Interventional cardiology in Europe 1994. Working Group Coronary Circulation of the European Society of Cardiology

The working group Coronary Circulation of the European Society of Cardiology conducts an annual survey of cardiac interventions in Europe with the support of the national societies of cardiology. A detailed questionnaire about cardiac interventions performed during 1994 was mailed to all members of the European Society of Cardiology. Incomplete or absent data from eight national members precluded their inclusion in the final analysis. Thus, this report summarizes the cardiac interventions performed during 1994 in 29 of 37 members of the European Society of Cardiology, representing a total population of approximately 490 million inhabitants.

CORONARY ANGIOGRAPHY

A total of 922,687 coronary angiograms were reported during 1994, representing an increase of 22% compared with 1993 and of 35% compared with 1992. The mean incidence of coronary angiograms was 1881/10(6) inhabitants, ranging from 4417/10(6) inhabitants in Germany to 35/10(6) inhabitants in Romania, Germany, France, Great Britain, and Italy with 50% of the European population performed 73% of all cardiac interventions.

CORONARY ANGIOPLASTY

During 1994, a total of 224,722 coronary angioplasty (PTCA) procedures were reported in Europe, an increase of 22% compared with 1993 and of 52% compared with 1992. Adjusted per capita, the mean incidence of coronary angioplasty was 458/10(6) inhabitants, ranging from 1091/10(6) inhabitants in Germany to 6/10(6) inhabitants in Romania. On average, the ratio PTCA per coronary angiogram was 0.24, ranging from 0.37 in the Netherlands to 0.06 in Cyprus. Ad hoc PTCA accounted for 22% of all PTCA cases. The majority (81%) of PTCAs were restricted to a single vessel. Major complications were reported in 2% of patients undergoing PTCA, including death (0.3%), myocardial infarction (1.0%) and need for emergency coronary artery bypass grafting (0.7%).

CORONARY STENTING

Coronary stents were utilized in 21,599 coronary interventions during 1994, an increase of 235% compared with 1993 and thus representing the fastest growth in interventional cardiology. The number of European countries employing stents during coronary angioplasty grew from 14 during 1993 to 24 during 1994. Elective use (38%) became the most frequent indication for coronary stenting during 1994, replacing bail-out stenting as the primary indication during 1993.

OTHER NEW DEVICES

Other new interventional therapeutic devices were employed in 8827 cases. Only the Rotablator was used more frequently during 1994 as compared with 1993. All other new therapeutic devices showed a decline. Coronary ultrasound was utilized in 3032 interventions and coronary angioscopy in 304 cases during 1994. NON-CORONARY INTERVENTIONS: Valvuloplasty remained the most frequent non-coronary intervention in Europe during 1994 with a total of 2622 mitral. 609 pulmonary and 506 aortic valvuloplasties.

CATHETERIZATION FACILITIES

The number of facilities per 10(6) inhabitants performing invasive cardiac procedures in Europe during 1994 ranged from 7.7 in Iceland to 0.2 in Romania (European mean 2.9). The number of trained operators per 10(6) inhabitants ranged from 24 in Germany to 0.4 in Romania (European mean 10). During 1994, a mean of 701 coronary angiograms and 170 PTCAs were performed per catheterization facility in Europe (range: 1052 coronary angiograms and 293 PTCAs per facility in Norway to 218 coronary angiograms and 37 PTCAs per facility in Romania).

CONCLUSIONS

The number of both coronary angiograms and coronary angioplasties continues to grow at an annual rate of approximately 20% in Europe. There is a wide range in the amount of revascularization procedures performed between western and eastern European countries. However, countries with the lowest numbers of coronary angiograms and coronary angioplasties, e.g. Romania, also show the fastest annual growth. About one quarter of all patients undergoing coronary angiography are subsequently revascularized by coronary angioplasty. (ABSTRACT TRUN

Assessment of myocardial viability in patients with chronic coronary artery disease. Rest-4-hour-24-hour 201Tl tomography versus dobutamine echocardiography

BACKGROUND

To date, late redistribution after resting 201Tl injection has not been evaluated. In addition, the concordance between resting 201Tl imaging and dobutamine echocardiography in identifying viable myocardium has not been assessed.

METHODS AND RESULTS

Forty patients with coronary artery disease underwent rest-4-hour-24-hour 201Tl tomography and dobutamine echocardiography (5 to 10 micrograms.kg-1.min-1). Late redistribution occurred in 46 (21%) of 219 persistent defects at 4 hours. Systolic function and contractile reserve were similar among persistent defects at 4 hours with and without late redistribution. Contractile reserve was more frequent in segments with normal 201Tl uptake (59%), completely reversible defects (53%), or mild to moderate defects at 4 hours (56%) compared with severe defects (14%; P < .02 versus all). Of 105 hypokinetic segments, 99 (94%) were viable by 201Tl, and 88 (84%) showed contractile reserve. In contrast, of 155 akinetic segments, 119 (77%) were viable by 201Tl, but only 34 (22%) had contractile reserve. Concordance between 201Tl and dobutamine was 82% in hypokinetic segments but 43% in akinetic segments. In 109 revascularized segments, positive accuracy for functional recovery was 72% for 201Tl and 92% for dobutamine, whereas negative accuracy was 100% and 65%, respectively. Sensitivity was 100% for 201Tl and 79% for dobutamine.

CONCLUSIONS

Late redistribution occurs in one fifth of persistent defects at 4 hours, and it does not correlate to systolic function or contractile reserve. Dobutamine and 201Tl yield concordant information in the majority of hypokinetic segments, whereas concordance is low in akinetic segments. Dobutamine demonstrates higher positive accuracy and sensitivity in predicting recovery of dysfunctional myocardium, whereas 201Tl shows higher negative predictive accuracy but reduced positive accuracy.

Prolonged impairment of regional contractile function after resolution of exercise-induced angina. Evidence of myocardial stunning in patients with coronary artery disease

BACKGROUND

Delayed recovery of contractile function in spite of normal perfusion (ie, "stunning") has been described in animal models of exercise-induced myocardial ischemia. Therefore, we investigated whether stunning may result from effort angina in patients.

METHODS AND RESULTS

Patients with coronary artery disease underwent exercise testing combined with quantitative measurements of contractile function for up to 240 minutes after exercise determined by either measurement of regional ejection fraction (99mTc radionuclide angiography; n = 17, group A) or computer-assisted measurement of systolic wall thickening (n = 14, group B). In the latter group, myocardial perfusion was also evaluated by 99mTc-sestamibi tomographic imaging. Angina induced marked contractile dysfunction. Hemodynamic and ECG changes brought about by ischemia were promptly normalized. Furthermore, no perfusion defects could be detected in group B patients 30 minutes after exercise, yet contractile function remained impaired well after cessation of exercise. Thirty minutes into recovery, regional ejection fraction of previously ischemic areas was still 82.6 +/- 4.6% of baseline in group A (P < .05). Similarly, in group B patients, systolic thickening of previously ischemic segments was still significantly impaired 60 minutes after exercise, averaging 33.8 +/- 2.8% versus 40.5 +/- 2.7% at baseline (P < .05). Contractile impairment was fully reversible, as the functioning of previously ischemic segments normalized between 60 and 120 minutes of recovery.

CONCLUSIONS

Prolonged yet ultimately reversible impairment of regional myocardial function may occur in patients after exercise-induced angina in the absence of perfusion abnormalities. These findings indicate that myocardial stunning may ensue after effort angina in patients with severe coronary artery disease.

Interventional cardiology in Europe 1993. Working Group on Coronary Circulation of the European Society of Cardiology

An annual survey on cardiac interventions in Europe is performed by the working group on Coronary Circulation of the European Society of Cardiology with the help of the national societies of cardiology. A questionnaire about cardiac interventions in 1993 was mailed to a representative of the national societies of 35 members of the European Society of Cardiology. The data collection of coronary interventions was delayed by slow backreporting and from 10 of the 35 national members data were missing or grossly incomplete. They were excluded from the analysis.

CORONARY ANGIOGRAPHY

A total of 756,822 coronary angiograms were reported resulting in an incidence of 1146 +/- 1024 per 10(6) inhabitants, ranging from 24 (Romania) to 3499 (Germany). This represents an increase of 12% compared to 1992. Germany (279,882 cases), France (157,237), the United Kingdom (77,000), Italy (44,934) and Spain (37,591) registered 79% of all the coronary angiograms performed.

PERCUTANEOUS TRANSLUMINAL CORONARY ANGIOPLASTY

A total of 183,728 percutaneous transluminal coronary angioplasty cases were reported in 1993, 24% more than in 1992. On average, they accounted for 18 +/- 7% (range 8 (Romania) to 35% (Sweden) of the coronary angiograms. Most of these percutaneous transluminal coronary angioplasties (82%) were confined to a single vessel. In 13% only, percutaneous transluminal coronary angioplasty took place immediately after the diagnostic study. Adjusted per capita. Germany ranks first with 873 percutaneous transluminal coronary angioplasties per 10(6) inhabitants, followed by France (737), Holland (725), Belgium (713), and Switzerland (665). The European mean of percutaneous transluminal coronary angioplasties per 10(6) inhabitants was 270 +/- 279, representing an increase of 14% compared with 1992. A major in-hospital complication was reported in 3.8% of the patients undergoing percutaneous transluminal coronary angioplasty: 0.6% hospital deaths, 1.5% emergency coronary artery bypass grafting, and 1.7% myocardial infarctions.

