Rapid hemodynamic improvement after reperfusion during right ventricular infarction

Short- and Long-Term Outcomes in Patients With Right Ventricular Infarction According to Modalities of Reperfusion Strategies in China: Data From China Acute Myocardial Infarction Registry

Purpose

We sought to investigate the short- and long-term outcomes in patients with right ventricular infarction in China.

Methods

Data from China Acute Myocardial Infarction (CAMI) Registry for patients with right ventricular infarction between January 2013 and September 2014 were analyzed.

Results

Of the 1,988 patients with right ventricular infarction, 733 patients did not receive reperfusion therapy, 281 patients received thrombolysis therapy, and 974 patients underwent primary PCI. Primary PCI and thrombolysis were all associated with lower risks of in-hospital (3.1 vs. 12.6%; adjusted OR: 0.48; 95% CI: 0.27–0.87; P = 0.0151 and 5.7 vs. 12.6%; adjusted OR: 0.43; 95% CI: 0.22–0.85; P = 0.0155, respectively), and 2-year all-cause mortality (6.3 vs. 20.9%; adjusted HR: 0.50; 95% CI: 0.34–0.73; P = 0.0003 and 11.0 vs. 20.9%; adjusted HR: 0.59; 95% CI: 0.38–0.92; P = 0.0189, respectively), compared with no reperfusion therapy. Meanwhile, primary PCI was superior to thrombolysis in reducing the risks of in-hospital atrial-ventricular block (4.2 vs. 8.9%; adjusted OR: 0.46; 95% CI: 0.23–0.91; P = 0.0257), cardiogenic shock (5.3 vs. 13.9%; adjusted OR: 0.43; 95% CI: 0.23–0.83; P = 0.0115), and heart failure (8.5 vs. 23.5%; adjusted OR: 0.35; 95% CI: 0.22–0.56; P < 0.0001). Primary PCI could reduce the risk of 2-year major adverse cardiac and cerebrovascular event (19.1 vs. 33.3%; adjusted HR: 0.72; 95% CI: 0.56–0.92; P = 0.0092) relative to no reperfusion therapy, whereas thrombolysis may increase the risk of 2-year revascularization (15.5 vs. 8.7%; adjusted HR: 1.90; 95% CI: 1.15–3.16; P = 0.0124) compared with no reperfusion therapy.

Conclusions

Timely reperfusion therapy is essential for patients with right ventricular infarction. Primary PCI may be considered as the default treatment strategy for patients with right ventricular infarction in the contemporary primary PCI era.

Long-term outcomes in inferior ST-segment elevation myocardial infarction patients with right ventricular myocardial infarction

OBJECTIVE

To evaluate the prognostic influence of the presence of right ventricular myocardial infarction (RVMI) on patients with inferior ST-segment elevation myocardial infarction (STEMI) in the contemporary reperfusion era.

METHODS

9308 patients with inferior STEMI were included from the prospective, nationwide, multicenter China Acute Myocardial Infarction Registry, including 1745 (18.75%) patients with RVMI and 7563 (81.25%) patients without RVMI. The primary outcome was two-year all-cause mortality. The secondary outcome was major adverse cardiac and cerebrovascular event (MACCE) defined as a composite of all-cause mortality, recurrent MI, revascularization, stroke, and major bleeding.

RESULTS

After two-year follow up, there were no significant differences between inferior STEMI patients with or without RVMI in all-cause mortality (12.0% vs 11.3%; adjusted HR: 1.05; 95% CI: 0.90 to 1.24; P = 0.5103). Inferior STEMI with RVMI was associated with higher risk of MACCE (25.6% vs 22.0%; adjusted HR: 1.17; 95% CI: 1.05 to 1.31; P = 0.0038), revascularization (10.3% vs 8.1%; adjusted HR: 1.23; 95% CI: 1.03 to 1.48; P = 0.0218), and major bleeding (4.6% vs 2.7%; adjusted HR: 1.56; 95% CI: 1.18 to 2.07; P = 0.0019). Primary percutaneous coronary intervention (PCI) and thrombolysis were independent predictors to decrease all-cause mortality. For patients who received timely reperfusion, RVMI involvement did not increase all-cause mortality, whereas for those who did not undergo reperfusion, RVMI increased all-cause mortality (20.3% vs 15.7%; HR: 1.34; 95% CI: 1.10 to 1.63).

CONCLUSION

RVMI did not increase all-cause mortality for inferior STEMI patients in contemporary reperfusion era, whereas the risk was increased for patients with no reperfusion treatment.

Cardiogenic shock due to predominantly right ventricular failure complicating acute myocardial infarction

AIMS

The objective was to describe patient characteristics, interventions, and outcome in acute myocardial infarction complicated by cardiogenic shock (AMICS), due to predominantly right ventricular (RV) failure after revascularization, in comparison with patients suffering from left ventricular (LV) failure as these patients remain sparsely characterized.

METHODS AND RESULTS

From 2010 to 2017, consecutive AMICS patients admitted to either of two tertiary heart centres, covering 3.9 million citizens, corresponding to two-thirds of the Danish population, were identified and individually reviewed through patient records. A total of 1716 AMICS patients were identified, of which 1482 underwent acute revascularization and included for analysis. Hereof, 101 (7%) patients developed cardiogenic shock due to predominantly RV failure, while 1381 (93%) had significant LV involvement. Female sex was the only demographic factor associated with RV failure (35% vs. 25%, P = 0.01). Despite having a preserved LV ejection fraction, patients with predominantly RV failure were comparable to patients with LV involvement, in terms of haemodynamic and metabolic profile, here among variables commonly used in the cardiogenic shock definition including blood pressure (82 mmHg vs. 83 mmHg, P = 0.90) and lactate level (5.7 mmol/L vs. 5.4 mmol/L, P = 0.70). Patients with RV AMICS had significantly lower 30-day mortality than LV AMICS, and this result persisted after multivariable adjustment (RV vs. LV; hazard ratio 0.61, 95% confidence interval 0.41-0.92, P = 0.01).

