Torsades de pointes in paced patients with sick sinus syndrome after disopyramide administration

Three ventricular inhibited mode (VVI) pacemaker implanted patients, all above 65 years, female and having sick sinus syndrome suffered from torsades de pointes; one patient after 2.5 years and the other two patients within a day of disopyramide therapy. All had hypopotassemia and plasma disopyramide was below the therapeutic range in two patients. Torsades de pointes was induced following ventricular paced beats and suppressed by cessation of disopyramide in all or by setting a higher pacing rate in one. In our department, permanent VVI pacemakers were implanted in 43 patients with sick sinus syndrome including 26 with bradycardia-tachycardia syndrome, nine of whom were treated by disopyramide. Torsades de pointes was observed only in those disopyramide treated bradycardia-tachycardia patients. Our report stresses the proarrhythmic nature of combined VVI pacing and antiarrhythmic agents in the presence of hypopotassemia.

Days required for 75% suppression of ventricular premature contractions by antiarrhythmic agents obtained from continuous in-hospital ECG monitoring

To determine the number of days required to obtain 75% suppression of ventricular premature contractions (VPCs) by antiarrhythmic agents, which was expressed as t1/4, we performed 32 in-hospital continuous all day ECG monitoring trials in four groups of 28 symptomatic patients (ages; 54 +/- 20 years-old) with frequent VPCs. Nine patients had no organic heart disease (group 1, 11 trials), nine had valvular heart disease (group 2, 10 trials), three had dilated cardiomyopathy (group 3, 3 trials) and seven had myocardial infarction within two to four weeks onset (group 4, 8 trials). All patients were monitored by ECG telemetry with an arrhythmia analyzer, which could count hourly and daily VPCs. Class I antiarrhythmic agents were given in 18 trials, class II in two trials and class I+ class II in 12 trials. Plasma concentrations of the antiarrhythmic agents were monitored in 11 trials. In 21 trials, t1/4 could be obtained; ten (91%), six (60%), three (100%) and two trials (25%) in the four groups, respectively (p < 0.05). The value of t1/4 in the four groups was 6 +/- 6, 7 +/- 6, 14 +/- 11 and 13 +/- 2 days, respectively (mean 8 +/- 7 days; N.S.). Immediate response to the initial antiarrhythmic agent administration, expressed as percent VPC count after three hours, correlated significantly with t1/4 (r = 0.696, p = 0.0006), but ejection fraction, patient's age, control VPC counts or plasma antiarrhythmic agent level did not correlate with t1/4. In conclusion, t1/4 is a useful index for the evaluation of VPC suppression, revealing wide inter-individual variations and can be roughly estimated from the immediate response to the initial antiarrhythmic agent administration.

Biological effects of the new platelet-activating factor receptor antagonist (+)-cis-3,5-dimethyl-2-(3-pyridyl)thiazolidin-4-one hydrochloride

SM-12502 ((+)-cis-3,5-dimethyl-2-(3-pyridyl)thiazolidin-4-one HCl, CAS 119383-00-5) inhibited platelet-activating factor (PAF)-induced aggregation of rabbit and human platelets with IC50 values of 2.3 mumol/l and 4.7 mumol/l, respectively, but did not inhibit platelet aggregation induced by adenosine diphosphate, collagen, thrombin, arachidonic acid, U46619 (a thromboxane A2 agonist) or Ca2+ ionophore A23187 at concentrations up to 400 mumol/l. SM-12502 competitively antagonized 3H-PAF binding to rabbit platelets with an IC50 of 1.0 mumol/l. In contrast, the anti-PAF activity of the optical isomer SM-12501 ((-)-cis-3,5-dimethyl-2-(3-pyridyl)thiazolidin-4-one HCl) was much weaker and its IC50 was more than 100 mumol/l. SM-12502 prevented PAF-induced death in mice with ID50 values of 4.8 mg/kg (i.v.) or 68.6 mg/kg (p.o.). In guinea pigs, SM-12502 inhibited PAF (0.1 micrograms/kg)-induced hemoconcentration with ID50 values of 1.9 mg/kg (i.v.) or 40.2 mg/kg (p.o.). In addition, SM-12502 inhibited PAF (10 ng/kg)-induced hypotension in rats with ID50 values of 2.0 mg/kg (i.v.) or 6.5 mg/kg (p.o.). The in vivo effects of SM-12501 were much weaker. Orally administered SM-12502 showed rapid absorption and a long duration of pharmacological activity in rats. SM-12502 afforded dose-dependent protection against anaphylactic death in mice with ID50 values of 18.4 mg/kg (i.v.) and 136 mg/kg (p.o.). It also inhibited endotoxin (E. coli 0.55:B5, 60 mg/kg)-induced death in mice, with ID50 values of 119 mg/kg (i.v.) and 182 mg/kg (p.o.).(ABSTRACT TRUNCATED AT 250 WORDS)

