When deriving the spatial QRS-T angle from the 12-lead electrocardiogram, which transform is more Frank: regression or inverse Dower?

Introduction

Our primary objective was to ascertain which commonly used 12-to-Frank-lead transformation yields spatial QRS-T angle values closest to those obtained from simultaneously collected true Frank-lead recordings.

Materials and Methods

Simultaneous 12-lead and Frank XYZ-lead recordings were analyzed for 100 postmyocardial infarction patients and 50 controls. Relative agreement, with true Frank-lead results, of 12-to-Frank-lead-transformed results for the spatial QRS-T angle using Kors' regression versus inverse Dower was assessed via analysis of variance, Lin's concordance, and Bland-Altman plots.

Results

Spatial QRS-T angles from the true Frank leads were not significantly different than those derived from the Kors' regression-related transformation but were significantly smaller than those derived from the inverse Dower-related transformation (P < .001). Independent of method, spatial mean QRS-T angles were also always significantly larger than spatial “maximum” (“peaks”) QRS-T angles.

Discussion

Spatial QRS-T angles are best approximated by regression-related transforms. Spatial mean and spatial “peaks” QRS-T angles should not be used interchangeably.     

Color of culprit lesion at 6 months after plain old balloon angioplasty versus stenting in patients with acute myocardial infarction

Background

Although the healing process of disrupted yellow plaques at myocardial infarction (MI) culprit lesions has been reported, the effect of stenting on this process has not been clarified. Stenting has been reported to deteriorate the endothelial function after percutaneous coronary intervention (PCI). Therefore, we compared the angioscopic morphology of culprit lesions at 6 months after plain old balloon angioplasty (POBA) and stenting to clarify the effect of stenting on the healing of disrupted culprit plaques of acute MI.

Methods

Patients with acute MI who had yellow culprit plaque, successful reperfusion therapy with POBA (n = 21) or stenting (n = 22), and a successful 6-month follow-up angioscopic examination were included in this study. Oral ticlopidine (200mg/day) was administered for 3 to 6 months after stenting.

Results

At 6 months after reperfusion therapy, the color of the culprit lesion became white in significantly more patients treated with stenting than treated with POBA (50% vs 14%; P = .01). However, the prevalence of thrombus appeared to be higher in patients treated with stenting than in patients treated with POBA (27% vs 5%; P = .04). Although there was some difference in the patients' characteristics in the groups, logistic regression analysis revealed no significant influence of those factors on the color of or on the prevalence of thrombus at the culprit lesion.

Conclusions

Coronary stenting in patients with acute MI leads to the disappearance of yellow color at a significantly higher rate than POBA; however, whether it stabilizes the plaque requires further investigation.     

Safety of abciximab in patients with chronic renal insufficiency who are undergoing percutaneous coronary interventions

Background

Patients with chronic renal insufficiency (CRI) have worse outcomes during and after percutaneous coronary interventions (PCI). Abciximab reduces complications, but may cause excessive bleeding in patients with CRI. Therefore, we sought to determine the safety of abciximab in patients with CRI.

Methods

Patients (n = 4158) undergoing PCI at the Mayo Clinic since abciximab became available were analyzed according to their estimated creatinine clearance (≥70, 50-69, or <50 mL/min) or need for dialysis. Major bleeding was defined as a cerebrovascular bleed or a decrease in the hematocrit level >15%. Minor bleeding was defined as a decrease in the hematocrit level of 10% to 15% with an identifiable site of bleeding.

Results

CRI was associated with increased bleeding in patients who received abciximab and patients who did not. However, there was only a trend toward an interaction between creatinine clearance and major bleeding with abciximab (odds ratio [OR], 1.18; P = .06) and no interaction with minor bleeding (OR, 1.01; P = .94) or any bleeding (OR, 1.10; P = .15).

Conclusion

CRI is associated with an increased risk of bleeding complications after PCI. Although abciximab increases the risk of bleeding in all patients, the increase in relative risk is not significantly greater in patients with CRI. Thus, abciximab may be given safely in patients with CRI who are undergoing PCI.     

