The effect of nitroglycerin on coronary blood flow and the hemodynamic response to exercise in coronary artery disease

Parker, John O.; West, Roxroy O.; Giorgi, Salvatore Di

doi:10.1016/0002-9149(71)90083-x

Cited by 108 publications

(19 citation statements)

References 27 publications

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“…The double product has been shown to be a useful noninvasive measure that correlates well with myocardial perfusion and oxygen utilization by the myocardium. [35][36][37][38] The double product at peak exercise in our studies was 2.7-2.8 times greater than that at rest, and at 1 minute after peak exercise, it was 1.7 times greater than that at rest in this group of normal volunteers. Therefore, an equivalent increase in perfusion was expected.…”

Section: Discussionsupporting

confidence: 40%

13N ammonia myocardial imaging at rest and with exercise in normal volunteers. Quantification of absolute myocardial perfusion with dynamic positron emission tomography.

Krivokapich¹,

Smith²,

Huang³

et al. 1989

Circulation

242

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Positron emission tomography (PET) was applied to the measurement of myocardial perfusion using the perfusion tracer 13N-labeled ammonia. 13N ammonia was delivered intravenously to 13 healthy volunteers both at rest and during supine bicycle exercise. Dynamic PET imaging was obtained in three cross-sectional planes for 10 minutes commencing with each injection. The left ventricle was divided into eight sectors, and a small region of interest was assigned to the left ventricular blood pool to obtain the arterial input function. The net extraction of 13N ammonia was obtained for each sector by dividing the tissue 13N concentration at 10 minutes by the integral of the input function from the time of injection to 10 minutes. With this approach for calculating net extractions, rest and exercise net extractions were not significantly different from each other. To obviate possible overestimation of the true 13N ammonia input function by contamination by '3N-labeled compounds other than 13N ammonia or by spillover from myocardium into blood pool, the net extractions were calculated using only the first 90 seconds of the blood and tissue time-activity curves. This approach for calculating net extractions yielded significant differences between rest and exercise, with an average ratio of exercise to rest of 1.38+0.34. Nonetheless, the increase was less than predicted from the average 2.7-2.8-fold increase in double product at peak exercise or the 1.7-fold increase in double product at 1 minute after exercise. However, when the first 90 seconds of dynamic data were fit with a two compartment tracer kinetic model, average perfusion rates of 0.75+±0.43 ml/min/g at rest and 1.50± 0.74 ml/min/g with exercise were obtained. This average increase in perfussion of 2.2-fold corresponded to similar average increases in double product. Thus, the noninvasive technique of PET imaging with 13N ammonia shows promise for future applications in determining absolute flows in patients with coronary artery disease. (Circulation 1989;80:1328-1337 T he reference standard for diagnosing coronary artery disease has long been considered to be coronary angiography. However, the limitations of this shadow technique, the variability of subjective readings of angiograms, and the variable relations of percent stenosis and coronary perfusion have emphasized the need for improved means to assess the functional severity of coronary

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Section: Discussionsupporting

confidence: 40%

13N ammonia myocardial imaging at rest and with exercise in normal volunteers. Quantification of absolute myocardial perfusion with dynamic positron emission tomography.

Krivokapich¹,

Smith²,

Huang³

et al. 1989

Circulation

242

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“…7). Sublingual nitroglycerin in the presence of a constant heart rate was not associated with increases in (dP/dt)/P or isolength velocity but coronary resistance fell slightly (20%), indicating that even when administered sublingually at a dose which produced changes in systemic hemodynamics similar to those reported for man (21)(22)(23)41), a distinct direct effect on the coronary vessels could be identified. Considering the minor rise in coronary flow and the moderate extent of coronary vasodilatation, it is not surprising that prior studies utilizing indirect techniques (22,24,42,43) or studies in open chest preparations in which the coronary bed may already have been partially dilated by the effects of anesthesia and surgery (4,8,9) could not identify an effect due to sublingual nitroglycerin.…”

Section: Discussionmentioning

confidence: 62%

Direct and reflex effects of nitroglycerin on coronary and left ventricular dynamics in conscious dogs

