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Biomedical subjects

M W Krucoff

Publications and source records attributed to M W Krucoff.

71 records · Page 4Linked to original sources
PubMed1990

Myocardial salvage after failed coronary angioplasty.

UNLABELLED: Patients undergoing coronary angioplasty have a 2% to 7% risk of requiring emergency coronary artery bypass graft surgery for impending infarction. These patients provide a unique model of early reperfusion because the exact time of compromise to blood flow and the composition of the reperfusion solution are known. However, the amount of myocardium salvaged is unknown. Between December 1981 and September 1985, 859 patients underwent coronary angioplasty. Forty-two patients had emergency surgery for objective evidence of impending infarction. Five patients died. Thirty-six patients were contacted for follow-up; 21 (58%) of 36 had a radionuclide ventriculogram performed at a mean of 39 +/- 13 months after surgery. These radionuclide studies were compared with the patient's preangioplasty contrast ventriculogram. One patient had a myocardial infarction 3 years after surgery. Eleven (55%) of the remaining 20 patients had a normal radionuclide ventriculogram at follow-up study (ejection fraction 65 +/- 9%). Five (25%) of the 20 patients had a depressed ejection fraction (46 +/- 4%) with wall motion abnormalities, but these were unchanged from the preangioplasty studies. Four patients (20%) had a significant decrease in ejection fraction over baseline (37 +/- 10%) with new wall motion abnormalities. IN CONCLUSION: 1) there is an 80% chance that left ventricular function will be unchanged at 3 year follow-up study in patients surviving emergency bypass grafting for failed angioplasty; 2) these data suggest that early revascularization for impending infarction in this setting is associated with a good late outcome; and 3) this patient group offers a unique opportunity to study the effects of early reperfusion in a human model.

Angioplasty, Balloon, Coronary↗
PubMed1990

Quantitative and qualitative ST segment monitoring during and after percutaneous transluminal coronary angioplasty.

Patients who undergo elective percutaneous transluminal coronary angioplasty (PTCA) provide a unique human model, with fully defined coronary anatomy and known sites and periods of coronary occlusion. High-resolution, quantitative ST segment monitoring during PTCA procedures allows characterization of the first moments of coronary occlusion, as well as the effect of interventions intended to reduce ischemia during occlusion. Data from more than 1,000 coronary occlusions are reviewed in this presentation. Intracoronary interventions during acute myocardial infarction (MI) and elective PTCA create a potentially unstable coronary nidus through their therapeutic effect. Angiographic evidence of the anatomic appearance remains the "gold standard" for real-time assessment of success although angiography has limited ability to identify the 2-4% of patients who suffer morbidity or mortality in the coronary care unit (CCU) after an apparently successful intervention. Standard CCU monitoring of patient symptoms and rhythms underestimates transient ischemic activity in 87% of patients who experience ischemia after interventions. The capabilities of real-time multilead ST segment monitoring are reviewed from 8,331 hours of monitoring in 338 patients after intracoronary interventions. The documentation of persistent ischemia after angiographically successful PTCA and the clinical potential of qualitative patient-specific, coronary site-specific, precordial "fingerprinting" for identification of high-risk patients before or in the absence of anginal symptoms are discussed.

Angina Pectoris↗
PubMed1989

Transient alterations of the QRS complex and ST segment during percutaneous transluminal balloon angioplasty of the right and left circumflex coronary arteries.

The dynamic QRS amplitude changes that appear during 1-vessel percutaneous transluminal coronary angioplasty of the right and left circumflex coronary arteries were studied in 20 patients using continuous 3-lead electrocardiographic recordings representing leads aVF, V2 and V5. The balloon inflations that produced the greatest extent of ST-segment deviation were identified for each lead ("maximally ischemic periods"). QRS amplitude measurements were performed manually at both the PR and shifted J-ST baselines at 10-second intervals during these periods to determine that baseline from which the R and S waves most nearly maintained their control amplitudes. There was no significant baseline relation for either the R or the S waves in leads V2 and V5 during ischemia. However, the R-wave changes in lead aVF were significantly associated with the PR- versus the J-ST-segment baseline (p = 0.007); the S wave, when it occurred, had no tendency for either baseline. The electrocardiographic records were also examined visually for characteristics of left posterior (inferior) "periischemic block" likely to occur uniquely in patients with a dominant right or left circumflex occlusion. There were 2 patients with obstruction of the right circumflex artery who exhibited the characteristics of periischemic block during percutaneous transluminal coronary angioplasty, as evidenced by an increase in R-wave duration, amplitude or both in lead aVF.

