The electrocardiogram in subarachnoid haemorrhage

Assessment of cardiac function in rat endovascular perforation model of subarachnoid hemorrhage; A model of subarachnoid hemorrhage-induced cardiac dysfunction

Although the association between cardiac dysfunction and subarachnoid hemorrhage (SAH) has been recognized, its precise underlying mechanism remains unknown. Furthermore, no suitable animal models are available to study this association. Here, we established an appropriate animal model of SAH-induced cardiac dysfunction and elucidated its mechanism. In this rat model, contrast-enhanced computed tomography of the brain confirmed successful induction of SAH. Electrocardiography detected abnormalities in 55% of the experimental animals, while echocardiography indicated cardiac dysfunction in 30% of them. Further evaluation of left ventriculography confirmed cardiac dysfunction, which was transient and recovered over time. Additionally, in this SAH model, the expression of the acute phase reaction protein, proto-oncogene c-Fos increased in the paraventricular hypothalamic nucleus (PVN), the sympathetic nerve center of the brain. Polymerase chain reaction analysis revealed that the SAH model with cardiac dysfunction had higher levels of the macrophage-associated chemokine (C-X-C motif) ligand 1 (CXCL-1) and chemokine (C-C motif) ligand 2 (CCL-2) than the SAH model without cardiac dysfunction. Our results suggested that SAH caused inflammation and macrophage activation in the PVN, leading to sympathetic hyperexcitability that might cause cardiac dysfunction directly and indirectly. This animal model may represent a powerful tool to investigate the mechanisms of the brain-heart pathway.

Acute Cardiac Complications in Critical Brain Disease

Acute cardiac complications in critical brain disease should be understood as a clinical condition representing an intense brain-heart crosstalk and might mimic ischemic heart disease. Two main entities (neurogenic stunned myocardium [NSM] and stress cardiomyopathy) have been better characterized in the neurocritically ill patients and they portend worse clinical outcomes in these cases. The pathophysiology of NSM remains elusive. However, significant progress has been made on the early identification of neurocardiac compromise following acute critical brain disease. Effective prevention and treatment interventions are yet to be determined.

Acute Cardiac Complications in Critical Brain Disease

Acute cardiac complications in critical brain disease should be understood as a clinical condition representing an intense brain-heart crosstalk and might mimic ischemic heart disease. Two main entities (neurogenic stunned myocardium [NSM] and stress cardiomyopathy) have been better characterized in the neurocritically ill patients and they portend worse clinical outcomes in these cases. The pathophysiology of NSM remains elusive. However, significant progress has been made on the early identification of neurocardiac compromise following acute critical brain disease. Effective prevention and treatment interventions are yet to be determined.

Partial Brain Tissue Oxygen Levels Predict Arrhythmia and Prognosis in Patients With Brain Injury

The objective of this study was to examine the clinical determinants of incidence and prognosis of arrhythmias in the setting of acute brain injury. Acute brain injury is known to cause electrocardiographic abnormalities and cardiac arrhythmias. The relation between partial brain tissue oxygen (PBTO) and intracranial pressure (ICP) with arrhythmia incidence and prognosis remains unknown. Consecutive patients with acute brain injury and intracranial bleed admitted to the neurosurgical intensive care unit were enrolled in the study. Baseline characteristics [demographics, medical history, etiology of brain injury, Glasgow Coma Scale (GCS) score, blood pressure, and respiratory rate] were documented. Patient's telemetry recordings were reviewed for daily mean heart rates and arrhythmias. If arrhythmia was noted, PBTO levels at the beginning of arrhythmia, ICP, brain tissue temperature, and outcomes were recorded. A total of 106 subjects (53% men, age 39 ± 18 years, 65 traumatic and 41 nontraumatic brain injuries) were studied. Overall, 62% of subjects developed a total of 241 arrhythmia episodes. Ventricular arrhythmias were associated with significantly higher daily mean heart rates, low PBTO levels, and low GCS scores, whereas atrial arrhythmias were associated with lower daily mean heart rates, normal PBTO levels, and higher GCS and ICP. Three or more episodes of arrhythmia predicted worse outcomes, including mortality (P = 0.001). In patients with acute brain injury, poor PBTO levels are associated with higher incidence of ventricular tachyarrhythmias. In contrast, atrial tachyarrhythmias occur in patients with normal PBTO levels and higher ICP. Incidence of ventricular arrhythmia in those with poor PBTO is associated with increased mortality.