CONCLUSION

In contemporary AMICS patients undergoing revascularization, patients with predominantly RV failure had comparable haemodynamics and metabolic derangement on admission compared to patients with LV failure but was associated with female sex and a significantly lower 30-day mortality.

Acute right ventricular myocardial infarction

INTRODUCTION

Acute right ventricular myocardial infarction (RVMI) is observed in 30-50% of patients presenting with inferior wall myocardial infarction (MI) and, occasionally, with anterior wall MI. The clinical consequences vary from no hemodynamic compromise to severe hypotension and cardiogenic shock depending on the extent of RV ischemia. Areas covered: The pathophysiological mechanisms, diagnostic steps, and novel therapeutic approaches of acute RVMI are described. Expert commentary: Diagnosis of acute RVMI is based on physical examination, cardiac biomarkers, electrocardiography, and coronary angiography, whereas noninvasive imaging modalities (echocardiography, cardiac magnetic resonance imaging) play a complementary role. Early revascularization, percutaneous or pharmacological, represents key step in the management of RMVI. Maintenance of reasonable heart rate and atrioventricular synchrony is essential to sustain adequate cardiac output in these patients. When conventional treatment is not successful, mechanical circulatory support, including right ventricle assist devices, percutaneous cardiopulmonary support, and intra-aortic balloon pump, might be considered. The prognosis associated with RVMI is worse in the short term, compared to non-RVMI, but those patients who survive hospitalization have a relatively good long-term prognosis.

Acute right ventricular infarction: insights for the interventional era

Acute right ventricular infarction is associated with higher in-hospital morbidity and mortality related to life-threatening hemodynamic compromise and arrhythmias during acute occlusion and abruptly with reperfusion, complications which have implications for interventional management. Acute right coronary artery occlusion proximal to the right ventricular (RV) branches results in depressed RV systolic function, leading to diminished transpulmonary delivery of left ventricular preload and resulting in low-output hypotension. Under these conditions, RV pressure generation and output are dependent on left ventricular-septal contraction via paradoxical septal motion. With culprit lesions distal to the right atrial (RA) branches, augmented RA contractility enhances RV performance and cardiac output, whereas proximal occlusions induce RA ischemia, which exacerbates hemodynamic compromise. Hypotension may respond to volume resuscitation and restoration of a physiologic rhythm. Refractory cases usually respond to parenteral inotropes, though in some cases mechanical support is required. The right ventricle is relatively resistant to infarction and usually recovers even after prolonged occlusion. Acute percutaneous mechanical reperfusion enhances recovery of RV performance and improves the clinical course and survival of patients with right ventricular infarction.

Right ventricular infarction--diagnosis and treatment

Right ventricular infarction (RVI) as assessed by various diagnostic methods accompanies inferior-posterior wall myocardial infarction (MI) in 30 to 50% of patients. Recognition of the syndrome of RVI is important as it defines a significant clinical entity, which is associated with considerable immediate morbidity and mortality and has a well-delineated set of priorities for its management. Patients may clinically present with hypotension, elevated jugular venous pulse (JVP), and occasionally shock, all in the presence of clear lung fields. The ST-segment elevation of > or = 0.1 mV in the right precordial leads V4R is a readily available electrocardiographic sign used for diagnosis of RVI. Other diagnostic approaches for assessing RVI include echocardiography, radionuclide ventriculography, technetium pyrophosphate scanning, and hemodynamic measurements. The proper management of RVI includes volume loading to maintain adequate right ventricular preload, ionotropic support, and maintenance of atrioventricular synchrony. Reperfusion therapy should be initiated at the earliest signs of right ventricular dysfunction. Finally, complete recovery over a period of weeks to months is a rule in a majority of patients, suggesting right ventricular "stunning" rather than irreversible necrosis has occurred.

What role does the right side of the heart play in circulation?

Right ventricular failure (RVF) is an underestimated problem in intensive care. This review explores the physiology and pathophysiology of right ventricular function and the pulmonary circulation. When RVF is secondary to an acute increase in afterload, the picture is one of acute cor pulmonale, as occurs in the context of acute respiratory distress syndrome, pulmonary embolism and sepsis. RVF can also be caused by right myocardial dysfunction. Pulmonary arterial catheterization and echocardiography are discussed in terms of their roles in diagnosis and treatment. Treatments include options to reduce right ventricular afterload, specific pulmonary vasodilators and inotropes.

Comparison of late survival in patients with cardiogenic shock due to right ventricular infarction versus left ventricular pump failure following primary percutaneous coronary intervention for ST-elevation acute myocardial infarction

This study compared late survival after primary percutaneous coronary intervention (PCI) in patients with cardiogenic shock due to right ventricular (RV) infarction versus left ventricular (LV) pump failure. Consecutive patients with ST-elevation myocardial infarction treated with primary PCI (n = 2,496) were prospectively enrolled in a registry from 1984 to 2004. Cardiogenic shock occurred before PCI in 189 patients (7.6%). Shock was attributed to predominant RV infarction when there was right coronary artery occlusion with preserved LV function and increased right atrial pressure. Patients with shock due to RV infarction (n = 30) versus LV pump failure (n = 136) had fewer previous infarctions (10% vs 29%, p = 0.03), less multivessel disease (20% vs 47%, p = 0.007), higher right atrial pressure (21 vs 16 mm, p = 0.003), and better LV ejection fraction (57% vs 32%, p <0.001). In-hospital mortality was lower with shock due to RV infarction (23% vs 50%, p = 0.01), and shock due to RV infarction was a significant independent predictor of late cardiac survival (hazard ratio 0.28, 95% confidence interval 0.13 to 0.62, p = 0.002). In conclusion, survival after primary PCI in patients with shock due to RV infarction is better than that in patients with shock due to LV pump failure. This is in contrast to most previous reports. Improved survival is likely related to lower risk profile and previously documented substantial recovery of RV function after primary PCI.

