Early time course of myocardial electrical impedance during acute coronary artery occlusion in pigs, dogs, and humans

Changes in myocardial electrical impedance (MEI) and physiological end points have been correlated during acute ischemia. However, the importance of MEI's early time course is not clear. This study evaluates such significance, by comparing the temporal behavior of MEI during acute total occlusion of the left anterior descending coronary artery in anesthetized humans, dogs, and pigs. Here, interspecies differences in three MEI parameters (baseline, time to plateau onset, and plateau value normalized by baseline) were evaluated using Kruskal-Wallis ANOVA and post hoc tests ( P < 0.05). Noteworthy differences in the MEI time to plateau onset were observed: In dogs, MEI ischemic plateau was reached after 46.3 min (SD 12.9) min of occlusion, a significantly longer period compared with that of pigs and humans [4.7 (SD 1.2) and 4.1 min (SD 1.9), respectively]. However, no differences could be observed between both animal species regarding the normalized MEI ischemic plateau value (15.3% (SD 4.7) in pigs, vs. 19.6% (SD 2.6) in dogs). For all studied MEI parameters, only swine values resembled those of humans. The severity of myocardial supply ischemia, resulting from coronary artery occlusion, is known to be dependent on collateral flow. Thus, because dogs possess a well-developed collateral system (unlike humans or pigs), they have shown superior resistance to occlusion of a coronary artery. Here, the early MEI time course after left anterior descending coronary artery occlusion, represented by the time required to reach ischemic plateau, was proven to reflect such interspecies differences.

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Changes in Myocardial Electrical Impedance Induced by Coronary Artery Occlusion in Pigs With and Without Preconditioning

Circulation ◽

10.1161/01.cir.96.9.3079 ◽

1997 ◽

Vol 96 (9) ◽

pp. 3079-3086 ◽

Cited By ~ 101

Author(s):

Juan Cinca ◽

Mark Warren ◽

Ana Carreño ◽

Màrius Tresànchez ◽

Lluís Armadans ◽

...

Keyword(s):

Coronary Artery ◽

Electrical Impedance ◽

Coronary Artery Occlusion ◽

Artery Occlusion

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Temporal relation between neutrophil accumulation and myocardial reperfusion injury

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.1988.255.5.h1060 ◽

1988 ◽

Vol 255 (5) ◽

pp. H1060-H1068 ◽

Cited By ~ 6

Author(s):

E. F. Smith ◽

J. W. Egan ◽

P. J. Bugelski ◽

L. M. Hillegass ◽

D. E. Hill ◽

...

Keyword(s):

Coronary Artery ◽

Reperfusion Injury ◽

Time Course ◽

Myocardial Injury ◽

Inflammatory Cells ◽

Coronary Artery Occlusion ◽

Artery Occlusion ◽

Neutrophil Accumulation ◽

Cell Responses ◽

Significant Linear Correlation

Infiltration of polymorphonuclear leukocytes (PMN) is associated with the progression of myocardial infarction and reperfusion injury. However, little is known about the time course of cellular infiltration. To investigate this issue, rats were subjected to 30 min of coronary artery occlusion followed by reperfusion for less than or equal to 96 h. Myocardial injury was determined by measuring the depletion of myocardial creatine phosphokinase activity, and PMN infiltration was assessed by measuring myeloperoxidase (MPO) activity. MPO activity increased from 0.7 U/g tissue in non-operated animals, to a peak of 6.7 +/- 0.8 and 6.4 +/- 1.4 U/g at 6 and 24 h after coronary artery reperfusion, respectively. MPO activity decreased to 3.3 +/- 0.8 U/g at 48 h and 1.1 +/- 0.4 U/g at 96 h, suggesting diminished PMN accumulation. Histological examination confirmed the accumulation and resolution of PMN over the 96-h period. At 24 h, there was a significant linear correlation between infarct size and MPO activity, whereas at 96 h no relationship was found. These data indicate that PMN infiltration occurs early in response to reperfusion injury and persists for only 24 h after initiation of reperfusion. These findings suggest that attempts to moderate inflammatory cell responses to myocardial injury should be administered early after coronary artery reperfusion to limit the accumulation of potentially deleterious inflammatory cells.

