Acute neurocardiogenic injury after subarachnoid hemorrhage

Clinical implications of midventricular obstruction and intravenous propranolol use in transient left ventricular apical ballooning (Tako-tsubo cardiomyopathy)

BACKGROUND

Persistent hypotension with dynamic midventricular obstruction (MVO) in patients with transient left ventricular (LV) apical ballooning (Tako-tsubo cardiomyopathy) is an important complication that needs to be treated.

PURPOSE

The objective of this study is to determine the effects of intravenous propranolol challenge on MVO in transient LV apical ballooning.

SUBJECTS AND METHODS

Thirty-four patients (12 males, 22 females, mean age 64 +/- 17 years, age range 22-84 years) with LV apical ballooning were enrolled. The hemodynamic and echocardiographic effects of propranolol (0.05 mg/kg, maximum 4 mg) were analyzed in 13 patients.

RESULTS

(1) Midventricular obstruction was present in 8 (24%) of 34 patients, and the pressure gradient (PG) ranged from 28 to 140 mm Hg. (2) Patients with MVO had similar demographic and clinical characteristics (symptoms, peak creatine kinase, plasma catecholamine levels) as those without MVO; however, in patients with MVO, abnormal Q waves on electrocardiogram and hypotension were more prevalent. (3) In the MVO group, intravenous propranolol changed the PG from 90 +/- 42 to 22 +/- 9 mm Hg, the systolic blood pressure (SBP) from 85 +/- 11 to 116 +/- 20 mm Hg, and the LV ejection fraction (LVEF) from 30% +/- 7% to 43% +/- 4%. (4) In all subjects, the changes in the PG after propranolol injection had a significant linear correlation with the SBP and LVEF changes: deltaSBP = 4.738 + 0.315 x deltaPG (r = 0.689 (P < .001) and deltaLVEF = 2.973 + 0.1321 x deltaPG (r = 0.715, P < .001).

CONCLUSION

Intravenous propranolol is useful for treating dynamic MVO in patients with transient LV apical ballooning.

Prognostic implications of left ventricular wall motion abnormalities associated with subarachnoid hemorrhage

Left ventricular (LV) dysfunction generally occurs early in the course of subarachnoid hemorrhage (SAH). We evaluated the prognostic value of electrocardiographic (ECG) abnormalities and echocardiographic LV dysfunction evaluated shortly after SAH. We prospectively enrolled 47 SAH patients (62 +/- 14 years, mean +/- SD) who were admitted to the neurosurgical care unit of our institute. Neurological status was rated on the day of admission. Twelve-lead ECG and 2-dimensional echocardiography were recorded 2 +/- 1 day after onset of SAH. ECG abnormalities (pathological Q-wave, ST-segment deviation, T-wave inversion, and QT prolongation) were evaluated and the incidences of global (LV ejection fraction < 50%) and segmental (regional wall motion abnormality [RWMA]) LV dysfunction were measured. During a follow-up period of 44 +/- 23 days, 17 (36%) patients died. ECG abnormalities, LV ejection fraction < 50%, and RWMA were observed in 62%, 11%, and 28% of patients, respectively. Univariate Cox proportional hazards regression analysis revealed that neurological status, rate-corrected QT interval, LV ejection fraction, and RWMA were significant predictors of death. After adjustment for these significant clinical variables, and age and sex, independent predictors of mortality were neurological status and RWMA. RWMA may provide significant prognostic information in patients with SAH.

Myocardial stress in patients with acute cerebrovascular events

Signs of myocardial involvement are common in patients with acute cerebrovascular events. ST segment deviations, abnormal left ventricular function, increased N-terminal pro-brain natriuretic peptide (NT-proBNP), prolonged QT interval, and/or raised troponins are observed in up to one third of the patients. The huge majority of these findings are fully reversible. The changes may mimic myocardial infarction, but are not necessarily identical to coronary thrombosis. Based on the literature these signs may represent an acute catecholamine release provoked by the cerebrovascular catastrophe itself and not coronary thrombosis. However, all patients with signs of cardiac involvement during acute cerebrovascular events should receive a cardiological follow-up in order to exclude concomitant ischemic heart disease.