The impact of right atrial ischemia on inferior myocardial infarction with extension to right ventricle: transesophageal echocardiographic examination

BACKGROUND

The role of the right atrium in adaptation to the hemodynamic changes produced by extension of myocardial infarction (MI) of the left ventricular inferior wall to the right ventricle is fundamental.

HYPOTHESIS

The aim of this study was analyze a group of patients with MI with extension of right chambers, and particularly right atrial alterations, by transesophageal echocardiography and to correlate it with clinical and angiographic variables.

METHODS

Thirty patients with right ventricular (RV) MI involving obstruction of the right coronary artery without stenosis of the left coronary artery were included; 18 underwent early reperfusion. Transesophageal echocardiography was performed on all within 5 days of coronary angiography. Follow-up was continued from hospitalization to the present.

RESULTS

When patients with right atrial ischemia were compared with those with normal right atrium, the RV wall movement score was significantly greater in the group with right atrial ischemia, severe RV dilatation was more frequent, and association with proximal occlusion of the artery responsible for the MI, as well as absence of right atrial branches and poor collateral circulation, were significant. Hospitalization was more prolonged in this group, and there was a higher incidence of arrhythmias, complete atrioventricular block, and mortality.

CONCLUSIONS

Right atrial ischemia associated with RV infarction leads to a higher incidence of complications and higher mortality. Transesophageal echocardiography is a safe, reproducible technique that provides detailed anatomic information about right chambers and aids in the determination of prognosis and therapeutic decisions.

Recording lead V4R is associated to enhanced use of fibrinolytic therapy in acute myocardial infarction

BACKGROUND

ST-segment elevation in the right-sided chest lead V(4)R in inferior wall myocardial infarction is recognized as a sign of proximal occlusion of the right coronary artery with evolving right ventricular myocardial infarction. Our objective is to study how often lead V(4)R is recorded in clinical practice and how this might be associated with use of reperfusion therapy and outcome of patients.

METHODS

Recording of lead V(4)R in 814 consecutive patients with acute myocardial infarction, administration of therapy, and outcome of the patients during a median follow-up of 285 days (174-313 days) were studied.

RESULTS

V(4)R was recorded in 52% of patients with inferior ST-elevation myocardial infarction. Patients with V(4)R recorded were more likely to receive fibrinolytic therapy compared with patients without recording (65% vs 51%; P = .035). In multivariate analysis, recording of lead V(4)R (odds ratio [OR] 1.6, 95% confidence interval [CI] 1.1-2.2; P = .006), along with age (P < .001), previous myocardial infarction (OR 2.2, 95% CI 1.3-3.5; P = .002), and diabetes (OR 3.9, 95% CI 1.1-2.4; P = .03) correlated to the use of reperfusion therapy. Patients with lead V(4)R recorded had less (P = .055) reinfarction, unstable angina, stroke, and/or death during follow-up.

CONCLUSIONS

Lead V(4)R was recorded in only half of patients with inferior ST-elevation myocardial infarction. Patients with V(4)R recorded were more likely to receive thrombolytic therapy than those without recording of the additional chest lead.

Effect of coronary occlusion site on angiographic and clinical outcome in acute myocardial infarction patients treated with early coronary intervention

In acute myocardial infarction that is treated with thrombolysis, proximal coronary artery occlusion is associated with worse prognosis, irrespective of the infarcted artery. Primary percutaneous coronary intervention (PCI) is currently the treatment of choice for ST-segment elevation acute myocardial infarction. Therefore, we evaluated the prognostic significance of proximal versus distal coronary artery occlusion in patients with acute myocardial infarction that was treated with primary PCI. Between 1994 and 2001, patients with a first acute myocardial infarction that was treated with primary PCI were analyzed. A lesion was considered proximal if it was located proximal to the first diagonal branch in the left anterior descending coronary artery (LAD), the first marginal obtuse branch in the left circumflex coronary artery, and the first right acute marginal branch in the right coronary artery. Lesions distal of these side branches were considered distal. In total, 1,468 patients were analyzed. Left ventricular ejection fraction (LVEF) for proximal LAD lesions was lower than that for distal ones (37 +/- 11% vs 42 +/- 11%, p <0.0001). Adjusted relative risk of 3-year mortality for proximal versus distal LAD was 4.04 (95% confidence interval 1.95 to 8.38). In patients with infarcts related to the right or left circumflex coronary artery, no significant association between lesion location and LVEF or mortality was seen. No difference was seen in adjusted 3-year mortality between distal LAD and non-LAD-related infarcts (p = 0.145). In conclusion, our analysis shows that, even in patients with acute myocardial infarction that is treated with primary PCI, infarcts related to the proximal LAD have the worst 3-year survival and lowest residual LVEF compared with distal LAD or non-LAD-related infarcts.

[Percutaneous transluminal coronary angioplasty in the right ventricle myocardial infarction treatment]

BACKGROUND/AIM

To present the results of percutaneous transluminal coronary angioplasty (PTCA) in the treatment of the patients with acute right ventricle myocardial infarction (ARVMI), with adjuvant analyses of the obtained results in the period of five years (2000-2004).