NEW DEVICES

In 1993 stents were implanted in 6444 patients (3.5% of all percutaneous transluminal coronary angioplasty patients), equally distributed between bail-out situations (53%) and elective procedures. The 14 stent implanting countries showed a mean increase in incidence of coronary stenting of 53% compared with 1992. Other interventional devices were applied in 7045 cases, 3.8% of all percutaneous transluminal coronary angioplasty cases. Coronary ultrasound (2194 cases) and coronary angioscopy (380 cases) were performed infrequently. NON-CORONARY INTERVENTIONS: Valvuloplasties were most frequently performed non-coronary interventions European countries performed more than 300 valvuloplasties each in 1993. Most of them were mitral valvuloplasties in southern countries.

CONCLUSIONS

Although partial backreporting might conclusions, several findings of this survey are noteworthy for the participating countries: The number of percutaneous taneous transluminal coronary angioplasties is universally increasing. There is an extremely wide range of coronary angiography and percutaneous translumina, coronary angioplasties performed per population. The most common additional procedure is a stent implantation while other new devices are only rarely applied. Mitral valvuloplasty is the most frequently performed non-coronary intervention.

Inotropic stimulation by dobutamine increases left ventricular regional function at the expense of metabolism in hibernating myocardium

The mechanism by which dobutamine increases the contraction of chronically dysfunctional myocardium and its effects on metabolism are still unknown. The aim of this study was to assess regional myocardial metabolism at rest and during an intracoronary dobutamine infusion in patients with hibernating myocardium. Eleven asymptomatic patients with single proximal stenosis of the left anterior descending coronary artery and persistent left ventricular dysfunction at rest (undergoing percutaneous transluminal coronary angioplasty [PTCA]) were studied prospectively. Regional left ventricular function was assessed by two-dimensional (2D) echocardiography and regional perfusion by thallium-201 single-proton-emission computed tomography. Great cardiac vein and aortic blood samples were obtained for measurements of lactate and plasma free fatty acid (FFA) concentrations. Inotropic challenge, obtained by using intracoronary dobutamine infusion, increases regional left ventricular function. However, the arteriovenous AV lactate difference was 0.206 = 0.070 mmol/L at rest, and it decreased to 0.018 = 0.069 mmol/L (p < 0.05 vs baseline) and 0.066 = 0.068 mmol/L (p < 0.05 vs baseline) at 4 and 10 minutes of dobutamine infusion, respectively. Thus the hibernating myocardium does not produce lactate at rest. However, when regional contraction is stimulated, dobutamine-induced inotropic challenge may cause a perfusion-contraction mismatch with an activation of anaerobic glycolysis.

Effects of diltiazem on left ventricular systolic and diastolic function in hypertrophic cardiomyopathy

Hypertrophic cardiomyopathy (HC) is characterized by impaired diastolic function, and left ventricular (LV) outflow tract obstruction in about one-fourth of patients. Verapamil improves diastolic properties, but may have dangerous adverse effects. This study investigates the effects of diltiazem on hemodynamics and LV function in 16 patients with HC who were studied with cardiac catheterization and simultaneous radionuclide angiography. Studies were performed during atrial pacing (15 beats above spontaneous rhythm) at baseline and during intravenous diltiazem administration (0.25 mg x kg(-1) over 2 minutes, and 0.014 mg x kg(-1) x min(-1). Diltiazem induced a systemic vasodilation (cardiac index: 3.4 +/- 1.0 to 4.0 +/- 1.0 L x min(-1) x m(-2), p = 0.003; aortic systolic pressure: 116 +/- 16 to 107 +/- 19 mm Hg, p = 0.007; systemic resistance index: 676 +/- 235 to 532 +/- 193 dynes x s x cm(-5) x m(-2), p = 0.006), not associated with changes in the LV outflow tract gradient. The end-systolic pressure/volume ratio decreased (30 +/- 42 to 21 +/- 29 mm Hg x ml(-1) x m(-2); p = 0.044). Pulmonary artery wedge pressure (11 +/- 5 to 15 +/- 6 mm Hg, p = 0.006), and peak filling rate increased (4.1 +/- 1.3 to 6.0 +/- 2.4 stroke counts x s(-1), p = 0.004). The time constant of isovolumetric relaxation tau decreased (74 +/- 40 to 59 +/- 38 ms, p = 0.045). The constant of LV chamber stiffness did not change. Thus, active diastolic function is improved by the acute administration of diltiazem by both direct action and changes in hemodynamics and loading conditions. LV outflow tract gradient does not increase despite systemic vasodilation. In some patients, however, a marked increase in obstruction and a potentially harmful elevation in pulmonary artery wedge pressure do occur. Passive diastolic function is not affected.

Effects of dual-chamber pacing in hypertrophic cardiomyopathy on left ventricular outflow tract obstruction and on diastolic function

Hypertrophic cardiomyopathy (HC) is characterized by impaired diastolic function and, in about 1/4 of patients, left ventricular (LV) outflow tract obstruction. Atrioventricular (AV) pacing diminishes LV outflow tract gradient in HC, but impairs diastolic function in the experimental animal and in different categories of patients. To investigate the effects of AV pacing on hemodynamics and LV function in obstructive HC, 16 patients with HC were studied by cardiac catheterization and simultaneous radionuclide angiography during atrial and AV pacing. The resting LV outflow tract gradient decreased with AV pacing from 60 +/- 34 to 38 +/- 37 mm Hg (mean +/- SD; p <0.001). Regional ejection fraction decreased significantly at the septal level from 0.81 +/- 0.21% to 0.69 +/- 0.27% (p <0.01). Pulmonary artery wedge pressure increased from 10 +/- 5 to 15 +/- 6 mm Hg (p <0.001). AV pacing induced asynchrony (i.e., the coefficient of variation of the time to end-systole increased from 7 +/- 4% to 14 +/- 10% (p <0.01). The time constant of isovolumetric relaxation (t) increased from 58 +/- 24 to 74 +/- 33 ms (p <0.02), and peak filling rate decreased from 491 +/- 221 to 416 +/- 184 ml/s (p <0.05). Thus, AV pacing greatly diminishes resting obstruction through a reduction in septal ejection fraction (i.e., an increase in LV outflow tract width in systole), but impairs active diastolic function and increases filling pressures. These latter effects are potentially detrimental in patients with HC in whom diastolic dysfunction is present.

Limb vasoconstriction after successful angioplasty of the left anterior descending coronary artery

BACKGROUND

Coronary vasoconstriction has been described after uncomplicated percutaneous transluminal coronary angioplasty (PTCA). However, it is still unknown whether this phenomenon is limited to coronary circulation. The present study was planned to assess the effects of a successful PTCA on forearm blood flow (FBF) and resistance. The role of alpha-adrenoceptors and calcium antagonist agents on PTCA-induced limb blood flow changes was also investigated.

METHODS AND RESULTS

We prospectively studied 37 patients scheduled for elective single PTCA of the left anterior descending coronary artery. All patients had evidence of exercise-induced myocardial ischemia. All vasoactive drugs were withdrawn for at least 48 hours before the study. FBF was measured by calibrated venous occlusion plethysmography. A significant reduction of FBF was observed at 1, 5, and 15 minutes after PTCA (from 3.7 +/- 1.2 to 2.7 +/- 1.5, 3.0 +/- 1.6, and 2.9 +/- 1.9 mL/100 mL tissue per minute, respectively; all P < .05 versus baseline). Vascular forearm resistance also increased at 1, 5, and 15 minutes after PTCA (from 27 +/- 8 to 42 +/- 16, 37 +/- 10, and 43 +/- 19 U, respectively; all P < .05 versus baseline). Phentolamine (12 microgram.kg-1.min-1, n = 7) or verapamil (3.5 micrograms.kg-1.min-1, n = 7) also was infused intra-arterially. PTCA-induced forearm vasoconstriction was completely abolished by pretreatment with regional infusion of phentolamine or verapamil.

CONCLUSIONS

After an uncomplicated PTCA of the left anterior descending coronary artery, a reduction in FBF and an increase in forearm vascular resistance were observed. This peripheral vasoconstrictive response was probably due to alpha-adrenergic stimulation and was abolished by intra-arterial infusion of calcium antagonist agents.

Dobutamine echocardiography predicts improvement of hypoperfused dysfunctional myocardium after revascularization in patients with coronary artery disease

BACKGROUND

In patients with coronary artery disease, dysfunctional hypoperfused myocardium at rest may represent either necrotic or viable hibernating myocardium. The accuracy of inotropic stimulation in identifying hypoperfused, reversibly dysfunctional myocardium has not been extensively investigated.

