Norman Sadick

Effect of prehospital triage on revascularization times, left ventricular function, and survival in patients with ST-elevation myocardial infarction.

Shorter reperfusion times lead to better outcomes in patients with ST-elevation myocardial infarction (STEMI). We assessed the efficacy of prehospital triage with bypass of community hospitals and early activation of the cardiac catheterization team on revascularization times, left ventricular (LV) ejection fraction, and survival. Patients with STEMI (624) were divided into 3 groups determined by site of triage: ambulance field triage (163), interventional center emergency department (202), and 3 community hospital emergency departments (259). Compared with community hospital and interventional center triages, ambulance field triage resulted in a significant median decrease in door-to-balloon times of 68 and 27 minutes, respectively (p <0.001). LV ejection fraction was highest in the field triage group (52 +/- 13%) compared with the interventional center (49 +/- 12%) and community hospital (48 +/- 12%, p = 0.017) groups. Thirty-day mortality was lowest in the ambulance field group (3%) compared with the interventional facility (11%) and community hospital (4%, p = 0.007) groups. There was a significant difference in long-term survival with up to 30-month follow-up among the 3 triage groups (p = 0.041). With time-dependent Cox regression modeling the difference in survival was significant only during the first week after STEMI (p = 0.020). Every extra minute of symptom onset to reperfusion time was associated with a relative risk of long-term mortality of 1.003 (95% confidence interval 1.000 to 1.006, p = 0.027). In conclusion, field triage of patient with STEMI decreased revascularization times, which preserved LV function, and improved early survival.

Clinical and Electrocardiographic Correlates of Normal Coronary Angiography in Patients Referred for Primary Percutaneous Coronary Intervention

This study sought to determine the prevalence as well as clinical and electrocardiographic correlates of patients referred for primary percutaneous coronary intervention (PCI) who had angiographically normal coronary arteries. Data for 690 consecutive patients with ST-elevation myocardial infarction (STEMI) referred for primary PCI within a metropolitan area health service were reviewed. Characteristics of patients with angiographically normal coronary arteries (n = 87; 13%) were compared with patients with angiographically shown culprit lesions (control group; n = 594). Nine patients with significant coronary disease, but no identifiable culprit lesion, were excluded. Electrocardiograms (ECGs) from both groups were reviewed by 2 cardiologists blinded to angiographic findings. Patients in the normal coronaries group were younger and had fewer risk factors. On expert review of ECGs, 55% of patients in the normal coronaries group had ST-elevation criteria for STEMI (vs 93% in the control group; p <0.001), but the ECG was considered consistent with a diagnosis of STEMI by both observers in only 33% (vs 92% in the control group; p <0.001). Left branch bundle block independently correlated with normal coronary arteries on multivariate analysis (odds ratio for STEMI 0.016, 95% confidence interval 0.004 to 0.064, p <0.001). The discharge diagnosis in the normal coronaries group was predominantly pericarditis (n = 72; 83%). In conclusion, the prevalence of angiographically normal coronary arteries in patients referred for primary PCI was 13%. Electrocardiographic correlation suggested that this can be reduced by adherence to conventional electrocardiographic criteria for STEMI diagnosis and review of ECGs by experienced clinicians.

Effect of reperfusion time on inducible ventricular tachycardia early and spontaneous ventricular arrhythmias late after ST elevation myocardial infarction treated with primary percutaneous coronary intervention.

BACKGROUND Prompt thrombolytic reperfusion reduces postinfarct ventricular electrical instability after ST elevation myocardial infarction (STEMI). OBJECTIVE The purpose of this study was to examine the relationship between reperfusion time and inducible ventricular tachycardia (VT) early and spontaneous ventricular arrhythmias (VAs) late after primary percutaneous coronary intervention (PCI) for STEMI. METHODS Consecutive patients were recruited if they (1) had no prior coronary disease, (2) had been reperfused with primary PCI, (3) had postinfarct ejection fraction ≤40%, and (4) had undergone cardiac electrophysiologic study (n = 128). Three groups were compared according to reperfusion time: early (≤3 hours, n = 26), intermediate (>3-5 hours, n = 45), or delayed reperfusion (>5 hours, n = 57). Spontaneous VA was a composite endpoint of sudden death or defibrillator-treated VA. RESULTS Mean ejection fraction (33% ± 5%, 31% ± 6%, and 31% ± 7%, P = .41) and peak creatinine kinase (P = .37) were similar between groups. VT was inducible in 11.5%, 17.8%, and 36.8% of patients in the early, intermediate, and delayed reperfusion groups, respectively (P = .003). At 2 years, the incidence of spontaneous VA was 0%, 8.9%, and 14% in the early, intermediate, and delayed reperfusion groups, respectively (P = .025). By multivariable analysis, delayed reperfusion conferred a sixfold increase in the odds of inducible VT (P = .01). Although inducible VT was the strongest predictor of spontaneous VA (hazard ratio 14.31, P = .001), delayed reperfusion conferred a threefold increase in risk when inducible VT was excluded from the multivariable model (P = .035). CONCLUSION Reperfusion time is a critical determinant of postinfarct ventricular electrical instability early and late after STEMI treated with primary PCI.