METHODS

Thrombolytic therapy and the primary percutaneous transluminal coronary angioplasty (PPTCA) was applied within the first 6 hours from the onset of anginous disorders, and rescue PTCA in the period from 6-24 hours from the onset of ARVMI. Results. A total number of 1175 patients, both sexes, 763 (64.8%) males and 412 females (35.2%), mean age 58.4 +/- 7.8 years, were treated for acute myocardial infarction (AIM) of different localization in the period of five years (2000-2004). Anterior infarction was found in 645 (54.8%) of the patients, and inferoposterior infarction (IPI) was localized in 530 patients (45.2%) patients of which in 134 (25.2%) AIMDK was proven. Out of 134 patients with proven acute myocardial of the right ventricle AIMDK, 53 (39.5%) got thrombolytic therapy, 64 patients (47.7%) were treated with the conservative heparin therapy, whereas in 17 patients (12.8%), primary percutaneous coronary angioplasty (PPTCA) was done. Delayed or rescue PTCA was done in 22 (18.8%) patients, in 8 (36.3%) from the group which got thrombolytic therapy, and in 14 (63.7%) treated with the heparin therapy. Out of the total number of 22 patients who got heparin or thrombolytic therapy combined with rescue PTCA, in 7 patients (31.8%) the complete clinical and angiographic effect of thrombolysis with AIM was achieved only by using a balloon. Baloon dilatation with the implantantion of intracoronary stent was performed in another 11 patients (50%), while 2 (9.1%) were sent to revascularization of the myocard due to diffusion changes in each of the 3 blood vessels, and 2 patients (9.1%) died. Of the patients, 17 (12.6%) had PPTCA with the implantation of intracoronary stent with the additional direct inhibitor of the platelet membrane glycoproteins IIb/IIIa (abciximab). All the patients treated in this way survived. They had no side effects nor serious complications. Their clinical recovery was satisfactory. In the first three weeks of the intrahospital period in the group of 45 patients (33.5%) with AIMDK, who got only thrombolytic therapy, 7 patients (15.5%) died, whereas in the group of 50 patients (37.3%) treated only with heparin, 13 (26%) died. In the group of 22 patients (18.8%) treated with the combined therapy with rescue PTCA and heparin or thrombolytic therapy, 2 patients (9.1%) died. In the group of 84 patients (62.6%) with AIMDK, who were treated with thrombolytic therapy with primary or rescue PTCA, 9 (10.7%) died. In the AIMDK group of 134 patients, 22 patients (16.4%) died in the period of 1 month of the hospital treatment, whereas in the second group of 396 patients with IPI, but without IDK, 36 (9.1%) died (chi2 = 4.789; p < 0.001). Out of the total number of 1175 patients with AIM in the five-year period of the intrahospital treatment, 145 patients (12.3%) died. In the group of patients with IPI, 58 patients out of 530 (10.9%) died, whereas 87 patients out of 645 (13.4%) with anterior infarction died, (chi2 = 0.567; p < 0.452).

CONCLUSION

The combination of thrombolytic therapy and PTCA shown in the obtained results completely justified this kind of treatment, and offered the patients with AIMDK a greater chance to surve than they had before.

Usefulness of low-dose dobutamine stress echocardiography for the evaluation of spontaneous recovery of stunned myocardium in patients with acute right ventricular infarction

Right ventricular (RV) infarction (RVI) is usually associated with severe RV global dysfunction representing predominantly stunned myocardium that may respond favorably to reperfusion. We assessed the efficacy of low-dose dobutamine stress echocardiography (DSE), performed early in the course of a reperfused RVI, to predict the recovery of RV systolic and diastolic function in 3 months, documenting the recovery of stunned myocardium. In all, 27 patients with acute, successfully thrombolyzed RVI comprised the study population. All patients underwent standard echocardiography at baseline and 3 months later for evaluation of RV systolic and diastolic function. At day 5 DSE was performed for evaluation of RV contractile reserve. Of the total number of segments analyzed, 69% were detected as stunned. At baseline, RV systolic and diastolic indices were seriously impaired showing significant improvement at follow-up. RV wall-motion score index during DSE was positively correlated with the same index at follow-up. DSE is a safe and precise modality to predict recovery of stunned myocardium in the setting of RVI.

Right ventricular involvement in myocardial infarction and cardiogenic shock

CONTEXT

Right ventricular involvement in acute myocardial infarction and cardiogenic shock has received little attention by clinicians and researchers, although its pathophysiology, clinical presentation, and natural history are distinctly different from those of left ventricular infarction and associated cardiogenic shock. Right ventricular shock has important therapeutic implications for the management of patients, which need to be recognised.

STARTING POINT

Investigators at the SHOCK Registry (Alice Jacobs and colleagues, J Am Coll Cardiol 2003; 341: 1273-79) evaluated 49 patients with cardiogenic shock predominantly due to right ventricular infarction and compared them with 884 patients with cardiogenic shock and predominantly left ventricular failure. Perhaps surprisingly, these investigators found that the in-hospital mortality of patients with right ventricular shock was not significantly lower than that of patients with left ventricular shock (53% vs 61%, p=0.296), despite the fact that patients with right ventricular shock were younger, with a lower prevalence of previous infarctions, fewer anterior infarct locations, and less multivessel disease. There was a shorter median time between index infarction and diagnosis of shock in patients with right ventricular shock. In multivariate analysis, right ventricular shock was not an independent predictor of lower in-hospital mortality. WHERE NEXT? The unexpectedly high mortality of patients with cardiogenic shock due to predominantly right ventricular infarction challenges the general notion that right ventricular involvement in myocardial infarction has only little relevance for patient's outcome. Therefore, more attention should be given to the detection of right ventricular involvement in acute myocardial infarction and particularly in cardiogenic shock. If right ventricular shock is diagnosed, urgent reperfusion of the infarct related artery and appropriate circulatory support are required.

Percutaneous atrial septostomy for urgent palliative treatment of severe refractory cardiogenic shock due to right ventricular infarction

We report a novel palliative treatment to improve refractory cardiogenic shock due to right ventricular ischemia. We performed percutaneous atrial septostomy to create an atrial septal defect, which resulted in immediate right ventricular decompression and increased left ventricular filling associated with prompt and dramatic hemodynamic and clinical improvement.

