Cardiovascular autonomic function in lateral medullary infarction

Sinus arrest following acute lateral medullary infarction

Lateral medullary syndrome (LMS) is an ischemic stroke of the medulla oblongata that involves the territory of the posterior inferior cerebellar artery. LMS is often missed as the cause of autonomic dysregulation in patients with recent brain stem stroke. Due to the location of the nucleus tractus solitarius (NTS), the dorsal vagal nucleus, and the nucleus ambiguous in the lateral medulla oblongata, patients with LMS occasionally have autonomic dysregulation–associated clinical manifestations. We report a case of LMS-associated autonomic dysregulation. The case presented by recurrent syncope, requiring permanent pacemaker placement. This case shows the importance of recognizing LMS as a potential cause of life-threatening arrhythmias, heart block, and symptomatic bradycardia. Extended cardiac monitoring should be considered for patients with medullary strokes.

Posterior circulation ischemic stroke not involving the brainstem is associated with cardiovascular autonomic dysfunction

BACKGROUND AND PURPOSE

Ischemic stroke may induce cardiovascular autonomic dysfunction. Yet, most previous studies included patients with anterior circulation ischemic stroke or brainstem stroke. It remains unclear whether posterior circulation ischemic stroke (PCIS) without brainstem involvement also compromises cardiovascular autonomic modulation (CAM). Therefore, we aimed to assess CAM in PCIS patients with and without brainstem involvement.

METHODS

In four subgroups of 61 PCIS-patients (14 occipital lobe, 16 thalamic, 12 cerebellar, and 19 brainstem strokes) and 30 healthy controls, we recorded RR-intervals (RRI), systolic, diastolic blood pressures (BPsys, BPdia), and respiration at supine rest during the first week after stroke-onset. We calculated parameters reflecting total CAM [RRI-standard-deviation (RRI-SD), RRI-total-powers], predominantly sympathetic CAM [RRI-low-frequency-powers (RRI-LF-powers) and BPsys-LF-powers] and parasympathetic CAM [Root-Mean-Square-of-Successive-RRI-Differences (RMSSD), RRI-high-frequency-powers (RRI-HF-powers)], sympathetic-parasympathetic balance (RRI-LF/HF-ratios), and baroreflex-sensitivity (BRS). Values were compared between the four PCIS-groups and controls using one-way ANOVA Kruskal-Wallis-tests, with post-hoc analyses. Significance was assumed for P<0.05.

RESULTS

In each PCIS-subgroup, values of RRI, RRI-SD, RMSSD, RRI-HF-powers, and BRS were significantly lower, while BPsys-LF-powers were higher than in the controls. Only in patients with occipital lobe stroke, RRI-LF/HF-ratios were significantly higher than in controls. Otherwise, autonomic parameters did not differ between the four PCIS-subgroups.

CONCLUSIONS

During the first week after stroke-onset, our PCIS patients with occipital lobe, thalamic, cerebellar, or brainstem strokes all had reduced cardiovagal modulation, compromised baroreflex, and increased peripheral sympathetic modulation. The RRI-LF/HF-ratios suggest that sympathetic predominance is slightly more prominent after occipital lobe stroke. PCIS may trigger cardiovascular autonomic dysfunction even without brainstem involvement.

Dorsal vagal nucleus involvement relates to QTc-prolongation after acute medullary infarction

BACKGROUND

Infarction of the medulla has been associated with prolongation of the QTc, severe arrhythmia, and sudden cardiac death, yet the precise anatomical substrate remains uncertain.

AIMS

We sought to determine the possible anatomical structures relating to QTc-prolongation in patients with acute medullary infarction.

METHODS

We included 12 subjects with acute ischemic medullary infarction on brain MRI, who presented within 4.5 h from the last known well time, with a 90-day follow-up. For an unbiased lesion analysis, medullary infarcts were manually outlined on diffusion weighted MRI and co-registered with an anatomical atlas.

RESULTS

Nine out of 12 had QTc-prolongation. Qualitative and semi-quantitative comparisons were made between infarct location and QTc-prolongation. Among patients with QTc-prolongation, the greatest degree of congruence of the infarct location was over the dorsal vagal nucleus (DVN, 8 out of 9). There was a significant correlation between the number of sections showing infarction of the DVN and presence of QTc-prolongation (r = .582, p = .047). Among patients without QTc-prolongation, the maximum lesion overlap included the medial aspect of the gigantocelluar reticular nucleus of the reticular formation.

CONCLUSION

We found that the DVN is a key anatomical substrate related to QTc-prolongation. Further studies with more patients and high-resolution, volumetric MRI are needed to confirm our findings.