Vasodilatory capacity of coronary resistance vessels in dilated cardiomyopathy

Both the endothelium-dependent and endothelium-independent vasodilatory responses of coronary resistance vessels were studied in patients with dilated cardiomyopathy (DCM). A 3F coronary Doppler catheter was placed in the proximal left anterior descending artery in 14 patients with DCM and in 10 patients with chest pain syndrome and a normal heart (control subjects). The ratio of maximum mean coronary blood flow velocity after intracoronary administration of the endothelium-independent vasodilator papaverine (10 mg) to resting mean coronary blood flow velocity (Vp/Vo) in patients with DCM was diminished compared with that in control subjects (2.2 +/- 0.6 vs 4.1 +/- 0.9, p < 0.001). The ratio after administration of the endothelium-dependent vasodilator acetylcholine (40 micrograms) (Va/Vo) in 10 DCM patients was also diminished compared with that in seven control subjects (1.3 +/- 0.5 vs 2.4 +/- 0.8, p < 0.01). In DCM patients, Vp/Vo was correlated with left ventricular end-diastolic pressure (r = -0.48, p < 0.05), left ventricular end-diastolic volume index (r = -0.68, p < 0.01), ejection fraction (r = 0.75, p < 0.01), and left ventricular end-diastolic wall stress (r = -0.73, p < 0.01). However, Va/Vo was not correlated with any of these parameters. These results indicate that impairment of the vasodilatory capacity of coronary resistance vessels in DCM may be related to endothelial dysfunction and to an extravascular factor resulting from left ventricular dysfunction.

QT prolongation and possibility of ventricular arrhythmias after intracoronary papaverine

The incidence of ventricular arrhythmias following the intracoronary injection of papaverine was assessed. A 3F coronary Doppler catheter was placed in the proximal left anterior descending artery and 6-12 mg of papaverine was injected into the left coronary artery in 42 patients. After intracoronary papaverine, the corrected QT interval on the electrocardiogram was prolonged from 0.43 +/- 0.03 to 0.49 +/- 0.07 s (p < 0.001). Occasional premature beats were observed in 2 patients (4.5%) with dilated cardiomyopathy. In 1 patient (2.3%) with 99% stenosis of the left anterior descending artery, polymorphous ventricular tachycardia with marked QT prolongation occurred. This patient also had hypokalemia (2.5 mEq/l) due to primary aldosteronism. In conclusion, careful use of intracoronary papaverine is necessary because of the risk of occasional serious ventricular arrhythmias.