Comparison of effectiveness of primary angioplasty for proximal versus distal right coronary artery culprit lesion during acute myocardial infarction

From the cohort of 4,023 patients enrolled in the Primary Angioplasty for Myocardial Infarction (PAMI) trials, we pooled clinical, angiographic, and outcomes data on 1,521 patients with culprit lesions in the right coronary artery (RCA). We compared angiographic results, procedural complications, and in-hospital and 1-year clinical outcomes between patients with proximal RCA (n = 572) versus nonproximal RCA culprit lesions (n = 949). Patients with proximal RCA culprit lesions were older, had lower systolic blood pressure, greater diameter stenosis, and were less likely to have Thrombolysis In Myocardial Infarction (TIMI) 2 or 3 flow (19% vs 31%; p <0.0001) before percutaneous coronary intervention (PCI). After PCI, the incidence of TIMI 3 flow (94% vs 93%) was similar between groups. Patients with proximal RCA lesions were more likely to have bradyarrhythmias (30% vs 23%, p = 0.016) and require an intra-aortic balloon pump (IABP; 4.6% vs 2%, p = 0.034) during PCI. In-hospital complications, including mortality (2.3% vs 2.2%) and reinfarction (1.4% vs 1.1%), and the 1-year incidence of death, reinfarction, ischemia driven target vessel revascularization, and major adverse cardiovascular events were similar between groups. After adjustment for baseline differences, proximal RCA location of the culprit lesion was independently associated with greater IABP use (odds ratio 2.41, 95% confidence interval 1.04 to 5.58) but not with bradyarrhythmias during PCI. Thus, in patients with acute myocardial infarction referred for primary angioplasty, proximal RCA location of the culprit lesion is associated with excellent clinical outcomes that are similar to nonproximal RCA lesions.

Pathophysiology and management of right heart ischemia

Acute right coronary artery occlusion proximal to the right ventricular (RV) branches results in right ventricular free wall dysfunction, exerting mechanically disadvantageous effects on biventricular performance. Depressed RV systolic function decreases transpulmonary delivery of left ventricular (LV) preload, resulting in diminished cardiac output. The ischemic right ventricle is stiff, dilated, and volume dependent, resulting in pandiastolic RV dysfunction and septally mediated alterations in LV compliance, which are exacerbated by elevated intrapericardial pressure. Under these conditions, RV pressure generation and output are dependent on LV-septal contractile contributions, governed by both primary septal contraction and paradoxical septal motion. When the culprit coronary lesion is distal to the right atrial (RA) branches, augmented RA contractility enhances RV performance and optimizes cardiac output. Conversely, more proximal occlusions result in ischemic depression of RA contractility, which impairs RV filling and performance, resulting in more severe hemodynamic compromise. Bradyarrhythmias limit output generated by the rate-dependent noncompliant ventricles. Hemodynamic compromise may respond to volume resuscitation and restoration of physiologic rhythm. Vasodilators and diuretics should generally be avoided. In some patients, parenteral inotropic stimulation may be required. The right ventricle appears to be relatively resistant to infarction and recovers even after prolonged occlusion. The term RV "infarction" appears to be somewhat of a misnomer, for in most patients acute RV dysfunction represents ischemic but predominantly viable myocardium. Although RV performance improves spontaneously even in the absence of reperfusion, recovery of function may be slow and associated with high in-hospital mortality. Reperfusion enhances recovery of RV performance and improves the clinical course and survival.

Patterns of coronary compromise resulting in acute right ventricular ischemic dysfunction

BACKGROUND

Although proximal right coronary artery (RCA) occlusion is the culprit commonly responsible for acute right ventricular (RV) infarction (RVI), the severity of RV dysfunction ranges broadly. This study was designed to delineate the patterns of coronary compromise that determine the magnitude of RV ischemic dysfunction.

METHODS AND RESULTS

In 125 patients with acute inferior myocardial infarction undergoing emergency angiography, the culprit infarct lesion was identified, RV branch flow assessed (TIMI flows and frame counts), and individual patient RV perfusion indices calculated by separately averaging the branch flows and frame counts, which were correlated with RV wall motion by ultrasound. RVI occurred in 53 (42%) patients, with the RCA as the culprit vessel and the lesion sufficiently proximal to compromise flow in at least one RV branch in all cases, thereby resulting in depressed RV perfusion (flow index, 0.7+/-0.2). In patients without RVI, the RCA was the culprit in 89%; the circumflex, in 11%. RCA culprits were proximal in 19% of such cases, with lack of RVI explained by preserved RV perfusion (flow index, 2.7+/-0.3; P=0.001) attributable to at least 1 patent RV branch, spontaneous reperfusion, or prominent collaterals. Overall, there was a strong correlation between RV perfusion and wall motion (Spearman correlation coefficient=0.79).

CONCLUSIONS

Proximal RCA occlusion compromising RV branch perfusion commonly results in RV ischemic dysfunction. In some cases with proximal RCA culprits, collaterals or spontaneous reperfusion preserve RV performance.

Acute right ventricular infarction: clinical spectrum, results of reperfusion therapy and short-term prognosis

BACKGROUND

The role of thrombolytic therapy (TT) and percutaneous coronary interventions (PCIs) in subgroups of patients with right ventricular infarction (RVI) has not been evaluated.

METHODS AND RESULTS

We risk-stratified 302 patients with RVI into three subsets upon admission. Class A (n=197) comprised patients without right ventricular (RV) failure, Class B (n=69) with RV failure and Class C (n=36) with cardiogenic shock. All eligible patients in Class A or B received either PCI or TT. Patients in Class C eligible for reperfusion were treated with PCI. All patients were evaluated for in-hospital major adverse cardiac events and short-term mortality. There was a statistically significant difference in in-hospital mortality among the classes. Classes B and C were the strongest indicators of in-hospital mortality. By multivariate analysis TT or PCI did not reduce mortality in Classes A and B, but a clinically favorable trend in mortality reduction was documented: both methods decreased RV dysfunction in Class B (from 97% to 61% with TT and to 28% with PCI; P < 0.001) and PCI reduced the risk of mortality in Class C (89.5% compared with 58%; P < 0.05).

CONCLUSIONS

Classification into types A, B or C allows the prediction of mortality. The use of TT or PCI suggests a clinical favorable trend in the reduction of mortality in Class A, either is beneficial in Class B for decreasing morbidity and PCI appears to be the most appropriate procedure for Class C since it reduced mortality.

Dominant right ventricular infarction: is angioplasty the optimal therapeutic approach?