The new universal definition of myocardial infarction criteria improve electrocardiographic diagnosis of acute coronary syndrome

Introduction/Methods

To assess whether revised electrocardiographic (ECG) criteria improve emergency department identification of patients with acute myocardial infarction (MI) or unstable angina (UA) and predict outcome, we studied 120 patients with a nondiagnostic initial ECG by prior criteria. Electrocardiograms were read in a blinded fashion months apart with standard and then revised criteria, and analyzed by χ² and logistic regression analysis.

Results

In 12 subjects (10%), the initial ECG was now interpreted as diagnostic of ischemia. Eleven (92%) had an MI, 1 had UA (8%), and none had a noncardiac diagnosis. Ischemic ECG changes were strongly associated with MI or UA (P = .003). At 1-year follow-up, ECG changes diagnostic of ischemia were associated with a trend toward higher mortality (25% vs 7%, P = .07), but after adjustment for clinical factors, ECG changes were not an independent predictor of 1-year mortality.

Conclusions

Revision of the ECG criteria for ischemia was associated with enhanced diagnostic performance and identified a subset of patients at higher risk.     

Metoprolol CR/XL in postmyocardial infarction patients with chronic heart failure: experiences from MERIT-HF

Background

The benefit of β-blockers post-myocardial infarction (MI) was established in the late 1970s. Major advances in the treatment of MI have since occurred. However, patients with chronic heart failure (CHF) were excluded from those trials. The purpose of this study was to assess the effect of β-blockers in post-MI patients with CHF receiving contemporary management.

Methods

This was a prespecified subgroup analysis of a double-blind, randomized trial: the Metoprolol CR/XL Randomized Intervention Trial in Heart Failure (MERIT-HF). Patients with CHF in New York Heart Association class II to IV with an ejection fraction (EF) ≤0.40 and a history of being hospitalized for an acute MI (n = 1926) were randomized to metoprolol succinate controlled release/extended release (CR/XL) versus placebo. Mean EF was 0.28, and the mean follow-up was 1 year.

Results

Metoprolol CR/XL reduced total mortality by 40% (95% CI 0.20-0.55, P = .0004), and sudden death by 50% (95% CI 0.26-0.66, P = .0004). The combined end point of all-cause mortality/hospitalization for worsening CHF was reduced by 31% (95% CI 0.16-0.44, P < .0001), and cardiac death/nonfatal acute MI by 45% (95% CI 0.26-0.58, P < .0001). A post-hoc analysis showed that the outcome in patients with earlier revascularization (44%) and outcome in those with more severe CHF (20%) was similar to the entire post-MI population.

Conclusions

In post-MI patients with symptomatic CHF, β-blockade continues to exert a profound reduction in mortality and morbidity in the presence of contemporary management that includes early and late revascularization, angiotensin-converting enzyme inhibitors, aspirin, and statins.     

Diagnostic utility of the spatial versus individual planar QRS-T angles in cardiac disease detection

Introduction

We compared the diagnostic utility of various planar QRS-T angles to that of the spatial QRS-T angle in detecting various cardiac diseases.

Materials and Methods

Electrocardiographic (ECG) and derived vectorcardiographic (VCG) data were analyzed from 370 patients with imaging-proven cardiac disease (coronary artery disease, hypertrophic cardiomyopathy, or left ventricular systolic dysfunction) and 210 apparently healthy controls. The areas under the curve (AUC) of the Receiver Operating Characteristic (ROC) for distinguishing cardiac health from disease for each disease condition were statistically compared for the spatial mean QRS-T angle versus the ECG-derived frontal and VCG-derived frontal, left sagittal and horizontal planar QRS-T angles.

Results

The AUC ROC of the spatial mean QRS-T angle, which ranged from 0.801 ± 0.035 to 0.987 ± 0.007 depending on the specific comparison, was always significantly greater than that of the ECG frontal planar QRS-T angle (range from 0.680 ± 0.043 to 0.796 ± 0.045) and usually significantly greater than that of all other QRS-T angles for the diseases studied.

Discussion

The spatial mean QRS-T angle is statistically significantly more diagnostically powerful than the ECG-derived frontal planar QRS-T angle and also generally more diagnostically powerful than all VCG-derived planar QRS-T angles in detecting cardiac disease. The ECG frontal planar QRS-T angle should not be considered an adequate diagnostic substitute for the spatial QRS-T angle.     