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The retrograde technique for recanalization of chronically occluded coronary arteries: Case series report

Vojnosanitetski pregled ◽

10.2298/vsp200606124j ◽

2020 ◽

pp. 124-124

Author(s):

Stefan Juricic ◽

Milorad Tesic ◽

Milan Dobric ◽

Srdjan Aleksandric ◽

Zlatko Mehmedbegovic ◽

...

Keyword(s):

Coronary Artery ◽

Case Series ◽

Interventional Cardiology ◽

Coronary Artery Occlusion ◽

Artery Occlusion ◽

Special Technique ◽

Retrograde Approach ◽

Total Occlusion ◽

Antegrade Approach ◽

Increased Risk

Background. Chronic total occlusion (CTO) of coronary artery still represents one of the most challenging lesion subset in field of interventional cardiology. Considering the complexity and increased risk posed by the retrograde approach, it is most often performed after a failed antegrade approach. Methods. We present a series of cases dedicated to the retrograde approach as a special technique for the treatment of chronic total coronary artery occlusion. All cases have some special characteristics that are today part of a dedicated portfolio in every cath lab. Results. In our series of cases all of three percutaneous coronary interventions (PCI) with retrograde approach finished with successful recanalization of CTO with different strategy and supported with rotational atherectomy (RA) or intravascular ultrasound (IVUS). Conclusion. In cases where there is the presence of interventional collaterals, as well as when the anterograde approach is very difficult, the retrograde approach can increase the success rate of procedures. The retrograde approach requires a long learning curve as well as very skilled and experienced operators who are able to perform the procedure independently.

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Vagal reflexes and survival during acute myocardial ischemia in conscious dogs with healed myocardial infarction

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.1991.261.1.h63 ◽

1991 ◽

Vol 261 (1) ◽

pp. H63-H69 ◽

Cited By ~ 15

Author(s):

G. M. De Ferrari ◽

E. Vanoli ◽

M. Stramba-Badiale ◽

S. S. Hull ◽

R. D. Foreman ◽

...

Keyword(s):

Myocardial Infarction ◽

Heart Rate ◽

Coronary Artery ◽

Ventricular Fibrillation ◽

Myocardial Ischemia ◽

Coronary Artery Occlusion ◽

Artery Occlusion ◽

Acute Myocardial Ischemia ◽

Acute Ischemia ◽

Control Test

The role of vagal tone and reflexes in the genesis of life-threatening arrhythmias was investigated in a clinically relevant animal model for sudden cardiac death. Forty-five dogs with a healed anterior myocardial infarction in which transient myocardial ischemia during exercise did not induce malignant arrhythmias were utilized for the study. They underwent a further exercise and ischemia test in which atropine (75 micrograms/kg) was injected before coronary artery occlusion. Novel occurrence of ventricular arrhythmia, or worsening of the type of arrhythmia present in the control test, occurred in 23 of 45 dogs (51%) and ventricular fibrillation occurred in 11 of 45 (24%, P = 0.001). Analysis of heart rate response to acute ischemia in the control test indicates that these 11 animals had powerful vagal reflexes during coronary artery occlusion, compared with the 34 survivors (-32 +/- 35 vs. +2 +/- 27 beats/min, P = 0.003). This study indicates that approximately 75% of animals resistant to ventricular fibrillation are characterized by weak sympathetic reflexes in response to acute myocardial ischemia. In the remaining 25% powerful vagal reflexes counteract concomitant reflex sympathetic hyperactivity, decrease heart rate, and are essential for survival.