Approximately 30% of all acute inferior myocardial infarctions (AIMI) are accompanied by acute right ventricular infarction (ARVI) as a consequence of proximal right coronary artery (RCA) occlusion. Fifty per cent of all patients with ARVI manifest hypotension, jugular venous distension, and dyspnoea with clear lung fields, which is then considered as dominant acute RVI (ARVI). The in hospital mortality rate of patients with ARVI who are treated traditionally is very high. Thrombolytic therapy is relatively ineffective, while primary angioplasty is a more recent approach yet to be established as optimal treatment for patients with ARVI. Thirty-eight patients with dominant ARVI were admitted to our CCU over a period of 24 months. The patients were retrospectively divided into 3 groups according to treatment: Group I (n = 16): traditional treatment; Group II (n = 12): thrombolytic therapy (streptokinase); Group III (n = 10): angioplasty after urgent coronarography. We tested the difference in the number of deaths in all groups by the Fisher exact test. There was a significant difference in the number of deaths between Group I and Group III (P < 0.05). Mortality reduction was also noted between Group II and Group III, which, however, proved to be statistically insignificant.

NONARRHYTHMIC COMPLICATIONS OF ACUTE MYOCARDIAL INFARCTION

Complications of acute myocardial infarction can be categorized as nonarrhythmic or arrhythmic; the latter is discussed elsewhere. Patients are at risk for a number of potentially serious or fatal complications during or after the acute infarction phase. These include shock, left ventricular free wall rupture, rupture of the interventricular septum, papillary muscle rupture, ventricular pseudoaneurysm, and stroke. Right ventricular infarction, which is typically associated with inferior myocardial infarction, will also be discussed.

Right Ventricular Infarction

Right ventricular (RV) ischemia occurs in a substantial proportion of patients with acute inferior myocardial infarction (MI), and may result in severe hemodynamic compromise. This defines a high-risk subset of patients with a mortality rate of 25% to 30%, as opposed to an overall mortality rate of approximately 6% patients with inferior MI without right ventricular infarction (RVI). Early recognition of RV ischemic dysfunction is of great importance in inferior MI with clinical evidence of low cardiac output, because the therapeutic approaches are very different from that for cardiogenic shock resulting predominantly from severe left ventricular (LV) failure. Management of RV ischemic dysfunction includes maintenance of RV preload with volume loading and maintenance of atrioventricular synchrony, inotropic support, and reduction of RV afterload in the setting of LV dysfunction. Reperfusion therapy should be initiated in patients with RV ischemic dysfunction. Though the RV appears to be relatively resistant to infarction and has a remarkable ability to recover even after prolonged occlusion, successful reperfusion of the right coronary artery and major RV branches rapidly improves RV ejection fraction and hemodynamic status, and decreases in-hospital mortality and morbidity.

Implications of the timing of onset of cardiogenic shock after acute myocardial infarction: a report from the SHOCK Trial Registry. SHould we emergently revascularize Occluded Coronaries for cardiogenic shocK?

OBJECTIVES

We sought to examine the implications of the timing of onset of cardiogenic shock (CS) after acute myocardial infarction (MI).

BACKGROUND

Little information is available about the relationships between timing, clinical substrate, management and outcomes of shock.

METHODS

The multinational SHOCK Trial Registry enrolled MI patients with CS from 1993 to 1997. Cardiogenic shock was predominantly attributable to left ventricular (LV) failure in 815 Registry patients for whom temporal data were available. We examined factors related to the timing of shock onset and the relation of temporal onset to in-hospital outcomes.

RESULTS

Overall, shock developed a median of 6.2 h after MI symptom onset. Shock onset varied by culprit artery: left main, median 1.7 h; right, 3.5 h; circumflex, 3.9 h; left anterior descending (LAD), 11.0 h; saphenous vein graft, 10.9 h (p = 0.025). Early shock (< 24 h) occurred in 74.1% and was associated with chest pain at shock onset, ST-segment elevation in two or more leads, multiple infarct locations, inferior MI, left main disease and smoking. Late shock (> or = 24 h) was associated with recurrent ischemia, Q waves in two or more leads and LAD culprit vessel. Mortality was higher in patients with early versus late shock (62.6% vs. 53.6%, p = 0.022).

CONCLUSIONS

Shock onset after acute MI occurred within 24 h in 74% of the patients with predominant LV failure. Mortality was slightly higher in patients developing shock early rather than later. Many factors influence when shock develops, which has implications for its management.

Pathophysiology and clinical management of right heart ischemia

Right ventricular (RV) ischemia occurs in 50% of patients with acute inferior myocardial infarction, and may result in severe hemodynamic compromise associated with poor clinical outcome. Right coronary artery occlusion proximal to the RV branches results in RV systolic dysfunction, which decreases transpulmonary delivery of left ventricular (LV) preload and diminishes cardiac output. The ischemic right ventricle is stiff, dilated, and volume dependent, resulting in pandiastolic RV dysfunction. Under these conditions, RV pressure generation and output depend on LV-septal contractile contributions. When the culprit coronary lesion is distal to the right atrial (RA) branches, augmented RA contractility enhances RV performance and optimizes cardiac output. Conversely, more proximal occlusions result in ischemic depression of RA contractility, which impairs RV filling and performance, leading to more severe hemodynamic compromise. Bradyarrhythmias limit the output generated by the rate-dependent noncompliant ventricles. Patients with RV ischemia and hemodynamic compromise often respond to volume resuscitation and restoration of a physiologic rhythm. In some patients, parenteral inotropic stimulation may be required. The ischemic right ventricle appears to be relatively resistant to infarction and has a remarkable ability to recover. The term RV infarction appears to be a misnomer, as RV performance improves spontaneously even in the absence of reperfusion. Reperfusion, however, enhances the recovery of RV performance and improves the clinical course.

Right ventricular involvement in acute myocardial infarction

The presence of right ventricular dysfunction in patients with acute myocardial infarction has important implications. It is a marker for in-hospital mortality and failure to recognize it may lead to inappropriate treatment with serious consequences for the patient. Patients surviving the acute event do, however, have a relatively good long-term prognosis.