ECG Changes in Subarachnoid Haemorrhage: A Synopsis

Subarachnoid haemorrhage (SAH) is a neurological emergency with high mortality rates. It is mainly caused by rupture of an aneurysm (congenital/infectious/traumatic) or rupture of an arteriovenous malformation. Electrocardiograms (ECGs) done in patients with SAH have shown morphological changes as well as arrhythmias. Subarachnoid haemorrhage (SAH) patients have often been misdiagnosed to have cardiac abnormalities based on their ECGs when in many of those instances the ECG change had been the result of the SAH itself. They have led to unnecessary and wasteful investigations and therapies in many occasions. Hence the current article is an effort at consolidating the information available in an attempt to avoid possible errors in diagnosis by house staff and internists. There are two mechanisms that might mediate ECG changes in patients with SAH, i.e. autonomic neural stimulation from the hypothalamus or elevated levels of circulating catecholamine. Hypothalamic stimulation may cause ECG changes without associated myocardial damage whereas elevated catecholamine levels have been correlated with QT-interval prolongation and myocardial damage.

Electrocardiographic abnormalities in acute cerebrovascular events in patients with/without cardiovascular disease

Objectives:

Electrocardiographic (ECG) changes are reported frequently after acute strokes. It seems that cardiovascular effects of strokes are modulated by concomitant or pre-existent cardiac diseases, and are also related to the type of cerebrovascular disease and its localization. We aimed to determine the pattern of ECG changes associated with pathophysiologic categories of acute stroke among patients with/without cardiovascular disease and to determine if specific ECG changes are related to the location of the lesion.

Materials and Methods

The electrocardiographic records of 361 patients with acute stroke were studied to assess the relative frequencies of ECG abnormalities among the pathophysiologic categories of stroke.

Results:

In the present study, the most common ECG abnormalities associated with stroke were T-wave abnormalities, prolonged QTc interval and arrhythmias, which were respectively found in 39.9%, 32.4%, and 27.1% of the stroke patients and 28.9%, 30.7%, and 16.2 of the patients with no primary cardiac disease. We observed that other ECG changes comprising pathologic Q- wave, ST-segment depression, ST-segment elevation, and prominent U wave may also occur in selected or non-selected stroke patients; thereby simulate an acute myocardial injury. We observed an increased number of patients with abnormal T-wave and posterior fossa bleedings and more rhythm disturbances for ischemic lesions, localized in the anterior fossa.

Conclusion:

Ischemia-like ECG changes and arrhythmias are frequently seen in stroke patients, even in those with no history or signs of primary heart disease, which support a central nervous system origin of these ECG abnormalities. Further study is necessary to better define the brain-heart interaction.

Cardiac manifestations of subarachnoid hemorrhage

INTRODUCTION

Cardiac manifestations of intracranial subarachnoid hemorrhage patients include mild electrocardiogram variability, reversible left ventricular dysfunction (Takotsubo), non-ST elevation myocardial infarction, ST-elevation myocardial infarction and cardiac arrest, but their clinical relevance is unclear. The aim of the present study was to categorize the relative frequency of different cardiac abnormalities in patients with subarachnoid hemorrhage and determine the influence of each abnormality on outcome. 

METHODS

A retrospective review of 617 consecutive patients who presented with non-traumatic aneurysmal subarachnoid hemorrhage at our institution was performed. A cohort of 87 (14.1%) patients who required concomitantly cardiological evaluation was selected for subgroup univariate and multi-variable analysis of radiographic, clinical and cardiac data. 

RESULTS

Cardiac complications included myocardial infarction arrhythmia and congestive heart failure in 47%, 63% and 31% of the patients respectively. The overall mortality of our cohort (23%) was similar to that of national inpatient databases. In our cohort a high World Federation of Neurosurgical Surgeons grading scale and a troponin level >1.0 mcg/L were associated with a 33 times and 10 times higher risk of death respectively.

CONCLUSIONS

Among patients suffering from cardiac events at the time of aneurysmal subarachnoid hemorrhage, those with myocardial infarction and in particular those with a troponin level greater than 1.0 mcg/L had a 10 times increased risk of death. 