METHODS AND RESULTS

Eighteen patients with stable chronic coronary artery disease underwent, while off drugs, quantitative 201Tl single-photon emission computed tomography after rest injection (2 to 3 mCi), two-dimensional echocardiography at rest and during dobutamine (5 to 10 micrograms/kg per minute i.v.), and radionuclide angiography. Single-photon emission computed tomography and echocardiography at rest were repeated 34 +/- 10 days after coronary revascularization, and radionuclide angiography was repeated 45 +/- 13 days after revascularization. Resting hypoperfusion was defined as 201Tl uptake < 80% of maximal activity. Systolic function was scored from 1 (normal) to 4 (dyskinesia), and functional improvement was defined as a score change > 1 grade. Of 79 dysfunctional hypoperfused segments, 48 (61%) improved function after revascularization. In 42 (88%) of these latter segments, function had improved during dobutamine. Conversely, systolic function after revascularization did not improve in 31 segments, and in 27 (87%), it had not improved during dobutamine. Functional improvement after revascularization was observed in 42 (91%) of 46 segments manifesting an improvement during dobutamine as opposed to 6 (18%) of 33 segments that did not improve during dobutamine. Resting 201Tl uptake (% of maximal activity) before revascularization (65 +/- 9%) significantly increased at follow-up in segments where function improved (70 +/- 12%, P < .005), whereas it did not change significantly in segments with unchanged systolic function after revascularization (from 57 +/- 13% to 60 +/- 17%, P = NS). In 10 patients with prerevascularization ejection fraction < 45%, left ventricular ejection fraction significantly increased from 36 +/- 7% before revascularization to 42 +/- 7% at follow-up (P < .05).

CONCLUSIONS

Inotropic stimulation using dobutamine echocardiography identifies hypoperfused reversibly dysfunctional myocardium. Functional improvement during dobutamine is highly predictive of improvement after revascularization.

[Coronary angioplasty for the recovery of myocardial function after acute myocardial infarction: mid- and long-term results]

Sixty-three patients with previous myocardial infarction and documented hypoperfused reversibly dysfunctional myocardium after 201thallium tomography and/or echo-dobutamine were candidates to coronary angioplasty. Patients were enrolled at four hospitals (Naples, Milan, Pisa and Varese) and evaluated by different study protocols, while endpoint (presence of myocardial viability and efficacy of coronary angioplasty to improve dysfunctional myocardium) was similar. Sixty-two patients underwent successful angioplasty, and early evaluation (between 1 and 3 months after procedure) showed the ability of either 201thallium tomography and/or dobutamine echocardiography, to identify hypoperfused reversibly dysfunctional myocardium. Ten patients underwent late (after 8 +/- 2 months) evaluation of both wall motion and myocardial perfusion showing a sustained improvement in 25/32 hypoakinetic myocardial segments. Our data confirm the efficacy of revascularization of hypoperfused dysfunctional myocardial segments by coronary angioplasty. Further studies are warranted to obtain a better patient stratification and to evaluate the long-term results.

Coronary artery vasoconstriction after successful single angioplasty of the left anterior descending artery

Percutaneous transluminal coronary angioplasty is associated with spontaneous transient vasoconstriction. The mechanisms by which coronary vasoconstriction occurs distally to a successful dilated stenosis after coronary artery angioplasty are still unknown. The present study was planned to investigate the effect of successful coronary artery angioplasty on coronary vasomotion distal to a dilated stenosis and in the control vessel and the role of alpha-adrenergic receptors on coronary vasomotion after successful coronary artery angioplasty. We prospectively studied 32 consecutive patients scheduled for elective single coronary artery angioplasty of the left anterior descending coronary artery. Only aspirin, 325 mg, or nitroglycerin was allowed in the week before the study; no premedication with diazepam or other drugs was given. In group 1 (control patients, n = 20), quantitative coronary angiography was performed in the control state; 5 and 15 minutes after coronary artery angioplasty; and after intracoronary nitroglycerin infusion, 300 micrograms. In group 2 (n = 12), intracoronary phentolamine, 2 mg, was infused regionally through the balloon catheter before the coronary artery angioplasty, and coronary angiography was performed at baseline, 15 minutes after balloon deflation, and after nitroglycerin infusion. In group 1, constriction of the coronary segment distal to a dilated stenosis (2.4 +/- 0.8 to 2.1 +/- 0.6 mm, -14.6% vs baseline; p < 0.05) and of the circumflex coronary artery segment (2.8 +/- 0.7 to 2.5 +/- 0.6 mm, -10.7% vs baseline, p < 0.05) occurred 15 minutes after coronary artery angioplasty. The degree of vasoconstriction was not correlated with the lesion severity before coronary artery angioplasty.(ABSTRACT TRUNCATED AT 250 WORDS)

Evaluation of left ventricular asynchrony by radionuclide angiography: comparison of phase and sector analysis

The aim of this study was to assess the optimal method to evaluate asynchrony in equilibrium radionuclide angiography (RNA).

METHODS

We studied 20 patients (14 males and 6 females, age range 25-60 yr) with RNA during atrial and sequential atrioventricular (AV) pacing, which increased left ventricular (LV) asynchrony. Both studies were performed at the same heart rate. Asynchrony was assessed either on phase images, by computing the standard deviation of the phase distribution (SD-P) and by sector analysis. Systolic and diastolic asynchrony were evaluated as the coefficient of variation of time to end systole (CV-TES) and time to peak filling rate (CV-TPFR) in four sectors. In addition, phase values were computed on time-activity curves from the same sectors, and their standard deviation (SD-Psec) was computed.

RESULTS

During atrial pacing SD-P was 32.3 degrees +/- 6.7 degrees and did not change during AV pacing (32.1 degrees +/- 5.6 degrees, p = n.s.). Both CV-TES and CV-TPFR had a significant increase during AV pacing (from 7.7% +/- 3.9% to 11.5% +/- 6.4%, p < 0.01, and from 8.4 degrees +/- 5.8 degrees to 12.9 degrees +/- 6.7 degrees, p < 0.001). AV pacing led to a significant increase in SD-Psec (from 6.3 degrees +/- 4.0 degrees to 12.6 degrees +/- 9.7 degrees, p < 0.05). Moreover, reproducibility was assessed in 15 additional age-matched patients. The results of the reproducibility study indicate a better repeatability for CV-TES and CV-TPFR.

CONCLUSIONS

The findings of this study suggest that sector analysis with calculation of indices of LV systolic and diastolic asynchrony is better suited for quantitation of LV temporal nonuniformity.

Influence of reversible segmental left ventricular dysfunction on heart period variability in patients with one-vessel coronary artery disease

OBJECTIVES

This study evaluated the relation between reversible segmental left ventricular dysfunction and frequency domain measures of heart period variability in patients with coronary artery disease.

BACKGROUND

Heart period variability is frequently reduced in patients with coronary artery disease. However, the mechanisms of this reduction are still unclear.

METHODS

Echocardiographic left ventricular wall motion and frequency domain measures of heart period variability were evaluated in 32 patients with one-vessel coronary artery disease before and 16 to 24 days after successful percutaneous transluminal coronary angioplasty. Of these, 12 patients (Group A) had normal and 20 patients (Group B) had abnormal regional wall motion. A control group of 15 healthy subjects (Group C) underwent 24-h Holter recording twice at 2-week intervals to check for spontaneous variations.

RESULTS

At baseline, low and high frequency power were lower in Group B than in Groups A and C, whereas no difference was detectable in ultra low and very low frequency and total power. After coronary angioplasty, regional wall motion and frequency domain measures of heart period variability were unchanged in Group A. In Group B the mean (+/- SD) summed segment score improved from 17.1 +/- 3.6 to 12.8 +/- 2.0 (p < 0.01), and mean low and high frequency power (logarithmic units) increased from 6.14 +/- 0.23 to 6.35 +/- 0.34 (p < 0.01) and from 5.43 +/- 0.32 to 5.68 +/- 0.52 (p < 0.01), respectively. Furthermore, low and high frequency power, lower at baseline in Group B than in the other two groups, were comparable in the three groups after coronary angioplasty.

CONCLUSIONS

This study demonstrates that segmental left ventricular dysfunction is involved in determining sympathovagal imbalance in patients with one-vessel coronary artery disease; the reversal of left ventricular dysfunction by successful coronary angioplasty improves the heart period power spectrum. Thus, alterations in cardiac geometry influence the discharge of afferent sympathetic mechanoreceptors, contributing to the derangement in autonomic control of heart rate.

[Effects of coronary angioplasty on heart rate variability explored in the domain of time and frequency in patients with one-vessel coronary disease]

BACKGROUND

Heart period variability is frequently reduced in patients with coronary artery disease. Although the mechanism for this reduction is still unclear, it seems to reflect alterations in cardiac autonomic control. In this study we have evaluated the relation between reversible segmental left ventricular dysfunction and time and frequency domain measures of heart period variability in patients with coronary artery disease.

METHODS AND RESULTS

Echocardiographic segmental left ventricular wall motion and time and frequency domain measures of heart period variability were evaluated in 32 patients with one-vessel coronary artery disease before and 16-24 days after successful percutaneous transluminal coronary angioplasty (PTCA). At baseline examination 12 patients (Group A) had normal and 20 (Group B) abnormal regional wall motion. Prevalence of previous myocardial infarction was higher and mean angiographic ejection fraction lower in Group B than in Group A. At baseline, time domain measures were comparable between the 2 groups, while low frequency (LF) and high frequency (HF) power were lower in Group B than in Group A. After PTCA, in Group A regional wall motion and time and frequency domain measures of heart period variability were unchanged. In Group B summed segment score improved from 17.1 +/- 3.6 to 12.8 +/- 2.0 (p < 0.01) and a significant increase occurred in standard deviation of the average normal RR (NN) intervals for all 5-minute segments of a 24-hour recording (SDNN index), in root mean square successive difference (r-MSSD) and in the percentage of differences between adjacent NN intervals > 50 msec (pNN50). In this group also LF and HF power (logarithmic units) increased from 6.14 +/- 0.23 to 6.35 +/- 0.34 (p < 0.01) and from 5.43 +/- 0.32 to 5.68 +/- 0.52 (p < 0.01) respectively. There was no correlation between measures of heart period variability, summed segment score, and left ventricular ejection fraction.