Prevention of central venous catheter-associated thrombosis: a meta-analysis

Purpose

Anticoagulant prophylaxis in patients with central venous catheters is controversial. We performed a meta-analysis of randomized controlled trials of anticoagulant prophylaxis in patients with central venous catheters.

Methods

MEDLINE and EMBASE were searched up to May 2006, supplemented by manual searches of conference proceedings and bibliographies.

Results

Fifteen trials were included. Unfractionated heparin infusion, oral fixed low-dose vitamin K antagonist, and subcutaneous low-molecular-weight heparin were evaluated. For all catheter-associated deep vein thrombosis (symptomatic and asymptomatic combined), the summary relative risks ranged from 0.31 to 0.73 (all achieved statistical significance). For symptomatic deep vein thrombosis, the summary relative risks ranged from 0.28 to 0.72, but did not achieve statistical significance for any individual regimen.

Conclusion

Anticoagulant prophylaxis is effective for preventing all catheter-associated deep vein thrombosis in patients with central venous catheters. The effectiveness for preventing symptomatic venous thromboembolism, including pulmonary embolism, remains uncertain.     

Resuscitation in the hospital: circadian variation of cardiopulmonary arrest

Purpose

Over 25 reports have found outpatient frequency of sudden cardiac death peaks between 6 am and noon; few studies, with inconsistent results, have examined circadian variation of death in hospitalized patients. This study assesses circadian variation in cardiopulmonary arrest of in-hospital patients across patient, hospital, and event variables and its effect on survival to discharge.

Methods

A retrospective, single institution registry included all admissions to the Medical Center of Central Georgia in which resuscitation was attempted between January 1987 and December 2000. The registry included 4692 admissions; only the first attempt was reported. Analyses of 1-, 2-, 4-, and 8-hour intervals were performed; 1- and 4-hour intervals are presented.

Results

Significant circadian variation was found at 1 hour (P = .01), but not at 4-hour intervals. Significant circadian variation was found for initial rhythms that were perfusing (P = .03) and asystole (P = .01). A significantly higher percentage of unwitnessed events were found as asystole during the overnight hours (P = .002). Using simple logistic regression, time in 4-hour intervals and rhythm were each significantly related to patient survival until hospital discharge (P = .003 and P <.0001). In multivariate analysis, only rhythm remained significant.

Conclusions

Circadian variation of cardiopulmonary arrest in this hospital has several temporal versions and is related to survival. Late night variation in witnessed events and rhythm suggests a delay between onset of clinical death and discovery, which contributes to poorer outcomes.     

Circadian variation of arrhythmia onset patterns in patients with persistent atrial fibrillation

Background

The circadian onset patterns and cycle lengths of atrial tachyarrhythmias (AT) were determined in a group of patients with persistent atrial fibrillation.

Methods

Fifteen patients, mean age 63 ± 14 years and 80% male, were implanted with the Jewel AF atrial defibrillator (Medtronic, Minneapolis, Minn) for persistent atrial fibrillation only. Onset times of AT and median onset atrial cycle lengths were determined from device memory.

Results

Over a follow-up period of 23.3 ± 7 months, 227 episodes of persistent AT were treated by patient-activated atrial defibrillation. The peak onset of persistent AT was nocturnal, with 74% of episodes initiating between 8 pm and 8 am. Eighty-seven percent of the patients experienced an additional 403 paroxysmal AT episodes. These episodes showed a “double-peaked” pattern with the least number of episodes occurring between midnight and 8 am. The mean onset atrial cycle length of persistent AT was significantly shorter than the paroxysmal AT episodes (200 ± 37 ms vs 240 ± 39 ms, P < .005). The atrial cycle lengths at arrhythmia onset of both paroxysmal and persistent AT episodes also demonstrated circadian variation.

Conclusion

There is a circadian distribution of onsets for persistent AT with predominance at night. Patients with persistent AF have >1 type of atrial arrhythmia with differences in the onset patterns and atrial cycle lengths, suggesting different triggers and onset mechanisms.     

Normal limits of the spatial QRS-T angle and ventricular gradient in 12-lead electrocardiograms of young adults: dependence on sex and heart rate

Background and purpose

Normal limits of the spatial QRS-T angle and spatial ventricular gradient (SVG) are only available from Frank vectorcardiograms (VCGs) of male subjects. We determined normal limits for these variables derived from standard 12-lead electrocardiograms (ECGs) of 660 male and female students aged 18 to 29 years.