Myocardial dysfunction after subarachnoid haemorrhage and tako-tsubo cardiomyopathy: a differential diagnosis?

The frequent occurrence of a reversible left ventricular dysfunction complicating subarachnoid haemorrhage raises a number of issues about the clinical and pathophysiological similarities with the transient left ventricular apical ballooning syndrome (TLVABS) or tako-tsubo cardiomyopathy (TTC). Given the latest clinical and pathophysiological evidence about neurogenic cardiomyopathies, the diagnosis of TTC should not be ruled out in patients experiencing acute brain injury and cerebrovascular events. Each type of reversible left ventricular dysfunction mediated by the central nervous system and initiated by acute brain injury, both physical, such as intracranial bleeding or head traumas, and psychological, such as sudden emotional stress, could be encompassed in a single definition with larger inclusion criteria, such as 'acute ballooning cardiomyopathy' (ABC), that is likely to be more representative of the real needs in the clinical setting.

The autonomic nervous system and ischemic stroke: a reciprocal interdependence

Signs and symptoms of autonomic nervous system (ANS) dysfunction are frequently reported after ischemic or haemorrhagic stroke and in many cases they exhibit peculiar patterns in relationship with the site and the extension of brain lesion. However if an ANS disorder can cause or predispose to a stroke is far from being correctly known. Evidences in favor of a pathogenetic mechanism of an ANS dysfunction are reported for myocardial infarction and such data are likely to be appropriate also for atherothrombotic type of ischemic stroke. On the other hand, it is well known that many risk factors for this pathology are strongly correlated with an altered functioning of ANS so that a reciprocal interdependence between ANS and stroke can be hypothesized. This review points to evidence the possible relationship existing between these two conditions and suggests a quite different diagnostic and therapeutic approach to both on the basis of their pathogenetic mechanisms.

The systemic implications of aneurysmal subarachnoid hemorrhage

Aneurysmal subarachnoid hemorrhage (SAH) is analogous to a pathophysiological watershed, disrupting brain integrity and function and precipitating an array of systemic derangements including cardiovascular, respiratory, endocrine, hematological, and immune dysfunction. Extracerebral organ dysfunction is closely linked to the magnitude of the primary neurological insult, suggesting neurogenic, neuroendocrine and neuroimmunomodulatory mechanisms. Systemic organ involvement is associated with increased mortality and neurological impairment, even after adjustment for other outcome predictors such as the severity of the initial neurological injury. This may be a reflection of secondary brain injury precipitated by hypoxemia, circulatory failure, fever, or hyperglycemia, all of which have been linked to adverse clinical outcomes. Interventions to avert or reverse these and other perturbations need to be tested in clinical trials as they represent opportunities to improve survival and neurological recovery in patients with SAH.

Cardiac complications after aneurysmal subarachnoid hemorrhage

BACKGROUND

Cardiac complications are frequently encountered by neurointensivists caring for patients with SAH. Our aim was to better characterize the natural history of various cardiac abnormalities in this population. We sought to determine the risk factors for cardiac abnormalities, patient outcome, and impact of treatment type on cardiac abnormalities.

METHODS

We performed a single center retrospective review of admissions of patients with aneurysmal SAH to the neurosurgical ICU in a large university hospital. Patient demographics, pertinent history, cardiac tests, hospital LOS, intervention type, and discharge outcome were collected.

RESULTS

Data from 266 patients were available for analysis. Of these patients, 50% (n = 133) demonstrated cardiac abnormalities as indicated by abnormal EKG, ECHO, or troponin I. Only age was determined to be an independent statistically significant predictor of cardiac abnormality (P = .01). There was no difference in mortality between the cardiac abnormality and control groups (P = .33). However, there was increased morbidity in the cardiac abnormality group as demonstrated by worse discharge disposition, in addition to increased length of hospital stay (22.6 vs 17.1 days, P < .01). The incidence of cardiac abnormalities was the same among surgical and endovascular treatment groups.

CONCLUSIONS

Cardiac abnormalities, including those that meet ACC criteria for MI, are common among patients with SAH. However, in contrast to cardiac events outside the context of SAH, these abnormalities do not increase mortality. They do, however, adversely affect discharge disposition and prolong hospital LOS. The type of aneurysm treatment does not affect the incidence or outcome of cardiac abnormalities.