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.

The cardiovascular toll of stress

Psychological stress elicits measurable changes in sympathetic-parasympathetic balance and the tone of the hypothalamic-pituitary-adrenal axis, which might negatively affect the cardiovascular system both acutely-by precipitating myocardial infarction, left-ventricular dysfunction, or dysrhythmia; and chronically-by accelerating the atherosclerotic process. We provide an overview of the association between stress and cardiovascular morbidity, discuss the mechanisms for this association, and address possible therapeutic implications.

Takotsubo cardiomyopathy or transient left ventricular apical ballooning syndrome: A systematic review

BACKGROUND

Transient left ventricular apical ballooning syndrome (TLVABS) is an acute cardiac syndrome mimicking ST-segment elevation myocardial infarction characterized by transient wall-motion abnormalities involving apical and mid-portions of the left ventricle in the absence of significant obstructive coronary disease.

METHODS

Searching the MEDLINE database 28 case series met the eligibility criteria and were summarized in a narrative synthesis of the demographic characteristics, clinical features and pathophysiological mechanisms.

RESULTS

TLVABS is observed in 0.7-2.5% of patients with suspected ACS, affects women in 90.7% (95% CI: 88.2-93.2%) with a mean age ranging from 62 to 76 years and most commonly presents with chest pain (83.4%, 95% CI: 80.0-86.7%) and dyspnea (20.4%, 95% CI: 16.3-24.5%) following an emotionally or physically stressful event. ECG on admission shows ST-segment elevations in 71.1% (95% CI: 67.2-75.1%) and is accompanied by usually mild elevations of Troponins in 85.0% (95% CI: 80.8-89.1%). Despite dramatic clinical presentation and substantial risk of heart failure, cardiogenic shock and arrhythmias, LVEF improved from 20-49.9% to 59-76% within a mean time of 7-37 days with an in-hospital mortality rate of 1.7% (95% CI: 0.5-2.8%), complete recovery in 95.9% (95% CI: 93.8-98.1%) and rare recurrence. The underlying etiology is thought to be based on an exaggerated sympathetic stimulation.

CONCLUSION

TLVABS is a considerable differential diagnosis in ACS, especially in postmenopausal women with a preceding stressful event. Data on longterm follow-up is pending and further studies will be necessary to clarify the etiology and reach consensus in acute and longterm management of TLVABS.

B-type natriuretic peptide as a marker for heart failure in patients with acute stroke

OBJECTIVE

To determine whether serum N-terminal pro-B-type natriuretic peptide (N-BNP), a biomarker of myocardial wall stress, is specific to acute heart failure (HF) in patients hospitalized with stroke.

DESIGN

Case-control study.

SETTING

Tertiary hospital, Neurosciences Critical Care Unit and Stroke Unit.

PATIENTS

Consecutive patients with acute ischemic or hemorrhagic stroke who were evaluated for HF.

INTERVENTION

None.

MEASUREMENTS AND RESULTS

Cases and controls were classified, respectively, as patients with or without HF, defined according to modified Framingham criteria. Seventy-two patients were evaluated, 39 with ischemic stroke, 22 with aneurysmal subarachnoid hemorrhage (SAH), and 11 with intracerebral hemorrhage (ICH). Thirty-four patients (47%) met criteria for HF, and 47 patients (65%) had systolic or diastolic left ventricular (LV) dysfunction on echocardiogram. Serum N-BNP was measured a median of 48 h following the onset of stroke and was increased (> 900 pg/ml) in 56 patients (78%), with higher levels in non-survivors (11898 +/- 12741 vs 4073 +/-5691; p = 0.001). In a multiple regression model, N-BNP elevation was not independently associated with HF (OR 5.4, 95% CI 0.8-36.0, p = 0.084). At a cut-off of 900 pg/ml, the sensitivity of N-BNP for HF was 94%, specificity 37%, positive predictive value (PPV) 57%, and negative predictive value (NPV) 88%. For systolic or diastolic LV dysfunction, the sensitivity of N-BNP was 89%, specificity 44%, PPV 75%, and NPV 69%.