Takotsubo cardiomyopathy associated with Paragonimiasis westermani

An 11-year-old boy collapsed during morning assembly at his junior high school. The automated external defibrillator detected ventricular fibrillation and provided shock delivery. He was successfully resuscitated and reverted to sinus rhythm. Electrocardiography showed ST-T elevation in the precordial leads. Echocardiography and angiography demonstrated akinesia of the apex and mid-wall of the left ventricle with preserved contraction of the basal segments, which suggested Takotsubo cardiomyopathy. The patient and his family had often eaten uncooked crab, and his father had a past history of infection with Paragonimiasis westermani. The patient had had a persistent cough and chest pain for several weeks. Chest radiograph showed cystic cavities in the left upper lung. Microbiological examination of the sputum demonstrated an egg of P. westermani and immunological assay showed a raised antibody titre to P. westermani. On the12th day of admission, he developed seizures, and magnetic resonance imaging demonstrated cerebral involvement. After the administration of praziquantel for 3 days, the clinical manifestations improved immediately, and echocardiography normalised within 3 weeks. The patient was discharged on the 32nd day + and follow-up was normal. Takotsubo cardiomyopathy following a potentially fatal arrhythmia is a rare cardiac complication associated with pulmonary and central nervous system infection by P. westermani.

Lateral medullary infarction with cardiovascular autonomic dysfunction: an unusual presentation with review of the literature

PURPOSE

We report an unusual case of lateral medullary infarction presenting with orthostatic hypotension with pre-syncope without vertigo or Horner's syndrome.

METHODS

Case report with review of the literature.

RESULTS

A 67-year-old man presented with pre-syncope and ataxia without vertigo. Initial brain CT and MRI were normal. Neurological evaluation revealed right-beating nystagmus with left gaze, vertical binocular diplopia, right upper-extremity dysmetria, truncal ataxia with right axial lateropulsion, and right-facial and lower extremity hypoesthesia. Bedside blood pressure measurements disclosed orthostatic hypotension. He had normal sinus rhythm on telemetry and normal ejection fraction on echocardiogram. A repeat brain MRI disclosed an acute right dorsolateral medullary infarct. Autonomic testing showed reduced heart rate variability during paced deep breathing, attenuated late phase II and phase IV overshoot on Valsalva maneuver, and a fall of 25 mmHg of blood pressure at the end of a 10-min head-up tilt with no significant change in heart rate. These results were consistent with impaired sympathetic and parasympathetic cardiovascular reflexes. He was discharged to acute rehabilitation a week later with residual right dysmetria and ataxia.

CONCLUSION

Lateral medullary infarctions are usually reported as partial presentations of classical lateral medullary syndrome with accompanying unusual symptoms ranging from trigeminal neuralgias to hiccups. Pre-syncope from orthostatic hypotension is a rare presentation. In the first 3-4 days, absence of early DWI MRI findings is possible in small, dorsolateral medullary infarcts with sensory disturbances. Physicians should be aware of this presentation, as early diagnosis and optimal therapy are associated with good prognosis.

Pacemaker Placement in Patients with Stroke-Mediated Autonomic Dysregulation

Lateral medullary syndrome (LMS) is an ischemic disease of the medulla oblongata, which involves the territory of the posterior inferior cerebellar artery. Lateral medullary syndrome is often missed as the cause of autonomic dysregulation in patients with recent brain stem stroke. Due to the location of the baroreceptor regulatory center in the lateral medulla oblongata, patients with LMS occasionally have autonomic dysregulation-associated clinical manifestations. We report a case of LMS-associated autonomic dysregulation. The case presented as sinus arrest and syncope, requiring permanent pacemaker placement. A dual-chamber pacemaker was placed, after failure of conservative measures to alleviate the patient's symptoms. Our case shows the importance of recognizing LMS as a potential cause for life-threatening arrhythmias, heart block, and symptomatic bradycardia. Placement of permanent pacemaker may be necessary in some patients with LMS presenting with syncope, secondary to sinus arrest.

Takotsubo-Like Myocardial Dysfunction in Ischemic Stroke: A Hospital-Based Registry and Systematic Literature Review

BACKGROUND AND PURPOSE

We investigated clinical and radiological characteristics of ischemic stroke patients with Takotsubo-like myocardial dysfunction.

METHODS

From multicenter stroke registry database, ischemic stroke patients who underwent transthoracic echocardiography were found. Among these, patients were classified if they had specific ventricular regional wall motion abnormalities discording with coronary artery distribution, such as apical (typical pattern) or nonapical ballooning (atypical pattern), considered as echocardiographic findings of Takotsubo cardiomyopathy. Patients with ischemic heart disease history, myocarditis, or pheochromocytoma were excluded. We compared patients with Takotsubo-like myocardial dysfunction with those without and further performed systematic literature review on those with Takotsubo cardiomyopathy.