CONCLUSIONS

This study demonstrates that segmental left ventricular dysfunction is involved in determining sympathovagal imbalance in patients with one-vessel coronary artery disease; the reversal of left ventricular dysfunction by successful PTCA improves heart period variability. These findings support the hypothesis that alterations in cardiac geometry may influence the discharge of afferent sympathetic mechanoreceptors, thus contributing to the derangement in autonomic control of heart rate.

[Heart function in chronic pressure overload caused by aortic stenosis: the role of collagen tissue]

The purpose of this study was to evaluate left ventricular (LV) structure-function interplay in aortic stenosis. LV structure was assessed from endomyocardial biopsies obtained in 27 patients with aortic stenosis. Total collagen volume fraction, orthogonal collagen fiber meshwork (cross-hatching) and endocardial fibrosis were determined by morphologic-morphometric evaluation. Control biopsy data were obtained from 6 pre-transplantation donor hearts whereas other 11 patients with normal cardiac function served as hemodynamic controls. LV biplane cineangiography and high-fidelity LV pressure measurement were carried out in all patients. Systolic function was assessed by LV biplane ejection fraction, diastolic function by time constant of relaxation, peak filling rates and passive elastic properties. Total collagen volume fraction (7.3 versus 1.6%, p < 0.01) as well as the degree of cross-hatching (1.7 versus 0.8 grade, p < 0.01) were significantly increased in patients with aortic stenosis with respect to controls. Endocardial fibrosis was present in 11/27 patients with aortic stenosis and in no patients of control group. In aortic stenosis in presence of increased total collagen volume fraction there were no changes in systolic and diastolic function, whereas in presence of changes in collagen architecture ejection fraction was depressed and passive elastic properties increased. In conclusion, in aortic stenosis, changes in collagen architecture are associated with altered systolic function and passive diastolic properties. The sole increase in total collagen volume fraction without a change in architecture leaves systolic and passive diastolic function unaltered. A prolongation of relaxation was present in aortic stenosis and appears to be mediated by muscle hypertrophy per se.

Local effect of serotonin released during coronary angioplasty

BACKGROUND

Serotonin is released after the aggregation of platelets, a phenomenon that may occur after coronary angioplasty. We sought to determine whether serotonin is released into the coronary circulation during coronary angioplasty and to assess whether serotonin can affect coronary-artery tone during angioplasty.

METHODS

Blood samples were drawn from the ascending aorta and the coronary sinus of eight patients scheduled to undergo angioplasty of the left anterior descending or circumflex coronary artery. Samples were obtained before angioplasty and after each balloon dilation. The dimensions of arterial segments distal to the site of dilation were measured angiographically before angioplasty and 5 and 15 minutes after the last dilation in these eight patients and in seven similar patients; the latter group was treated with ketanserin, a serotonin2-receptor antagonist, before angioplasty.

RESULTS

Before the eight patients underwent angioplasty, their mean (+/- SE) plasma serotonin level in the aorta was 2.5 +/- 0.7 ng per milliliter and that in the coronary sinus was 2.3 +/- 0.6 ng per milliliter (P = 0.34). The serotonin level in plasma from the coronary sinus rose significantly, to 31.5 +/- 13.5, 17.6 +/- 5.3, and 29.1 +/- 8.1 ng per milliliter after the first, second, and third dilations, respectively (P = 0.014 for the comparison with preoperative levels). In contrast, the serotonin level in plasma from the ascending aorta did not change. The cross-sectional area of the coronary artery was significantly reduced 5 and 15 minutes after the last dilation (from a preoperative value of 3.7 +/- 0.5 mm2 to 2.7 +/- 0.4 mm2 15 minutes after the last dilation; P = 0.011). This vasoconstriction was significantly blunted in the seven patients who received ketanserin (from 3.7 +/- 0.5 mm2 before angioplasty to 3.9 +/- 0.4 mm2 after 15 minutes) (P = 0.017 for comparison with the eight patients who did not receive ketanserin).

CONCLUSIONS

Serotonin is released into the coronary circulation during angioplasty, and this vasoactive substance may contribute to the occurrence of vasoconstriction distal to the dilated site. The vasoconstriction is attenuated by ketanserin, a serotonin2-receptor antagonist.

[The effects of the selective intracoronary administration of nifedipine on left ventricular filling anomalies during coronary angioplasty]

Eighteen patients with isolated stenosis of left anterior descending artery, were randomly given 0.2 mg of nifedipine (Group II) or its solvent (Group I) via balloon catheter positioned across the lesion immediately prior balloon occlusion. Peak velocity of early (E peak) and late (A peak) filling, velocity flow integral at early (E area) and late (A area) filling and their ratios (by echo-Doppler) and heart rate, mean aortic and wedge (W) pressures were measured at baseline, 15 and 30 s during balloon occlusion and 10 min after balloon deflation. In Group I we observed a significant decrease in either E peak at 15 and 30 s (-24.7%, -29.3% respectively) and E area (-32.8%, -40.0% respectively) with a non significant increase in both A peak and A area. Accordingly, either E/A peak ratio and E/A area ratio decreased significantly. In Group II no significant changes were observed in the echo-Doppler parameters of left ventricular filling. Wedge pressure also significantly increased in Group I at 15 and 30 s (68.7% and 97.9% respectively), while a significant increase in Group II occurred only at 30 s (32.5%). Heart rate significantly increased only in Group I at 15 and 30 s (10.3% and 11% respectively), while aortic pressure remained unchanged in both groups. Thus, nifedipine given intracoronary in the post-stenotic area just before balloon occlusion prevents left ventricular filling dynamic alteration by preserving early filling.

Effects of induced asynchrony on left ventricular diastolic function in patients with coronary artery disease

OBJECTIVES

This study was designed to increase asynchrony with sequential atrioventricular (AV) pacing and to study its effects on left ventricular isovolumetric relaxation, rapid filling and stiffness.

BACKGROUND

Left ventricular nonuniformity is a major determinant of diastolic function.

METHODS

Thirteen patients with coronary artery disease were studied by simultaneous equilibrium radionuclide angiography and cardiac catheterization during atrial and AV pacing. Ejection fraction and peak filling rate were measured by radionuclide angiography. Regional analysis was obtained by analyzing time-activity curves of four left ventricular sectors; systolic and diastolic asynchrony were evaluated as the coefficient of variation of time to end-systole and, respectively, time to peak filling rate in the four sectors. Cardiac index and left ventricular pressure were measured with high fidelity catheters at cardiac catheterization. The time constant of isovolumetric relaxation was derived from left ventricular pressure. Pressure-volume loops were assembled and constants of chamber stiffness were computed.

RESULTS

Atrioventricular pacing led to a decrease in cardiac index (3.7 +/- 0.9 to 3.3 +/- 0.8 liters/min per m2, p = 0.01) and peak filling rate (352 +/- 125 to 287 +/- 141 ml/s, p = 0.03; 2.4 +/- 0.8 to 2.0 +/- 0.8 end-diastolic counts/s, p = 0.02; 4 +/- 1.3 to 3.2 +/- 1.0 stroke counts/s, p = 0.008). The time constant of isovolumetric relaxation increased (57 +/- 10 to 64 +/- 12 ms, p = 0.04) and the global diastolic pressure-volume relation shifted upward.

CONCLUSIONS

Atrioventricular pacing induces left ventricular asynchrony, which is associated with a slower rate of isovolumetric relaxation. The isovolumetric relaxation lasts after the filling phase has begun, thereby reducing the rate of rapid filling.

Evaluation of myocardial perfusion and function by technetium-99m methoxy isobutyl isonitrile before and after percutaneous transluminal coronary angioplasty. Preliminary results

Myocardial perfusion and function were evaluated with Tc-99m MIBI myocardial scintigraphy before and after percutaneous angioplasty in six patients. In addition to conventional stress-rest images (3 projections: 45 degrees left anterior oblique, anterior, and left lateral), gated images were obtained at rest and during stress before and after angioplasty. Improvement in myocardial perfusion after angioplasty was demonstrated in all patients. The increase from rest to stress of radionuclide fractional shortening (an index of global left ventricular function computed on gated images) was greater after angioplasty than before (9% +/- 7% versus--0.5% +/- 8%, respectively, p < 0.05). Systolic wall thickening (an index of regional left ventricular function) showed a significantly greater rest-to-stress increase after angioplasty than before it in the regions supplied by treated vessels. Thus, Tc-99m MIBI myocardial scintigraphy is capable of evaluating myocardial perfusion and function.