CONCLUSIONS

These results demonstrate that N-BNP elevation is not specific to HF or LV dysfunction in patients with acute ischemic stroke, SAH, and ICH.

Non-neurologic organ dysfunction in acute brain injury

Patients with acute brain injury are a distinct group within the ICU who may develop non-neurologic organ dysfunction in the absence of systemic injury or infection. This dysfunction may arise directly as a result of the brain injury or indirectly with complications of brain-specific therapies. This article reviews the current literature with respect to the incidence of organ dysfunction or failure and its association with outcome in patients with acute brain injury. Organ system-specific etiologic considerations and management are discussed.

Neurocardiogenic injury in neurovascular disorders

cardiac injury occurs frequently after stroke; and the most widely investigated form of neurocardiogenic injury is aneurysmal subarachnoid hemorrhage. Echocardiography and screening for elevated troponin and B-type natriuretic peptide levels may help prognosticate and guide treatment of stroke. Cardiac catheterization is not routinely recommended in subarachnoid hemorrhage patients with left ventricular dysfunction and elevated troponin. The priority should be treatment of the underlying neurologic condition, even in patients with left ventricular dysfunction. Cardiac injury that occurs after subarachnoid hemorrhage appears to be reversible. In contrast to subarachnoid hemorrhage patients, patients with ischemic stroke are more likely to have concomitant significant heart disease. For patients who develop brain death, cardiac evaluation under optimal conditions may help increase the organ donor pool.

Myocardial perfusion in apical ballooning syndrome correlate of myocardial injury

BACKGROUND

The pathophysiology of the apical ballooning syndrome (ABS) is poorly understood. This study evaluated myocardial perfusion abnormalities at the time of presentation in patients with ABS and examined whether abnormal microvascular blood flow predicts the extent of myocardial injury.

METHODS

We evaluated 42 consecutive patients, all women, with a diagnosis of ABS and technically adequate angiograms for the assessment of the TIMI myocardial perfusion grade (TMPG), an index of myocardial perfusion.

RESULTS

Abnormal myocardial perfusion was present in 29 (69%) patients. There were no differences in age, frequency of conventional coronary atherosclerosis risk factors, left ventricular ejection fraction at either presentation or follow-up, congestive heart failure at presentation, or length of hospital stay between patients with normal versus those with abnormal TMPG. Patients with abnormal TMPG had higher peak troponin level compared with patients with normal TMPG (0.84 +/- 0.68 vs 0.42 +/- 0.33 ng/mL, P = .047). Similarly, ST elevation or deep T-wave inversion on the electrocardiogram was more common in patients with abnormal perfusion (86% vs 46%, P = .006).

CONCLUSION

Impaired myocardial perfusion due to abnormal microvascular blood flow is frequently present in patients with ABS and correlates with the extent of myocardial injury. Microvascular dysfunction likely play a pivotal role in the pathogenesis of myocardial stunning in ABS.

Effects of temperature on inotropic responses of isolated canine atria under spontaneous or electrically paced rhythm

Effects of temperature on atrial contractility were investigated on isolated, blood-perfused canine atrial preparations which were spontaneously beating or constantly paced at 2 Hz and 2.5 Hz. The contrctility was increased by cooling from 37 degrees C to 27 degrees C in spontaneously beating hearts (the rate decreased from 100 to 56 beats/min) but in the paced atrium the increase of contactile force was followed by a slight decrease under 29 degrees C usually with pulsus alternans. The durations of shortening and relaxation of the developed tension were increased in parallel with cooling of temperature. The rate of shortening was slightly increased by cooling in both spontaneous rate and constant rate. On the other hand, the rate of relaxation was not so influenced in spontaneously beating hearts but slightly increased in paced atria but not significantly. The frequency-force relationship showed the positive staircase phenomenon (2 to 3.5 Hz) at 37 degrees C. However, at lower temperature the positive staircase was not clear and rather negative staircase appeared (1--3 Hz).