Intoxicación severa por Nicotiana glauca (Palán Palán) con miocardio atontado / Severe poisoning by Nicotiana glauca (Palán Palán) with stunned myocardium

Resumen Nicotiana glauca también llamada Palán Palán, es un arbusto con hojas verdes azuladas y despulidas y una flor amarilla tubular pendulante que presenta alcaloides piridínicos, como nicotina, nornicotina, anatabina y anabastina (análogo estructural de la Nicotina). Se presenta el caso clínico de una paciente de 50 años con cuadro agudo de debilidad muscular generalizada que evoluciona con paro respiratorio, tras la ingesta accidental de una cantidad desconocida de hojas de Nicotiana glauca, cultivadas en una huerta hogareña mediante técnica de hidroponía y confundidas por su conviviente con espinaca. Presentó aumento de lactato y Troponina Ultra Sensible e Hipoquinesia Global de Ventrículo Izquierdo en el ecocardiograma, compatible con Aton tamiento Miocárdico (AM), que evolucionó favorablemente. Si bien hay pocos reportes, se han informado muertes de animales y humanos, tras la ingesta accidental de Nicotiana glauca. El inicio del cuadro es rápido, con patrón bifásico, con vómitos y estímulo simpático, seguido por bloqueo ganglionar y neuromuscular, pudiendo presentar paro respiratorio, shock, convulsiones y coma. El AM es una disfunción miocárdica prolongada con retorno gradual de la actividad contráctil, posterior a un episodio breve de isquemia grave, puede ser asintomático, pudiendo presentar alteraciones en el electrocardiograma, enzimas cardíacas o ecocardiograma. Generalmente presenta pronóstico favorable, pudiendo presentar insuficiencia cardíaca ante patologías concurrentes o aumento de requerimientos de oxígeno.

Abstract Nicotiana glauca is a shrub with bluish green leaves and a pendulous tubular yellow flower. It has pyridine alkaloids, such as nicotine, nornicotine, anatabine and anabastine (structural analog of Nicotine). We present the case of a 50 years old pa- tient with acute generalized muscle weakness that evolves to respiratory arrest, after accidentally ingesting an unknown quantity of Nicotiana glauca leaves, grown in a home vegetable garden, using a hydroponic technique and confused by her cohabiting with spinach. She presented increased lactate and Ultra Sensitive Troponin and Left Ventricular Global Hypokinesia in the echo- cardiogram, compatible with Myocardial Stunned, that it evolved favorably. There are few reports, animal and human deaths have been reported following accidental ingestion of Nicotiana glauca. The onset of the symptoms is early, with a biphasic pattern, with vomiting and sympathetic stimulation, followed by ganglionic and neuromuscular blockage and may present respiratory arrest, shock, seizures and coma. Myocardial Stunned is a prolonged myocardial dysfunction with gradual return of contractile activity after a brief episode of severe ischemia, it can be asymptomatic, and it can present alterations in the electrocardiogram, cardiac enzymes or echocardiogram. Generally presents a benign prognosis, being able to present heart failure with concurrent patholo- gies or increased requirements.

Neurogenic Stunned Myocardium in Severe Neurological Injury.

PURPOSE OF REVIEW: Neurogenic stunned myocardium (NSM) is a poorly recognized cardiac manifestation of neurological illness. This review addresses the contemporary understanding of NSM pathophysiology, epidemiology, diagnosis, and clinical management. RECENT FINDINGS: While the precise pathophysiology and diagnosis remain unclear, NSM is phenotypically atypical stress cardiomyopathy that can be partially attributed to excess catecholaminergic toxicity. NSM is a diagnosis of exclusion where electrocardiography, echocardiography, and cardiac biomarkers are frequently abnormal. Clinical expertise is crucial to evaluate and differentiate NSM from acute coronary syndrome and in the evaluation of potential cardiac transplantation donors after unsalvageable severe neurological injury. Neurogenic stunned myocardium is a relatively common and clinically impactful condition. More research is needed, particularly to refine clinical prognostication of NSM and rule out intrinsic cardiac injury in order to optimize donor candidacy in the event of brain death.

Prevalence and Localization of Hibernating Myocardium Among Patients with Left Ventricular Dysfunction.