Cardiopulmonary complications of brain injury

Cardiac and pulmonary complications following acute neurologic injury are common and may be a cause of morbidity and mortality in this population. Examples include hypertension, arrhythmias, ventricular dysfunction, pulmonary edema, shock, and sudden death. Primary neurologic events are represented by stroke, subarachnoid hemorrhage, traumatic brain injury, epilepsy, and encephalitis and have been frequently reported. Given the high frequency of these conditions, it is important for physicians to become familiar with their pathophysiology, allowing for more prompt and appropriate treatment.

Role of autonomic nervous dysfunction in electrocardio-graphic abnormalities and cardiac injury in patients with acute subarachnoid hemorrhage

Electrocardiographic abnormalities, cardiac injury, and autonomic nervous function were investigated in patients with acute-phase subarachnoid hemorrhage (SAH) (42 patients with SAH related to ruptured aneurysm and 42 control subjects). Electrocardiogram and Holter electrocardiogram for spectral analysis of heart rate variability (HRV) were recorded. Concentrations of cardiogenic enzymes (ie, creatine kinase-myocardial fraction [CK-MB], myosin light chain I, and troponin T), plasma concentrations of catecholamine (ie, noradrenaline, adrenaline, 3-methoxy-4-hydroxy-phenylethylene glycol [MHPG]) and HRV were compared in the acute and chronic phase of SAH, and with the values in the controls subjects. As previously reported, patients with acute SAH exhibited electrocardiographic (ECG) abnormalities and increased concentrations of both cardiogenic enzymes and plasma catecholamines, suggesting that acceleration of sympathetic activity is involved. However, HRV analysis showed enhanced parasympathetic activity, probably associated with increased intracranial pressure after the onset of SAH, which may be explained by accentuated antagonism, negative feedback of noradrenaline to the center, and reduction of sympathetic activity after reaching a peak level. The results suggest that not only sympathetic activity but also vagal activity is enhanced during the acute phase of SAH, thus contributing to the ECG abnormalities and the onset of cardiac injury.

Cardiac manifestations after subarachnoid hemorrhage: a systematic review of the literature

Cardiac alterations associated with subarachnoid hemorrhage (SAH) have been recognized and frequently reported. We systematically reviewed the literature on MEDLINE using the key words: SAH + (heart, cardiac, electrocardiogram, cardiac enzymes, troponin, myoglobin, echocardiography, scintigraphy, Holter, and regional wall motion abnormalities) and included all articles describing cardiac abnormalities in the course of SAH whether spontaneous or secondary. The diagnosis of SAH was established by computed tomography scan, lumbar puncture, or brain autopsy. Cardiac abnormalities were identified by electrocardiogram, enzymatic elevation, Holter monitoring, echocardiography, cardiac scintigraphy, coronary angiography, or autopsy. Despite the considerable literature describing cardiac alterations during the course of SAH, epidemiological, pathophysiological, and prognostic aspects are yet to be clarified. Further studies are needed to evaluate the magnitude of this problem.

Electrocardiographic Abnormalities in Patients With Subarachnoid Hemorrhage

Subarachnoid hemorrhage is a serious neurological disorder that is often complicated by the occurrence of electrocardiographic abnormalities unexplained by preexisting cardiac conditions. These morphological waveform changes and arrhythmias often are unrecognized or misinterpreted, potentially placing patients at risk for inappropriate management. Many previous investigations were retrospective and relied on data collected in an unsystematic manner. More recent studies that included use of serial electrocardiograms and Holter recordings have provided new insight into the high prevalence of electrocardiographic changes in subarachnoid hemorrhage. Research on the prevalence, duration, and clinical significance of these electrocardiographic abnormalities and on associated factors and etiological theories is reviewed.

Newly diagnosed atrial fibrillation and acute stroke. The Framingham Study

BACKGROUND AND PURPOSE

When atrial fibrillation (AF) is first documented at the time of onset of acute stroke, it is difficult to establish a temporal relationship between AF and stroke. Did AF precede and precipitate the stroke, or did the arrhythmia appear as a result of stroke? Following the course of the newly diagnosed AF may help to clarify this relationship.

METHODS

The Framingham Study cohort of 5070 members, aged 30 to 62 years and free of cardiovascular disease at entry, has been under surveillance for the development of cardiovascular disease, including stroke. We followed the course of AF, which was documented for the first time on or soon after hospital admission for stroke.

