TQ-ST segment mapping: Critical review and analysis of current concepts

Holland, Roger P.; Brooks, Harold L.

doi:10.1016/0002-9149(77)90109-6

Cited by 184 publications

(52 citation statements)

References 164 publications

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“…Eight adult mongrel dogs weighing [20][21][22][23][24][25][26][27][28][29][30] kg (mean 26 kg) were anesthetized with sodium pentobarbital (30 mg/kg). Under sterile conditions, a left thoracotomy was performed in the fifth left intercostal space, the left circumflex coronary artery was dissected free near its origin and a hydraulic occluder made from polyvinyl tubing was positioned around it.…”

Section: Methodsmentioning

confidence: 99%

“…The difference in findings may be due in part to differences in experimental preparations, including the location of the ischemic area (left anterior descending vs cir- During complete coronary occlusions, surface ECG ST-segment changes occurred rapidly (30 seconds) and, on the average, slightly preceded the development of epicardial and endocardial ST-segment changes, which became significant 30-60 seconds later. The reason for the relatively more sensitive detection of complete occlusion by the surface leads, compared with the greater sensitivity of the intramyocardial leads for detecting partial stenosis, is not entirely clear, but may relate to differences in the location of electrodes and in the size of the ischemic zone, as well as to the intensity of the current of injury at the boundary between ischemic and nonischemic tissue.1 25 Based on solid-angle theory, it might be expected that production of a large ischemic area by coronary occlusion would result in relatively more marked STsegment changes in the body surface leads, with less marked changes in the local electrograms.2' However, because partial coronary artery stenosis produces an area of ischemia that is predominantly intramural or in the subendocardial region26 and involves a smaller ischemic area than with complete occlusion, the body surface leads would subtend this smaller angle; or, if the zone were intramural, these leads might even be electrically silent for injury.2`Intramyocardial leads, which reflect local intensity of the injury and subtend a relatively large angle of the injured area, however, might be expected to detect such ischemia.…”

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confidence: 99%

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Dissociation between regional myocardial dysfunction and ECG changes during ischemia in the conscious dog.

Battler¹,

Froelicher²,

Gallagher³

et al. 1980

Circulation

147

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SUMMARY The relations between regional ventricular function and regional and surface ECGs were studied in eight conscious dogs during complete and partial coronary obstructions. Wall thickness and local ECGs were measured using an implanted sonomicrometer, and 11 subcutaneous electrodes were implanted in a modified McFee vectorcardiographic array. Complete obstruction of the circumflex coronary artery (using a hydraulic occluder) produced regional hypokinesia after 15 seconds and regional dyskinesia at 1 minute. Significant ECG changes occurred first in the surface vectorcardiogram, ST segments changed at 30 seconds and mean epicardial and endocardial ECG ST segments increased after 1 minute. During mild partial coronary stenosis that produced stable reductions of systolic wall thickening (%AWT) of less than 25% of control, no ST-segment changes occurred in the surface vectorcardiogram during the 10-minute study period, although ST segments increased significantly in the endocardial and epicardial ECG. With moderate coronary stenoses that produced immediate 25-48% reductions of %AWT (average reduction 36 ± 4%), significant mean ST displacements occurred after 2 minutes in the endocardial ECG, after 3 minutes in the epicardial ECG and after 4 minutes in the surface vectorcardiogram. With coronary stenoses that produced more than 50% reduction of %A.WT (average reduction 69 ± 2%), mean endocardial ST-segment changes were noted after 2 minutes, and changes in both the mean epicardial ECG and the surface vectorcardiogram occurred after 3 minutes. Thus, during mild coronary stenosis, regional myocardial dysfunction can occur without surface ECG changes, while during moderate coronary stenosis, it occurs before endocardial ST-segment changes and precedes surface ECG alterations by several minutes. The surface ECG was slightly more sensitive than the local ECG during complete coronary occlusion and less sensitive during partial coronary obstruction. We conclude that regional contractile abnormalities provide a more sensitive indicator of ischemia than electrocardiographic ST-segment changes.REGIONAL VENTRICULAR dysfunction and STsegment displacement on the ECG are valuable indicators of myocardial ischemia. However, STsegment displacement on the body surface ECG is not specific for ischemia,' and both false-negative and false-positive ECG findings during exercise testing for detecting coronary artery disease have been reported.2 In the experimental setting, regional wall function dynamics are highly sensitive to local ischemia both at rest5 and during exercise in the conscious dog;6 in clinical studies, simultaneous recordings of ventricular function using radionuclide angiographic techniques and ECG recordings during exercise have suggested superiority of mechanical over electrical events for the detection of temporary myocardial ischemia.7-9 Nevertheless, the exercise test with ECG recordings is still the most popular and economical screening test for coronary artery disease in man, 4 1' and further understanding of ...

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Section: Methodsmentioning

confidence: 99%

mentioning

confidence: 99%

Dissociation between regional myocardial dysfunction and ECG changes during ischemia in the conscious dog.