OBJECTIVE: This study evaluated how much of the myocardium was hibernating in patients with left ventricle dysfunction and/or comorbidities who planned to undergo either surgical or interventional revascularization. Furthermore, this study also identified which irrigation areas of the coronary arteries presented more scar and hibernating tissue. METHODS: At rest, Tc-99m MIBI SPECT and cardiac F-18 FDG PET/CT images collected between March 2009 and September 2016 from 65 patients (55 men, 10 women, mean age 64±12) were retrospectively analyzed in order to evaluate myocardial viability. The areas with perfusion defects that were considered metabolic were accepted as hibernating myocardium, whereas areas with perfusion defects that were considered non-metabolic were accepted as scar tissue. RESULTS: Perfusion defects were observed in 26% of myocardium, on average 48% were associated with hibernation whereas other 52% were scar tissue. In the remaining Tc-99m MIBI images, perfusion defects were observed in the following areas in the left anterior descending artery (LAD; 31%), in the right coronary artery (RCA; 23%) and in the Left Circumflex Artery (LCx; 19%) irrigation areas. Hibernation areas were localized within the LAD (46%), LCx (54%), and RCA (64%) irrigation areas. Scar tissue was also localized within the LAD (54%), LCx (46%), and RCA (36%) irrigation areas. CONCLUSION: Perfusion defects are thought to be the result of half hibernating tissue and half scar tissue. The majority of perfusion defects was observed in the LAD irrigation area, whereas hibernation was most often observed in the RCA irrigation area. The scar tissue development was more common in the LAD irrigation zone.

Radiofrequency catheter ablation versus balloon cryoablation of atrial fibrillation: markers of myocardial damage, inflammation, and thrombogenesis.

BACKGROUND: Evidence from animal and human studies suggests that cryoablation might be associated with a lesser inflammatory response and activation of coagulation compared with radiofrequency ablation. The study was aimed at comparing the effect of cryoballoon and radiofrequency catheter ablation of paroxysmal atrial fibrillation on markers of myocardial damage, inflammation, and activation of coagulation. METHODS: Forty-one patients received either cryoballoon (n = 23) or radiofrequency (n = 18) ablation of atrial fibrillation. We measured troponin I, high-sensitivity CRP, and interleukin 6 at baseline from the cubital vein, and from the right and left atrium before and after ablation, and from the cubital vein the following day. Prothrombin fragments 1 + 2, soluble P­selectin, and D­dimer were measured before and after ablation from both atria. RESULTS: We observed higher troponin I release in the cryoballoon than in the radiofrequency group (7.01 mcg/l (interquartile range [IQR]: 5.30-9.09) vs 2.32 mcg/l (IQR: 1.45-2.98), p < 0.001). The levels of inflammatory markers (high-sensitivity CRP and interleukin 6) in the two groups were comparable, as were the levels of markers of coagulation activation. Procedure duration, fluoroscopy times, and mid-term success (23 months, IQR 7-32) of the two groups were also comparable. CONCLUSIONS: Cryoballoon ablation of atrial fibrillation causes more significant myocardial damage, that is, more extensive ablation lesions, compared with radiofrequency catheter ablation. However, no major differences between these two ablation techniques with regard to the inflammatory response and activation of the coagulation system were observed.

Impact of metabolic syndrome on myocardial injury and clinical outcome after percutaneous coronary intervention.

AIMS: This study tested the associations between metabolic syndrome, postprocedural myocardial injury, and clinical outcome after percutaneous coronary intervention. PATIENTS AND METHODS: We evaluated 204 patients who fulfilled the study criteria and were scheduled for elective percutaneous coronary intervention. The patients were divided into a metabolic syndrome group and a control group according to the definition of metabolic syndrome. Creatine kinase-MB and troponin I levels were measured at baseline, at 8 h, and 24 h after the procedure, while clinical outcomes were followed up for 1 year. RESULTS: The incidence of postprocedural myocardial injury was significantly higher in the metabolic syndrome group than in the control group as indicated by either blood creatine kinase-MB elevation (32.9 % vs. 17.2 %, p = 0.010) or troponin I elevation (34.2 % vs. 17.2 %, p = 0.006). Postprocedural peak values of creatine kinase-MB (5.724 ± 7.678 ng/ml vs. 3.097 ± 5.317 ng/ml, p < 0.001) and troponin I (0.066 ± 0.093 ng/ml vs. 0.038 ± 0.079 ng/ml, p < 0.001) were also significantly higher in the metabolic syndrome group than in the control group. On multiple regression analysis, metabolic syndrome was independently associated with troponin I elevation (odds ratio 2.24, 95 % confidence interval, CI, 1.04-4.80, p = 0.039). During the 1-year follow-up, cardiac events occurred in 28.9 % of patients with metabolic syndrome and 17.9 % of controls, and there was a trend toward increased adverse outcomes in the metabolic syndrome group (hazard ratio 1.67, 95 % CI 0.93-3.00, p = 0.071, log rank test). CONCLUSION: The results of this study demonstrate that metabolic syndrome is associated with postprocedural myocardial injury and with increased cardiac events.

