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

Efficacy and Safety of a Pharmaco-Invasive Strategy Using Half-Dose Recombinant Human Prourokinase in Patients with ST-Segment Elevation Myocardial Infarction During Hospitalization

This study investigated the efficacy and safety of pharmaco-invasive strategy with half-dose recombinant human prourokinase (PHDP) during hospitalization for patients with ST-segment elevation myocardial infarction (STEMI) to provide references for the treatment of STEMI. Patients with STEMI who fulfilled the inclusion and exclusion criteria and attended Chengde Central Hospital, Hebei Province, China, between September 3, 2019, and December 28, 2021, were included in this study. The experimental group received PHDP and the control group underwent primary percutaneous coronary intervention (PPCI). This study enrolled 150 patients with STEMI, 75 in the experimental group and 75 in the control group. Coronary angiography revealed successful thrombolysis in 64 (85.33%) patients. Compared with the control group, the experimental group had shorter first medical contact-reperfusion time (P < 0.001), less slow flow/no-reflow (P < 0.001), and a lower utilization rate of Tirofiban (P < 0.001). Validity endpoints: no statistically significant differences between the two groups. Safety endpoints: no statistically significant differences between bleeding and major adverse cardiovascular and cerebrovascular events (MACCEs), but the experimental group was more prone to arrhythmias (P = 0.040), particularly premature ventricular beats (PVB) (P = 0.008). In conclusion, the efficacy and safety of PHDP in the treatment of patients with STEMI were positive. Complete epicardial and myocardial reperfusion rates, risk for bleeding during hospitalization, and incidence of MACCEs were similar to those of the PPCI strategy. Although the PHDP group has a higher incidence of PVB, it does not increase the incidence of malignant arrhythmia. This study aimed to provide a new therapeutic strategy for the treatment of STEMI in hospitals without adequate PPCI resources condition.

Influence of standard modifiable risk factors on ventricular tachycardia after myocardial infarction

Background

Inducible ventricular tachycardia (VT) at electrophysiology study (EPS) predicts sudden cardiac death because of ventricular tachyarrhythmia, the single greatest cause of death within 2 years after myocardial infarction (MI).

Objectives

We aimed to assess the association between standard modifiable risk factors (SMuRFs) and inducible VT at EPS early after MI.

Methods

Consecutive patients with left ventricle ejection fraction ≤40% on days 3-5 after ST elevation MI (STEMI) who underwent EPS were prospectively recruited. Positive EPS was defined as induced sustained monomorphic VT cycle length ≥200 ms for ≥10 s or shorter if hemodynamically compromised. The primary outcome was inducibility of VT at EPS, and the secondary outcome was all-cause mortality on follow-up.

Results

In 410 eligible patients undergoing EPS soon (median of 9 days) after STEMI, 126 had inducible VT. Ex-smokers experienced an increased risk of inducible VT [multivariable logistic regression adjusted odds ratio (OR) 2.0, p = 0.033] compared with current or never-smokers, with comparable risk. The presence of any SMuRFs apart from being a current smoker conferred an increased risk of inducible VT (adjusted OR 1.9, p = 0.043). Neither the number of SMuRFs nor the presence of any SMuRFs was associated with mortality at a median follow-up of 5.4 years.

Conclusions

In patients with recent STEMI and impaired left ventricular function, the presence of any SMuRFs, apart from being a current smoker, conferred an increased risk of inducible VT at EPS. These results highlight the need to modify SMuRFs in this high-risk subset of patients.

In-hospital predictors for primary prevention of sudden death after acute myocardial infarction with cardiac dysfunction

BACKGROUND

Current guidelines recommend prophylactic defibrillator implantation in patients with acute myocardial infarction (AMI) and left ventricular ejection fraction (LVEF) ≤40 % or LVEF ≤35 % plus heart failure symptoms or inducible ventricular tachyarrhythmias during an electrophysiology study at 40 days after AMI or 90 days after revascularization. In-hospital predictors of sudden cardiac death (SCD) after AMI during the index hospitalization remain unsettled. We sought to examine in-hospital predictors of SCD in patients with AMI and LVEF ≤40 % evaluated during the index hospitalization.