Methods

A computer algorithm was used that constructed approximated VCG leads by inverse Dower matrix transformation of the 12-lead ECG and subsequently calculated the spatial QRS-T angle, SVG magnitude, and orientation.

Results

In female subjects, the QRS-T angle was more acute (females, 66° ± 23°; normal, 20°-116°; males, 80° ± 24°; normal, 30°-130°; P < .001), and the SVG magnitude was smaller (females, 81 ± 23 mV·ms; normal, 39-143 mV·ms; males, 110 ± 29 mV·ms; normal, 59-187 mV·ms; P < .001) than in male subjects. The male SVG magnitude in our study was larger than that computed in Frank VCGs (79 ± 28 mV·ms; P < .001).

Conclusions

The spatial QRS-T angle and SVG depend strongly on sex. Furthermore, normal limits of SVG derived from Frank VCGs differ markedly from those derived from VCGs synthesized from the standard ECG. As nowadays, VCGs are usually synthesized from the 12-lead ECG; normal limits derived from the standard ECG should preferably be used.     

Aspirin resistance and adverse clinical events in patients with coronary artery disease

Purpose

We sought to determine the clinical significance of aspirin resistance measured by a point-of-care assay in stable patients with coronary artery disease (CAD).

Methods

We used the VerifyNow Aspirin (Accumetrics Inc, San Diego, Calif) to determine aspirin responsiveness of 468 stable CAD patients on aspirin 80 to 325 mg daily for ≥4 weeks. Aspirin resistance was defined as an Aspirin Reaction Unit ≥550. The primary outcome was the composite of cardiovascular death, myocardial infarction (MI), unstable angina requiring hospitalization, stroke, and transient ischemic attack.

Results

Aspirin resistance was noted in 128 (27.4%) patients. After a mean follow-up of 379 ± 200 days, patients with aspirin resistance were at increased risk of the composite outcome compared to patients who were aspirin-sensitive (15.6% vs 5.3%, hazard ratio [HR] 3.12, 95% confidence intervals [CI], 1.65-5.91, P < .001). Cox proportional hazard regression modeling identified aspirin resistance, diabetes, prior MI, and a low hemoglobin to be independently associated with major adverse long-term outcomes (HR for aspirin resistance 2.46, 95% CI, 1.27-4.76, P = .007).

Conclusions

Aspirin resistance, defined by an aggregation-based rapid platelet function assay, is associated with an increased risk of adverse clinical outcomes in stable patients with CAD.     

Regional variation in the treatment and outcomes of myocardial infarction: investigating New England's advantage

Background

Previous studies have reported that myocardial infarction (MI) treatment in New England differs from that of other regions of the United States. We sought to determine whether regional differences in MI treatment were independent of regional differences in patient, hospital, or physician characteristics, and whether the New England region’s practice pattern was associated with better outcomes than those of patients in other regions.

Methods

We evaluated 167,180 patients aged ≥65 years who were hospitalized with MI between 1994 to 1996 to assess regional variations in quality of care. Patients were evaluated for the use of reperfusion therapy, aspirin, and β-blockers on admission and 30-day mortality rate. Hierarchical logistic regression models were used to determine whether practice patterns specific to New England were independent of regional variations in patient, physician, hospital, or other geographic characteristics.

Results

New England had the highest use of β-blockers (72% vs 52% other regions, P < .001), and aspirin (80% vs 76% other regions, P < .001), a lower use of reperfusion therapy (61% vs 67% other regions, P < .001), and the lowest risk-standardized 30-day mortality rate (15% vs 19% other regions, P < .001). These differences persisted after adjusting for patient, physician, and hospital characteristics.

Conclusions

Patients with MI in New England have higher rates of medical therapy use and lower 30-day mortality rates than patients in other US regions. This pattern is independent of patient or provider characteristics, suggesting other factors likely contribute to better short-term outcomes in New England.     

Alcohol consumption as a trigger of recurrent gout attacks

Background

Alcohol consumption has long been considered a trigger for recurrent gout attacks; however, this hypothesis has not been formally tested.