RESULTS

During 38 years of follow-up, 115 of 656 initial stroke events occurred in association with AF: 89 had previously documented AF, 21 had AF discovered for the first time on admission for the stroke, and 5 were admitted with sinus rhythm but developed AF after admission. Of the 21 subjects with AF diagnosed on admission, in 12 (57%) AF persisted thereafter (chronic AF). Among the other 9 persons presenting with nonpersistant AF, paroxysms recurred in 3 (14%) and became chronic AF in 4 (19%). AF was transient and did not recur in only 2 persons (10%). Of the 5 subjects who developed AF after admission, AF was sustained from the initial diagnosis in 2 and recurred in paroxysms or became established as chronic in 3.

CONCLUSIONS

Ninety-two percent (24/26) of subjects presenting with newly discovered AF at the time of acute stroke continued to have this rhythm disturbance in a chronic or paroxysmal form. In only 2 subjects (8%) was the arrhythmia short-lived and nonrecurrent. These follow-up data suggest that in most instances AF was probably the precipitant rather than the consequence of stroke.

Electrocardiographic and echocardiographic changes associated with malignant catatonia

We describe a case of malignant catatonia manifested by catatonic symptoms, fever, hemodynamic instability, and acute neurologic decline that was associated with electrocardiographic and echocardiographic abnormalities similar to those noted in patients with other central nervous system processes. The patient's electrocardiographic and echocardiographic abnormalities resolved after successful electroconvulsive therapy for the underlying neuropsychiatric disorder. The theoretic, physiologic, and clinical significances of this case are discussed.

Electrocardiographic changes associated with acute cerebrovascular disease: a clinical review

Patients with acute vascular disorders of the CNS demonstrate an abundance of both rhythm and morphologic changes in their ECG. Of these a few will demonstrate myocardial dysfunction and or damage. The value of the ECG in evaluating and predicting which patients will have myocardial dysfunction or damage is questionable. One would assume the echocardiogram would be of more help than the ECG in identifying patients with myocardial damage; however, little data are available. The reason for the poor correlation between ECG findings and clinical correlates has not been explained to date, but it is possible to postulate a theory. There are two mechanisms that might mediate ECG changes in these patients, ie, autonomic neural stimulation from the hypothalamus or elevated circulating catecholamines. Hypothalamic stimulation may cause ECG changes without associated myocardial damage whereas elevated catecholamines may result in myocardial damage. This might explain why so many patients have ECG changes and very few have demonstrable myocardial damage in general, or ischemic damage in particular. That cardiac antiischemic therapy does not change mortality may relate to the fact that treatment has been directed towards patients with ECG changes, which in turn do not correlate with myocardial damage. Better patient selection for such therapy might rest upon demonstration of wall motion abnormalities on echocardiogram. The weakness of this strategy is that many patients with stroke have preexisting coronary disease and wall motion abnormalities and thus echo findings may only document remote infarction rather than acute ischemia.

Serial electrocardiographic recording in aneurysmal subarachnoid hemorrhage

We prospectively studied serial electrocardiograms in 61 patients with aneurysmal subarachnoid hemorrhage. Electrocardiographic changes were related to the initial level of consciousness, to subsequent events, and to outcome after 3 months. All 61 patients had at least one abnormal electrocardiogram, but cardiac disease did not contribute directly to morbidity or mortality. Fast rhythm disturbances, ischemic changes, or both on the electrocardiograms were significantly correlated with poor outcome but not with specific outcome events, particularly not with rebleeding or cerebral ischemia. The Glasgow Coma Scale score on admission and the amount of cisternal and (to a lesser extent) intraventricular blood on the initial computed tomogram were also significantly correlated with poor outcome, but these factors only partially confounded the relation between electrocardiographic abnormalities and poor outcome. We conclude that in patients with aneurysmal subarachnoid hemorrhage, electrocardiographic abnormalities do not herald impending cardiac disease but indirectly reflect adverse intracranial factors. Electrocardiographic abnormalities may therefore have some independent value in predicting poor outcome.