Adult↗
PubMed1989

Dissociation of ST segment elevation and regional wall motion with open-artery, intracoronary Fluosol.

Intracoronary infusion of oxygenated Fluosol during percutaneous transluminal coronary angioplasty has been shown to reduce chest pain and preserve contractile function. In spite of this evidence for reduced severity of myocardial ischemia, ST elevation is frequently observed on the electrocardiogram. To determine if Fluosol produces ST segment elevation by a mechanism other than myocardial ischemia, closed-chest dogs underwent three interventions: (1) an infusion of oxygenated Fluosol into the unoccluded left anterior descending (LAD) coronary artery; (2) an identical infusion of unoxygenated Ringer's lactate; and (3) a transient occlusion of the LAD coronary artery. Open-artery infusions were chosen to minimize ischemia by permitting antegrade coronary blood flow. ST segments were monitored continuously and contrast left ventriculography was performed to assess regional systolic function. Coronary occlusion for 1 minute resulted in significant ST segment elevation from baseline (0.8 +/- 0.2 to 3.2 +/- 0.6 mm, p less than 0.05) and marked depression in regional ejection fraction (45 +/- 7% to -3 +/- 4%, p less than 0.05). Infusion of Fluosol produced a similar degree of ST segment elevation (0.9 +/- 0.3 to 2.8 +/- 0.4 mm, p less than 0.05), but no change in regional ejection fraction. Ringer's lactate infusion also resulted in ST segment elevation associated with preservation of regional contractility. Because regional systolic function (a sensitive indicator of regional ischemia) was preserved and an open-artery infusion was used, it is concluded that intracoronary infusion of Fluosol causes ST segment elevation by a mechanism other than myocardial ischemia.(ABSTRACT TRUNCATED AT 250 WORDS)

Angioplasty, Balloon↗
PubMed1989

Instrumentation and practice standards for electrocardiographic monitoring in special care units. A report for health professionals by a Task Force of the Council on Clinical Cardiology, American Heart Association.

The proposed recommendations for continuous electrocardiographic monitoring systems represent goals for future development. Description of a technique in the report does not constitute an endorsement of its clinical use. Lead systems for ECG monitoring must adequately sense the cardiac electrical field and the leads should be standardized. Future monitors should be capable of simultaneously displaying and analyzing multiple leads. Recommendations for electrode placement and position of patient are made. Important parameters in each category of standards for instrumentation published in 1983 in the American National Standard for Cardiac Monitors, Heart Rate Meters, and Alarms are listed. Selected procedures proposed by the Association for the Advancement of Medical Instrumentation to inform users of minimally acceptable accuracy of computerized systems in a standardized manner are presented. Emphasis is placed on the importance of nursing and medical staff capabilities. Personnel qualifications and training as well as systems to assure and maintain quality of immediate ECG diagnosis are highlighted.

Allied Health Personnel↗
PubMed1988

Transient alterations of the QRS complex and ST segment during percutaneous transluminal balloon angioplasty of the left anterior descending coronary artery.

Using continuous 3-lead electrocardiographic (ECG) recordings in 19 patients undergoing elective percutaneous transluminal coronary artery angioplasty (PTCA) of the left anterior descending (LAD) artery, this study described the dynamic changes of the ST segment and the R- and S-wave amplitudes that occur during transient myocardial ischemia. The waveforms from lead V2 were quantified at 10-second intervals during the length of the balloon inflation that produced the greatest extent of ST-segment deviation. The simultaneous changes that occurred in leads aVF and V5 were also observed, but not quantified. Measurements of R- and S-wave amplitudes were performed during maximal ischemia from both the PR- and the J-ST-segment baselines to determine which of these most nearly maintained its control position during ischemia. The results indicate that the R-wave amplitude is best determined from the PR-segment baseline (p = 0.0007), while the S wave is best determined from the J-ST-segment baseline (p = 0.03). However, only a portion of the QRS changes observed during PTCA could be accounted for by the baseline shift. There were additional QRS changes during ischemia in 11 of the patients (58%) suggestive of conduction disturbances in 3 endocardial sites: left septal, right septal and left anterosuperior. It is hypothesized that these changes may represent ischemia-induced delay in conduction ("periischemic block") previously thought to occur only with myocardial infarction.