Features of coronary artery lesions related to left ventricular aneurysm formation in anterior myocardial infarction

To determine the factors of left ventricular aneurysm formation in acute myocardial infarction, the authors studied the distribution of coronary artery lesions and the left ventricular wall motion of 43 patients with anterior myocardial infarction. Of 15 patients with aneurysm, 9 (60%) showed a single-vessel disease with severe stenosis of the proximal left anterior descending artery. Of 9 patients with triple-vessel disease, 8 (89%) had no aneurysm. In patients with the aneurysm, the Gensini score of the culprit lesion was significantly higher (p < 0.05) and the score except for the culprit lesion was less (chi 2 = 5.7, p < 0.05). In 23 patients with single-vessel disease, the collateral score was significantly less (p < 0.05) in patients with the aneurysm. The systolic wall motion on the ventriculogram appeared more impaired in the anterior infarct area but well maintained in the posterior noninfarct area in patients with the aneurysm. In conclusion, the important factors of left ventricular aneurysm formation were as follows: (1) A culprit lesion of the myocardial infarction was severe, but other coronary artery lesions were mild. (2) Collateral vessels were poor. (3) The left ventricular wall motion of the infarct area was impaired, but that of the noninfarct area was relatively good.

[Respiratory changes in the blood flow pattern of the superior vena cava in patients with chronic obstructive pulmonary diseases]

Blood flow patterns in the superior vena cava (SVC) obtained from 20 elderly cases of COPD (aged 60-81) were compared with those from 24 elderly normal subjects (aged 61-80). The peak flow velocity and duration of two major antegrade flows during systole and diastole (S & D wave) were both qualitatively and quantitatively assessed with pulsed Doppler echocardiography. While peak flow velocity and duration of the S and D waves increased during inspiration and decreased during expiration in normal subjects, respiratory variations of these antegrade waves were extremely greater in patients with COPD with augmented and/or fused antegrade waves during inspiration, and there decrease was associated with an upward shift above the zero level during expiration. The duration of the D wave was significantly longer in COPD patients than in normal subjects and also revealed a significantly positive correlation with FEV1.0%. These findings suggest that SVC flow pattern is useful for the assessment of early right ventricular dysfunction in patients with COPD, but further clinical studies are required to confirm this thesis.

[ST-T changes associated with severe hypoxia in a case of obstructive sleep apnea syndrome]

A 59-year-old man with obesity was admitted with nocturnal dyspnea and nocturnal precordial oppression. Catheter data disclosed no cardiac failure. Polysomnography was performed for a total of 3 nights. The diagnosis of obstructive sleep apnea syndrome was made because apnea index was 50 times/hour in average, the max apnea time was about 80 seconds and disappearance of airflow during decrease of endoesophageal pressure was observed. At the max apnea time, ST-T change in leads V2-5 was observed with severe desaturation (arterial oxygen saturation: 49%). It was considered that myocardial hypoxia following sleep apnea might be the cause of nocturnal precordial oppression.

Pronounced ST-segment depression during paroxysmal supraventricular tachycardia

To determine the clinical significance of ST-segment depression observed in paroxysmal supraventricular tachycardia (PSVT), we evaluated the 12-lead electrocardiogram (ECG) during spontaneous PSVT in 54 patients (27 men and 27 women: mean age +/- SD; 47 +/- 18 years), who came to our clinic for the treatment of PSVT. Coronary angiography was performed in 16 patients (16 to 74 years; mean = 50 +/- 18) and treadmill exercise testing was performed in 21 patients. A cardiac electrophysiological study was carried out in 24 patients. During PSVT, ST-segment score was calculated as the sum of the ST-segment depression in 12 leads. The correlations between the ST-segment score, PSVT rate and age of the patient were analyzed as follows: The most significant positive correlation was observed between the ST-segment score and the PSVT rate (r = 0.615, p < 0.000001). The next most significant correlation was found between the PSVT rate and the age of the patient (r = -0.500, p = 0.00011). A negative correlation was also observed between the ST-segment score and the age of the patient (r = -0.429, p = 0.0012). In 13 of 16 patients, coronary angiography did not reveal any significant (> or = 75% in area) stenosis. Exercise testing induced significant ST-segment depression in 3 patients, of whom two had significant coronary artery lesions. PSVT was due to atrioventricular reentry via an overt (n = 3) or concealed accessory pathway (n = 15), atrioventricular nodal reentry (n = 5) and sinus node reentry (n = 1). In conclusion, patients with a faster PSVT rate revealed more pronounced ST-segment depression than did those with a slower PSVT rate, possibly reflecting the modified repolarization process instead of coronary artery involvement.