ECG abnormalities in patients with subarachnoid haemorrhage and intracranial tumours

The incidence of and possible factors influencing ECG abnormalities were analysed in one patient group with subarachnoid haemorrhages (n = 406) and another with intracranial tumours (n = 400). The highest incidence of each ECG abnormality was always found in the patients with subarachnoid haemorrhages. In this group an ECG pattern, possibly attributable to the cerebral disease and comprising abnormalities of the T and U waves and prolongation of the Q-Tc interval, was frequently identified.

Autonomic dysfunction in polyneuropathies: a report on 106 cases

Autonomic dysfunction is a common feature in various forms of polyradiculoneuropathy. This study investigated the kinds and frequency of of autonomic dysfunction in 106 cases. Denervation insufficiency of organs associated with supersensitivity of reflex mechanisms was found to be the best explanation of the pathophysiology. Early insertion of a transient cardiac pacemaker is recommended to counteract life-threatening cardiac failure.

A small animal model for electrocardiographic abnormalities observed after an experimental subarachnoid hemorrhage

The male Sprague-Dawley rat was successfully used to produce increases in arterial blood pressure and electrocardiographic abnormalities similar to those seen in patients after a subarachnoid hemorrhage. The model employs a less expensive, easily available laboratory animal than other existing models. Whole heparinized blood is introduced in the area of the circle of Willis to simulate a subarachnoid hemorrhage. This model ensures a constant body-blood volume and minimizes damage to brain tissue as no blood vessel has to be punctured. The volume of blood required to produce bradycardia and other electrocardiographic abnormalities can be controlled and calculated for each animal. The model produced a sudden onset and progression of cardiovascular symptoms. Blood apparently is specific for producing electrocardiographic abnormalities as compared to 0.9% saline, Dextran 40 and Gentran 75 when introduced in the area of the circle of Willis. This specificity was not maintained when blood and saline were introduced into the cisterna magna as electrocardiographic abnormalities were observed with both agents.

A study of ECG abnormalities and myocardial specific enzymes in patients with subarachnoid haemorrhage

Twenty-two patients with subarachnoid haemorrhage were investigated for changes in myoglobin, total CK, CK-MB and CK-BB in serum and for the incidence of ECG abnormalities. Serial ECG's showed abnormalities in 20 patients; 15 of these had T wave changes, 15 Q-Tc prolongation, ten had S-T depression and nine U waves and in seven cases arrhythmias were found. The purpose of the study was to find out whether a relationship could be established between the ECG abnormalities and changes in serum myoglobin and enzymes. However, in no patient could myoglobin or enzyme patterns consistent with acute myocardial or cerebral damage be observed and therefore the ECG abnormalities do not seem to be related to detectable myocardial damage.

Electrocardiographic changes in acute ulcerative colitis

Two young women with acute ulcerative colitis were found to have electrocardiographic abnormalities which returned to normal with clinical improvement and corticosteroid therapy. Clinical and biochemical monitoring failed to reveal any cause for this previously unrecognized association and it is postulated that an aetiological agent or toxin produced by the inflammatory process may have damaged the myocardium or its autonomic supply.

Electrocardiographic alterations in subarachnoid haemorrhage. Correlation between spasm of the arteries of the left side on the brain and T inversion and QT prolongation

In a retrospective study of 89 patients with subarachnoid haemorrhage (SAH), the frequency and specificity of changes in the electrocardiogram (ECG) were determined, as well as electrocardiographically established arrhythmias. The ECG changes were correlated with neurological as well as angiographic findings (localization of the aneurysm and vascular spasm). Abnormal ECGs were found in about 80% of the patients. The following abnormalities were found with decreasing frequency: depression and elevation of the ST segment, prolongation of the QT interval, flattening and inversion of the T wave, U waves and TU fusion waves, and arrhythmias (sinus tachycardia and bradycardia, extrasystole). A verified correlation (chi-square test) was shown between angiographically demonstrated spasm of the brain arteries of the left side and negative T waves as well as a prolongation of the QT interval. These results are related to the causal role of the left stellate ganglion in the generation of ECG changes and arrhythmias (animal experiments, and the success by blockade or surgical removal of the stellate ganglion in hereditary QT prolongation.

