Akira Shinozuka

The Significance of Cardiac Sympathetic Nervous System Abnormality in the Long-Term Prognosis of Patients with a History of Ventricular Tachyarrhythmia

Severe left ventricular dysfunction or cardiac sympathetic nervous system (SNS) abnormality predicts cardiac death in various heart diseases, including arrhythmogenic disorders. However, it is not clear whether SNS abnormality predicts sudden cardiac death during long-term follow-up in patients with a history of ventricular tachyarrhythmia. We hypothesized that SNS abnormality would be associated with recurrent ventricular arrhythmic events. Methods: 123I-metaiodobenzylguanidine (MIBG) scintigraphy was performed on 86 patients (mean age ± SD, 46 ± 19 y, 65.1% men) with a history of ventricular tachycardia or fibrillation. 123I-MIBG (111 MBq) was intravenously administered under resting conditions, and planar images were obtained 15 min and 4 h later (anterior view for 6 min; 512 × 512 matrices; zoom ratio, 1.0). SNS activity was assessed using the heart-to-mediastinum ratio on delayed imaging. Results: During about 11 y of follow-up (mean ± SD, 5.2 ± 3.7 y), 3 patients (3.5%) had sudden cardiac death and 21 patients (24.4%) had sustained ventricular tachyarrhythmic events. SNS abnormality, defined as a heart-to-mediastinum ratio of less than 2.8, and left ventricular dysfunction, defined as a left ventricular ejection fraction of less than 50%, were associated with sudden cardiac death or recurrent ventricular tachyarrhythmic events (18/40 patients [45%] with SNS abnormality, vs. 6/46 patients [13%] without, P = 0.004; 9/15 patients [60%] with left ventricular dysfunction, vs. 15/71 patients [21.1%] without, P = 0.008). After adjustment for potential confounding variables such as age, sex, coronary risk factors, medication use, history of structural heart disease, and left ventricular function, SNS abnormality was a powerful predictor of recurrent arrhythmic events, with a hazard ratio of 3.6 [95% confidence interval, 1.4–9.2, P = 0.007]). Further, SNS abnormality had incremental and additive prognostic power in combination with left ventricular dysfunction, with an adjusted hazard ratio of 4.4 [95% confidence interval, 1.9–9.9, P < 0.0001]). Conclusion: SNS abnormality predicted recurrent ventricular tachyarrhythmic events during long-term follow-up. 123I-MIBG scintigraphic evaluations for SNS abnormality may be an option for screening patients at high risk for sudden cardiac death.

Iodine-123 mIBG Imaging for Predicting the Development of Atrial Fibrillation

OBJECTIVES we investigated whether cardiac sympathetic nervous system (SNS) activity measured by iodine-123 meta-iodobenzylguanidine ((123)I-mIBG) imaging would be associated with both the occurrence of heart failure (HF) and the transit to permanent atrial fibrillation (AF) in patients with paroxysmal AF. BACKGROUND atrial fibrillation occurs suddenly and transiently and can persist, and results in the occurrence of HF. An important feature of AF and HF is their propensity to coexist not only because they share antecedent risk factors, but also because the one may directly predispose the heart to the other. However, a useful modality for predicting the occurrences of both those has not been established in patients with paroxysmal AF. METHODS the (123)I-mIBG scintigraphy was performed to evaluate cardiac SNS activity presented as the heart/mediastinum ratio in 98 consecutive patients (age 66 ± 13 years, 63.3% male) with idiopathic paroxysmal AF and preserved left ventricular ejection fraction (≥ 50%). RESULTS during 4 ± 3.6 years of follow-up, the transit to permanent AF was associated with the occurrence of HF (34.3% in 12 of 35 patients with permanent AF vs. 6.3% in 4 of 63 patients without, p < 0.0001). Lower heart/mediastinum ratio and lower left ventricular ejection fraction were the independent predictors of the transit to permanent AF with adjusted hazard ratios of 3.44 (95% confidence interval [CI]: 1.9 to 6.2, p < 0.0001) and 1.04 (95% CI: 1.01 to 1.08, p = 0.014). Further, these factors and higher plasma brain natriuretic peptide concentration were the independent predictors of the occurrence of HF with permanent AF, with adjusted hazard ratios of 5.08 (95% CI: 1.5 to 17.5, p = 0.011), 1.11 (95% CI: 1.03 to 1.19, p = 0.004), and 1.004 (95% CI: 1.001 to 1.008, p = 0.014). CONCLUSIONS cardiac SNS abnormality was associated with the occurrence of both HF and permanent AF in paroxysmal AF patients, and (123)I-mIBG imaging may be a useful modality for predicting the development of AF.