METHODS

We retrospectively evaluated 441 consecutive patients with AMI and LVEF ≤40 % admitted to our hospital between 2001 and 2014 (77 % male gender; median age: 70 years; median hospitalization length: 23 days). The primary endpoint was a composite of SCD or aborted SCD at ≥30 days after AMI onset (composite arrhythmic event). LVEF and QRS duration (QRSd) on electrocardiography were measured at a median of 12 days and 18 days, respectively.

RESULTS

During a median follow-up of 7.6 years, the incidence of composite arrhythmic events was 7.3 % (32 of 441 patients). In multivariable analysis, QRSd ≥100 msec (beta-coefficient = 1.54, p = 0.003), LVEF ≤23 % (beta-coefficient = 1.14, p = 0.007), and onset-reperfusion time > 5.5 h (beta-coefficient = 1.16, p = 0.035) were independent predictors of composite arrhythmic events. The combination of these 3 factors was associated with the highest rate of composite arrhythmic events compared with 0-2 factors (p < 0.001).

CONCLUSIONS

The combination of QRSd ≥100 msec, LVEF ≤23 %, and onset-reperfusion time > 5.5 h during the index hospitalization provides precise risk stratification for SCD in patients early after AMI.

Correlation of exit sites of inducible ventricular tachycardia post-ST elevation myocardial infarction on electrophysiology study, with region of infarct

BACKGROUND

Ventricular arrhythmia (VA) is the most common cause of sudden cardiac death post-ST elevation myocardial infarction (STEMI). Ventricular tachycardia (VT) may be inducible in electrophysiology studies (EPS) early (<40 days) post-STEMI. Whether it originates from the infarct site remains unknown. We examined the correlation between inducible VT and infarct location post-STEMI.

AIMS

To investigate the correlation between inducible VT and infarct location post-STEMI.

METHODS

We retrospectively analysed 46 patients from 2005 to 2017 with STEMI who underwent early programmed ventricular stimulation through EPS (>48 h post-STEMI and <40 days from admission). Gated heart pool scans were used to visualise infarct scar regions, and VT exit sites were derived from induction 12-lead electrocardiography. Patients were followed up for primary outcomes of recurrent VA and all-cause mortality.

RESULTS

Forty-six patients were included for analysis, with 50 uniquely induced VT exit sites. Mean left ventricular ejection fraction was 30 ± 8.7% and 22% had impaired right ventricular ejection fraction. Mean time from presentation to EPS was 16 ± 31.3 days. Of the induced VT, 44 (88%) were from within scar and scar-border regions, whereas 6 (12%) of the induced VT were found to be remote to imaging-derived scar. Over a median follow-up period of 75 months, 6 (13%) patients died, and 7 (15%) patients had recurrent VA. No deaths occurred in patients with remote VT.

CONCLUSION

The majority of early inducible post-infarct VT arises from acute myocardial scar; however, a small portion arises from sites remote from scars with a possible focal aetiology.

Optimizing electrophysiology studies to prevent sudden cardiac death after myocardial infarction

AIMS

This study assessed associations of minimum final extrastimulus coupling interval utilized within electrophysiology study (EPS) after myocardial infarction (MI) and possible site of origin of induced ventricular tachycardia (VT) with long-term occurrence of spontaneous ventricular tachyarrhythmia and long-term survival.

METHODS AND RESULTS

This prospective study recruited consecutive patients with left ventricular ejection fraction (LVEF) ≤ 40% who underwent EPS days 3-5 after MI between 2004 and 2017. Positive EPS was defined as sustained monomorphic VT cycle length ≥200 ms for ≥10 s or shorter duration if haemodynamic compromise occurred. Each of the four extrastimuli was shortened by 10 ms at a time, until it failed to capture the ventricle (ventricular refractoriness) or induced ventricular tachyarrhythmia. Outcomes included spontaneous ventricular tachyarrhythmia occurrence and all-cause mortality. Shorter coupling interval length of final extrastimulus that induced VT was associated with higher risk of spontaneous ventricular tachyarrhythmia (P < 0.001). Significantly higher rates of spontaneous ventricular tachyarrhythmia (65.2% vs. 23.2%; P < 0.001) were observed for final coupling interval at EPS <200 ms vs. >200 ms. Right bundle branch block (RBBB) morphology of induced VT, with possible site of origin from the left ventricle, was associated with all-cause mortality [hazard ratio (HR) 3.2, P = 0.044] and a composite of spontaneous ventricular tachyarrhythmia recurrence or mortality (HR 1.8, P = 0.043).