Methods

We conducted an Internet-based case-crossover study to assess several putative risk factors, including alcohol consumption, thought to trigger recurrent gout attacks. Subjects who had an attack within the past year were recruited online and asked to provide access to medical records pertaining to their gout. Data were obtained on the amount and type of alcoholic beverage consumed on each day over the 2-day period before a gout attack and on each day over a 2-day period during the intercritical period. We examined the amount and type of alcohol consumption and the risk of recurrent gout attacks using a conditional logistic regression adjusting for diuretic use and purine intake.

Results

A total of 197 subjects were recruited online over a 10-month period. Of those, 179 (91%) fulfilled the American College of Rheumatology Criteria for gout. Compared with no alcohol consumption, odds ratios for recurrent gout attacks were 1.1, 0.9, 2.0, and 2.5 for 1 to 2, 3 to 4, 5 to 6, and 7 or more drinks consumed over the 2-day period, respectively (P<.005). A dose-response relationship of risk of gout attacks was more evident for alcohol consumed over the last 24 hours. An increased risk of recurrent gout attacks was found for each type of beverage consumed.

Conclusion

Alcohol consumption triggers recurrent gout attacks. This effect was likely to occur within 24 hours after its consumption.     

Importance of standardized assessment of late gadolinium enhancement for quantification of infarct size by cardiac magnetic resonance: implications for comparison with electrocardiogram

Background

Cardiac magnetic resonance (CMR) is currently considered the reference standard for in vivo assessment of myocardial infarction (MI). There is, however, no international consensus on how MI quantification from CMR should be performed. The aim of this study was to test how previously published manual quantification of MI using CMR images compares with MI quantification using a semiautomated, validated method and how this impacts the relationship with MI size estimated by 12-lead electrocardiogram (ECG).

Methods

Twenty-five patients, from a previously published cohort, were included in the study. All patients had presented with clinical signs of acute coronary syndrome 6 to 12 months before undergoing a CMR examination. The patients had a standard 12-lead ECG recorded at the time of the CMR examination. The previously reported manually quantified MI size was compared with MI size determined using a semiautomated method validated by computer phantom data, experimental in vivo and ex vivo data, and patient data. The MI sizes from the 2 CMR approaches were then compared with the ECG-estimated MI size.

Results

There was a strong correlation between MI size determined with the 2 CMR methods (r² = 0.94, P < .001). There was, however, a systematic overestimation of MI size of approximately 50% by the previously published manually quantified MI size compared with the semiautomated method. This affected the comparison with estimated MI size by ECG, which showed a significant underestimation of MI size compared with manual CMR measurements, but no bias compared with the semiautomated CMR method.

Conclusions

Manual quantification of MI size by CMR can differ significantly from semiautomated, validated methods taking partial volume effects into account and can lead to erroneous conclusions when compared with ECG.     

Regional differential expression of TREK-1 at left ventricle in myocardial infarction

Background

Altered membrane electrophysiology contributes to arrhythmias after myocardial infarction (MI). TREK-1 channel is essential in various physiological and pathological conditions through its regulation on resting membrane potential and voltage-dependent action potential duration.

Objectives

The aim of this study was to investigate changes in gene expression and electrophysiology of TREK-1 in the left ventricle in a MI model.

Methods

Fifty-five rats were divided into 5 groups: sham-operated group, 6 hours, 24 hours, 3 days, and 7 days post MI group (n = 11 per group). TREK-1 messenger RNA (mRNA) expression level in the infarct region (IR) and infarct border region (IBR) were quantified by real-time polymerase chain reaction (PCR), and TREK-1 current density at the IBR was recorded with whole-cell patch-clamp technique.

Results

TREK-1 mRNA expression decreased significantly in both endocardial and epicardial cells in the infarct region after MI. Conversely, TREK-1 increased significantly in endocardial and epicardial cells from the IBR (P < 0.01). Current density of TREK-1 at IBR increased significantly in both epicardial and endocardial cells after MI (P < 0.01).

Conclusions

TREK-1 demonstrates specific changes in expression and electrophysiological function in left ventricle post MI. These results suggest that TREK-1 may participate in pathophysiologic alteration and electrical remodelling of left ventricular myocardium after MI, which may eventually lead to post-MI ventricular arrhythmias.     