Venoarterial carbon dioxide tension gradient in acute heart failure

The venoarterial carbon dioxide tension gradient (P[v-a]CO2) was studied in patients with acute myocardial infarction. Seven patients with congestive heart failure (CHF group) and 10 patients without heart failure (control) were enrolled in this study. In all patients, hemodynamics were continuously monitored. Simultaneously, arterial and mixed venous blood were sampled, and blood gases and lactate concentration were analyzed. At the initial measurement before therapy, arterial and mixed venous pH and bicarbonate values were within the normal range, and there was no significant difference between the CHF group and controls. There was also no difference in arterial oxygen tension under the differential conditions of oxygen inhalation. However, cardiac index and mixed venous oxygen saturation (SvO2) were significantly lower, while the oxygen extraction ratio (OER) and arterial lactate were significantly higher in the CHF group than in the controls. On the other hand, P[v-a]CO2 was significantly higher in the CHF group (7.8 +/- 2.6 vs. 3.5 +/- 2.2 mm Hg, p < 0.01). This finding was due to the elevated mixed venous carbon dioxide tension in the CHF group, since arterial carbon dioxide tension was the same in both groups. Analysis of a total of 42 measurements obtained during the therapeutic course in the CHF group revealed a correlation of P[v-a]CO2 with cardiac index (r = -0.3, p < 0.05), OER (r = 0.57, p < 0.001), SvO2 (r = -0.56, p < 0.001) and lactate (r = 0.62, p < 0.001). The increase in P[v-a]CO2 observed in acute heart failure suggests the evidence of intracellular acidosis despite the absence of acidemia.(ABSTRACT TRUNCATED AT 250 WORDS)

Coronary flow reserve in patients with dilated cardiomyopathy

Coronary flow reserve was studied in patients with dilated cardiomyopathy. A 3F coronary Doppler catheter was placed in the proximal left anterior descending artery in each of 10 patients with dilated cardiomyopathy (CDM group), seven patients with coronary artery disease that involved only the left anterior descending artery (CAD group), and seven patients with chest pain syndrome and normal hearts (control group). Coronary flow reserve was calculated as the ratio of the maximum mean coronary blood flow velocity after intracoronary administration of papaverine (10 mg) to resting flow velocity (M/R). The time until maximum flow velocity was reached after papaverine administration (Tmax) was also measured. M/R was lower in the DCM (p < 0.001) and CAD (p < 0.001) groups when compared with the control group. Tmax was not abnormal in the DCM group but was prolonged in the CAD group (p < 0.05). In the DCM group, the M/R ratio correlated with the left ventricular end-diastolic pressure (r = -0.69; p < 0.05), the left ventricular end-diastolic volume index (r = -0.7; p < 0.05), the ejection fraction (r = 0.82; p < 0.01), the left ventricular mass (r = -0.7; p < 0.05), and the left ventricular end-diastolic wall stress (r = -0.84; p < 0.001). These results indicate that coronary flow reserve was decreased in patients with dilated cardiomyopathy and that the mechanism of its reduction may differ from that in patients with coronary artery disease.

[A case of coronary artery embolism associated with combined valvular heart disease]

A 53-year-old-man afflicted with combined valvular heart disease and atrial fibrillation was admitted to our department complaining of chest pain. ST elevation on ECG (II, III, aVF) and elevated CPK value were recognized. He was diagnosed as having acute myocardial infarction, and percutaneous transluminal coronary recanalization was performed immediately. The coronary angiogram showed occlusions at the proximal left branch (#12). But these lesions could not be recanalized by 960000 IU urokinase administration. The cineangiogram after one month revealed perfect recanalization of these occlusions. Mitral stenosis with neovascularity to the left atrium and aortic regurgitation were recognized. We supposed this infarction caused by coronary embolism originated from left atrial thrombi. Acute myocardial infarction associated with mitral stenosis has been reported in fifteen cases previously in Japan, but only three cases revealed coronary occlusion in the acute phase with normal coronary artery in the chronic stage. However, there has been no report, except for this case, demonstrating occlusion in two coronary arteries at the same time. So, our case is the first report of the involvement of two coronary artery occlusions.