[Coronary vasoconstriction induced by digoxin in normal subjects and in patients with coronary atherosclerosis]

This study evaluated the effects of digoxin infusion (0.014 mg/kg in 10 min i.v.) on large coronary arteries measured by quantitative digital angiography. Twenty-two patients (aged 47 +/- 12), divided in 3 groups were studied. The effects of digoxin infusion (after 10 and 20 min) and sublingual administration of isosorbide dinitrate were investigated in Group I (patients with angiographically normal coronary arteries, n = 9) and in Group II (patients with atherosclerotic coronary arteries, n = 8). In Group III (n = 5) to determine whether or not the effects of digoxin were mediated by activation of alpha-adrenergic receptors, coronary angiographies were performed after alpha-adrenoceptor blockade (phentolamine 0.11 mg/kg, i.v.). In Group I, 10 min after the end of digoxin infusion, cross-sectional area decreased from 7.7 +/- 4.1 mm2 to 6.0 +/- 2.2 mm2, and after 20 min to 5.6 +/- 2.6 mm2 (p < 0.05). Isosorbide dinitrate reverted digoxin-induced vasoconstriction as cross-sectional area increased to 8.5 +/- 3.4 mm2 (NS versus baseline). By 20 min after digoxin infusion heart rate was significantly reduced from 79 +/- 16 to 74 +/- 13 b/min (p < 0.01). Peripheral vascular resistances increased significantly 10 min after digoxin infusion (from 1396 +/- 693 to 1693 +/- 984 dyne*s*cm-5, p < 0.05), whereas cardiac output did not change. In Group II, minimal stenosis diameter decreased significantly 20 min after digoxin infusion from 1.6 +/- 0.5 mm to 1.4 +/- 0.5 mm (p < 0.05). Again, isosorbide dinitrate reverted digoxin-induced vasoconstriction as minimal stenosis diameter increased (NS versus control).(ABSTRACT TRUNCATED AT 250 WORDS)

Indirect pathway of liver glycogen synthesis in humans is predominant and independent of beta-adrenergic mechanisms

The relative contribution of the direct and indirect pathways to liver glycogen formation was assessed in humans by using a combined tracer-hepatic vein catheterization technique. An oral glucose load (75 g) labelled with 1-14C-glucose was administered to five subjects (control group) and 4.5 h later hepatic glycogen was flushed with glucagon and analysed to determine the randomization of 14C. The specific activity (SA) of the glycogen derived glucose (1-14C-glucose SA+recycled 14C-glucose SA) was 61 +/- 7% of the mean blood glucose SA of the interval 0-180 min after the oral glucose load. The relative values due to 1-14C-glucose and recycled 14C-glucose were 33 +/- 7 and 28 +/- 3%, respectively. The data indicate that the indirect pathway of glycogen formation is not only active in humans but contributes substantially (at least 50%) to liver glycogen formation. In order to investigate whether the basal adrenergic tone plays a role in the maintenance of the indirect pathway, the same protocol was also performed in a second group of subjects (n = 5) who received propranolol before the oral glucose load (propranolol group). The SA of the glycogen-derived glucose was considerably smaller than that of the control group (18 +/- 5 vs. 61 +/- 7%, P < 0.001), suggesting lesser glycogen formation. However, the ratio of 1-14C to recycled-14C in the glucose molecule was similar in the control (1.3 +/- 0.4) and propranolol group (1.9 +/- 1.2). We conclude that the basal adrenergic tone does not play any role in the operation of the indirect pathway of liver glycogen synthesis.

Role of alpha 2-adrenoceptors in normal and atherosclerotic human coronary circulation

BACKGROUND

Experimental studies on the effects of alpha 2-adrenoceptors on regional coronary blood flow in normal and ischemic myocardium are highly controversial. A beneficial effect on regional ischemic myocardium has been demonstrated in different animal preparations with either alpha 2-adrenoceptor blockade or stimulation. Animal studies also demonstrated that postsynaptic alpha 2-adrenoceptors mediate vasoconstriction in coronary and femoral vascular beds. The aims of the study were 1) to investigate the effects of regional alpha 2-adrenoceptor stimulation on regional coronary blood flow in subjects with angiographically normal coronary arteries, 2) to assess the effect of alpha 2-adrenoceptor blockade on coronary circulation in control subjects, and 3) to examine the influence of atherosclerosis on coronary blood flow response to alpha 2-adrenoceptor blockade.

METHODS AND RESULTS

The effect of regional administration of BHT 933 (a selective alpha 2-adrenoceptor agonist) was studied in eight subjects with angiographically normal coronary arteries. The coronary blood flow velocity was measured using a subselective intracoronary 3F Doppler catheter and coronary diameter by quantitative coronary angiography. BHT 933 induced a reduction in coronary artery diameter from 2.5 +/- 0.6 mm to 1.8 +/- 0.4 mm (p less than 0.05) as well as in coronary blood flow velocity (from 6.4 +/- 0.9 cm/sec to 4.6 +/- 1.9 cm/sec, p less than 0.01). In some subjects, ST segment abnormalities occurred. In patients with angiographically normal coronary arteries (n = 6), the regional infusion of a selective alpha 2-adrenoceptor blocking agent after beta-blockade did not change coronary diameter or coronary blood flow velocity. In contrast, in patients with significant coronary stenoses (n = 6), regional infusion of an alpha 2-adrenoceptor blocking agent reduced regional coronary artery diameter (from 2.3 +/- 0.5 mm to 2.1 +/- 0.6 mm, p less than 0.01) as well as coronary blood flow velocity (from 5.8 +/- 0.8 cm/sec to 3.7 +/- 0.6 cm/sec, p less than 0.05); in addition, alpha 2-adrenoceptor blockade significantly increased coronary sinus plasma norepinephrine levels (from 300 +/- 144 pg/ml to 429 +/- 207 pg/ml, p less than 0.01).

CONCLUSIONS

The selective in vivo stimulation of alpha 2-adrenoceptors produces a reduction in coronary blood flow and diameter in humans with angiographically normal coronary arteries. alpha 2-Adrenergic blockade does not change coronary blood flow in subjects with angiographically normal coronary arteries (suggesting no resting alpha 2-adrenergic vasoconstrictor tone), whereas in patients with coronary artery stenosis, regional coronary blood flow decreases after alpha 2-receptor blockade. Finally, our data also suggest that alpha 2-adrenoceptors participate in the modulation of sympathetic neuronal norepinephrine release in the human heart.

Digoxin-induced vasoconstriction of normal and atherosclerotic epicardial coronary arteries

This study evaluated the effect of bolus infusion of digoxin (0.014 mg/kg in 10 minutes, intravenously) on large coronary arteries measured by quantitative digital angiography. Twenty-two patients (mean age +/- standard deviation 47 +/- 12 years) divided into 3 groups were studied. The effects of digoxin infusion (after 10 and 20 minutes) and sublingual administration of isosorbide dinitrate were investigated in group I (patients with angiographically normal coronary arteries, n = 9) and in group II (patients with atherosclerotic coronary arteries, n = 8). To determine whether the effects of digoxin were mediated by activation of alpha-adrenergic receptors, coronary angiography was performed in group III after alpha-adrenoceptor blockade (phentolamine 0.11 mg/kg, intravenously) (n = 5). Ten minutes after the end of digoxin infusion, the cross-sectional area decreased from 7.7 +/- 4.1 to 6.0 +/- 2.2 mm2, and after 20 minutes to 5.6 +/- 2.6 mm2 (p less than 0.05) in group I. Isosorbide dinitrate reverted digoxin-induced vasoconstriction as cross-sectional area increased to 8.5 +/- 3.4 mm2 (p = not significant versus baseline). Twenty minutes after digoxin infusion, heart rate significantly decreased from 79 +/- 16 to 74 +/- 13 beats/min (p less than 0.01). Ten minutes after digoxin infusion, peripheral vascular resistance increased significantly from 1,396 +/- 693 to 1,693 +/- 984 dynes.s.cm-5 (p less than 0.05), whereas cardiac output did not change. Twenty minutes after digoxin infusion, minimal stenosis diameter decreased significantly from 1.6 +/- 0.5 to 1.4 +/- 0.5 mm (p less than 0.05) in group II.(ABSTRACT TRUNCATED AT 250 WORDS)

Assessment of left ventricular diastolic function: comparison of contrast ventriculography and equilibrium radionuclide angiography

Twenty-two patients with coronary artery disease were studied first by radionuclide angiography (RNA) and then by contrast ventriculography. Cardiac medications were discontinued at least 72 hr before study. The patients were studied during atrial pacing at heart rates close to their spontaneous sinus rhythm. Contrast ventriculography was performed at 50 frames/sec in the 30 degrees right anterior oblique projection using 40 ml of a nonionic contrast medium (iopamidol) at a flow rate of 10-12 ml/sec. The contours of the left ventricular silhouette at contrast ventriculography were traced, frame by frame, on a graphic table with a digitizing penlight. Equilibrium 99mTc RNA was performed in the best septal 45 degrees left anterior oblique projection, acquiring 150,000 cts/frame, at 50 frames/sec and with a 5% gate tolerance. Time-activity curves from both end-diastolic and end-systolic ROIs were built and interpolated. Both RNA and contrast ventriculography volume curves were filtered with Fourier five harmonics. A close relationship was found between RNA and contrast ventriculography measurements of peak filling rate normalized to end-diastolic cps (r = 0.87, p less than 0.001) and stroke count (r = 0.87, p less than 0.001), ejection fraction (r = 0.94, p less than 0.001). Thus, in patients with coronary artery disease, LV filling can be accurately assessed using RNA.