Angioplasty, Balloon↗
PubMed1988

Stability of multilead ST-segment "fingerprints" over time after percutaneous transluminal coronary angioplasty and its usefulness in detecting reocclusion.

Multilead ST-segment recordings taken during percutaneous transluminal coronary angioplasty (PTCA) could function as an individualized noninvasive template or "fingerprint," useful in evaluating transient ischemic episodes after leaving the catheterization laboratory. To evaluate the reproducibility of such ST-segment patterns over time, these changes were analyzed in patients grouped according to the time between occlusion and reocclusion. For the patients in group 1, the study required comparing their "fingerprints" in repeat balloon inflation during PTCA (reocclusion in less than 1 hour), for those in group 2, comparing ST "fingerprints" during PTCA with ST changes during spontaneous early myocardial infarction (reocclusion in 24 hours) and in group 3, comparing ST "fingerprints" with ST changes during repeat PTCA for restenosis greater than 1 month after the initial PTCA. The ST "fingerprints" among the 20 patients in group 1 were identical in 14 cases (70%) and clearly related in another 4 (20%). Of the 23 patients in group 2, 12 (52%) had the same and 8 (35%) had related patterns. Of 19 patients in group 3, 8 (42% had the same pattern and 8 (42%) had related patterns. Thus, ST fingerprints were the same or clearly related with reocclusion in the same patient from less than 1 hour to greater than 1 month after initial occlusion in 87% of patients overall, in 90% in less than 1 hour, in 87% in less than 24 hours and in 84% greater than 1 month later. Multilead pattern ST-segment "fingerprints" may serve as a noninvasive marker for detecting site-specific reocclusion.

Aged↗
PubMed1988

Quantitative ST-segment recovery following angiographically successful angioplasty: a useful warning of early complications.

The angiographic/anatomic appearance of the TCA site and transstenotic gradient trending are two available intraprocedural variables that help to identify patients at high risk for early complications after successful angioplasty. We have reported on an additional variable, the rate of ST recovery following the final balloon deflation as a physiologic marker to identify patients at risk for early complications. Slow ST recovery was present in 52% of patients with early complications of myocardial infarction, urgent or emergent coronary bypass surgery, and/or death, whereas normal ST recovery was seen in 97% of patients with uncomplicated courses. ST trending is a non-invasive modality that is available in all patients undergoing TCA and should be a useful adjunct in identifying patients at high and low risk for early major complications following angiographically successful angioplasty. A prospective study of ST recovery during TCA deserves consideration.

Angioplasty, Balloon↗
PubMed1988

Noninvasive assessment of patients following coronary artery angioplasty.

PTCA alters the natural history of coronary artery disease and thus presents a challenge for the cardiologist to detect the variety of changes that may occur. Continuous electrocardiographic monitoring with automatic detection of ST segment changes has proved valuable during the immediate post-PTCA procedure. Radionuclide ventriculography and thallium-201 perfusion scans are most important in providing physiologic evidence of improved functional blood flow, particularly in patients with limited revascularization. Finally, the important unsolved problem with PTCA, that of restenosis, is best detected by repeat noninvasive testing in the first months after successful PTCA.

Angioplasty, Balloon↗
PubMed1987

Quantitation of ischemia during total coronary occlusion with computer-assisted high resolution ST-segment monitoring: effect of collateral flow.