Oxygen demand-supply relationship in peripheral tissues as a therapeutic indicator in acute myocardial infarction with advanced heart failure

Oxygen demand-supply relationships in peripheral tissues were studied in 14 patients who had acute myocardial infarction with advanced pump failure. Seven patients with acute myocardial infarction but without pump failure were studied as a control. In all patients, a Swan-Ganz catheter and a radial arterial cannula were inserted for the purpose of hemodynamic monitoring, and arterial and mixed venous blood were sampled. Initially, oxygen delivery (DO2) (p < 0.01) was lower, and oxygen extraction ratio (OER) (p < 0.001) and oxygen tension at 50% saturation (P50) (p < 0.01) were higher in patients with pump failure than in the controls. During the therapeutic course, with an increase in the cardiac index and DO2, oxygen uptake (VO2) did not change but OER (p < 0.001) and P50 (p < 0.01) significantly decreased in 6 survivors with pump failure. In contrast, an increased VO2 (p < 0.01) and no change of OER and P50 were observed in 8 nonsurvivors with pump failure. These results suggest that reversibility of oxygenokinetics might be an important factor for recovery from critical heart failure.

In vitro study of a novel atypical beta-adrenoceptor agonist, SM-11044

SM-11044 (L-threo-3-(3,4-dihydroxyphenyl)-N-[3-(4-fluorophenyl) propyl] serine pyrrolidine amide hydrobromide) stimulated the relaxation of guinea pig ileum (EC50: 3.0 x 10(-8) M), trachea (EC50: 1.3 x 10(-7) M), lung parenchyma (EC50: 2.1 x 10(-6) M) and the increase in right atrial rate (EC50: 6.9 x 10(-6) M). It also induced lipolysis of rat white adipocytes (EC50: 1.2 x 10(-6) M). Both the relaxant response of ileum and the lipolytic response of adipocytes to SM-11044 were resistant to inhibition by propranolol (10(-6) M), but were antagonized by cyanopindolol (10(-6) M). In contrast, the responses to SM-11044 in trachea, lung parenchyma and right atrium were almost completely abolished by propranolol (10(-6) M). Furthermore, the selectivity of SM-11044 relative to isoproterenol was ileum greater than adipocytes greater than trachea (beta 2) greater than lung (beta 2) greater than atrium (beta 1). These results suggest that SM-11044 is a selective agonist of atypical beta-adrenoceptors that are resistant to antagonism by propranolol but sensitive to cyanopindolol. The receptor binding and adenylate cyclase stimulating activity of SM-11044 were also examined on transfected Chinese hamster ovary cells expressing human beta 1-, beta 2- or beta 3-adrenoceptors. SM-11044 inhibited the binding of [125I]iodocyanopindolol to the three types of receptors in a concentration-dependent manner. The selectivity in terms of Ki values was beta 3 (Ki: 1.3 x 10(-6) M) greater than beta 2 (Ki: 4.1 x 10(-6) M) greater than beta 1 (Ki: 18.1 x 10(-6) M)-adrenoceptors.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of BRL-35135 on LTB4-induced guinea pig eosinophil chemotaxis