Combined effect of age and right ventricular involvement on acute inferior myocardial infarction prognosis

BACKGROUND

In patients with acute inferior myocardial infarction (AIMI), right ventricular involvement (RVI) is one of the strongest predictors of in-hospital death. We hypothesized that the impact of RVI on AIMI prognosis depends on the patient's age.

METHODS AND RESULTS

The in-hospital clinical outcome of 798 consecutive patients admitted to the coronary care unit within 48 hours of symptom onset with AIMI was analyzed according to patient age and to the presence of RVI diagnosed by ECG and/or echocardiographic criteria. The total incidence of RVI was 37%, and it increased as age advanced. Patients with RVI had a significantly higher incidence of major complications (45% versus 19%, P<0.0001) and a higher in-hospital mortality rate (22% versus 6%, P<0.0001). The prognostic effect of RVI was independent of sex, smoking, diabetes, shock on admission, left ventricular ejection fraction, and reperfusion therapy, all age-dependent predictors. A multivariate analysis showed a significant (P=0.03) interaction between age and RVI on AIMI mortality. RVI increased mortality risk only in the oldest patients.

CONCLUSIONS

In patients with AIMI, RVI substantially increases mortality risk in elderly patients, whereas it has a nonsignificant effect in young subjects.

Effects of thrombolytic therapy in acute inferior myocardial infarction with or without right ventricular involvement. HIT-4 Trial Group. Hirudin for Improvement of Thrombolysis

OBJECTIVES

This study assessed the prognostic impact of right ventricular involvement (RVI) in streptokinase-treated patients with inferior acute myocardial infarction (AMI) stratified for small or large AMI.

BACKGROUND

Only scant data exist from small studies about the impact of reperfusion therapy on survival in patients with RVI during inferior AMI.

METHODS

Right ventricular involvement was assessed by ST-segment elevation > or =0.1 mV in lead V4R and infarct size by the extent of ST-segment deviation on the baseline electrocardiogram: small AMI=sum ST-segment elevation < or =0.8 mV and no precordial ST-segment depression (small ST); large AMI=presence of precordial ST-segment depression or sum ST-segment elevation >0.8 mV (large ST) in 522 inferior AMI patients of the Hirudin for Improvement of Thrombolysis (HIT-4) Trial. In 187 patients, 90-min coronary angiography was performed.

RESULTS

Right ventricular involvement was present in 169 patients (32%). Higher 30-day cardiac mortality rates with RVI (5.9% vs. 2.5%) were related to larger infarct size rather than to RVI. For large ST, a proximal right coronary artery lesion was observed in 52% with and in 23% without RVI. Patency rates at 90 min were similar (54% vs. 52%). In the 28% of patients who had small ST, cardiac mortality was less than 1% irrespective of the presence of RVI. Coronary artery lesions were mostly located distally. Patency rates were 27% with and 80% without RVI.

CONCLUSIONS

ST-segment elevation of > or =0.1 mV in V4R in inferior AMI patients is associated with larger infarct size and higher 30-day mortality rates. Right ventricular involvement is not an independent predictor of survival. In patients with small ST, cardiac mortality is low, even if ST V4R is > or =0.1 mV.

Effect of reperfusion on biventricular function and survival after right ventricular infarction

BACKGROUND

Although the salutary effects of reperfusion in patients with left ventricular infarction are well documented, the benefits in patients with acute right ventricular infarction are less clear.

METHODS

To determine whether primary angioplasty improves right ventricular function and the clinical outcome in patients with right ventricular infarction, we performed echocardiographic studies before and after angioplasty in 53 patients with acute right ventricular infarction.

RESULTS

Complete reperfusion, defined as normal flow in the right main coronary artery and its major right ventricular branches, was achieved in 41 patients (77 percent), leading to prompt and striking recovery of right ventricular function (mean [+/-SE] score for free-wall motion, 3.0+/-0.1 at base line and 1.4+/-0.1 at three days; P<0.001). Twelve patients (23 percent) had unsuccessful reperfusion, defined as the failure to restore right ventricular branch flow, with or without patency of the right main coronary artery. Unsuccessful reperfusion was associated with lack of recovery of right ventricular function (score for free-wall motion, 3.2+/-0.2 at base line and 3.0+/-0.9 at three days; P= 0.55), as well as persistent hypotension and low cardiac output (in 83 percent of the patients, vs. 12 percent of those with successful reperfusion; P=0.002) and a high mortality rate (58 percent, vs. 2 percent for those with successful reperfusion; P=0.001).

CONCLUSIONS

In patients with right ventricular infarction, complete reperfusion of the right coronary artery by angioplasty results in the dramatic recovery of right ventricular performance and an excellent clinical outcome. In contrast, unsuccessful reperfusion is associated with impaired recovery of right ventricular function, persistent hemodynamic compromise, and a high mortality rate.

Usefulness of pulmonary regurgitation Doppler tracings in predicting in-hospital and long-term outcome in patients with inferior wall acute myocardial infarction

Right ventricular (RV) involvement is frequent during inferior wall acute myocardial infarction (AMI) and has been reported as a risk factor for in-hospital morbidity and mortality. The objectives of the present study were: (1) to evaluate in-hospital events in patients with and without RV involvement as diagnosed by abnormal flow characteristics derived from pulmonary regurgitation (PR) analysis (pressure half-time of PR, PHT(PR) < or = 150 ms and the lowest mid-diastolic to peak early diastolic velocity ratio, Vmin/Vmax < or = 0.5); and (2) to determine the influence of RV involvement in complications at long-term follow-up. Among 126 consecutively admitted patients with inferior wall AMI (mean age, 58 +/- 13 years), 101 had PR. We determined the prognostic significance of in-hospital and long-term events for the following variables: age > or = 65 years, ST-segment elevation > or = 1 mm in lead V4R, RV dilation, PHT of PR < or = 150 ms and Vmin/Vmax < or = 0.5, thrombolytic therapy, 3-vessel disease, and diabetes mellitus. We found that the PR derived Doppler index (PHT of PR < or = 150 ms and Vmin/Vmax < or = 0.5) was the only predictor of overall in-hospital clinical events (hazards ratio, 2.7, 95% confidence interval, 1.2 to 6.1, p = 0.016). At long-term follow-up (mean: 20 +/- 12 months, range 12 to 69), event-free survival analysis showed that age > or = 65 years was the only predictor of any event (relative risk, 3.7, 95% confidence interval, 2.1 to 6.3, p < 0.0001). Thus, RV involvement diagnosed with the use of PR flow-derived variables is an accurate and independent predictor of in-hospital complications. However, RV involvement does not influence long-term prognosis.