[The effects of atrial natriuretic peptide on left ventricular function in subjects with heart failure]

The effects of atrial natriuretic peptide (ANP) infusion was evaluated in 11 patients with congestive heart failure undergoing cardiac catheterization. Data were obtained at rest and during steady-state phase of alpha-human (1-28) ANP infusion (1 microgram/kg bolus dose, 0.1 microgram/kg/min iv for 30 min). Mean blood pressure decreased from 104 +/- 20 to 89 +/- 21 mmHg (p less than 0.05) 15 min after ANP infusion, as well as left ventricular end-diastolic pressure (from 27 +/- 6 to 14 +/- 11 mmHg, p less than 0.05) and wedge pressure (from 22 +/- 5 to 13 +/- 7 mmHg, p less than 0.05). Left ventricular ejection fraction increased significantly after ANP infusion from 39 +/- 7 to 47 +/- 2%, p less than 0.01. The ANP infusion significantly increased cardiac output from 4.9 +/- 0.8 to 5.8 +/- 1.41/min, p less than 0.05, and decreased the relaxation constant from 69 +/- 17 to 48 +/- 18, p less than 0.05. These results demonstrate that in patients with congestive heart failure ANP infusion decreased wedge pulmonary pressure, left ventricular end-diastolic pressure and increased cardiac output and left ventricular ejection fraction.

Divergent effects of serotonin on coronary-artery dimensions and blood flow in patients with coronary atherosclerosis and control patients

BACKGROUND

Studies in animals have shown that serotonin constricts coronary arteries if the endothelium is damaged, but in vitro studies have revealed a vasodilating effect on isolated coronary segments with an intact endothelium. To investigate the effect of serotonin in humans, we studied coronary-artery cross-sectional area and blood flow before and after the infusion of serotonin in seven patients with angiographically normal coronary arteries and in seven with coronary artery disease.

METHODS

We measured the cross-sectional area of the coronary artery by quantitative angiography and coronary blood flow with an intracoronary Doppler catheter. Measurements were obtained at base line and during intracoronary infusions of serotonin (0.1, 1, and 10 micrograms per kilogram of body weight per minute, for two minutes). We repeated the measurements after an infusion of ketanserin, an antagonist of serotonin receptors that is thought to block the effect of serotonin on receptors in the arterial wall but not in the endothelium.

RESULTS

In patients with normal coronary arteries, the highest dose of serotonin increased cross-sectional area by 52 percent (P less than 0.001) and blood flow by 58 percent (P less than 0.01). The effect was significantly potentiated by administration of ketanserin. In patients with coronary-artery atherosclerosis, serotonin reduced cross-sectional area by 64 percent (P less than 0.001) and blood flow by 59 percent (P less than 0.001). Ketanserin prevented this effect.

CONCLUSIONS

Serotonin has a vasodilating effect on normal human coronary arteries; when the endothelium is damaged, as in coronary artery disease, serotonin has a direct, unopposed vasoconstricting effect. When considered with other evidence, these data suggest that platelet-derived factors such as serotonin may have a role in certain acute coronary ischemic syndromes.

Usefulness of late coronary thrombolysis (recombinant tissue-type plasminogen activator) in preserving left ventricular function in acute myocardial infarction

This study assesses whether administration of recombinant tissue-type plasminogen activator (rt-PA) up to 8 hours after onset of symptoms of acute myocardial infarction (AMI) may result in a significant improvement in left ventricular function. Sixty patients were classified into 3 groups: group A (n = 21) received rt-PA within 4 hours from symptom onset; the remaining 39 patients, admitted between 4 and 8 hours, were randomized into 2 groups--group B (n = 19) received rt-PA, and group C (n = 21) was treated with conventional therapy. Coronary and left ventricular angiograms were recorded 8 to 10 days after rt-PA administration. The patency rate of the infarct-related artery was 76% in group A, and 63 and 35% in group B and C, respectively. The Thrombolysis in Myocardial Infarction trial perfusion grade was higher in group A and B than in group C (A vs C: p less than 0.005; B vs C: p less than 0.01). Left ventricular ejection fraction was significantly higher in group A (60.2 +/- 10%) and B (54.7 +/- 12%) compared with group C (44.2 +/- 12%) (A vs C: p less than 0.01; B vs C: p less than 0.05). Regional wall motion of the entire ischemic zone was better in group A and B than in group C (A vs C: p less than 0.001; B vs C: p less than 0.01). In contrast, the kinesis of the central ischemic zone was significantly better in group A than in both group B and C (A vs B: p less than 0.05; A vs C: p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Are ioxaglate and iopamidol equally safe and well tolerated in cardiac angiography? A randomized, double-blind clinical study

A randomized, double-blind, parallel-group study was performed in 50 patients undergoing left ventriculography and coronary arteriography to evaluate ECG changes and the effects on left ventricular function of a low-osmolar ionic contrast agent, ioxaglate, as compared with a low-osmolar nonionic contrast medium, iopamidol. Twenty-five patients received ioxaglate (group 1) and 25 patients received iopamidol (group 2). All patients underwent 48 hours of continuous ECG recording beginning 24 hours before the cardiac catheterization. Left ventricular systolic and end-diastolic pressure, peak positive dp/dt, and dp/dt/P ratio were measured immediately before and after left ventriculography and 3 minutes later. Left ventricular systolic pressure did not change after injection of either contrast medium. Left ventricular end-diastolic pressure increased by 30% in group 1 (p less than 0.01) and by 22% in group 2 (p less than 0.01) immediately after left ventriculography. A further increase by 45% in group 1 (p less than 0.01) and by 24% in group 2 (p less than 0.01) was observed 3 minutes later. No differences were observed between values obtained in the two groups. Peak positive dp/dt did not change immediately after injection of either contrast medium but decreased by 5% (not significant) in group 1 and by 7% (p less than 0.02) in group 2 three minutes after left ventriculography. There were no significant differences between the two groups. Analysis of continuous 48-hour ECGs showed that both ioxaglate and iopamidol induced a slight increase (by 8% and 7%, respectively; p less than 0.05) in heart rate during injection with early and complete recovery.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of intravenous verapamil on left ventricular relaxation and filling in stable angina pectoris

Left ventricular (LV) diastolic function is often impaired in coronary artery disease (CAD). To assess whether verapamil could improve LV diastolic properties, 12 patients with CAD undergoing right- and left-sided cardiac catheterization, as well as simultaneous radionuclide angiography, were studied before and during intravenous administration of verapamil (0.1 mg/kg as a bolus followed by 0.007 mg/kg/min). The heart rate was kept constant by atrial pacing in both studies. LV pressure-volume relations were obtained. Verapamil decreased LV systolic pressure (130 +/- 22 to 117 +/- 16 mm Hg, p less than 0.01) and the end-systolic pressure/volume ratio (2.4 +/- 1.3 to 1.6 +/- 0.5 mm Hg/ml, p less than 0.05), and increased LV end-diastolic (13 +/- 4 to 16 +/- 4 mm Hg, p less than 0.02) and pulmonary capillary pressures (10 +/- 5 to 12 +/- 5 mm Hg, p less than 0.005). Despite such negative inotropic effects, cardiac index increased (3.4 +/- 0.7 to 3.9 +/- 0.6 liters/min/m2, p less than 0.02). The time constant of isovolumic relaxation shortened (63 +/- 14 to 47 +/- 9 ms, p less than 0.02); peak filling rate increased (370 +/- 155 to 519 +/- 184 ml/s, p less than 0.001; 2.6 +/- 1.1 to 3.3 +/- 0.9 end-diastolic counts/s, p less than 0.02; and 4.1 +/- 1.6 to 5.5 +/- 1.5 stroke counts/s, p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Assessment of left ventricular function using radionuclide angiography after dipyridamole infusion

Thirty-six patients with significant coronary artery stenosis and no previous myocardial infarction and 25 subjects with normal coronary arteries underwent 99mTc RNV before and after coronary vasodilatation induced by dipyridamole, 0.75 mg/kg, given IV over 10 min. In subjects with normal coronary arteries, dipyridamole induced an increase in LVEF (from 66 +/- 8 to 76 +/- 8 percent; mean +/- SD; p less than 0.001); in patients with significant coronary artery stenosis (greater than or equal to 75 percent narrowing of at least one major vessel), dipyridamole injection did not affect LVEF (from 63 +/- 12 to 62 +/- 12 percent). In ten patients a complete, successful PTCA was performed and the RNV with the dipyridamole test repeated. The EF did not change with the dipyridamole test before PTCA (63 +/- 7 to 65 +/- 9 percent), but increased significantly after PTCA (62 +/- 11 to 70 +/- 9 percent; p less than 0.01). Sensitivity and specificity of EF changes after dipyridamole infusion were 75 and 76 percent, respectively. The test produced no major side effects or complications. Radionuclide angiography with dipyridamole helps to detect coronary artery stenosis and might be used to assess the effects of angioplasty on coronary flow reserve.

Myocardial release of hypoxanthine and lactate during percutaneous transluminal coronary angioplasty

The response of myocardial lactate and hypoxanthine metabolism during percutaneous transluminal coronary angioplasty was studied in a series of 15 patients undergoing this procedure. A minimum of 4 balloon inflations was performed per patient with an average duration per occlusion of 49 +/- 11 seconds (mean +/- standard deviation) for a total occlusion time of 192 +/- 40 seconds. Thermodilution coronary venous blood flow measured in the great cardiac vein decreased from control values of 72 +/- 4 ml/min (mean +/- standard error of the mean) to 47 +/- 10 ml/min with the fourth coronary occlusion (p less than 0.005). Arteriovenous lactate and hypoxanthine showed peak differences during the reactive hyperemia after the first 2 occlusions which did not increase after subsequent occlusions. Within minutes after the procedure, lactate and hypoxanthine efflux was no longer seen, demonstrating the reversibility of the metabolic disturbances after repeated ischemia. The results of this study indicate that there is no permanent alteration in lactate or hypoxanthine metabolism after percutaneous transluminal coronary angioplasty with 4 coronary occlusions of 40 to 60 seconds' duration, with a total occlusion time of 192 +/- 40 seconds.