CONCLUSION

Ventricular tachycardia induced with shorter coupling intervals was associated with higher risk of spontaneous ventricular tachyarrhythymia on follow-up, indicating that the final extrastimulus coupling interval at EPS early after MI should be determined by ventricular refractoriness. Induced VT with possible origin from left ventricle was associated with increased risk of spontaneous ventricular tachyarrhythmia recurrence or death.

Predictive value of serum HIF-1α and VEGF for arrhythmia in acute coronary syndrome patients

Percutaneous coronary intervention (PCI) has been widely used in the alleviation of myocardial ischemia in patients with acute coronary syndrome (ACS). However, the incidence of reperfusion arrhythmia (RA) after PCI is high, which seriously affects the prognosis of ACS patients. Therefore, this study aimed to study the predictive value of serum HIF-1α and VEGF levels before PCI for RA in ACS patients post PCI. A total of 200 ACS patients who underwent PCI were selected and divided into those with RA after PCI (RA, n = 93) and those without RA after PCI (non-RA, n = 107) according to Lown grade. Spearman correlation analysis was applied for the relationship between serum hypoxia inducible factor-1α (HIF-1α) and vascular endothelial growth factor (VEGF) levels and Lown grade. Patients with RA after PCI tended to have higher levels of creatine kinase muscle and brain isoenzyme (CK-MB), serum HIF-1α and VEGF before surgery. Low left ventricular ejection fraction (LVEF), high CK-MB, high serum VEGF and HIF-1α were risk factors for RA in ACS patients within 24 h after PCI. Receiver operating characteristic (ROC) analysis revealed that serum HIF-1α and VEGF levels could predict RA in ACS patients after PCI, and the combined detection could increase the sensitivity of single HIF-1α detection and the specificity of single VEGF detection. Lown grade was positively correlated with the serum HIF-1α and VEGF concentrations. In conclusion, serum HIF-1α and VEGF levels before PCI are risk factors for the occurrence of RA in ACS patients after PCI, and have certain predictive values for the occurrence of RA in ACS patients after PCI.

In-depth look into urban and rural disparities in prehospital delay in patients with acute ST-elevation myocardial infarction and its impact on prognosis: a prospective observational study

OBJECTIVES

In line with the cardiac fast track, the 'green pathway for patients with heart attack' policy in China is implemented to reduce door-to-balloon time in patients with ST-segment elevation myocardial infarction (STEMI). However, the difference in prehospital delay between urban and rural areas of China and its impact on prognosis is unclear.

DESIGN

Prospective observational study.

SETTING

This study was conducted in a tertiary hospital, the only nationally accredited chest pain centre with percutaneous coronary intervention (PCI) capacity in Pizhou, China.

PARTICIPANTS

394 patients with STEMI without patients with in-hospital STEMI or patients lost to follow-up were included.

PRIMARY OUTCOME MEASURES

Primary outcome was major adverse cardiovascular events (MACEs), including cardiac death, non-fatal myocardial infarction and heart failure.

RESULTS

Among 394 patients enrolled, 261 (66.2%) were men, the median age was 69 years (interquartile range: 61-77 years), and 269 (68.3%) were from rural areas. Symptom-to-door (S2D) time was significantly longer for rural patients than for urban patients (p<0.001). Cox regression analyses revealed living in rural areas was independently associated with prolonged S2D time (adjusted HR 0.59; 95% CI 0.43 to 0.81; p=0.001). HR of <1 indicates that the S2D time is longer for patients in the rural group (group of interest). During 1-year follow-up, the incidence of MACEs was higher in rural patients (p=0.008). The unadjusted OR for MACEs between rural and urban patients was 2.22 (95% CI 1.22 to 4.01). Adjusting for sex did not attenuate the association (OR 2.06; 95% CI 1.13 to 3.76), but after further adjusting for age, cardiac function classification, S2D time and performance of primary PCI, we found that odds were similar for rural and urban patients (OR 1.19; 95% CI 0.59 to 2.38).

