjects with congenital dextrocardia and situs inversus viscerum

The chest leads of seven persons with congenital dextrocardia and situs inversus viscerum were studied. None of the seven showed any clinical evidence of heart disease. One subject, however, because she had systolic hypertension, was believed to be potentially abnormal, and was considered separately from the other six. The standard leads of this one subject were normal, but she had inverted T waves in CF_1–4 and diphasic T waves in CF₅ and CF₆. The data indicate that the chest leads of a person with congenital dextrocardia and situs inversus are approximately identical with those of an individual whose heart is on the left side, provided the technique of making the leads is altered to conform to the dextro-position of the heart.     

Spatial Properties of QT and the T‐Wave Morphology

Objective: To describe the relation between the QT interval and the T‐wave morphology. Material and methods: Frank orthogonal leads X, Y, Z of one subject and resting 12‐lead ECG of 40 subjects. QT was measured by the tangent method. The QT values are organized according to the anatomic orientation of the leads: I, ‐aVR, II, aVF, III, ‐aVL, ‐I, aVR, ‐II, ‐aVF, ‐III, aVL. and: V₁, V₂, V₃, V₄, V₅, V₆, ‐V₁ ‐V₂, ‐V₃, ‐V₄, ‐V₅, ‐V₆. The T‐wave amplitudes and QT were categorized according to QT into four groups with increasing mean QT. Results: Kruskal‐Wallis nonparametric test showed that the shortest and longest QT values are measured on the T wave with the smallest amplitudes (P < 0.001). Inspection of plots of QT and T waves reveals that the shortest and longest QT values are usually measured in leads with a small difference in orientation (neighbor leads). The mechanism behind these characteristics is mainly that the shortest and longest QT values are measured on T waves that are close to a lead orientation, whereas the T waves are flat or biphasic. We also observed an almost significant (P = 0.057) decrease in the T‐wave amplitude with increasing dispersion. Conclusion: The relation between T‐wave morphology and QT in the same cardiac plane is highly organized. The shortest and longest QT values are measured on the T wave with the smallest amplitudes (P < 0.001).     

Myocardial Stunning Following Combined Modality Combretastatin‐Based Chemotherapy: Two Case Reports and Review of the Literature

Myocardial stunning, known as stress cardiomyopathy, broken‐heart syndrome, transient left ventricular apical ballooning, and Takotsubo cardiomyopathy, has been reported after many extracardiac stressors, but not following chemotherapy. We report 2 cases with characteristic electrocardiographic and echocardiographic features following combined modality therapy with combretastatin, a vascular‐disrupting agent being studied for treatment of anaplastic thyroid cancer. In 1 patient, an ECG performed per protocol 18 hours after drug initiation showed deep, symmetric T‐wave inversions in limb leads I and aVL and precordial leads V₂ through V₆. Echocardiography showed mildly reduced overall left ventricular systolic function with akinesis of the entire apex. The patient had mild elevations of troponin I. Coronary angiography revealed no epicardial coronary artery disease. The electrocardiographic and echocardiographic abnormalities resolved after several weeks. The patient remains stable from a cardiovascular standpoint and has not had a recurrence during follow‐up. An electrocardiogram performed per protocol in a second patient showed deep, symmetric T‐wave inversions throughout the precordial leads and a prolonged QT interval. Echocardiography showed mildly reduced left ventricular function with hypokinesis of the apical‐septal wall. Acute coronary syndrome was ruled out, and both the electrocardiographic and echocardiographic changes resolved at follow‐up. Although the patient remained pain‐free without recurrence of anginal symptoms during long‐term follow‐up, the patient developed progressive malignancy and died. Copyright © 2009 Wiley Periodicals, Inc.     

The electrocardiogram in right ventricular cardiomyopathy/dysplasia. How can the electrocardiogram assist in understanding the pathologic and functional changes of the heart in this disease?

The electrocardiogram (ECG) provides important information to aid in the diagnosis of arrhythmogenic right ventricular cardiomyopathy/dysplasia (ARVC/D). The ECG changes may be explained by the pathophysiology of the disease. The proximity of the right ventricle (RV) to the anterior chest leads (V₁ to V₄) explains why the characteristic ECG abnormalities are most prominent in those lends. The specific ECG abnormalities reflect the pathophysiology of the disease including T-wave inversion due to scarring of the free wall of the RV, prolonged S-wave duration due to slow depolarization of the terminal part of the QRS because the RV is the last part of the heart to undergo depolatization, and epsilon waves due to slow conduction in the RV. The extent of ECG abnormalities correlate with the degree of structural change in the RV.     

The false positive stress test : Multivariate analysis of 215 subjects with hemodynamic,angiographic and clinical data

Factors causing the false positive stress test and the ability of the computer to improve test classification were studied in 95 patients with a positive stress test and normal coronary angiograms and 125 patients with a true positive stress test. Multivariate analysis revealed that in men the following clinical findings other than S-T depression were useful in correct stress test classification: (1) maximal heart rate, (2) maximal systolic blood pressure, (3) contour of S-T segment, (4) age, (5) history of chest pain, (6) T waves in resting record, (7) chest pain during test, (8) S-T and T changes with hyperventilation, (9) resting electrocardiogram, (10) time of onset of S-T depression, and (11) increase in P wave negativity in lead V₁ with exercise. These variables, presented in order of importance, had a different ranking in women.