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Stretch-induced ventricular arrhythmias during acute ischemia and reperfusion

Journal of Applied Physiology ◽

10.1152/japplphysiol.01235.2001 ◽

2004 ◽

Vol 97 (1) ◽

pp. 377-383 ◽

Cited By ~ 16

Author(s):

Kevin Kit Parker ◽

James A. Lavelle ◽

L. Katherine Taylor ◽

Zifa Wang ◽

David E. Hansen

Keyword(s):

Coronary Artery ◽

Ventricular Arrhythmias ◽

Mechanical Stretch ◽

Coronary Artery Occlusion ◽

Artery Occlusion ◽

Acute Ischemia ◽

Ischemia And Reperfusion ◽

A Value ◽

Action Potential Waveform ◽

Electrophysiological Effects

Mechanical stretch has been demonstrated to have electrophysiological effects on cardiac muscle, including alteration of the probability of excitation, alteration of the action potential waveform, and stretch-induced arrhythmia (SIA). We demonstrate that regional ventricular ischemia due to coronary artery occlusion increases arrhythmogenic effects of transient diastolic stretch, whereas globally ischemic hearts showed no such increase. We tested our hypothesis that, during phase Ia ischemia, regionally ischemic hearts may be more susceptible to triggered arrhythmogenesis due to transient diastolic stretch. During the first 20 min of regional ischemia, the probability of eliciting a ventricular SIA ( PSIA) by transient diastolic stretch increased significantly. However, after 30 min, PSIA decreased to a value comparable with baseline measurements, as expected during phase Ib, where most ventricular arrhythmias are of reentrant mechanisms. We also suggest that mechanoelectrical coupling may contribute to the nonreentrant mechanisms underlying reperfusion-induced arrhythmia. When coronary artery occlusion was relieved after 30 min of ischemia, we observed an increase in PSIA and the maintenance of this elevated level throughout 20 min of reperfusion. We conclude that mechanoelectrical coupling may underlie triggered arrhythmogenesis during phase 1a ischemia and reperfusion.

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A Sign to Heaven: aVR Lead Elevation and Myocardial Infarction

The Scientific World JOURNAL ◽

10.1100/tsw.2011.63 ◽

2011 ◽

Vol 11 ◽

pp. 662-665

Author(s):

Amir M. Nia ◽

Natig Gassanov ◽

Hannes Reuter ◽

Fikret Er

Keyword(s):

Myocardial Infarction ◽

Coronary Artery ◽

Proximal Part ◽

Coronary Artery Occlusion ◽

Artery Occlusion ◽

Correct Treatment ◽

Total Occlusion ◽

St Segment Elevation ◽

St Segment ◽

Long Time

Isolated ST-segment elevation only in the aVR lead, reflecting an acute myocardial infarction due to a left main coronary artery occlusion, was ignored as part of physicians' training in emergency medicine for a long time. The recognition of aVR lead elevation is becoming more accepted as a mandatory diagnostic tool, in particular for physicians working at emergency departments. We report a typical myocardial infarction with total occlusion of the proximal part of the left anterior coronary artery, presenting with ST-segment elevation in the aVR lead, which was misinterpreted as diffuse ischemia. The lacking mandatory awareness of this entity endangered prompt and correct treatment.

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The Influence of Collateral Flow on the Antegrade and Retrograde Distribution of Cardioplegia in Patients with an Occluded Right Coronary Artery

Anesthesiology ◽

10.1097/00000542-199811000-00009 ◽

1998 ◽

Vol 89 (5) ◽

pp. 1099-1107 ◽

Cited By ~ 11

Author(s):

Solomon Aronson ◽

Eric Jacobsohn ◽

Robert Savage ◽

Mario Albertucci

Keyword(s):