Left frontotemporal hyperperfusion in a patient with post-stroke mania

A 78-year-old housewife with major depression developed a right-sided infarction in the territory of the middle cerebral arteries, followed by acute post-stroke mania. Comparison between pre- and post-stroke SPECT scans demonstrated a unique pattern of left orbitofrontal hyperperfusion with extensive right frontal hypoperfusion. A functional imbalance between right and left orbitofrontal cortices may be important in mania.

Reversible T‐Wave Inversions and Neurogenic Myocardial Stunning in a Patient with Recurrent Stress‐Induced Cardiomyopathy

A 72‐year‐old female was diagnosed as a stress‐induced cardiomyopathy from apical ballooning pattern of left ventricular dysfunction without coronary artery stenosis after the mental stress. ECG showed the transient T‐wave inversions after the ST‐segment elevations. By the mental stress after 1 year, she showed a transient dysfunction with similar ECG changes again. T‐wave inversions recovered earlier, and cardiac sympathetic dysfunction showed a lighter response corresponding to the less severe dysfunction than those after the first onset. Wellens’ ECG pattern was associated with the degree of neurogenic myocardial stunning with sympathetic hyperinnervation caused by mental stress.

Pulmonary Vein Obstruction After Catheter Ablation Following Atrial Fibrillation

The patient was 68-year-old man with highly symptomatic paroxysmal atrial fibrillation. Transoesophageal echocardiography was performed to confirm no left atrial embolism, and contrast-enhanced 64-row multidetector computed tomography (MDCT) was performed to clarify the anatomic forms and routes of pulmonary veins (PV) before ablation (Figure 1A). The circumferential ablation procedure was performed using electroanatomical mapping (Figure 1B). Radiofrequency catheter energy was delivered with a closed irrigation cool-tip ablation catheter. The patient was kept on oral anticoagulation with a controlled international normalized ratio between 2 and …

Thallium-201 and I-123 beta-methyl iodophenyl-pentadecanoic acid dual isotope single photon emission computed tomography for evaluating reperfusion injury after successful reperfusion therapy.

We report a reperfusion injury after rotational coronary atherectomy (RA) in a 66-year-old man with coronary artery disease. Submaximal exercise with thallium-201 single photon emission computed tomography (SPECT) imaging before reperfusion showed partially reversible perfusion defects in the apex and reversible perfusion defects in the anteroseptal area. Thallium-201 and I-123 beta-methyl iodophenyl-pentadecanoic acid (BMIPP) dual isotope SPECT was performed 5 days before and 1 hour after RA, and 1 month after RA. SPECT images at 1 hour after recovery of no reflow phenomenon after RA revealed enlargement of the defect sizes on thallium-201 and BMIPP uptakes in the anteroseptal area including the apex compared with those before RA. The defect size of thallium-201 uptake was progressively improved on 5 hour delayed redistribution imaging and 1 month after reperfusion compared with that of BMIPP uptake. In conclusion, the changes for the worse of thallium-201 uptake and fatty acid metabolism immediately after the no reflow phenomenon may indicate an injured membrane integrity with altered myocardial metabolism rather than myocardial ischemia. Thallium-201 and I-123 BMIPP dual isotope SPECT is useful for evaluating reperfusion injury after successful reperfusion therapy in a patient with acute coronary syndrome.

Electrocardiographic change after recanalization in a patient with recent extensive anterior wall myocardial infarction

In a 66-year-old male with subacute extensive anterior wall myocardial infarction, we report a change in ST vector orientation from a basal anterior to a mid anterior after coronary artery recanalization of the proximal left anterior descending coronary artery with rotational atherectomy. The ST vector shift on the frontal plane after recanalization was consistent with a change toward more distal location of the ischemia on thallium-201 single photon emission computed tomography images compared to the findings during an exercise test before intervention. These findings may be correlated with local occlusion caused by distal microvascular embolization which was not visualized on coronary angiography following recanalization.