The effect of increasing grades of collateral flow to the distal target vessel on the clinical and electrocardiographic manifestations of ischemia was evaluated in 118 patients undergoing transluminal coronary angioplasty (TCA). A qualitative scoring system for collateralization was defined as follows: 0--no visible collaterals; 1--visualization of collateral vessels only with no filling of the distal TCA vessel; 2--partial filling of the distal TCA vessel, and; 3--complete filling of the distal TCA vessel. All patients underwent computerized ST-segment monitoring using 3-channel Holter recorders. Criteria for an ischemic ST-segment response was 1.0 mm ST-segment deviation from ST baseline measured 60 msec after the J-point. Episodes of chest pain during and after the procedure were noted. Patients with collateral filling (collateral scores 2 and 3) of the distal TCA vessel had a significantly decreased incidence of angina and diagnostic ischemic ST-segment changes (42% and 15% respectively) as compared to patients without collateral filling (collateral scores 0 and 1) (83% and 74%) (p less than .001). Fifty-eight percent of patients without collateral filling had ischemic ST-segment responses on every balloon inflation as opposed to only 9% with collateral filling (p less than .0001). After TCA, the incidence of angina and ischemic ST-segment changes was similar in both groups (20% and 17% without collateral filling vs. 9% and 9%). We conclude that: 1. increasing qualitative collateralization protects against the development of myocardial ischemia during TCA, but; 2. the similar incidence of late episodes of ischemia after successful TCA suggests that collateral flow may no longer be adequate.

Angioplasty, Balloon↗
PubMed1987

Computer-assisted ST-segment monitoring: experience during and after brief coronary occlusion.

As the technology of computer-assisted ECG analysis continues to advance the frontier of multi-lead acquisition and real time analysis, conceptual approaches to the research applications as well as to the electrical and clinical validity of changes in the ECG signal amongst heterogeneous patient groups need to be continually reassessed. Comparisons between different devices, lead configurations, rates of acquisition, approaches to analysis, and patient populations may have large gaps that will require cautious extrapolation and careful investigation.

Coronary Disease↗
PubMed1986

Noninvasive detection of coronary artery patency using continuous ST-segment monitoring.

Continuous ST-segment Holter recordings were analyzed from 46 patients with acute myocardial infarction (AMI) receiving intracoronary streptokinase (SK) during the first 48 hours of hospitalization. Changes in ST deviation and the time periods of these changes were quantitated and correlated with angiographic evidence of reperfusion. Thirty-six patients had total occlusion of the infarct vessel and 10 had subtotal occlusion. Of the 36 vessels that were totally occluded, 19 were reperfused and 17 were not. In patients in whom reperfusion was successful, an ST steady state was achieved 55 +/- 32 minutes after SK administration. In patients in whom it was not successful, a steady state was achieved in 219 +/- 141 minutes (p less than 0.001). Achievement of steady state within 100 minutes after SK reperfusion indicated successful reperfusion with 89% sensitivity and 82% specificity. All patients with subtotal occlusion achieved an ST steady state before SK infusion. No patient with total occlusion achieved a steady state before SK. Achievement of ST steady state before SK infusion was 100% sensitive and 100% specific for subtotal occlusion at initial angiography. Continuous, quantitative ST-segment analysis is a sensitive and specific noninvasive technique for following coronary artery patency during AMI.

Coronary Vessels↗
PubMed1986

Ventricular arrhythmias during reperfusion.

Accelerated idioventricular rhythm has been used as a marker for coronary reperfusion. The incidence of accelerated idioventricular rhythm and ventricular tachycardia was evaluated in 52 consecutive patients undergoing thrombolysis with intracoronary streptokinase during acute myocardial infarction. Complete 12-hour Holter recordings during and after intracoronary streptokinase were obtained in 39 patients. Reperfusion was documented in 17 patients (44%), no reperfusion in 14 (36%), and subtotal occlusion in eight (20%). Accelerated idioventricular rhythm occurred in 83%, 57%, and 63% of patients by group, respectively (p greater than 0.05). Ventricular tachycardia occurred in 100%, 71%, and 100% of patients by group, respectively (p less than 0.05). These data demonstrate that accelerated idioventricular rhythm is not specific for reperfusion and cannot be used as a marker for this event, and that ventricular tachycardia is more common with reperfusion and subtotal occlusion.

Cardiac Catheterization↗