Clinical characteristics of myocardial stunning in acute stroke.

Neurogenic stunned myocardium (NSM) after subarachnoid hemorrhage (SAH) is well known, but there is a paucity of data regarding its occurrence following acute stroke. The aim of this study is to investigate the clinical characteristics of NSM in acute non-hemorrhagic stroke. We performed an electronic literature search with Medline and Google Scholar for English-language articles using the terms "ischemic stroke" along with "stunned myocardium" or "Takotsubo cardiomyopathy". The search resulted in seven case reports/series, but no prospective studies. The mean age of patients with myocardial stunning following ischemic stroke was 72.5 years and 77% of these patients were females. Insular cortex was involved in 38.4% of cases. Mean National Institutes of Health Stroke Scale (NIHSS) score at admission was 12.6 and mean NIHSS at discharge was 10.8. T-wave inversions and ST-segment elevations were noted in 84.6% and 69.2% of patients, respectively. Mean troponin elevation was 0.64 mcg/dL and mean left ventricular ejection fraction (LVEF) was 34.4%. In terms of outcomes, 84.6% of patients had significant improvement in LVEF, mostly within 4 weeks of onset of symptoms. To summarize, NSM was more common in females, with favorable prognosis. Less than half the patients with NSM following stroke had insular involvement. The mean troponin level in NSM after stroke was only half of that seen in SAH. While the lack of prospective studies on NSM in stroke patients precludes drawing further conclusions, more studies are warranted to investigate the risk factors for NSM and the effect on stroke outcomes.

A meta-analysis comparing SPECT with PET for the assessment of myocardial viability in patients with coronary artery disease.

OBJECTIVE: The aim of this meta-analysis was to examine the diagnostic accuracy of single-photon emission computed tomography (SPECT) for the assessment of myocardial viability in patients with coronary artery disease as compared with PET. MATERIALS AND METHODS: The literature was searched using the following keywords: single-photon emission computed tomography, positron emission tomography, perfusion, viability, myocardial infarction. Studies involving patients with coronary artery disease, left ventricular dysfunction, or a history of myocardial infarction and that compared SPECT and PET for the assessment of myocardial viability were included in the analysis. RESULTS: Eight studies including 310 patients were included in the meta-analysis. The total number of myocardial segments analyzed was 3580. The sensitivity and specificity of SPECT for the eight studies ranged from 59 to 95% and from 79 to 100%, respectively. The pooled sensitivity of SPECT was 82% [95% confidence interval (CI): 81-84%]. The pooled specificity of SPECT was 88% (95% CI: 86-90%). For all studies, the pooled diagnostic odds ratio was 62.60 (95% CI: 19.29-203.15) and the area under the receiver-operating characteristic curve was 0.945, indicating that SPECT could accurately assess myocardial viability. CONCLUSION: The meta-analysis indicated that SPECT can accurately assess myocardial viability, as compared with PET, and supports the use of SPECT for the assessment of myocardial viability in patients with coronary artery disease.

N-terminal Pro-B-type natriuretic peptide and its correlation to haemodialysis-induced myocardial stunning.