Coronary Artery ◽

Right Ventricle ◽

Right Coronary Artery ◽

Contrast Echocardiography ◽

Coronary Artery Occlusion ◽

Artery Occlusion ◽

Collateral Flow ◽

Predictive Values ◽

Antegrade Cardioplegia ◽

The Right

Background The predictive value of electrocardiography (ECG) and coronary angiography for cardioplegia distribution in patients with an occluded right coronary artery was evaluated. Methods Coronary angiograms and ECGs were evaluated in 15 patients with right coronary artery occlusion. Prediction of antegrade cardioplegia distribution was based on ECG evidence of infarction and coronary collateral flow determined from the angiogram. Antegrade and retrograde delivery of cardioplegia was directly assessed in all patients by myocardial contrast echocardiography. Intraoperative transesophageal echocardiographic images of the right ventricular free wall, the apex, and the intraventricular septum were recorded while 4 ml of Albunex (Mallinckrodt Medical, St. Louis, MO) was injected into antegrade and retrograde cardioplegic catheters during cardioplegia delivery. The observed (myocardial contrast echocardiography) cardioplegia distribution was compared to the predicted cardioplegia distribution. Sensitivity, specificity, positive predictive values, and negative predictive values were calculated. Results Eighty seven of 90 (97%) segments were analyzed. Angiography and ECG poorly predicted incomplete cardioplegia distribution. Electrocardiography was a better predictor of inadequate cardioplegia distribution to the right ventricle than was angiography. The negative predicted values of cardioplegia distribution ranged from 20 to 50% for the septum and right ventricle, respectively, with ECG criteria and from 0 to 33% for the septum and apex, respectively, with angiographic criteria. Antegrade cardioplegia delivery was distributed to the right ventricle in 31% of patients, despite 100% occlusion of the right coronary artery; whereas retrograde cardioplegia delivery to the right ventricle occurred 20% of the time. Conclusions In the presence of 100% right coronary artery occlusion, retrograde cardioplegia delivery is not often observed and antegrade delivery of cardioplegia to the right ventricle is not easily predicted. The preoperative angiography and ECG are not predictive of coronary collateral circulation and therefore not predictive of cardioplegia distribution to the right ventricle.

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Abstract 3341: Human Coronary Collaterals Inversely Correlate with Indices of Ischemic Left Ventricular Diastolic Dysfunction during Coronary Balloon Occlusion.

Circulation ◽

10.1161/circ.116.suppl_16.ii_752-d ◽

2007 ◽

Vol 116 (suppl_16) ◽

Author(s):

Stephen P Hoole ◽

Paul A White ◽

Patrick M Heck ◽

Michael O’Sullivan ◽

Sarah C Clarke ◽

...

Keyword(s):

Coronary Artery ◽

Diastolic Dysfunction ◽

Diastolic Pressure ◽

Coronary Artery Occlusion ◽

Artery Occlusion ◽

Left Ventricular ◽

Balloon Occlusion ◽

Flow Index ◽

Collateral Flow ◽

Coronary Collaterals

Background: Coronary collaterals are thought to reduce myocardial ischemia during coronary artery occlusion. Coronary collaterals, defined angiographically, reduce end diastolic LV dilatation during coronary occlusion. However, counter to a role in reducing ischemia, they appear to be associated with an increase in LV end diastolic pressure. These changes may be explained if coronary collaterals act as an external LV scaffold. We aimed to re-evaluate this relationship by simultaneously measuring coronary collaterals and LV contractility quantitatively. Methods: Ten patients with normal LV function and single vessel coronary disease awaiting PCI were recruited. Collateral flow index, derived by pressure-wire measurement (CFI p = [P distal (occluded) − P venous ] / [P aorta − P venous ]) and change in LV end-diastolic pressure (LVEDP), volume (LVEDV) and Tau, measured by an LV cavity conductance catheter, were recorded simultaneously after 1 minute coronary balloon occlusion. A mean of 5 cardiac cycles was analyzed. Measurements were repeated after a recovery period of 30 minutes. Results: Percentage change in LVEDP and Tau inversely correlated with CFI p (ΔLVEDP vs. CFI p : y = −216.6x +63.4, r = 0.57, p=0.01; ΔTau vs. CFI p : y = −64.1x + 27.8, r = 0.47, p<0.05) (Figure ). There was also an inverse relationship between ΔLVEDV vs. CFI p (y = −8.4x + 1.5, r = 0.35, p = 0.15). Conclusion: Coronary collaterals inversely correlate with LV end diastolic stiffness and dilatation after 1 minute of coronary artery occlusion. This reflects a role in reducing ischemic LV diastolic dysfunction, by providing an alternative blood supply to the LV myocardium, rather than acting as an LV scaffold.

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