CONCLUSIONS

Rural patients with STEMI had a longer S2D time, which led to a higher incidence of MACEs. This study provides rationales for taking all the measures to avoid prehospital delay.

Characteristics, Process Metrics, and Outcomes Among Patients With ST-Elevation Myocardial Infarction in Rural vs Urban Areas in the US: A Report From the US National Cardiovascular Data Registry

Importance

Patients with ST-segment elevation myocardial infarction (STEMI) living in rural settings often have worse clinical outcomes compared with their urban counterparts. Whether this discrepancy is due to clinical characteristics or delays in timely reperfusion with primary percutaneous coronary intervention (PPCI) or fibrinolysis is unclear.

Objective

To assess process metrics and outcomes among patients with STEMI in rural and urban settings across the US.

Design, Setting, and Participants

This cross-sectional multicenter study analyzed data for 70 424 adult patients with STEMI from the National Cardiovascular Data Registry Chest Pain-MI Registry in 686 participating US hospitals between January 1, 2019, and June 30, 2020. Patients without a valid zip code were excluded, and those transferred to a different hospital during the course of the study were excluded from outcome analysis.

Main Outcomes and Measures

In-hospital mortality and time-to-reperfusion metrics.

Results

This study included 70 424 patients with STEMI (median [IQR] age, 63 [54-73] years; 49 850 [70.8%] male and 20 574 [29.2%] female; patient self-reported race: 6753 [9.6%] Black, 60 114 [85.4%] White, and 2096 [3.0%] of another race [including American Indian, Alaskan Native, Native Hawaiian, and Pacific Islander]; 5281 [7.5%] individuals of Hispanic or Latino ethnicity) in 686 hospitals (50 702 [72.0%] living in urban zip codes and 19 722 [28.0%] in rural zip codes). Patients from rural settings were less likely to undergo PPCI compared with patients from urban settings (14 443 [73.2%] vs 43 142 [85.1%], respectively; P < .001) and more often received fibrinolytics (2848 [19.7%] vs 937 [2.7%]; P < .001). Compared with patients from urban settings, those in rural settings undergoing PPCI had longer median (IQR) time from first medical contact to catheterization laboratory activation (30 [12-42] minutes vs 22 [15-59] minutes; P < .001) and longer median (IQR) time from first medical contact to device (99 minutes [75-131] vs 81 [66-103] minutes; P < .001), including those who arrived directly at PPCI centers (83 [66-107] minutes vs 78 [64-97] minutes; P < .001) and those who transferred to PPCI centers from another treatment center (125 [102-163] minutes vs 103 [85-135] minutes; P < .001). Among those who transferred in, median (IQR) door-in-door-out time was longer in patients from rural settings (63 [41-100] minutes vs 50 [35-80] minutes; P < .001). Out-of-hospital cardiac arrest was more common in patients from urban vs rural settings (3099 [6.1%] vs 958 [4.9%]; P < .001), and patients from urban settings were more likely to present with heart failure (4112 [8.1%] vs 1314 [6.7%]; P < .001). After multivariable adjustment, there was no significant difference in in-hospital mortality between rural and urban groups (adjusted odds ratio, 0.97; 95% CI, 0.89-1.06).

Conclusions and Relevance

In this large cohort of patients with STEMI from US hospitals participating in the National Cardiovascular Data Registry Chest Pain-MI Registry, patients living in rural settings had longer times to reperfusion, were less likely to receive PPCI or meet guideline-recommended time to reperfusion, and more frequently received fibrinolytics than patients living in urban settings. However, there was no difference in adjusted in-hospital mortality between patients with STEMI from urban and rural settings.

Factors that predict ventricular arrhythmias in the late phase after acute myocardial infarction

Aims

Little is known regarding factors that predict the occurrence of lethal ventricular arrhythmias (VAs) occurring after acute myocardial infarction (AMI). This observational cohort study aimed to identify factors that predicted lethal VAs during the late phase after AMI in patients with reduced left ventricular ejection fraction (LVEF).