RESULTS

This study included 23 patients (0.42%). The mean age was 70.7±13.9 years, with predominance of women (73.9%) and typical pattern of Takotsubo-like myocardial dysfunction (91.3%). They were associated with short-term poor functional outcomes, including high mortality, neurological deterioration, and functional status at discharge, compared with those without (39.1% versus 2.4%, 47.8% versus 7.4%; and median [interquartile range], 5 [5-6] versus 3 [2-4]; all P<0.001). They had a higher inflammatory marker level and lower triglyceride level. Ischemic lesions were more commonly found in the right anterior circulation with specific dominant regions being the insula and peri-insular areas. In addition, a trend toward a remarkable mortality rate and higher prevalence of insular involvement was observed in the propensity-score matching, subgroup fulfilling the strict Takotsubo cardiomyopath criteria, and was as reported in literature review.

CONCLUSION

Stroke patients with Takotsubo-like myocardial dysfunction may differ from those without in clinical outcomes, laboratory findings, and radiological features.

Identification of autonomic neuronal chains innervating gingiva and lip

The major goals of this present study were 1) to further clarify which parasympathetic ganglion sends postganglionic fibers to the lower gingiva and lip that may be involved in the inflammatory processes besides the local factors; 2) to separately examine the central pathways regulating sympathetic and parasympathetic innervation; and 3) to examine the distribution of central premotor neurons on both sides. A retrogradely transported green fluorescent protein conjugated pseudorabies virus was injected into the lower gingiva and lip of intact and sympathectomized adult female rats. Some animals received virus in the adrenal medulla which receive only preganglionic sympathetic fibers to separately clarify the sympathetic nature of premotor neurons. After 72-120h of survival and perfusion, the corresponding thoracic part of the spinal cord, brainstem, hypothalamus, cervical, otic, submandibular and trigeminal ganglia were harvested. Frozen sections were investigated under a confocal microscope. Green fluorescence indicated the presence of the virus. The postganglionic sympathetic neurons related to both organs are located in the three cervical ganglia, the preganglionic neurons in the lateral horn of the spinal cord on ipsilateral side; premotor neurons were found in the ventrolateral medulla, locus ceruleus, gigantocellular and paraventricular nucleus and perifornical region in nearly the same number on both sides. The parasympathetic postganglionic neurons related to the gingiva are present in the otic and related to the lip are present in the otic and submandibular ganglia and the preganglionic neurons are in the salivatory nuclei. Third order neurons were found in the gigantocellular reticular and hypothalamic paraventricular nuclei and perifornical area.

Cardiovascular autonomic neuropathy in rheumatoid arthritis assessed by cardiovascular autonomic function tests: A cross-sectional survey

Objective:

In this study, we aimed to evaluate cardiovascular autonomic neuropathy (CAN) in RA patients by cardiovascular autonomic function tests. Because CAN was reported of patients with automimmune rheumatic diseases those may in sudden death or myocardial infarction.

Methods:

A total of 44 patients with RA and 44 age-and sex-matched healthy volunteers participated in this cross-sectional study. Assessment of CAN was performed using cardiovascular reflex tests. These five tests were: 1) beat-to-beat heart rate variation during deep breathing; 2) heart rate response to standing up; 3) heart rate response to the Valsalva maneuver; 4) blood pressure response to standing up; and 5) blood pressure response to sustained handgrip.

Results:

The mean age was 43.15 (SD, 12.18) years (range, 23-68 years) in the RA group, and 38 were women. In beat-to-beat heart rate variation during deep breathing, expiration-to-inspiration ratio was abnormal in 3 cases with RA (6.8%) but in 1 (2.3%) control subject (p=0.3), and maximum minus minimum heart rate was abnormal in 8 patients (18.2%) and in 3 (6.8%) control subjects (p=0.1). 2) In heart rate response to standing up, all patients and controls had normal results. Valsalva ratio was abnormal in 7 RA patients (15.9%) and in 7 control subjects (15.9%). Blood pressure response to standing up was normal in RA patients but abnormal in 1 (2.3%) control subject (p=0.4). Blood pressure response to sustained handgrip was abnormal in 5 RA patients (11.4%) and 2 (4.6%) control subjects (p=0.2).

Conclusion:

Our study failed to show any statistically significant difference between cardiovascular autonomic function tests in RA patients with control subjects by our test done.