Battler¹,

Froelicher²,

Gallagher³

et al. 1980

Circulation

147

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“…Administration of ISO also showed a decline in R-R interval, and increase in QRS time and heart rate. These changes could be due to the damage of cell membrane in injured cardiac muscle [23]. It has been exposed that a rise in heart rate is responsible for augmented oxygen consumption causing to enhanced necrosis of myocardial tissue [24].…”

Section: Discussionmentioning

confidence: 99%

Cardio Protective Effects of Hydroalcholic Citrus Aurantium Extract on Myocardial Infarction Induced by Isoproterenol in Male Rats

2017

JCCR

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The citrus aurantium has traditionally been used by the people of Iran. The aim of this study was to evaluate the protective effects of hydroalcholic citrus aurantium extract on electrocardiographic, biochemical and pathological changes after myocardial infarction induced by isoproterenol in rats. 24 male Wistar rats were divided randomly into 4 groups: Control, extract, isoproterenol, and isoproterenol + pre-treatment with extract for two weeks. At the end of the experiment, ECG was recorded in lead II. Finally, blood samples were taken and cardiac marker enzymes such as creatine kinase, lactate dehydrogenase, aspartate aminotransferase, alanine aminotransferase, and alkaline phosphatase, along with oxidative stress markers such as malondialdehyde, superoxide dismutase, catalase, glutathione reductase, glutathione peroxidase, and lipid profile were determined.Myocardial infarction induced by isoproterenol produced a significant increase in the heart rate, ST-segment elevation, decrease in R amplitude, and a significant increase in the level of cardiac marker enzymes: LDH, CK-MB, AST, ALT and ALP in serum. Also, isoproterenol significantly reduced SOD, CAT, GSH, GP X and increased MDA activity, disturbance in lipid profile, and inflammatory process in cardiac myocytes. Pretreatment with citrus aurantium extract for two weeks significantly reduced the effect of isoproterenol on electrocardiographic parameters, cardiac biomarkers, oxidative stress indices, lipid profile and cardiac myocytes injuries.Results indicated that citrus aurantium extract ameliorates the cardio-toxic effects of isoproterenol through reinforcement of antioxidant defense system and may be of value in treatment of myocardial infarction. Further studies are required to determine the precise mechanism of the therapeutic effect of the extract.

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“…increased ventricular diameter [24]. The ST elevation may be observed due to cellular membrane damage occurred by oxidative stress [25]. Test groups, treated with MELU and OLU, reflected the least prolongation of QT interval significantly compared to disease control group.…”

Section: Beneficial Effects Of Digoxin and Methanolic Extract Of Seedmentioning

confidence: 99%

Evaluation of Beneficial Effects of Linum Usitatissimum in Congestive Heart Failure

Tirgar

Kalpesh

2017

Int J Pharm Pharm Sci

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Original Article EVALUATION OF BENEFICIAL EFFECTS OF LINUM USITATISSIMUM IN CONGESTIVE HEART FAILURE PRAVIN TIRGAR, LIMBASIYA KALPESHSchool of Pharmacy, RK University, Rajkot, Gujarat, India Email: pravin.tirgar@rku.ac.inObjective: Evaluation of beneficial effects of the seed of Linum usitatissimum in congestive heart failure.Methods: Methanolic extract of seeds of Linumusitatissimum (MELU) was prepared using soxhlet apparatus and oil of seed of Linumusitatissimum (OLU) was isolated using Clevenger apparatus. The positive inotropic action of methanolic extract of seeds of Linum usitatissimum was evaluated using Langendorff's assembly (in vitro study). Beneficial effects of methanolic extract and oil of seeds of Linum usitatissimum were carried out by doxorubicin (1 mg/kg, i. p. within 3 w) to induce congestive heart failure (in vivo study). Parameters like electrocardiogram (ECG) recording and cytosolic Ca 2+Keywords: Seeds of Linum usitatissimum, Langendorff's assembly, Positive inotropic, Diuretic action, Congestive heart failure level and histopathology of the heart were carried out. In same study diuretic action was evaluated using Lipschitz model. Results:Methanolic extract of seeds of Linum usitatissimum showed significantly increased in positive inotropic effect (force of contraction 48.8±1.53 mm) as compared to control group (force of contraction 17.5±0.76 mm) on Langendorff"s study (in vitro study). In doxorubicin-induced congestive heart failure both MELU and OLU showed significant decreased QT (Note: In cardiology, the QT interval is a measure of the time between the start of the Q wave and the end of the T wave in the heart's electrical cycle. There is no full form for this medical word) interval. The histopathologic study indicated the least damage to the architecture of myocardial membrane. MELU and OLU increased urine output (5.66±0.16 ml and 6.58±0.15 ml respectively) significantly in Lipschitz model as compared to disease control group (4.58±0.15 ml). Conclusion:Present research work emphasizes that the seeds of Linum usitatissimum is beneficial in the management of congestive heart failure because of having positive inotropic effect, diuretic activity and control of rhythmicity of heart.

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TQ-ST segment mapping: Critical review and analysis of current concepts

Cited by 184 publications

References 164 publications

Dissociation between regional myocardial dysfunction and ECG changes during ischemia in the conscious dog.

Dissociation between regional myocardial dysfunction and ECG changes during ischemia in the conscious dog.

Cardio Protective Effects of Hydroalcholic Citrus Aurantium Extract on Myocardial Infarction Induced by Isoproterenol in Male Rats

Evaluation of Beneficial Effects of Linum Usitatissimum in Congestive Heart Failure

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