Methods and results

Data were collected from our AMI database regarding consecutive patients with an LVEF of ≤40% after AMI (January 2012 to July 2018). The ‘late phase’ was defined as ≥7 days after AMI onset, and the primary endpoint was defined as lethal VAs in the late phase. The study included 136 patients (82% men; mean age: 66 ± 13 years). The average LVEF at admission was 32.7 ± 8.2%. During a mean follow‐up period of 20.7 months, 14 patients (10%) experienced lethal VAs, including ventricular fibrillation (n = 8) and sustained ventricular tachycardia (n = 10). Univariate analyses revealed that lethal VAs were predicted by age and LVEF at admission. Receiver operating characteristic curve analysis indicated that the optimal cut‐off value was 23% for using the LVEF at admission to predict the primary endpoint (area under the curve: 0.77, P < 0.0001). Multivariable analysis also demonstrated that LVEF at admission was an independent predictor of the primary endpoint (risk ratio = 7.12, P = 0.001).

Conclusions

Lethal VAs in the late phase are common in patients with AMI, and reduced LVEF and cardiac function at admission play a significant role in the risk stratification for future lethal VAs in this population.

Cardiac arrhythmias in the emergency settings of acute coronary syndrome and revascularization: an European Heart Rhythm Association (EHRA) consensus document, endorsed by the European Association of Percutaneous Cardiovascular Interventions (EAPCI), and European Acute Cardiovascular Care Association (ACCA)

Despite major therapeutic advances over the last decades, complex supraventricular and ventricular arrhythmias (VAs), particularly in the emergency setting or during revascularization for acute myocardial infarction (AMI), remain an important clinical problem. Although the incidence of VAs has declined in the hospital phase of acute coronary syndromes (ACS), mainly due to prompt revascularization and optimal medical therapy, still up to 6% patients with ACS develop ventricular tachycardia and/or ventricular fibrillation within the first hours of ACS symptoms. Despite sustained VAs being perceived predictors of worse in-hospital outcomes, specific associations between the type of VAs, arrhythmia timing, applied treatment strategies and long-term prognosis in AMI are vague. Atrial fibrillation (AF) is the most common supraventricular tachyarrhythmia that may be asymptomatic and/or may be associated with rapid haemodynamic deterioration requiring immediate treatment. It is estimated that over 20% AMI patients may have a history of AF, whereas the new-onset arrhythmia may occur in 5% patients with ST elevation myocardial infarction. Importantly, patients who were treated with primary percutaneous coronary intervention for AMI and developed AF have higher rates of adverse events and mortality compared with subjects free of arrhythmia. The scope of this position document is to cover the clinical implications and pharmacological/non-pharmacological management of arrhythmias in emergency presentations and during revascularization. Current evidence for clinical relevance of specific types of VAs complicating AMI in relation to arrhythmia timing has been discussed.

Duration of Inducible Ventricular Tachycardia Early After ST-Segment-Elevation Myocardial Infarction and Its Impact on Mortality and Ventricular Tachycardia Recurrence

Background

The clinical significance of the duration of inducible ventricular tachycardia (VT) at electrophysiology study (EPS) in patients soon after ST‐segment–elevation myocardial infarction and its predictive utility for VT recurrence are not known.

Methods and Results

Consecutive ST‐segment–elevation myocardial infarction patients with day 3 to 5 left ventricular ejection fraction ≤40% underwent EPS. A positive EPS was defined as sustained monomorphic VT with cycle length ≥200 ms. The induced VT was terminated by overdrive pacing or direct current shock at 30 s or earlier if hemodynamic decompensation occurred. Patients with inducible VT duration 2 to 10 s were compared with patients with inducible VT >10 s. The primary end point was survival free of VT or cardiac mortality. From 384 consecutive ST‐segment–elevation myocardial infarction patients who underwent EPS, 29% had inducible VT (n=112, 87% men). After mean follow‐up of 5.9±3.9 years, primary end point occurred in 35% of patients with induced VT 2 to 10 s duration (n=68) and in 22% of patients with induced VT >10 s (n=41) (P=0.61). This was significantly different from the noninducible VT group, in which primary end point occurred in 3% of patients (n=272) (P=0.001).

Conclusions

This study is the first to show that in patients who undergo EPS early after myocardial infarction, inducible VT of short duration (2–10 s) has similar predictive utility for ventricular tachyarrhythmia as longer duration (>10 s) inducible VT, which was significantly different to those without inducible VT. It is possible that immediate cardioversion of rapid VT might have contributed to some of the short durations of inducible VT.