Vatner¹,

Higgins²,

Millard³

et al. 1972

J. Clin. Invest.

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A B S T R A C T The effects of intravenous and sub-lingual glyceryl trinitrate (nitroglycerin), 40 Ag/kg, were studied on coronary blood flow and resistance, left ventricular (LV) pressures (P) and diameters (D), rate of change of pressure (dP/dt), (dP/dt)/P, and on the velocity (V) of myocardial fiber shortening in conscious dogs. Nitroglycerin i.v. caused substantial coronary vasodilatation prior to any changes in systemic hemodynamics. Mean coronary flow increased by a maximum of 47 ml/min and coronary sinus P02 rose from 16 to 26 mm Hg while pressure and diameter began to fall, and heart rate began to rise. After the maximal fall in mean arterial pressure (-26 mm Hg), a secondary peak in coronary flow occurred which was associated with increases in heart rate (100 beats/min), (dP/dt)/P (22%), and isolength V (12%). Beta blockade prevented the reflex increases in contractility but only a part of the reflex tachycardia; the remainder was prevented by cholinergic blockade. Maintaining heart rate constant minimized the decreases in LV D and increases in contractility. When the reflex inotropic and chronotropic effects were prevented by a combination of atrial pacing and beta blockade the early coronary vasodilatation was unaltered, but the later coronary vasodilatation was minimized. creases in contractility and heart rate. The decreases in diameter are largely the result of tachycardia. Sublingual nitroglycerin produced directionally similar, but quantitatively lesser effects on coronary flow and resistance, LV D, LV P, and contractility.

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“…For example, during mechanical ventilation, increased intrathoracic pressure may shift a portion of the circulating blood volume away from the chest, decreasing cardiac filling and reducing cardiac output.1 2 Other investigators, however, have observed increased right and left atrial filling pressures during ventilation with positive end-expiratory pressure (PEEP) and have hypothesized that depressed myocardial function may be significant.3 A circulating negative inotropic agent in the blood of dogs ventilated with PEEP has been reported.4 Alterations in ventricular geometry and septal shifting that could contribute to reduced cardiac output have also been noted.5'6 Because the pulmonary vasculature hemodynamically couples the right and left ventricles, alterations in the pulmonary circulation induced by airway pressure could change the functional characteristics of the ventricles in opposite directions and contribute to abnormal ventricular interaction. 7,8 …”

Section: Discussionmentioning

confidence: 99%

Effects of exercise training on ventricular function in patients with recent myocardial infarction.

Cobb¹,

Williams²,

McEwan³

et al. 1982

Circulation

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SUMMARY We evaluated the effects of 6 months of exercise training (bicycle ergometry, walking and jogging) on exercise performance and ventricular function in patients with recent myocardial infarction. Fifteen patients were selected on the basis of myocardial infarction at least 6 weeks but not more than 6 months before the study and age younger than 65 years. The patients were evaluated by maximal treadmill exercise testing and radionuclide angiography at rest and exercise before and after training.Before exercise training, maximal treadmill exercise time ranged from 1.5 to 11 minutes, ejection fraction at rest from 18% to 67% and end-diastolic volume from 108 to 208 ml. The mean EF was 48 ± 5% (± SD) at rest and did not change at maximal exercise (48.5 ± 5%). All 11 patients who completed the exercise training program achieved a significant training effect, as defined by a reduction in heart rate at 50% maximal pretraining effort or an increase in maximal treadmill time. The mean ejection fraction and end-diastolic volume and wall motion abnormalities at rest and at comparable pretraining exercise work loads and heart rates were not significantly different after training.Despite a wide range of rest and exercise ventricular function, patients with recent uncomplicated myocardial infarcts significantly increased their exercise performance. Because rest and exercise ventricular function were comparable before and after training, improvement in exercise performance probably resulted from training effects on the peripheral vasculature.PATIENTS with coronary artery disease demonstrate a wide range of impaired cardiovascular adjustments during exercise.' Although exercise performance in certain patients with coronary artery disease may not be different from that in age-matched normal subjects, most patients have lower maximal cardiac output and maximal oxygen consumption,lA a decreased heart rate response to exercise and a decreased stroke volume at submaximal work loads. 1-' During mild supine exercise, left ventricular filling pressures are often elevated$'0 and systolic ejection rate and the rate of rise of pressure at a given ventricular pressure are reduced."1-3 Noninvasive evaluation of ventricular function using radionuclide angiography has shown that the left ventricular ejection fraction frequently decreases and regional wall motion abnormalities appear during exercise in patients with coronary disease.I-'7 These findings indicate that left ventricular dysfunction commonly occurs in patients with coronary artery disease during exercise stress.Exercise training improves exercise tolerance in most patients with coronary disease.2' 5, 18-22 Clausen' summarized the central and peripheral effects of exercise training and pointed out that the effects are qualitatively similar in subjects with and without coronary artery disease. In patients with coronary disease and no chest pain, training may improve maximal exercise

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The effect of nitroglycerin on coronary blood flow and the hemodynamic response to exercise in coronary artery disease

Cited by 108 publications

References 27 publications

13N ammonia myocardial imaging at rest and with exercise in normal volunteers. Quantification of absolute myocardial perfusion with dynamic positron emission tomography.

13N ammonia myocardial imaging at rest and with exercise in normal volunteers. Quantification of absolute myocardial perfusion with dynamic positron emission tomography.

Direct and reflex effects of nitroglycerin on coronary and left ventricular dynamics in conscious dogs

Effects of exercise training on ventricular function in patients with recent myocardial infarction.

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