Right heart ischemia: pathophysiology, natural history, and clinical management

Right ventricular (RV) ischemia occurs in 50% of patients with acute inferior myocardial infarction, and may result in severe hemodynamic compromise associated with poor clinical outcome. Acute right coronary artery (RCA) occlusion proximal to the RV branches results in right ventricular free wall (RVFW) dysfunction. The ischemic, dyskinetic RVFW exerts mechanically disadvantageous effects on biventricular performance. Depressed RV systolic function leads to a decrease in transpulmonary delivery of left ventricular (LV) preload, resulting in diminished cardiac output. The ischemic right ventricle is stiff, dilated, and volume dependent, resulting in pandiastolic RV dysfunction and septally-mediated alterations in LV compliance, which are exacerbated by elevated intrapericardial pressure. Under these conditions, RV pressure generation and output are dependent on LV-septal contractile contributions, governed by both primary septal contraction and paradoxical septal motion. When the culprit coronary lesion is distal to the right atrial (RA) branches, augmented RA contractility enhances RV performance and optimizes cardiac output. Conversely, more proximal occlusions result in ischemic depression of RA contractility, which impairs RV filling, thereby resulting in further depression of RV performance and more severe hemodynamic compromise. Bradyarrhythmias limit the output generated by the rate-dependent noncompliant ventricles. Patients with right ventricular infarction and hemodynamic compromise often respond to volume resuscitation and restoration of a physiological rhythm. Vasodilators and diuretics should generally be avoided. In some, parenteral inotropic stimulation may be required. The right ventricle appears to be relatively resistant to infarction and has a remarkable ability to recover even after prolonged occlusion. Therefore, the term RV infarction appears to be somewhat of a misnomer, for in most patients a substantial proportion of acute RV dysfunction represents ischemic but viable myocardium. Although RV performance improves spontaneously even in the absence of reperfusion, recovery of function may be slow and associated with high in-hospital mortality. Reperfusion enhances the recovery of RV performance and improves the clinical course and survival of patients with ischemic RV dysfunction.

Revisiting reperfusion therapy in inferior myocardial infarction

Although thrombolytic therapy for acute myocardial infarction (MI) is recommended without regard for infarct location, treatment results are less impressive for inferior than for anterior MI because the amount of myocardium at risk is smaller and less strategically located, and the mortality risk is lower. Whereas the risks associated with anterior MI are relatively constant, high risk subsets of patients with an inferior MI can be identified by simple electrocardiographic criteria, including left precordial ST segment depression, complete atrioventricular heart block and right precordial ST segment elevation. Unfortunately, none of the placebo-controlled, randomized trials have analyzed the benefit of thrombolytic therapy for inferior MI in high risk versus low risk subsets. Thrombolytic therapy should be more successful in reducing infarct size and decreasing mortality in high risk patients with an inferior MI. Thrombolytic therapy may not decrease hospital mortality in low risk patients (baseline risk 2% to 4%) or those with symptom duration > 6 h. Whereas it is arguable whether coronary angioplasty is superior to thrombolytic therapy in anterior MI, there are no mortality data to support using angioplasty as a primary or rescue reperfusion strategy instead of thrombolytic therapy in inferior MI, unless thrombolytic contraindications are present or the patient is in cardiogenic shock.

Impact of early accelerated dose tissue plasminogen activator on in-hospital patency of the infarcted vessel in patients with acute right ventricular infarction

OBJECTIVE

To assess the efficacy of early accelerated dose tissue plasminogen activator on in-hospital patency of the infarct related artery in patients with inferior myocardial infarction with and without right ventricular involvement.

DESIGN

Single centre prospective assessment before discharge of infarct related vessel patency after early thrombolysis.

SETTING

Tertiary cardiac referral centre at a university hospital.

PATIENTS AND METHODS

90 consecutive unselected patients with acute myocardial infarction, of whom 35 (39%) had electro-cardiographic evidence of right ventricular involvement (ST segment elevation greater than 0.1 mV in right precordial lead V4R), were studied. All patients received accelerated dose tissue plasminogen activator 100 mg within six hours from the onset of symptoms and had control angiography before discharge.

MAIN OUTCOME MEASURES

Infarct related coronary artery patency using the Thrombolysis in Myocardial Infarction (TIMI) grading system before discharge. Incidence of prolonged systemic hypotension, sinus bradycardia, complete atrioventricular block, and ventricular tachyarrhythmia during early hospitalisation.

RESULTS

Despite aspirin and bolus heparinisation before thrombolysis and high dose heparinisation thereafter for at least 48 hours the infarct related artery was more likely to be occluded (TIMI 0 or 1 flow) in patients with right ventricular involvement than in those without (69 v 29%, P < 0.001), as shown by control angiography performed a mean of 12.8 days after thrombolysis. These findings may be explained, at least in part, by predominant involvement of the proximal right coronary artery (66 v 31%, P < 0.05) and a low cardiac output syndrome, being indirectly reflected by a high incidence of prolonged hypotension (26 v 7%, P = 0.02), bradycardia (34 v 14%, P = 0.03), and complete atrioventricular block (37 v 5%, P = 0.0001).

CONCLUSION

Primary angioplasty should be considered as the treatment of choice in patients with acute inferior infarction with right ventricular involvement because of the high failure rate of thrombolysis.