BACKGROUND: Haemodialysis (HD) is able to induce recurrent myocardial ischemia and segmental left-ventricular dysfunction (myocardial stunning). The association of N-terminal Pro-B-type natriuretic peptide (NTpro-BNP) with HD-induced myocardial stunning is unclear. METHODS: In 70 prevalent HD patients, HD-induced myocardial stunning was assessed echocardiographically at baseline and after 12 months. The extent to which pre-dialysis NTpro-BNP was associated with the occurrence of HD-induced myocardial stunning was assessed as the primary endpoint. RESULTS: The median Ntpro-BNP concentration in this cohort was 2,154 pg/ml (IQR 1,224-3,014). Patients experiencing HD-induced myocardial stunning at either time point displayed elevated NTpro-BNP values (2,418 pg/ml, IQR, 1,583-3,474 vs. 1,751 pg/ml, IQR (536-2,029), p = 0.02). NTpro-BNP levels did not differ between patients showing HD-induced stunning at baseline and those developing stunning during the observational period (p = 0.8). NTpro-BNP levels drawn at the beginning of the dialysis session achieved a poor diagnostic accuracy for the detection of myocardial stunning (area under the ROC curve 0.61, 95% CI 0.45-0.77), but provided an accurate rule out for myocardial stunning during the subsequent year (AUC 0.85, 95% CI 0.70-0.99). The calculated cut-off of 1,570 pg/ml achieved a sensitivity of 66% and a specificity of 78% for the exclusion of myocardial stunning at any time point. In logistic regression analysis, only low NTpro-BNP levels (OR 0.92 for every additional 100 pg/ml, 95% CI 0.85-0.99, p = 0.03) were significantly associated with absence of myocardial stunning at any time point. CONCLUSION: Predialytic NTpro-BNP levels fail to adequately diagnose current dialysis-induced myocardial stunning, but help to identify patients with a propensity to develop dialysis-induced myocardial stunning at any time during the next 12 months.

Association of ST-elevation and non-ST-elevation presentation on ECG with transmurality and size of myocardial infarction as assessed by contrast-enhanced magnetic resonance imaging.

BACKGROUND: It is the general perception, that ST-elevation myocardial infarction is associated with transmural ischemia while Non-ST elevation myocardial infarction is found in non-transmural subendocardial ischemia. This association, however, derives primarily from post mortem studies. METHODS: A total of 220 patients with acute myocardial infarction (MI) who had PCI on admission and contrast-enhanced cardiac magnetic resonance imaging (CMR) within one week were included into the study. Size and transmural extent of MI was quantified by CMR and correlated with the ECG on admission. RESULTS: Based on the ECG findings, 57% were classified as STEMI and 43% as NSTEMI. CMR infarct size was significantly larger in STEMI than NSTEMI (23.2 vs. 14.2 LV%, p<0.001). As assessed by CMR, STEMI patients were transmural in 63% as compared to 27% of patients with NSTEMI (p<0.001). In a multivariable logistic regression model, total infarct size was significantly associated with presence of STEMI (OR: 1.045, 95% CI [1.014-1.077], p=0.004) whereas the number of transmural segments did not significantly add further information for a STEMI/NSTEMI classification (p=0.054, change of c-index from 0.69 to 0.70). CONCLUSIONS: The electrocardiographic STEMI/NSTEMI classification does rather characterize the total size of MI than the transmural extent as assessed by CMR.

Left ventricular dysfunction and cerebral infarction from vasospasm after subarachnoid hemorrhage.

BACKGROUND: Although neurogenic stunned myocardium (NSM) after aneurysmal subarachnoid hemorrhage (SAH) is well described, its clinical significance remains poorly defined. We investigated the influence of left ventricular (LV) dysfunction and cerebral vasospasm on cerebral infarction, serious cardiovascular events, and functional outcome after SAH. METHODS: Of the 481 patients enrolled in the University Columbia SAH Outcomes Project between 10/96 and 05/02, we analyzed a subset of 119 patients with at least one echocardiogram, serial transcranial Doppler (TCD) data, and with no prior history of cardiac disease. LV dysfunction was defined as an ejection fraction <40% on echocardiography. Infarction from vasospasm was adjudicated by the study team after comprehensive review of all clinical and imaging data. Functional outcome was assessed at 15 and 90 days with the modified Rankin Scale (mRS). RESULTS: Eleven percent of patients had LV dysfunction (N = 13). Younger age, hydrocephalus, and complete filling of the quadrigeminal and fourth ventricles were associated with LV dysfunction (all P < 0.05). Despite a similar frequency of pre-existing hypertension, 0% of patients with LV dysfunction reported taking antihypertensive medication, compared to 35% of those without (P = 0.009). There was a significant association between LV dysfunction and infarction from vasospasm after adjusting for clinical grade, age, and peak TCD flow velocity (P = 0.03). Patients with LV dysfunction also had higher rates of hypotension requiring vasopressors (P = 0.001) and pulmonary edema (P = 0.002). However, there was no association between LV dysfunction and outcome at 14 days after adjustment for established prognostic variables. CONCLUSIONS: LV dysfunction after SAH increases the risk of cerebral infarction from vasospasm, hypotension, and pulmonary edema, but with aggressive ICU support does not affect short-term survival or functional outcome. Antihypertensive medication may confer cardioprotection and reduce the risk of catecholamine-mediated injury after SAH.

