"False-positive" myocardial perfusion scintigraphy findings in patients with angiographically normal coronary arteries: insights from intravascular sonography studies.

UNLABELLED: Abnormal exercise perfusion findings have been described as false-positive for coronary artery disease in patients with suspected angina and angiographically normal coronary arteries. METHODS: The significance of this finding was further investigated by obtaining intravascular sonograms and Doppler guidewire measurements of at least 2 coronary arteries in 20 consecutive patients who had chest pain, normal coronary angiography findings, and positive stress-rest sestamibi SPECT findings. The summed reversible score was used to describe the extent and severity of reversible perfusion defects. On the basis of scintigraphy findings, vessels were grouped as supplying underperfused myocardial segments (target vessels, n = 20) or normal territories (reference vessels, n = 25). The presence and extension of atherosclerotic disease of the epicardial arteries were assessed by intracoronary sonography. Measurements of plaque area (PA), vessel area (VA), and relative cross-sectional PA (RPA) (RPA = PA/VA) were obtained at the site of maximum plaque concentration. The coronary flow velocity reserve (CFR) was assessed during adenosine-induced hyperemia, and the relative flow reserve was calculated as the target-to-reference coronary reserve ratio. RESULTS: The median summed reversible score was 3 (range, 1-6). Intracoronary sonography showed occult atherosclerosis in 19 patients (95%), with RPA greater than 40% in 16 patients (80%). Mean RPA was significantly greater in the target vessels (46% +/- 14%) than in reference vessels (12% +/- 18%; P < 0.0001). Doppler flow velocity measurements showed abnormal vasodilation capacity (CFR < 2.5) in 14 patients (70%). Mean CFR was significantly lower in the target vessels than in the reference vessels (2.3 +/- 0.5 versus 3.1 +/- 0.6; P < 0.0001). A significant inverse correlation was seen between the summed reversible score and the coronary reserve ratio (y = 9.05x - 9.9; r = 0.70; P < 0.005). CONCLUSION: Reversible perfusion defects seen on SPECT images are often associated with angiographically unrecognized occult atherosclerotic changes and an abnormal vasodilation capacity of the coronary circulation. The tendency to dismiss abnormal exercise perfusion findings as false-positive in these patients may be unjustified.

Transcoronary platelet thromboxane A2 formation without platelet trapping in patients with coronary stenosis-effect of sulphinpyrazone treatment.

Platelet count, and plasma thromboxane B2 (TXB2) and circulating platelet aggregates (CPA) were determined in the coronary sinus (CS), aortic bulb (AO) and cubital vein (V) in 21 patients with stable angina and in 6 control subjects before and after atrial pacing (AP). TXB2 measurements were repeated before and after AP in 6 of the 21 angina patients after 15 days' sulphinpyrazone treatment. Platelet count and CPA ratio were similar in angina patients and controls at all three sampling sites and were unchanged at AP peak. In the controls, basal TXB2 values in CS, AO and V were not significantly different and were unchanged at AP peak. In the angina patients compared with the controls, basal TXB2 values in the AO, CS and V were not significantly different whereas the CS/AO TBX2 ratio was significantly higher; at AP-induced ischaemia, CS TXB2 was significantly increased and the CS/AO TXB2 ratio was increased. A weak but significant direct correlation was found between CS/AO TXB2 ratio and coronary score. Sulphinpyrazone treatment reduced CS TXB2 levels at rest and after AP, but not the ischaemic threshold at AP.

Reliability of standard apexcardiography for the measurement of sudden variations in mean pulmonary capillary wedge pressure.

We simultaneously registered the left apexcardiogram together with the left intraventricular pressure curve immediately before and after ventricular angiography in order to evaluate whether the relation existing between apexcardiographic protodiastolic filling period duration (cR interval) and left ventricular mean diastolic pressure (LVMDP) was maintained even in the presence of sudden variations of LVMDP. Administration of contrast media resulted in a significant increase of LVMDP (from 11.8 to 23.9 mm Hg) and in a simultaneous decrease of the cR interval (from 108.5 to 71.0 msec) and noninvasive LVMDP calculated as 36-0.24* cR closely correlated with the invasive values both before and after angiography (overall correlation r = 0.94). Apexcardiography thus confirms to be the only highly reliable noninvasive technique which can be used by the clinical cardiologist to measure LVMDP and/or mean pulmonary capillary wedge pressure.

[The Italian Group for the Study of Streptokinase in Myocardial Infarct: Coronarographic and ventriculographic study]. / G.I.S.S.I.: Studio coronarografico e ventricolografico.