Electrocardiographic abnormalities and autonomic dysfunction in Guillain-Barré syndrome

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Early pronounced ST segment depression with marked J point decline heralding acute lethal clinical myocardial infarction: Necropsy-electrocardiographic correlative study

Marked ST segment depression (greater than or equal to 2 mm J point decline with horizontal or downsloping ST) was correlated with necropsy findings in 105 cases. Acute myocardial infarction (AMI) was most frequently (70%) responsible for development of the abnormal ST pattern, thereby indicating the diagnosis and severe prognosis of the AMI. In 23% of patients the ST segment depression pattern was associated with chronic heart disease without AMI; all were severely ill with 92% receiving digitalis. Sudden worsening of the basic heart disease or circulatory shock were frequently found to coincide with the abnormal ST pattern; necropsy revealed extensive old MI or myocardial fibrosis in these patients. Marked ST segment depression was also found in five patients without underlying heart disease at autopsy; an acute cerebral accident or circulatory shock was considered to have produced the abnormal ST segment pattern.

Subarachnoid haemorrhage and the electrocardiogram - a review

Electrocardiographic abnormalities occur in approximately 50% of patients with subarachnoid haemorrhage. The changes can resemble those of myocardial damage, although in most cases post-mortem studies show no macroscopic evidence of injury. Failure to appreciate this can lead to misdiagnosis of organic cardiac disease, cause delay in surgical treatment or even lead to inappropriate therapy. This review deals with the changes that may occur in the electrocardiogram, discusses the explanations put forward, and examines how this may influence future trends in management.

The activity of the sympathetic nervous system following severe head injury

The activity of the sympathetic nervous system during the course of severe closed head injury has been evaluated in 15 patients by measuring plasma levels of epinephrine and norepinephrine. With the onset of the transition stage from midbrain syndrome to the apallic syndrome the plasma levels mainly of norepinephrine started to increase and remained high during the further course of the disease. During the remission from the apallic syndrome the elevated norepinephrine levels started to decline. The data indicate that a longlasting overactivity of the sympathetic nervous system is a characteristic feature in the course of severe head injury. As a rational therapy to protect the peripheral tissues against the consequences of a longlasting sympathetic overactivity we suggest the use of beta-adrenergic blocking agents and adrenergic neuron blocking drugs.

On the mechanism of sudden death with subarachnoid hemorrhage

The mechanism of death in some patients with subarachnoid hemorrhage is cardiac arrhythmia. Prevention of cardiac arrhythmias by suitable drugs might save the life of patients whose brain is still good.

Prinzmetal's variant angina associated with subarachnoid hemorrhage: A case report

Prinzmetal's variant of angina occurred in a 48-year-old man who sustained two attacks of subarachnoid hemorrhage within 10 days. The first anginal pain started at the same time that the second cerebrovascular accident developed, but subsequent anginal episodes were not accompanied by other symptoms or signs that indicated new development of subarachnoid hemorrhage. Twelve days later, when nuchal rigidity was fairly improved, the episodes of chest pain ended. A vasospasm of the large coronary arteries--probably due to the derangement of the autonomic nervous system caused by subarachnoid hemorrhage--was presumed to contribute to the occurrence of the variant angina. Based on this case and on review of the literature, we propose that coronary arterial spasm is one of several causes of the cardiac changes seen in subarachnoid hemorrhage.

Sympathetic nervous system activity in patients with subarachnoid hemorrhage

In patients with subarachnoid hemorrhage there were increased concentrations of plasma epinephrine and norepinephrine when compared with those concentrations in a group of patients admitted to hospital with other illness. Reassessment after a variable period showed that in patients whose eventual clinical result was poor the plasma epinephrine and norepinephrine concentrations increased further while in those with a good result those concentrations showed a decline. No such changes were evident in plasma dopamine-beta-hydroxylase activities which were within normal range. In a sub-group of patients who had neurosurgery after admission for clipping an aneurysm, the post-operative changes of plasma epinephrine and norepinephrine concentrations were related to the clinical condition of the patients.