Stress/rest myocardial perfusion scintigraphy in patients without significant coronary artery disease.

AIM: To define the prognostic impact of stress myocardial perfusion scintigraphy (MPS) in patients with angiographic exclusion of significant coronary artery disease. METHODS: Angiographic and MPS databases were matched to define patients without significant coronary artery disease by quantitative angiography (diameter stenosis <50%) who underwent stress MPS and coronary angiography within a time period of 3 months. A total of 118 patients were identified and followed for a mean of 6.3 +/- 1.2 years for death, a composite of death, myocardial infarction, bypass surgery, or percutaneous coronary intervention [MAE]) as well as occurrence of symptoms (angina or dyspnoe class CCS II to IV). Stress and rest MPS (using (99m)Tc-MIBI or tetrofosmin) were analyzed by quantitative perfusion SPECT (QPS) for summed stress and rest scores (SSS/SRS). RESULTS: There were 16 deaths, 29 MAE, and 76 patients with MAE or significant symptoms during follow-up. Significant differences in SSS were found between patients who died (9.5 +/- 6.9 vs. 5.4 +/- 5.6, P = 0.012), had MAE (8.7 +/- 7.2 vs. 5.2 +/- 5.0, P = 0.010), or had MAE or significant clinical symptoms (7.2 +/- 7.1 vs. 4.6 +/- 6.2, P = 0.042) compared to those without the respective event. Logistic regression analysis demonstrated SSS to be a predictor of death (OR = 1.074 [95% CI: 1.004-1.149], P = 0.026) and MAE (OR = 1.087 [95% CI: 1.004-1.181], P = 0.027). CONCLUSIONS: In patients without significant angiographic coronary artery disease, the result of stress MPS is a predictor of long-term prognosis. Quantitative analysis of MPS allows definition of patients with a higher likelihood to develop clinical events or symptoms.

Hemodialysis-induced repetitive myocardial injury results in global and segmental reduction in systolic cardiac function.

BACKGROUND AND OBJECTIVES: Hemodialysis (HD)-induced regional wall motion abnormalities (RWMAs) are common in HD patients and driven by ischemia. In nondialysis patients, repeated ischemia leads to chronic reduction in left ventricular (LV) function. HD-induced myocardial ischemia may initiate the same process. We examined the effect of HD-induced repetitive myocardial stunning on global and regional LV function. DESIGN, SETTING, PARTICIPANTS & MEASUREMENTS: We analyzed data from 30 patients, previously identified as developing HD-induced myocardial ischemia. Serial echocardiographic assessments of global and regional LV performance were performed at baseline and repeated after 12 mo. RESULTS: Several patients developed segments with a fixed reduction in systolic function of >60% after 1 yr. In this patient group, there was a significant reduction in resting LV ejection fraction (EF) from 61.5 +/- 10.1% to 52.9 +/- 8.6% (P < 0.007). Peak LV EF in response to dialysis also decreased from 59.5 +/- 10% versus 49.9 +/- 6.5% (P < 0.003), with a consequent increase in HD-induced hypotension (P < 0.0001). CONCLUSIONS: HD-induced myocardial stunning may progress over 12 mo to the development of regional fixed systolic dysfunction, consistent with underlying myocardial hibernation and fibrosis. This may be an important and potentially modifiable process in the development of heart failure in HD patients.

Imaging myocardial scar and arrhythmic risk prediction--a role for the electrocardiogram?