Focal Ventricular Tachycardias in Structural Heart Disease: Prevalence, Characteristics, and Clinical Outcomes After Catheter Ablation

OBJECTIVES

This study sought to summarize the procedural characteristics and outcomes of patients with structural heart disease (SHD) who have focal ventricular tachycardia (VT).

BACKGROUND

Scar-mediated re-entry is the predominant mechanism of VT in SHD. Some SHD patients may have a focal VT mechanism that remains poorly described.

METHODS

An extended induction protocol incorporating programmed electrical stimulation, right ventricular burst pacing and isoprenaline was used to elucidate both re-entrant and focal VT mechanisms.

RESULTS

Eighteen of 112 patients (16%) with SHD undergoing VT ablation over 2 years had a focal VT mechanism elucidated (mean age 66±13 years; ejection fraction 46±14%; nonischemic cardiomyopathy 10). Repetitive failure of termination with antitachycardia pacing (ATP) (69% of patients) or defibrillator shocks (56%) was a common feature of focal VTs. A median of 3 VTs per patient were inducible (28 focal VTs, 34 re-entrant VTs; 53% of patients had both focal and re-entrant VT mechanism). Focal VTs more commonly originated from the right ventricle (RV) than the left ventricle (LV) (67% vs. 33%, respectively). In the RV, the RV outflow tract was the most common site (33% of all focal VTs), followed by the RV moderator band (22%), apical septal RV (6%), and lateral tricuspid annulus (6%). The lateral LV (non-Purkinje) was the most common LV focal VT site (16%), followed by the papillary muscles (17%). After median follow-up of 289 days, 78% of patients remained arrhythmia-free; no patients had recurrence of focal VT at repeat procedure. In patients with recurrence, defibrillator therapies were significantly reduced from a median of 53 ATP episodes pre-ablation to 10 ATP episodes post-ablation. During follow-up, 2 patients (11%) underwent repeat VT ablation; none had recurrence of focal VT.

CONCLUSIONS

Focal VTs are common in patients with SHD and often coexist with re-entrant forms of VT. High failure rate of defibrillator therapies was a common feature of focal VT mechanisms. Uncovering and abolishing focal VT may further improve outcomes of catheter ablation in SHD.

Risk assessment model for predicting ventricular tachycardia or ventricular fibrillation in ST-segment elevation myocardial infarction patients who received primary percutaneous coronary intervention

Ventricular tachycardia/ventricular fibrillation (VT/VF) is a kind of malignant arrhythmia in ST-segment elevation myocardial infarction (STEMI) patients who received primary percutaneous coronary intervention (PPCI). However, there are no risk assessment tools to anticipate the occurrence of VT/VF.This study is to build a risk assessment model to predict the possibility of VT/VF onset in STEMI patients undergoing PPCI.A retrospective study was conducted to analyze the patients who underwent PPCI from January 2006 to May 2015. Subjects were divided into VT/VF group and no VT/VF group based on whether VT/VF had occurred or not. In addition, the VT/VF group was further separated into early-onset group (from the time that symptoms began to before the end of PPCI) and late-onset group (after the end of PPCI) based on the timing of when VT/VF happened. Multivariate regression analysis was carried out to distinguish the independent risk factors of VT/VF and an additional statistical method was executed to build the risk assessment model.A total of 607 patients were enrolled in this study. Of these patients, 67 cases (11%) experienced VT/VF. In addition, 91% (61) of patients experienced VT/VF within 48 h from the time that the symptoms emerged. Independent risk factors include: age, diabetes mellitus, heart rate, ST-segment maximum elevation, ST-segment total elevation, serum potassium, left ventricular ejection fraction (LVEF), culprit artery was right coronary artery, left main (LM) stenosis, Killip class > I class, and pre-procedure thrombolysis in myocardial infarction (TIMI) flow zero grade. Risk score model and risk rank model have been established to evaluate the possibility of VT/VF. Class I: ≤ 4 points; Class II: > 4 points, ≤ 5.5 points; Class III: > 5.5 points, < 6.5 points; and Class IV ≥ 6.5 points. The higher the class, the higher the risk.The incidence of VT/VF in STEMI patients undergoing PPCI is 11% and it occurs more frequently from the time that symptoms begin to before the end of PPCI, which, in most cases, occurs within 48 h of the event. Our risk assessment model could predict the possible occurrence of VT/VF.

