scholarly journals Sympathetic stimulation increases dispersion of repolarization in humans with myocardial infarction

2012 ◽  
Vol 302 (9) ◽  
pp. H1838-H1846 ◽  
Author(s):  
Marmar Vaseghi ◽  
Robert L. Lux ◽  
Aman Mahajan ◽  
Kalyanam Shivkumar
Keyword(s):  
Myocardial Infarction ◽  
Regional Differences ◽  
Normal Tissue ◽  
Ventricular Arrhythmias ◽  
Sympathetic Stimulation ◽  
Recovery Interval ◽  
Dispersion Of Repolarization ◽  
Border Zones ◽  
Sympathetic Nervous ◽  
Nitroprusside Infusion

The sympathetic nervous system is thought to play a key role in genesis and maintenance of ventricular arrhythmias. The myocardial effect of sympathetic stimulation on myocardial repolarization in humans is poorly understood. The purpose of this study was to evaluate the effects of direct and reflex sympathetic stimulation on ventricular repolarization in patients with postinfarct cardiomyopathy (ICM). The effects of direct sympathetic stimulation were assessed using isoproterenol, while those of reflex sympathetic stimulation were assessed with nitroprusside infusion in ICM patients ( n = 5). Five patients without cardiomyopathy were also studied. Local repolarization was measured from intracardiac electrograms that were used to calculate the activation recovery interval (ARI), a surrogate of action potential duration. Isoproterenol significantly increased heterogeneity in repolarization in patients with ICM; the decrease in ARI from baseline was 72.9 ± 9.1 ms in more viable regions, 64.5 ± 8.9 ms in the scar, and 54.9 ± 9.1 ms in border zones ( P = 0.0002 and 0.014 comparing normal and scar to border zones, respectively). In response to nitroprusside, the ARI at the border zones decreased significantly more than either scar or surrounding viable myocardium, which showed an increase in ARI ( P = 0.014 and 0.08 comparing normal tissue and scar to border zones, respectively). Furthermore, isoproterenol increased ARI dispersion by 70%, while nitroprusside increased ARI dispersion by 230% when ICM patients were compared to those with structurally normal hearts ( P = 0.0015 and P < 0.001, respectively). In humans, both direct and reflex sympathetic stimulations increase regional differences in repolarization. The normal tissue surrounding the scar appears denervated. Dispersion of ARI in response to sympathetic stimulation is significantly increased in patients with ICM.

scholarly journals Focal myocardial infarction induces global remodeling of cardiac sympathetic innervation: neural remodeling in a spatial context

2013 ◽  
Vol 305 (7) ◽  
pp. H1031-H1040 ◽  
Author(s):  
Olujimi A. Ajijola ◽  
Daigo Yagishita ◽  
Krishan J. Patel ◽  
Marmar Vaseghi ◽  
Wei Zhou ◽  
...  
Keyword(s):  
Myocardial Infarction ◽  
Sympathetic Innervation ◽  
Stellate Ganglion ◽  
Sympathetic Stimulation ◽  
Global Pattern ◽  
Cardiac Sympathetic Innervation ◽  
Dispersion Of Repolarization ◽  
Border Zones ◽  
The Impact ◽  
Neural Remodeling

Myocardial infarction (MI) induces neural and electrical remodeling at scar border zones. The impact of focal MI on global functional neural remodeling is not well understood. Sympathetic stimulation was performed in swine with anteroapical infarcts (MI; n = 9) and control swine ( n = 9). A 56-electrode sock was placed over both ventricles to record electrograms at baseline and during left, right, and bilateral stellate ganglion stimulation. Activation recovery intervals (ARIs) were measured from electrograms. Global and regional ARI shortening, dispersion of repolarization, and activation propagation were assessed before and during sympathetic stimulation. At baseline, mean ARI was shorter in MI hearts than control hearts (365 ± 8 vs. 436 ± 9 ms, P < 0.0001), dispersion of repolarization was greater in MI versus control hearts (734 ± 123 vs. 362 ± 32 ms2, P = 0.02), and the infarcted region in MI hearts showed longer ARIs than noninfarcted regions (406 ± 14 vs. 365 ± 8 ms, P = 0.027). In control animals, percent ARI shortening was greater on anterior than posterior walls during right stellate ganglion stimulation ( P = 0.0001), whereas left stellate ganglion stimulation showed the reverse ( P = 0.0003). In infarcted animals, this pattern was completely lost. In 50% of the animals studied, sympathetic stimulation, compared with baseline, significantly altered the direction of activation propagation emanating from the intramyocardial scar during pacing. In conclusion, focal distal anterior MI alters regional and global pattern of sympathetic innervation, resulting in shorter ARIs in infarcted hearts, greater repolarization dispersion, and altered activation propagation. These conditions may underlie the mechanisms by which arrhythmias are initiated when sympathetic tone is enhanced.