The evaluation of an electrocardiographic myocardial ischemia acuteness score to predict the amount of myocardial salvage achieved by early percutaneous coronary intervention : Clinical validation with myocardial perfusion single photon emission computed tomography and cardiac magnetic resonance

Background

The time from symptom onset to reperfusion in acute myocardial infarction (MI) has been shown to be a poor predictor of patient outcome. Acute electrocardiographic (ECG) changes, however, have been shown useful for estimated acuteness of myocardial ischemia using the Anderson-Wilkins ECG ischemia acuteness score (AW-acuteness score). The aim was to study whether acute ischemic ECG changes can predict the amount of salvageable myocardium in patients with acute ST-elevation MI.

Methods

Thirty-eight patients treated with primary percutaneous coronary intervention for first-time ST-elevation MI were retrospectively enrolled. Myocardium at risk (MaR) was determined by myocardial perfusion single photon emission computed tomography acutely or by T2-weighted cardiac magnetic resonance after 1 week, at the same time when final MI size was determined by late gadolinium enhancement. Myocardial salvage was calculated as (MaR − MI size)/MaR and compared with AW-acuteness score and time from symptom onset to primary percutaneous coronary intervention.

Results

The AW-acuteness score correlated significantly with salvageable myocardium for right coronary artery (RCA) occlusions (r = −0.57; P = .02) but not for left anterior descending artery (LAD) occlusions (r = −0.04; P = .88). Time from symptom onset did not correlate with the amount of salvageable myocardium (LAD, r = 0.04 and P = .87; RCA, r = −0.40 and P = .13).

Conclusions

There is a moderate correlation between AW-acuteness score and salvageable myocardium in patients with acute RCA occlusion but not in patients with LAD occlusion.     

Effect of direct stenting on clinical outcome in patients treated with percutaneous coronary intervention on saphenous vein graft

Background

Percutaneous coronary intervention (PCI) of saphenous vein graft (SVG) is associated with frequent postprocedural enzyme elevation and late cardiac events. New strategies are proposed to minimize distal embolization and to improve the outcome of patients treated with stenting for SVG lesions. The objectives of the current study were to examine direct stenting (DS) strategy of PCI in SVG lesions and its effects on creatine-kinase (CK) release, major adverse cardiac events (MACE), and late outcome when compared to conventional stenting (CS).

Methods

A consecutive series of 527 patients treated with stent implantation for SVG stenosis was analyzed. In this cohort, 170 patients with 229 lesions were treated with DS and 357 patients with 443 lesions were treated with CS. The inhospital and 12-month follow-up events were recorded and reported.

Results

Baseline clinical and postprocedural angiographic characteristics were similar between the 2 groups except for higher preprocedural prevalence of thrombus-containing lesions in the DS group. Patients in the DS group had less CK-MB release (P < .001), and less non-Q-wave myocardial infarction (P = .024). Multivariate analysis detected unstable angina (odds ratio [OR] = 1.8, P = .03) as a correlate for non-Q-wave MI; DS was inversely associated with non-Q-wave myocardial infarction (OR = 0.65, P = .04). At 1 year, the target lesion revascularization-MACE was significantly lower in the DS group (P = .021). Multivariate analysis showed that DS (OR = 0.47, P = .007) was associated with reduction of the target lesion revascularization-MACE.

Conclusions

When feasible, DS may be the best approach for treating SVG stenosis.     

Early sustained ventricular arrhythmias complicating acute myocardial infarction

Objective

Sustained ventricular arrhythmias complicate 2% to 20% of acute myocardial infarctions (MIs) and are associated with increased in-hospital mortality. However, it remains unclear whether successful mechanical revascularization improves outcomes in these patients. The objective of this analysis was to identify predictors of sustained ventricular arrhythmias after acute MI and to determine the influence of successful revascularization on in-hospital mortality.

Methods

We conducted a retrospective cohort study of all patients who underwent percutaneous coronary intervention for acute MI in New York State between 1997 and 1999.