Cardiac effects of atrial natriuretic peptide in subjects with normal left ventricular function

The effects of atrial natriuretic peptide (ANP) infusion were determined in 9 subjects undergoing cardiac catheterization that did not disclose heart disease. Data were obtained at rest and during the steady-state phase of alpha-human-(1-28)-atrial natriuretic peptide infusion (0.5 micrograms/kg bolus, 0.05 micrograms/kg/min intravenously for 10 minutes). Mean blood pressure decreased from 105 +/- 3 to 98 +/- 4 mm Hg (p less than 0.05); pressure measurements and left ventricular (LV) angiograms suitable for analysis were available in 7 of 9 subjects at matched heart rate. The ANP infusion reduced LV end-diastolic and end-systolic volume indexes from 93 +/- 6 to 80 +/- 6 ml/m2 (p less than 0.01) and from 25 +/- 3 to 17 +/- 1 ml/m2 (p less than 0.05), respectively. The LV ejection fraction increased insignificantly from 72 +/- 5 to 77 +/- 4%. End-systolic pressure/volume ratio showed a slight but not significant increase (from 3 +/- 0.4 to 4 +/- 0.8). Initial plasma levels of ANP (48 +/- 12 pg/ml) increased to 1,890 +/- 423 pg/ml (p less than 0.001) during the infusion and individual hemodynamic responses were not related to plasma ANP concentrations. These data suggest that the administration of ANP has no negative effects on LV function and the ANP-induced changes on cardiac performance are related to the reduced cardiac load.

Influence of left ventricular asynchrony on filling in coronary artery disease

To evaluate whether the extent of left ventricular (LV) asynchrony plays a role in the impairment of LV rapid filling in patients with coronary artery disease (CAD), 48 patients underwent both radionuclide angiography and cardiac catheterization. Patients were divided into group I (n = 33), with normal LV kinesis or only mild hypokinesia, and group II (n = 15), with LV dyskinesia or akinesia. Radionuclide ejection fraction was higher in group I than in group II (62 +/- 12 vs 44 +/- 20%; p less than 0.001). Peak filling rate was significantly lower in group II (1.9 +/- 0.8 vs 2.6 +/- 0.9 end-diastolic counts/s; p less than 0.01). Time to end-systole coefficient of variation, an index of the extent of LV asynchrony, was significantly higher in group II than in group I (43 +/- 10 vs 35 +/- 6; p less than 0.0002). In group I, a highly significant inverse relation was found between this index of asynchrony and peak filling rate (r = 0.71; p less than 0.0001). This correlation was found even when time to end-systole coefficient of variation was normalized to the RR interval (r = 0.49; p less than 0.01) and when peak filling rate was expressed in stroke counts (r = 0.57; p less than 0.001). The correlation between peak filling rate and index of asynchrony was maintained up to an end-systole coefficient of variation value of approximately 35. In group II patients (most with an asynchrony value greater than or equal to 35) no relation was found between time to end-systole coefficient of variation and peak filling rate.

Short-term assessment of left ventricular function, coronary hemodynamics, and catecholamine balance in severe congestive heart failure after a single oral dose of milrinone

Systemic and coronary hemodynamics were measured before and every 10 min after oral milrinone (10 mg) administration for 50 min, together with the drug plasma level in 14 patients with congestive heart failure. Left ventricular pressure (tip manometry), volume (angiography), and derived indexes were simultaneously assessed before and 60 min after milrinone treatment. Peak positive dP/dt, Vmax, and peak velocity of contractile element significantly increased 30 min after milrinone administration by 15%, 37%, and 30%, respectively. An increase in cardiac output (25%) with a consistent decrease in systemic vascular resistance (20%) occurred after 40 min without major changes in heart rate and aortic pressure. Right atrial pressure and minimal and end-diastolic left ventricular pressures decreased significantly after 50 min, by 30%, 25%, and 20%, respectively. Peak -dP/dt increased despite a slight change in end-systolic pressure. The time constants of relaxation, tau 1 and tau 2, significantly decreased by 15% after 50 min and by 16%. A transient but significant increase of 40% in coronary sinus blood flow was observed after 30 min, while myocardial oxygen consumption was unchanged 50 min after milrinone treatment. No changes were observed in catecholamine balance with milrinone. Ejection fraction increased significantly (22%) after milrinone administration, as well as the net work of left ventricle (27%). The increase of inotropism in failing hearts with a parallel reduction in preload and afterload makes milrinone a drug potentially useful in the oral treatment of severe heart failure.

[Percutaneous brachial approach in left heart catheterization with 5 French catheters. Preliminary experience]

This describes our preliminary experience with percutaneous brachial approach for cardiac catheterization, by using 5 French (F) preformed catheters. Thirty patients (pts) were studied from the left arm (Group A) with a 5F sheath and 5F Judkins catheters and 30 from the right arm (Group B) with 5F sheath and 5F Amplatz catheters. Pigtail catheters (5F) were used for the left ventricular angiograms in all patients. In 10 patients arterial velocity signals and radial and ulnar artery blood pressures were monitored with the Doppler ultrasonic velocity detector before and immediately after each procedure, and 24 hours later. Arterial puncture was carried out successfully in each patient by using a 18-gauge Potts-Cournand needle. The puncture site was as close as possible to the ante cubital fossa where the artery is less mobile. Both coronary arteries were selectively opacified and the left ventricular angiography was done on every patient. The diagnostic quality of the angiograms was evaluated by the visual analogue scale and the results were not different from those obtained with the femoral approach in our catheterization laboratory. In 3 out of 30 pts in group B it was impossible to obtain a good left coronary opacification with Amplatz catheters for anatomical reasons, thus the right femoral approach was preferred. Brachial artery occlusion occurred in 1 patient from group B and needed surgical thrombectomy carried out to restore normal radial and ulnar pulses.(ABSTRACT TRUNCATED AT 250 WORDS)

Electromechanical events during spontaneous angina

The electromechanical events occurring during acute myocardial ischemia were assessed in 10 patients who developed spontaneous angina during cardiac catheterization. Aortic pressure and electrocardiogram were recorded, and heart rate and systolic and diastolic time intervals were measured under control conditions, at the onset of angina and during the relief of chest pain. In 5 patients spontaneous angina was accompanied by an increase in heart rate and systemic arterial pressure and by ST segment changes in anterior or anterolateral precordial leads. Diastolic time, expressed as percent of cardiac cycle, shortened from 48.8 +/- 3.6% at rest to 33.6 +/- 4.8% (p less than 0.01) at the onset of angina, as a consequence of a significant increase in both electromechanical systole and heart rate, and returned to control values within 10 min after sublingual nitroglycerin. In the remaining 5 patients, spontaneous angina was accompanied by a decrease in heart rate and systemic arterial pressure and by ST segment changes in the inferior or inferolateral leads. The diastolic time increased significantly (p less than 0.05) from 39.4 +/- 6.1% at rest to 47.8 +/- 9% at the onset of angina, as a consequence of a significant decrease in heart rate and a slight decrease in electromechanical systole. Since coronary perfusion takes place mainly during diastole, our results suggest that the reflex increase in adrenergic tone may worsen myocardial ischemia by affecting diastolic perfusion time. In contrast, the increase in vagal tone may contribute to spontaneous relief of angina by prolonging diastolic perfusion time.

Effect of a single oral dose of milrinone on left ventricular diastolic performance in the failing human heart

In 14 patients with severe congestive heart failure, left ventricular pressure (measured by tip manometer) and derived variables were measured before and every 10 minutes after administration of oral milrinone (10 mg) for 50 minutes along with measurements of coronary sinus blood flow and drug plasma levels. Arterial and coronary sinus catecholamines were measured only before and 50 minutes after milrinone. Left ventricular pressure, volume (as determined by angiography) and derived indexes were simultaneously assessed at matched atrial paced heart rate before and 60 minutes after milrinone. Three patients who did not achieve a therapeutic plasma level (less than 150 ng/ml) were excluded. Peak negative first derivative of left ventricular pressure (-dP/dt) progressively and significantly increased (10%) together with a decrease in the two exponential time constants of relaxation, namely, Tau 1 (19%) and Tau 2 (22%), which represent the fit for and after the first 40 ms, respectively. Coronary flow significantly increased by 43% within 30 minutes, whereas the decrease (-13%) in coronary vascular resistance failed to be statistically significant. No change occurred in catecholamine concentrations after milrinone. Peak filling rate significantly increased by 15%. Pressure-volume curves showed a leftward and, in four patients, a downward shift; a significant decrease in minimal left ventricular diastolic and end-diastolic pressures (by 55 and 38%, respectively) and in end-diastolic volume (18%) occurred. The constant of elastic chamber stiffness measured by the simple elastic model tended to decrease, but failed to achieve a statistically significant level. Thus, oral milrinone improved left ventricular early relaxation and filling as well as chamber distensibility. This global improvement of diastolic function makes milrinone a potentially useful drug in the oral treatment of heart failure.