The effect of an atypical beta-adrenoceptor agonist, BRL-35135 on leukotriene B4-induced-guinea pig eosinophil chemotaxis was studied. BRL-35135 and SC-41930 (leukotriene B4-antagonist) inhibited the chemotaxis in a concentration-dependent manner (IC50 = 9.0 x 10(-6) and 2.6 x 10(-7) M, respectively). However, isoproterenol, fenoterol and another atypical beta-agonist, BRL-37344 had no effects. The inhibitory effect of BRL-35135 was not affected by (+/-)-propranolol (10(-4) M). In contrast, the nonselective beta-adrenoceptor antagonist, (-)-alprenolol (10(-4) M) dextrally shifted the inhibitory curve of BRL-35135. The response to BRL-35135 was antagonized in a competitive manner by (-)-alprenolol, with the slope of the Schild plot close to unity, and a pA2 value of 5.62. These findings suggest that guinea pig eosinophils possess an "atypical receptor", which differs from either beta 1-, beta 2- or atypical beta-adrenoceptor on guinea pig ileum, and through which eosinophil chemotaxis can be modulated by BRL-35135.

Left ventricular diastolic dysfunction in coronary artery disease: effects of coronary revascularization

Left ventricular diastolic dysfunction was studied globally and regionally in patients with coronary artery disease, and the effects of coronary revascularization were evaluated. A total of 25 patients with angina pectoris who had a stenotic lesion (greater than or equal to 90%) in only left anterior descending branch underwent coronary revascularization [percutaneous transluminal coronary angioplasty (PTCA) in 13 patients and coronary artery bypass graft (CABG) in 12]. Nine patients with normal coronary artery were studied as controls. Left ventricular volume and radial axes were measured on serial frames of one cardiac cycle by cine left ventriculography. The radial axes were drawn from the left ventricular gravity to left ventricular wall at every 20 degrees. Left ventricular filling fraction and distension rate of radial axes were calculated at the times of 25%, 50%, 75%, and 100% of diastolic period, 100% being end-diastole. Although there were no significant changes of the systolic function by revascularization, the filling fraction increased from 11.2 +/- 2.6 to 14.5 +/- 3.5% (p less than 0.001) at 25% time of diastole, from 29.9 +/- 4.9 to 32.5 +/- 5.0% (p less than 0.05) at 50% time in the PTCA group, and from 11.8 +/- 3.7 to 13.4 +/- 3.8% (p less than 0.01) at 25% time in the CABG group. The distension rate of radial axis to the anterior wall also increased significantly at 25% and 50% time of diastole after revascularization, and the change was marked in the PTCA group. However, these increases did not apply to the control patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Hemofiltration as treatment for patients with refractory heart failure

Hemofiltration was performed in 15 patients with refractory congestive heart failure. All of these patients had oliguria, although intensive treatment with diuretics, digitalis, vasodilators, and catecholamines was prescribed. Hemofiltration was performed under hemodynamic monitoring in 14 patients. The water removal by hemofiltration decreased pulmonary arterial pressure, pulmonary capillary wedge pressure and right atrial pressure. Despite these hemodynamic improvements, nine patients (60%) died within one month after the start of hemofiltration; the causes were fatal arrhythmia in three, renal failure in two, sepsis in one and irreversible cardiogenic shock in three. Oliguria for over 15 h or a serum creatinine concentration of more than 4.0 mg/dl at the start of hemofiltration related to poor prognosis. In view of these results, hemofiltration for refractory heart failure should be started earlier and performed carefully in order to avoid arrhythmia, cardiogenic shock, and other complications.

[A case of angina pectoris with cardiac arrest at treadmill stress test]

We reported a case of angina pectoris with cardiac arrest immediately after treadmill exercise test, and the effect of PTCA in the same case. A 69-year-old Japanese male had chest oppression on exertion. Initial treadmill test showed 2 mm ST-segment depression in leads V4-6. Two minutes after exercise, he had atrio-ventricular (A-V) block and cardiac arrest with episodes of fainting. He was resuscitated by chest thump. Coronary angiography showed 90% stenosis in the right coronary artery (RCA). PTCA for RCA was able to dilate the stenotic lesion. The second treadmill test after PTCA did not induce bradycardia nor A-V block. It was suggested that the RCA lesion may play a critical role.