The clinical challenge of preventing sudden cardiac death immediately after acute ST-elevation myocardial infarction

Unfortunately, of all patients experiencing acute myocardial infarction (MI), usually in the form of ST-elevation MI, 25-35% will die of sudden cardiac death (SCD) before receiving medical attention, most often from ventricular fibrillation. For patients who reach the hospital, prognosis is considerably better and has improved over the years. Reperfusion therapy, best attained with primary percutaneous coronary intervention compared to thrombolysis, has made a big difference in reducing the risk of SCD early and late after ST-elevation MI. In-hospital SCD due to ventricular tachyarrhythmias is manageable, with either preventive measures or drugs or electrical cardioversion. There is general agreement for secondary prevention of SCD post-MI with implantation of a cardioverter defibrillator (ICD) when malignant ventricular arrhythmias occur late (>48 h) after an MI, and are not due to reversible or correctable causes. The major challenge remains that of primary prevention, that is, how to prevent SCD during the first 1-3 months after ST-elevation MI for patients who have low left ventricular ejection fraction and are not candidates for an ICD according to current guidelines, due to the results of two studies, which did not show any benefits of early (<40 days after an MI) ICD implantation. Two recent documents may provide direction as to how to bridge the gap for this early post-MI period. Both recommend an electrophysiology study to guide implantation of an ICD, at least for those developing syncope or non-sustained ventricular tachycardia, who have an inducible sustained ventricular tachycardia at the electrophysiology study. An ICD is also recommended for patients with indication for a permanent pacemaker due to bradyarrhythmias, who also meet primary prevention criteria for SCD.

Ventricular arrhythmias and sudden cardiac death

Management strategies for ventricular arrhythmias are guided by the risk of sudden death and severity of symptoms. Patients with a substantial risk of sudden death usually need an implantable cardioverter defibrillator (ICD). Although ICDs effectively end most episodes of ventricular tachycardia or ventricular fibrillation and decrease mortality in specific populations of patients, they have inherent risks and limitations. Generally, antiarrhythmic drugs do not provide sufficient protection from sudden death, but do have a role in reducing arrhythmias that cause symptoms. Catheter ablation is likewise important for reducing the frequency of spontaneous arrhythmias and is curative for some patients, usually those with idiopathic arrhythmias and no heart disease. Arrhythmia surgery is now infrequent, offered by only a few specialised centres for refractory arrhythmias. Advances in understanding of genetic arrhythmia syndromes and in technology for mapping and ablation of ventricular arrhythmias, and enhanced algorithms in implantable devices for rhythm management, have contributed to improved outcomes.

Endo-epicardial homogenization of the scar versus limited substrate ablation for the treatment of electrical storms in patients with ischemic cardiomyopathy

OBJECTIVES

This study investigated the impact on recurrences of 2 different substrate approaches for the treatment of these arrhythmias.

BACKGROUND

Catheter ablation of electrical storms (ES) for ventricular arrhythmias (VAs) has shown moderate long-term efficacy in patients with ischemic cardiomyopathy.

METHODS

Ninety-two consecutive patients (81% male, age 62 ± 13 years) with ischemic cardiomyopathy and ES underwent catheter ablation. Patients were treated either by confining the radiofrequency lesions to the endocardial surface with limited substrate ablation (Group 1, n = 49) or underwent endocardial and epicardial ablation of abnormal potentials within the scar (homogenization of the scar, Group 2, n = 43). Epicardial access was obtained in all Group 2 patients, whereas epicardial ablation was performed in 33% (14) of these patients.

RESULTS

Mean ejection fraction was 27 ± 5. During a mean follow-up of 25 ± 10 months, the VAs recurrence rate of any ventricular tachycardia (VTs) was 47% (23 of 49 patients) in Group 1 and 19% (8 of 43 patients) in Group 2 (log-rank p = 0.006). One patient in Group 1 and 1 patient in Group 2 died at follow-up for noncardiac reasons.

CONCLUSIONS

Our study demonstrates that ablation using endo-epicardial homogenization of the scar significantly increases freedom from VAs in ischemic cardiomyopathy patients.