The effects of intravenous thrombolytic treatment on the reperfusion of infarct related coronary artery and left ventricular function were assessed in 251 pts. with first episode of myocardial infarction, enrolled in the G.I.S.S.I. trial, in which coronary angiography and left ventriculography have been performed within the second and third week from the onset of symptoms. A total of 251 pts. were randomized in two groups--133 treated with streptokinase (SK) and 118 controls. Among those treated with SK, in 71 (57.9%) the treatment was started within 3 hours and in 56 (42.1%) after 3 hours from the onset of symptoms. The infarct related vessel was occluded in 43 (32.3%) patients treated and in 60 (50.9%) controls (p less than 0.01). No significant difference was found in the left ventricular ejection fraction among the treated patients and controls while a significant difference resulted in the percentage of patients who had left ventricular ejection fraction greater than or equal to 50% in the group of patients with SK within 3 hours in comparison to controls. Left ventricular ejection fraction remained normal without any correlation with the type and time of the treatment, if the infarct related vessel resulted open at the coronary angiography. The study of the regional wall motion of left ventricle did not show any significant difference neither in the infarct size nor in the type and the time of treatment. In conclusion, the thrombolitic treatment with SK in acute myocardial infarction using the protocol adopted in the G.I.S.S.I. trial, obtains the reopening of infarct related vessel in an high percentage of patients; this event helps in great measure to conserve left ventricular function, especially in patients with anterior myocardial infarction if the treatment was started within the first 3 hours from the onset of symptoms.

Emergency coronary angioplasty in patients with severe left ventricular dysfunction or cardiogenic shock after acute myocardial infarction.

Emergency percutaneous transluminal coronary angioplasty (PTCA) was performed during an acute myocardial infarction (AMI) after either systemic or intracoronary thrombolytic therapy in six patients with severe ischaemic left ventricular dysfunction or cardiogenic shock, among 37 patients (17%) who were treated with PTCA during AMI over a 13-month period. Thrombolytic therapy with streptokinase (1.5 x 10 Units) was initiated after a mean (+/- SD) time delay of 5.5 +/- 1.3 h from the onset of symptoms. The infarct-related artery was found to be occluded (TIMI grade 0-1) in three patients and partially reperfused (TIMI grade 2) in the remaining patients at baseline coronary angiography. Intracoronary administration of urokinase (100-200,000 Units) was ineffective in those patients failing systemic thrombolysis and resulted in only a slight increase of residual lumen in three patients. The coronary artery could be opened by a guidewire mechanical technique in patients with persistent coronary artery occlusion and coronary dilation could be done in all patients. The mean percentage diameter stenosis of the infarct-related vessel was reduced from 98.8 +/- 2% to 27 +/- 11% (P less than 0.005). After the procedure, left ventricular ejection fraction increased from 27 +/- 8% to 41 +/- 7% (P less than 0.02), systemic blood pressure and cardiac index increased respectively from 86 +/- 10 to 126 +/- 14 mmHg (P less than 0.005) and from 2.2 +/- 0.6 to 3.3 +/- 0.6 (P less than 0.01). Left ventricular end-diastolic pressure decreased from 26 +/- 8 to 18 +/- 3 mmHg (P less than 0.05). Severe mitral regurgitation was relieved in one patient.(ABSTRACT TRUNCATED AT 250 WORDS)

Myocardial uptake of indium-111 antimyosin after coronary angioplasty. Relationship with the total burden of ischaemia.

Indium-111 antimyosin scintigraphy was performed in 24 consecutive patients after percutaneous transluminal coronary angioplasty to assess whether repeated periods of ischaemia during balloon inflation results in myocardial cell damage even after a successful procedure. Patients with unstable angina, prior myocardial infarction and whose procedure was complicated were excluded. Indium-111 monoclonal antimyosin antibodies (80 MBq) were injected 24 h after coronary angioplasty and planar images were collected 24 h later. The relative antimyosin uptake was assessed subjectively and by a heart/lung count density ratio. In addition, the intracardiac gradient of activity was assessed by a count density profile analysis of the cardiac region of interest to distinguish better the focal as opposed to the diffuse antimyosin uptake. The antimyosin uptake index was calculated by multiplying the heart/lung ratio to the intracardiac gradient of activity. After coronary angioplasty, nine patients had minor ST-T wave changes on the surface ECG, but no patient demonstrated a new Q wave. Only three patients showed a mild rise in cardiac enzyme (CK-MB) serum levels. Indium-111 antimyosin uptake (heart/lung > 1.55) was present in eight patients (33%) and was intense (heart/lung > 1.9) in five (21%). Antimyosin uptake was always seen in myocardial segments corresponding to the treated coronary artery. Patients with a positive antimyosin scan had a longer duration of balloon-induced ischaemia compared with patients with no evidence of antimyosin uptake (541 +/- 211 vs 331 +/- 137 s, P < 0.007).(ABSTRACT TRUNCATED AT 250 WORDS)

Myocardial dissection following successful chemical ablation of ventricular tachycardia.

We describe a case of fatal myocardial rupture and tamponade following a successful transcoronary chemical ablation of incessant ventricular tachycardia. Pathological examination showed a subepicardial dissection of the heart at the ablation site with fibrous and fatty degeneration of the myocardium. The present report calls for caution, underlying a possible lethal complication of ethanol ablation which has not been described before.

Aspergillus flavus-infection of a pacemaker wire: continuing evidence for active management of infected pacemakers.

A rare case of fungal endocarditis (Aspergillus flavus) on a permanent pacemaker is described. Owing to negative blood culture and non-specific echocardiographic findings, a complete diagnosis was made only on histologic examination of the surgically removed material. In our opinion this case supports an active management of infected pacemakers.