Effects of secondary organ failure on compensation of acute heart failure in patients with myocardial infarct and dilated cardiomyopathy

Compensation for heart failure can be influenced by cardiac loads due to organ failure. This investigation studied the effect of secondary organ failure on the hemodynamics of acute heart failure. Of 106 patients with acute heart failure due to myocardial infarction or dilated cardiomyopathy, 49 (46%) patients had secondary organ failure, either kidney, liver, brain or blood. Their acute heart failure was sustained for significantly longer than that of 57 patients without organ failure. A transient but severe decompensation induced secondary organ failure, although the left ventricular ejection fraction was not different from that of the control without heart failure. Hypervolemia in cases of renal failure, bradycardia in loss of consciousness, hyperdynamic state in anemia and low blood pressure in liver dysfunction caused the sustained acute heart failure. These results suggested that secondary organ failure might occur in 46% of patients with acute heart failure, and might disrupt compensation by different kinds of hemodynamic loads in low cardiac function.

Platelet-activating factor (PAF) plays an important role in the immediate asthmatic response in guinea-pig by augmenting the response to histamine

1. To investigate the role of platelet activating factor (PAF) in the immediate asthmatic response, we examined the bronchial reactivity to histamine after administration of PAF to guinea-pigs or antigen challenge to passively sensitized guinea-pigs. 2. A bolus injection of PAF (20-40 ng kg-1), which did not cause a significant increase in intrathoracic pressure (ITP), augmented the bronchial response to histamine almost 8 fold. This airway hyperreactivity was observed even 1 min after PAF treatment. 3. A subthreshold dose of antigen (0.01 mg kg-1, i.v.) also provoked hyperreactivity to histamine, which became significant 6 and 11 min after the antigen treatment. 4. The specific PAF-antagonists, SM-10661 and CV-6209 (i.v.) dose-dependently inhibited both PAF- and antigen-induced airway hyperreactivities to histamine. 5. These results suggest that PAF plays an important role in antigen-induced acute airway responses by augmenting the activities of spasmogens.

Higher Gensini score of coronary arteries in acute inferior myocardial infarction with precordial ST-segment depression

To investigate the significance of precordial ST-segment depression in acute inferior myocardial infarction, we compared the Gensini score of coronary artery stenosis between 2 groups of patients with and without precordial ST-segment depression. Group I consisted of 28 patients who showed ST-segment depression on admission (greater than or equal to 1 mm in V2-V6) and Group II (n = 16) those without ST-segment depression (less than 1 mm). The Gensini score of the coronary arteries (56 +/- 29 vs. 28 +/- 18; p less than 0.001), the partial score of the infarction-related artery (29 +/- 16 vs. 17 +/- 11; p less than 0.01) and of the infarction-nonrelated artery (27 +/- 24 vs. 11 +/- 12; p less than 0.02) were significantly higher in Group I than in Group II. The Killip score (greater than or equal to II) (34% vs. 6%; p less than 0.05), frequency of arrhythmias (75% vs. 38%; p less than 0.02) and peak CK value (3,676 +/- 2,290 vs. 1,818 +/- 1,153 IU/L; p less than 0.005) were higher in Group I than in Group II. Four patients in Group I died following admission, while no patient died in Group II (N.S.). Autopsy findings from the 4 Group I patients revealed fresh extensive inferior infarction and healed diffuse subendocardial infarction which could not be predicted from electrocardiograms. All patients who survived the acute stage performed treadmill exercise testing and 22 patients underwent exercise thallium-201 single photon emission computer tomography (SPECT). On treadmill exercise test, there was no significant difference between the 2 groups in the frequency of angina pectoris and ST-segment depression. On SPECT, the perfusion defect area under 55% of maximum uptake at the redistribution phase was 45.8 +/- 19.6 cm2 in Group I (n = 14) and 34.7 +/- 21.3 cm2 in Group II (n = 8; N.S.). In conclusion, precordial ST-segment depression in acute inferior myocardial infarction suggested advanced atherosclerosis in both the infarction-related and nonrelated coronary arteries, indicating a larger infarct size.