Effects of oral salt load on arginine-vasopressin secretion in normal subjects

Arginine-vasopressin (AVP) plays an important role in regulating water balance in humans. Its secretion is under control of several mechanisms, some of which are not completely understood. The purpose of the present study was to evaluate the effects of an acute oral salt load on AVP secretion in normal subjects. Six normal volunteers received 350 mEq of NaCl per os. Pulmonary capillary wedge pressure and right atrial pressure, plasma AVP, plasma sodium and potassium concentration, plasma osmolality, hematocrit, urinary sodium and potassium excretion, and urinary flow were measured at baseline and every 30 minutes for two hours after the salt load. Hemodynamics as well as urinary sodium and potassium excretion did not change over the study. Ninety minutes after the salt load, plasma AVP increased from the basal value of 6.0 +/- 0.9 pg per ml to 10.1 +/- 1.2 pg per ml (mean +/- SE, p less than 0.005) and a significant reduction in diuresis of about 50% was observed. However, plasma osmolality and plasma sodium concentration increased significantly only 120 min after the salt load, from the initial value of 277.7 +/- 2.2 mOsm per kg and 145.3 +/- 1.4 mEq per 1 (mean +/- SE) to 284.8 +/- 2.5 mOsm per kg and 148.7 +/- 1.5 mEq per 1, respectively (p less than 0.01). Ninety minutes after the salt load, no correlation was found between plasma osmolality and plasma AVP concentration, indicating that AVP secretion was independent of changes in systemic blood osmolality.(ABSTRACT TRUNCATED AT 250 WORDS)

Regional cardioprotection by subselective intracoronary nifedipine is not due to enhanced collateral flow during coronary angioplasty

Twelve patients with proximal stenosis of the left anterior descending artery, normal myocardial wall motion but without angiographically demonstrable collateral circulation, were studied during transluminal occlusion. Prior to the first transluminal occlusion before crossing the lesion with the balloon, patients were randomly given 0.2 mg nifedipine or its solvent in the left mainstem. The same dose was repeated via the balloon catheter, positioned across the lesion, immediately prior to the second transluminal occlusion. In all patients great cardiac venous flow and ST-elevation were monitored during and after each transluminal occlusion. The lactate extraction ratio A-GCV/A (A = arterial, GCV = great cardiac vein) was determined prior to the angioplasty procedure, 10-15 seconds after each transluminal occlusion and 10 minutes after the third transluminal occlusion. Great cardiac venous flow rose significantly to an average of 160% of basal flow when nifedipine was administered into the mainstem before the angioplasty procedure while its solvent had no effect. During each transluminal occlusion, great cardiac venous flow diminished on average by 30% in those who received nifedipine and by 28% in those who received only its solvent. This difference was statistically not significant. After angioplasty great cardiac venous flow was slightly, but not significantly, increased in both groups with respect to basal flow (104% resp. 120% of control). Patients who received nifedipine in the post-stenotic area just before the second transluminal occlusion, had significantly lower lactate production, measured immediately after the transluminal occlusion compared with the patients who received only its solvent (P less than 0.01). The ST-elevation during the second transluminal occlusion was significantly lower in the nifedipine group (0.1 mm in nifedipine group versus 1.4 mm in solvent group; P less than 0.05, unpaired t-test). Nifedipine given intracoronary in the post-stenotic area just before coronary angioplasty reduces lactate release and electrocardiographic signs of myocardial ischemic injury. This regional cardioprotective effect seems not due to an enhanced collateral flow, but to a regional cardioplegic effect, which precedes the ischemic event.

Sequential dilatation of septal and left anterior descending artery: single guiding catheter and double guide wire technique

A new technique was used to dilate sequentially a bifurcation lesion involving the left anterior descending artery and the origin of a large septal branch. Two steerable long guide wires (300 cm) were advanced through a single guiding catheter and placed across each lesion. The balloon catheters were introduced into the target arteries for angioplasty one at a time over the pre-positioned guide wires. After the septal branch had been successfully dilated, the balloon catheter was completely withdrawn from the manifold and a second balloon catheter positioned in the left anterior descending artery over the guide wire already placed across the stenosis. Such a technique is feasible and safe, and overcomes the potential risks of the conventional kissing balloon technique.

Impaired left ventricular filling dynamics during percutaneous transluminal angioplasty for coronary artery disease

The effects of brief periods of major coronary artery occlusion on global and regional peak left ventricular (LV) filling rates were studied during angioplasty in 10 patients. No patient had had a previous myocardial infarction. High-fidelity LV pressure and volume were determined by angiography before and 20 and 50 seconds after the onset of transluminal coronary occlusion and soon after the last balloon inflation. Segmental wall motion was analyzed frame by frame along 20 hemiaxes. Global peak filling rate decreased significantly both after 20 (29%, p less than 0.05) and 50 seconds (27%, p less than 0.05) from the onset of the occlusion. The term sigma delta t1 was defined as the sum of the absolute values of the time differences from the occurrence of global peak filling rate and the segmental peak filling rate in 20 segments. This variable increased significantly during both periods of transluminal occlusion (by 73% and by 72% [both p less than 0.005], respectively), indicating asynchrony in the occurrence of regional peak filling rate. Simultaneously, the sum of intervals between aortic valve closure (end systole) and occurrence of peak segmental shortening, sigma delta t2, measured in the 20 segments, increased by 63% after 20 seconds and by 87% after 50 seconds (both p less than 0.005), showing major asynchrony in segmental contraction. A significant negative correlation was found between global peak filling rate and both sigma delta t1 and sigma delta t2 (r = 0.64, p less than 0.001 and r = 0.70, p less than 0.0001, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Early changes in wall motion and wall thickness during percutaneous transluminal coronary angioplasty in man

Epicardial wall motion, myocardial wall thickness and segmental wall motion during percutaneous transluminal coronary angioplasty, a situation which resembles the experimental abrupt occlusion of a major coronary artery in the animal laboratory, have been studied in patients undergoing the procedure. Epicardial wall motion was analyzed using biplane cineradiography with frame to frame measurements of distances between pairs of radiopaque epicardial markers, placed at the time of previous cardiac surgery in a patient with a stenosis of a coronary artery bypass graft. Bypass graft occlusion led to early onset of biphasic epicardial late systolic lengthening and early diastolic shortening similar to the regional wall motion abnormality preceding the procedure. Continuous M-mode echocardiogram throughout coronary luminal occlusion, showed a decreased systolic thickening in the septum with a concomitant, prominent notch in early diastole occurring after the seventh beat following occlusion. At the 28th beat, septal systolic motion was absent while only an early diastolic septal motion was observed. Contemporaneously the end-diastolic septal thickness results decreased. Segmental wall motion analysis during ischemia was carried out performing a left ventricular angiogram before, 20 and 50 seconds after the onset of balloon inflation, 5 minutes after completion of the procedure. During the early phase of ischemia, in the ischemic segments, a late systolic lengthening with an early diastolic shortening was observed. We refer to this biphasic motion as the "W" phenomenon which appears to be the early and characteristic change in wall motion and thickness during coronary angioplasty in man.

Values and limitations of transstenotic pressure gradients measured during percutaneous coronary angioplasty

The pressure gradient across coronary stenoses is measured routinely during angioplasty. Due to the finite size of the angioplasty catheter within the stenotic cross section, the remaining luminal area is further reduced and the transstenotic gradient may be overestimating the "true" pressure drop. This "true" pressure gradient can be approximated from the mean coronary blood flow and the stenosis geometry from theoretical models. Goal of this study was to assess the values and limitations of the in vivo measurements of the pressure gradient versus the calculated values. Therefore, flow in the great cardiac vein was measured in 13 patients before and/or after angioplasty of a proximal left anterior descending stenosis, not filled by collaterals. The Poiseuille and turbulent contributions to flow resistance were determined from stenosis geometry assessed by quantitative coronary angiography. A fourfold increase in the luminal area (from 0.7 mm2 pre- to 2.8 mm2 post angioplasty) was associated with a fourfold decrease in the in vivo measured transstenotic gradient (from 59 mm Hg pre- to 13 mm Hg post angioplasty). The occlusion area and the measured gradient were linearly correlated: gradient = 69-17 X occlusion area (r = 0.76). However, as expected, the transstenotic gradient systematically overestimated the theoretical gradient calculated from the laws of fluid dynamics. A nonlinear relation was found between the calculated gradient P and the occlusion area As: P = 15 X As-2 (r = 0.87).

Systolic and diastolic time intervals during spontaneous angina

In 5 patients who suffered spontaneous angina during cardiac catheterization, aortic pressure and electrocardiographic lead (V5) were recorded at rest, at the onset of anginal pain, 5 and 10 min after 0.6 mg sublingual nitroglycerin (NTG). Heart rate, systemic arterial pressure, systolic, and diastolic time intervals were measured. Heart rate and systemic arterial pressure rose significantly immediately after the onset of angina and declined progressively within 10 min from NTG administration. Preejection period did not change during angina, while left ventricular ejection time and electromechanical systole lengthened. As a consequence, diastolic time, expressed as percent of cardiac cycle, shortened sharply. All parameters considered went back to basal values within 10 min from NTG administration, and were preceded by relief or reduction of anginal pain. We concluded that a fall in diastolic time, secondary to a prolongation of electromechanical systole occurring during angina, may further increase the degree of ischemia resulting in a vicious cycle than can be interrupted by NTG administration.