Results

Of the 9015 patients who underwent percutaneous coronary intervention for acute MI, 472 (5.2%) developed sustained ventricular tachycardia (VT) or ventricular fibrillation (VF) before revascularization. After multivariable adjustment, independent predictors of sustained VT/VF included cardiogenic shock (odds ratio [OR], 4.10; 95% confidence interval [CI], 3.20-5.58; P <.001), heart failure (OR, 2.86; 95% CI, 2.24-3.67: P <.001), chronic kidney disease (OR, 2.58; 95% CI, 1.27-5.23; P = .009), and presentation within 6 hours of symptom onset (OR, 1.46; 95% CI, 1.18-1.81; P = .001). Patients with sustained VT/VF had greater in-hospital mortality (16.3% vs 3.7%, P <.001). Although successful percutaneous coronary intervention was associated with decreased in-hospital mortality in patients with VT/VF (P <.001), patients with sustained VT/VF and successful revascularization experienced increased mortality compared with patients without sustained ventricular arrhythmias (P <.001).

Conclusion

Among patients undergoing percutaneous coronary intervention for acute MI, sustained VT/VF remains a significant complication associated with a 4-fold increased risk of in-hospital mortality. Early mortality is reduced after successful percutaneous coronary intervention, but remains elevated in this high-risk group.     

Does 24-hour ST-segment resolution postfibrinolysis add prognostic value to a Q wave? An ASSENT 2 electrocardiographic substudy

Background

Both ST resolution and Q-wave development postfibrinolysis provide important prognostic insights in patients with acute myocardial infarction (MI). However, the relative contributions of these 2 factors to risk assessment have not been examined prospectively.

Methods and results

ST resolution and Q development were evaluated 24 to 36 hours (24-36h) postfibrinolysis in ASSENT-2: 13,100 out of 16,949 patients who had both baseline and 24-36h electrocardiograms free of confounders (left bundle branch block, ventricular rhythm, reinfarction before 24-36h electrocardiograms) were included in this analysis. Q-wave MI evolved in 10,466 patients (79.9%) and 2634 patients (20.1%) had non-Q-wave MI at 24-36h postfibrinolysis. Mortality rates at 1-year were 7.0% for patients with Q-wave MI and 5.8% for non-Q-wave MI patients, respectively (P = .046). Patients with Q-wave MI versus those without were less likely to have complete ST-segment resolution (49.1% vs 59.1%) and more likely to have partial (37.1% vs 27.8%) or no resolution (13.8% vs 13.1%) at 24 to 36 hours postfibrinolysis (P < .001). Mortality rates at 1 year for Q-wave MI with complete, partial, and no resolution were 5.2%, 8.1%, and 10.1%, respectively (P < .001), and for non-Q-wave MI with complete, partial, and no resolution were 4.5%, 7.6%, and 8.0% (P = .003).

Conclusion

These results demonstrate the additional prognostic significance of ST-segment resolution to Q-wave development at 24 to 36 hours after fibrinolysis.     

Usefulness of body surface potential mapping for early identification of the intraventricular conduction disorders in young patients with chronic kidney disease

Background

Cardiovascular complications are considered a significant problem in patients with chronic kidney disease (CKD). Body surface potential mapping (BSPM) is a noninvasive method that is useful in detecting early changes involving the heart. The aim of the study was to evaluate possible abnormalities within the cardiac intraventricular conduction system in young patients with CKD using the BSPM method.

Methods

Based on the BSPM registrations, the QRS-T isointegral maps were created in 42 young patients with CKD (on hemodialysis, subgroup Ia; on peritoneal dialysis, subgroup Ib; on conservative treatment, group II) and in 26 healthy subjects. Serum levels of electrolytes, urea, and creatinine were also assessed in the entire study population.

Results

In the healthy subjects, the maximums of the group mean QRS-T isointegral map were located in the left lower anterior part of the thorax, whereas in the Ia patients, the maximums were focused at the medial sternum line. The QRS-T maps, both for Ib and II groups, showed the positive integrals covering the left part of the anterior thorax. In all the patients with CKD, standard 12-lead electrocardiogram (ECG) and echocardiography findings were within the reference range.

Conclusions

In the hemodialyzed patients with CKD, the group-mean QRS-T isointegral map distribution suggested a significant delay of excitation propagation in the left bundle branch, although no abnormalities were found with standard ECG. In the patients with CKD treated with peritoneal dialysis or conservatively, the group-mean QRS-T isointegral maps were characteristic for the early phase of conduction disturbances within the left bundle branch, which again was not observed on the standard ECG recordings.