Randomized double-blind trial of sotalol versus lignocaine in out-of-hospital refractory cardiac arrest due to ventricular tachyarrhythmia.

Abstract

Prognostic Impact of Q Waves on Presentation and ST Resolution in Patients With ST-Elevation Myocardial Infarction Treated With Primary Percutaneous Coronary Intervention

Q waves can develop early in infarction and indicate infarct progression better than symptom duration. ST resolution (STR) is a predictor of reperfusion success. Our aim was to assess the prognostic impact of Q waves on presentation and STR after primary percutaneous coronary intervention (PPCI) for ST-elevation myocardial infarction. The combined end point was of mortality and adverse cardiovascular events (MACE; death, repeat myocardial infarction, or heart failure). Q waves on presentation (Q wave, n = 332; no Q wave, n = 337) was associated with significantly less mean STR, greater incidence of akinetic, dyskinetic, or aneurysmal regional wall motion, lower left ventricular ejection fraction, and worse in-hospital and 1-year MACEs (1 year 24% vs 8.2%, p <0.001). In addition, Q waves on presentation compared to no Q waves were associated with worse 1-year MACE regardless of infarct presentation in < or =3 hours, infarct location, and adequate STR (> or =70%). Q waves on presentation and inadequate STR (<70%), but not symptom duration, were independent predictors of MACE by multivariable analysis (adjusted hazard ratios of 2.7 and 2.4 for Q waves and STR, respectively). Compared to group A (no Q waves on presentation with STR), patients in group B (no Q waves with inadequate STR), group C (Q waves with STR), and group D (Q waves with inadequate STR) had hazard ratios of 3.0, 3.6, and 7.7, respectively (p <0.05) for the occurrence of MACE. In conclusion, assessment of Q-wave status on presentation and STR immediately after PPCI provides a simple and early clinical predictor of outcomes in ST-elevation myocardial infarction.

Predictive Value of ST Resolution Analysis Performed Immediately Versus at Ninety Minutes After Primary Percutaneous Coronary Intervention

ST segment resolution (STR) predicts epicardial and microvascular reperfusion after primary percutaneous coronary intervention (PPCI) or thrombolysis for ST-elevation myocardial infarction. Immediate restoration of epicardial coronary flow, with improved microvascular perfusion, is much more likely with PPCI. However, the predictive value of immediate STR compared to 90 minutes after PPCI remains unknown. In 622 consecutive patients with ST-elevation myocardial infarction (mean age 59 +/- 13 years), 217 had complete STR immediately after PPCI (group A), 188 had complete STR only at 90 minutes (group B), and 217 had incomplete STR at either point (group C). The primary end point was mortality and adverse cardiovascular events ([MACE] death, nonfatal repeat myocardial infarction, and heart failure). Group A had a greater left ventricular ejection fraction (53%, 47%, and 46%, p <0.001) and lower all-cause mortality (1.8%, 3.2%, and 6%, p = 0.07), lower heart failure (1.8%, 4.3%, and 7.8%, p <0.001), and MACE (5.1%, 9.6%, and 16.1%, p = 0.001) at 30 days compared to groups B and C, respectively. The rate of MACE at 1 year was 7.6%, 17.1%, and 20.2% in groups A, B, and C, respectively (p <0.001). Immediate STR independently predicted MACE (adjusted hazard ratio 0.36, 95% confidence interval 0.21 to 0.61, p = 0.001, group A vs C), and STR at 90 minutes did not. In conclusion, STR analysis performed immediately after PPCI provided superior differentiation for adverse cardiovascular events compared to STR at 90 minutes. Immediate STR should be the contemporary goal of reperfusion with PPCI.

Optimisation of coronary angiography exposures requires a multifactorial approach and careful procedural definition

OBJECTIVE This study investigates the factors associated with higher doses for both single-plane and biplane procedures and establishes centre-specific 75th percentile levels. METHODS 602 patients undergoing coronary angiography in a large hospital at Sydney were recruited to the study, and causal agents for high radiation doses were investigated: gender, procedural complexity, severity of coronary artery disease, presence of coronary bypass grafts, entry approach (radial or femoral), level of operator experience; and a single-plane or a biplane imaging system was employed. RESULTS The 75th percentile levels were calculated. The results demonstrated that, for both systems, higher exposures were associated with patients who were male (p<0.001), had coronary vessel disease (p<0.001) and had a history of coronary bypass grafts (p<0.001). In addition, for biplane systems, procedural complexity (p<0.001), types of entry approach (p<0.001) and levels of operator experience (p<0.001) significantly impacted upon the dose. Biplane examinations recorded higher doses than single-plane procedures (p<0.001) and the inclusion of left-sided ventriculography contributed to the overall dose by up to 10%. CONCLUSION The 75th percentile levels in this study represent the tentative reference levels and are 48.9, 44.2 and 56 Gy cm(2) for all exposures, single-plane- and biplane-specific exposures, respectively, and compare favourably with the diagnostic reference level values established elsewhere internationally, with only the UK and Irish data being lower. ADVANCES IN KNOWLEDGE Specific agents have been identified for dose-reducing strategies and the importance of operator training is highlighted. The assumption that biplane procedures may reduce the patient dose should be treated with caution.