RESEARCH THE VALUE OF THE COMBINATION OF T WAVE ALTERNANS AND NT-PROBNT IN PREDICTING SUDDEN CARDIAC DEATH

2012 ◽  
pp. 74-83
Author(s):  
Anh Tien Hoang ◽  
Nhat Quang Nguyen
Keyword(s):  
Myocardial Infarction ◽  
Sudden Cardiac Death ◽  
Cardiac Death ◽  
Ventricular Arrhythmias ◽  
Healthy Person ◽  
Treadmill Test ◽  
T Wave ◽  
T Wave Alternans

Background: Decades of research now link TWA with inducible and spontaneous clinical ventricular arrhythmias. This bench-to-bedside foundation makes TWA, NT-ProBNP a very plausible index of susceptibility to ventricular arrythmia, and motivates the need to define optimal combination of TWA and NT-ProBNP in predicting ventricular arrythmia in myocardial infarction patients. We research this study with 2 targets: 1. To evaluate the role of TWA in predicting sudden cardiac death in myocardial infarction patients. 2. To evaluate the role of NT-ProBNP in predicting sudden cardiac death in myocardial infarction patients 3. Evaluate the role of the combined NT-ProBNP and TWA in predicting sudden cardiac death in myocardial infarction patients. Methods: Prospective study with follow up the mortality in 2 years: 71 chronic myocardial infarction patients admitted to hospital from 5/2009 to 5/20011 and 50 healthy person was done treadmill test to caculate TWA; ECG, echocardiography, NT-ProBNP. Results: Cut-off point of NT-ProBNP in predicting sudden cardiac death is 3168 pg/ml; AUC = 0,86 (95% CI: 0,72 - 0,91); Cut-off point of TWA in predicting sudden cardiac death is 107 µV; AUC = 0,81 (95% CI: 0,69 - 0,87); NT-ProBNP can predict sudden cardiac death with OR= 7,26 (p<0,01); TWA can predict sudden cardiac death with OR= 8,45 (p<0,01). The combined NT-ProBNP and TWA in predicting ventricular arrythmia in heart failure patients: OR= 17,91 (p<0,001). Conclusions: The combined NT-ProBNP and TWA have the best predict value of sudden cardiac death in myocardial infarction patients, compare to NT-ProBNP or TWA alone

Regional variation in appropriate care for ST-elevation myocardial infarction in Finland

2020 ◽  
Vol 30 (Supplement_5) ◽  
Author(s):  
E Reissell ◽  
S Lumme ◽  
M Satokangas ◽  
K Manderbacka
Keyword(s):  
Myocardial Infarction ◽  
Regional Variation ◽  
Regional Differences ◽  
Coronary Intervention ◽  
Register Data ◽  
St Elevation Myocardial Infarction ◽  
Academic Affiliation ◽  
Episode Of Care ◽  
Appropriate Care ◽  
St Elevation

Abstract Background Timely primary percutaneous coronary intervention (PCI) is currently the treatment of choice for ST-elevation myocardial infarction (STEMI). Although cardiac units were established in all central hospitals in late 1990s for sparsely populated Finland, studies have shown that regional variation has increased. Additionally, the dense Finnish hospital network includes non-cardiac facilities where patients may be inappropriately admitted and then transferred for PCI. We aim to investigate the current regional differences in receiving timely PCI, determinants of these variations and the effect of hospital transfers. Methods Finnish Hospital Discharge Register data on PCIs for STEMI patients in 2015-17 were linked to register data on socio-demographics. In these preliminary analyses we used logistic regression modelling. Results Our results suggest that there were significant regional differences both for timely PCI in STEMI patients and in the probability of hospital transfers during an episode of care. The regional odds ratios (OR) for receiving PCI on time varied from 0.41 (95% confidence interval 0.33-0.52) to 2.73 (2.09-3.57) compared with the capital region when controlling for age, gender and hospital transfers. The ORs for being transferred during an episode of care varied from 0.26 (0.15-0.44) to 16.6 (11.6-23.6). Patients not transferred were more likely to receive PCI (OR 1.89 (1.67-2.15)). Men received PCI on time more often (OR 1.31 (1.18-1.46)) and women were more likely to be transferred (OR 1.29 (1.15-1.45)). Conclusions The probability for receiving PCI on time was related to the size of the hospital's population base and academic affiliation and inversely to transfers between hospitals. Hospital transfers during care episode and atypical symptoms often seen in women may cause critical delays for PCI. Other determinants for variation of timely PCI and its effects on equity will be analysed using multilevel modelling. Key messages Appropriate care for STEMI varies across regions and reflects inept practices in provider network. These findings are more pronounced in women showing persisting gender-related inequity.

Sustained ventricular arrhythmias and mortality among patients with acute myocardial infarction: Results from the GUSTO-III trial

2003 ◽  
Vol 145 (3) ◽  
pp. 515-521 ◽  
Author(s):  
Sana M. Al-Khatib ◽  
Amanda L. Stebbins ◽  
Robert M. Califf ◽  
Kerry L. Lee ◽  
Christopher B. Granger ◽  
...  
Keyword(s):  
Myocardial Infarction ◽  
Acute Myocardial Infarction ◽  
Ventricular Arrhythmias
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