Risk stratification for sudden cardiac death (SCD) has become increasingly important to identify candidates for implantable cardioverter-defibrillators (ICDs). Existing clinical guidelines to identify patients for ICDs focus on reduced left ventricular ejection fraction (LVEF); however, the average annual rate of appropriate ICD shocks is only 5.1% in this select group (LVEF

International variations in the ischemic burden post-acute myocardial infarction: prognostic implications.

OBJECTIVES: To determine if there is a variation in the ischemic burden post-acute myocardial infarction (AMI), as assessed by myocardial perfusion imaging (MPI), between different populations in different geographic locations and to see if this variation is associated with different clinical outcomes. METHODS AND RESULTS: We characterized the MPI findings in 104 stable patients who were hospitalized with AMI at the American University of Beirut Medical Center (AUBMC), a tertiary referral hospital in an East Mediterranean country and we compared them to 126 patients who were enrolled according to a similar protocol in a previous study done at Baylor College of Medicine (BCM), Houston, Texas. There were no differences between the two populations with respect to prevalence of diabetes, hypertension, smoking, the use of thrombolysis, percentage of anterior MIs, Q-wave MIs, and multivessel disease on coronary angiography. However, the quantified ischemic defect size in the BCM population was double that in the AUBMC population (12 +/- 12% vs 6 +/- 8%, P < .01). This was associated with almost doubling of the 1 year event rate of death/myocardial infarction (18.3% vs 10.6%, P = .02) in the BCM population. CONCLUSION: Our study suggests that the ischemic burden post-AMI, as assessed by MPI, might vary between different populations in different geographic locations. This variation carries important prognostic implications and is associated with different patient outcomes.

Myocardial scar and insulin resistance predict cardiovascular events in severe ischaemic myocardial dysfunction: a perfusion-metabolism positron emission tomography study.

BACKGROUND: Clinical outcome can be predicted by metabolism-perfusion positron emission tomography (PET) in patients with severe ischaemic left ventricular dysfunction. This study determined whether the amount of viable or non-viable myocardium detected with a PET scan or clinical-functional parameters might predict cardiovascular events. METHODS: All patients had previous myocardial infarction (>6 months previously) and left ventricular ejection fraction (LVEF) <40%. Metabolism-perfusion PET, echocardiogram and coronary angiography were provided. All subjects underwent short euglycaemic-hyperinsulinaemic clamp before the metabolism study. The dysfunctioning segment was defined as hibernating myocardium when metabolism was normal-moderately reduced with impaired perfusion (mismatch flow-metabolism). Cardiac death, hospital admission for myocardial infarction or heart failure were considered cardiovascular events. RESULTS: Ninety-three patients (71 males, aged 64.2 years) were studied. The LVEF was 30.2+/-7.7%; 48 (51.6%) suffered an anterior myocardial infarction. Fifty-three (54.1%) subjects were treated with coronary revascularization; all had optimal medical therapy. Cardiovascular events occurred in 20/93 patients at 1-year follow-up (event group). Age (P=0.7), diabetes mellitus (P=0.6) and rate of coronary revascularization (P=0.3) were not different in the two groups. Patients who experienced cardiovascular events had larger non-viable myocardium (5.8+/-2.7 vs. 4.1+/-2.6, P=0.01), lower metabolic rate glucose (1.3+/-0.6 vs. 1.7+/-0.7 ml . kg . min, P=0.04) but similar hibernating myocardium (1.6+/-1.6 vs. 1.7+/-2, P=0.8) and baseline LVEF (28.1+/-4.8 vs. 30.7+/-8.3%, P=0.08). Having more then five non-viable segments and a metabolic rate for glucose of <0.9 mg . kg . min predicted a worse prognosis (P=0.04, log rank, 3.89; and P=0.004, log rank, 8.1, respectively). CONCLUSION: Non-viable myocardium revealed with PET predicts mid-term clinical prognosis. Insulin resistance seems to influence the outcome.

Hibernating myocardium: diagnosis and patient outcomes.

Approximately 50% of the patients with chronic obstructive coronary artery disease resulting in chronic contractile dysfunction have hibernating myocardium and may benefit from revascularization. This pooled analysis describes the relative merits of dobutamine echocardiography, thallium-201 and technetium-99m scintigraphy, positron emission tomography, and magnetic resonance imaging, for the diagnosis of hibernating myocardium and prediction of patient outcomes.