The effect of high-dose intravenous nitroglycerin on cardiovascular hemodynamic features and left ventricular function at rest and during exercise in patients with exertional angina.

Abstract Intravascular pressures, cardiac output and left ventricular function were measured at rest and during exercise in 14 patients with stable angina pectoris before and during an intravenous nitroglycerin infusion. Nitroglycerin was infused at a rate sufficient to reduce mean arterial pressure at rest by 15 to 25 mm Hg. At rest, the end-diastolic volume index decreased from 57 ± 13 to 39 ± 3 ml/m 2 , stroke volume index from 32 ± 6 to 24 ± 5 ml/m 2 and mean arterial pressure from 112 ± 16 to 91 ± 14 mm Hg. The cardiac output was maintained by an increase in heart rate from 73 ± 9 to 92 ± 37 beats/min. The left ventricular ejection fraction increased from 57 ± 7 to 62 ± 9% because the stroke volume decreased less than the end-diastolic volume. All 14 patients were limited by angina in the prenitroglycerin exercise study, and the mean ST-segment depression at maximal work load was 2.2 ± 1.2 mm. At identical work loads in the nitroglycerin study, only 4 patients had angina, and the mean ST-segment depression was 0.3 ± 0.5 mm. Ten of the 14 patients improved their exercise performance by at least 30 W. Comparing the 2 exercise studies at the maximal work load achieved in the prenitroglycerin study, the mean pulmonary artery wedge pressure was decreased from 23 ± 6 to 6 ± 4 mm Hg, the end-diastolic volume index from 38 ± 15 to 27 ± 12 ml/m 2 , and the mean arterial pressure from 132 ± 8 to 114 ±13 mm Hg. The stroke volume index and the heart rate were not significantly altered and the ejection fraction increased from 56 ± 8% to 66 ± 8%. Thus, in the high dose administered, nitroglycerin decreased left ventricular filling pressure, heart size, and stroke volume at rest and increased the ejection fraction. During exercise, nitroglycerin decreased myocardial ischemia and improved exercise tolerance. An increase in exercise ejection fraction was associated with an increase in the ratio of systolic pressure to end-systolic volume, suggesting that there was an improvement in contractile performance.

Prognostic implication of ST‐segment resolution following primary percutaneous transluminal coronary angioplasty for ST‐elevation acute myocardial infarction

Background : ST‐segment changes have been shown to correlate with myocardial tissue perfusion. Complete ST‐segment resolution after thrombolysis in acute myocardial infarction is associated with lower mortality and better left ventricular function. Primary percutaneous transluminal coronary angioplasty (PTCA) for acute myocardial infarction restores better epicardial coronary flow to the infarct‐related artery than thrombolysis. However, ST changes may persist and flow can remain poor despite a patent vessel.

Can the electrophysiologic study predict treatment outcome in patients with sustained ventricular tachyarrhythmias unrelated to coronary artery disease

UNLABELLED Sustained ventricular tachyarrhythmias unrelated to coronary artery disease are uncommon. Currently there are no clear guidelines to aid selection of the most appropriate treatment strategy. Therefore, factors potentially predictive of arrhythmia recurrence and death and the ability of the electrophysiologic study to predict treatment outcome in patients with spontaneous sustained ventricular tachyarrhythmias unrelated to coronary artery disease were examined in 41 medically treated patients followed for a median of 25 (range 1-76) months. Examined factors were: syncope associated with the spontaneous arrhythmia, the morphology and cycle length of the presenting arrhythmia, underlying ventricular function, cardiac pathology, and the results of drug assessment at electrophysiologic study. Random variability in the ease of arrhythmia induction at electrophysiologic study was measured for the group as a whole and was allowed for in prediction of an effective drug response. The 95% confidence intervals for variability in the ease of repeat arrhythmia induction at the same study were < or = 1 extrastimulus and for variability in the ease of repeat arrhythmia inductions at different studies were < or = 2 extrastimuli. Poisson regression models were used for data analysis. Arrhythmia recurrence was most likely in: (1) patients on treatment not predicted to be anti-arrhythmic at electrophysiologic study; (2) patients whose treatment was not assessable at electrophysiologic study because the arrhythmia was not reliably inducible; (3) patients with impaired ventricular function; and (4) re-entered patients whose arrhythmia had recurred on previously allocated therapy. The risk of arrhythmia recurrence decreased with time from hospital assessment. All five deaths occurred in patients with impaired ventricular function. CONCLUSIONS drug efficacy should be tested at electrophysiologic study in patients with reproducibly inducible clinical arrhythmias. Treatment not proven to be anti-arrhythmic at electrophysiologic study is usually ineffective. Patients with ventricular dysfunction are at highest risk of death from arrhythmia recurrence and should be considered for an implantable defibrillator, arrhythmia surgery, or heart transplantation if drug treatment is not predicted to be effective or is not assessable at electrophysiologic study.