Effects of bilateral and unilateral stellate stimulation on canine ventricular refractory periods at sites overlapping innervation

The efffects of unilateral right, unilateral left, and bilateral stellate stimulation on ventricular refractory periods at sites of overlapping cardiac sympathetic innervation were studied in 11 pentobarbital anesthetized dogs. The stellates were stimulated with 10 Hz pulses 4 msec in duration with intensities strong enough to produce T wave changes in a vertical ECG lead and just below the intensity at which control of drive of the ventricle at a 400-msec cycle length was lost. Refractory periods shortened more with left stellate stimulation, 17.8 +/- 5.9 msec (mean +/- SD) than with right stellate stimulation, 10.3 +/- 5.1 msec, P less than 0.001. During bilateral stimulation, shortening of refractory periods was no greater whether stimulation was applied first to the left and then right stimulation was added, 19.7 +/- 6.9 msec, or the stimulation was applied first to the left and then right stimulation was added, 18.3 +/- 6.5 msec. The shortening of refractory periods with bilateral stellate stimulation was not significantly different from that with left stellate stimulation alone. The results of this study suggest that ventricular recovery properties in areas of overlapping cardiac sympathetic innervation are less influenced by increases in tone of the right sympathetics than by increases in left sympathetic tone. In addition, the findings indicate that a bilateral increase in cardiac sympathetic tone has no greater effect on recovery properties than the effects of the left cardiac sympathetics alone.

Electrocardiographic changes and myocardial damage in patients with acute cerebrovascular accidents

In 100 consecutive patients with acute cerebrovascular accident, due to cerebral thrombosis in 72, cerebral hemorrhage in 12, embolus in 6, and subarachnoid hemorrhage in 10, there were 90 who had electrocardiographic abnormalities during the first three days after admission, compared to 50% in a control group. The patients with cerebrovascular accident had a 7- to 10-fold higher incidence of ST segment depression, prolonged Q-Tc interval and atrial fibrillation, and a 2- to 4-fold higher incidence of T wave inversion, conduction defects, premature ventricular beats and left ventricular hypetrophy. Patients who died had a 2-, 3- and 5-fold higher incidence of electrocardiographic evidence of recent myocardial infarction, atrial fibrillation and conduction defects than those who survived, but these changes occurred in only 5, 21 and 14% of all patients, and other electrocardiographic changes could not be correlated with mortality. During the first three days after admission 29 patients had elevation of serum enzymes which may be derived from cardiac muscle, particularly CPK, which was increased 6-fold, compared to 2-fold increases in HBDH, GOT, and LDH. Only 5 of these patients had electrocardiographic evidence of recent myocardial infarction. Patients with elevated serum CPK had a 2-fold higher incidence of ST segment depression, T wave inversion, conduction defects and atrial fibrillation than those with normal CPK, and a mortality of 66%, compared to 30%. Of 41 patients who died, 49% had elevated serum CPK, compared to 15% of 59 patients who survived. These differences were significant (P less than 0.01). Serum CPK was more frequently helpful than the electrocardiogram in evaluating the extent of cardiac damage and in predicting mortality. Patients with acute cerebrovascular accident should have repeated evaluation of serum CPK and the ECG, and be monitored for arrhythmias.

Cardiac arrhythmias in experimental subarachnoid hemorrhage

Experimental subarachnoid hemorrhage (SAH) in dogs was produced by introducing blood into the subarachnoid space through a catheter connected to an artery of the animal. The intact animals and those with preserved vagi and heart sympathetic innervation, developed arrhythmias with short latencies which correlated with the sudden increase in the intracranial pressure. The animals with sections of both vagi and heart sympathetic innervation, but with an intact spinal cord, developed arrhythmias that were delayed and did not correlate with the changes in intracranial pressure. These arrhythmias were preceded by changes in the QT interval, T wave and ST segment. It was concluded that the arrhythmias could be produced either by direct autonomic discharges to the heart or by increased circulating and tissue catecholamines. The clinical implications of these findings are discussed.

Brain energetics and circulatory control after subarachnoid hemorrhage

Ischemia-provoking factors such as vasospasm, decreased cerebral perfusion pressure, and intravascular thrombosis may be present after subarchnoid hemorrhage (SAH). When these factors were not present during controlled SAH, a primary depression of cerebral glycolysis associated with normal stores of energy-rich phosphates was found. Although cerebral blood flow usually changes in response to changes in cerebral metabolic needs, this influence on the circulation was not evident in the early hours after SAH. After 3 to 4 hours an erratic decrease in blood flow occurred, probably related to vasospasm, and there were measurable decreases in energy-rich phosphates similar to those occurring after more severe and prolonged ischemias. These findings are indicative of abnormally erratic vascular responses to metabolic cues and may play a role in producing the encephalopathy of SAH.