Resolution of complete heart block after right coronary artery angioplasty

An Interesting Case of Atherosclerotic Occlusion of the First Septal Perforator in a Physically Young and Fit Individual Causing Complete Heart Block

Complete heart block (CHB) is an unfortunate complication of an anterior and inferior myocardial infarction (MI). We present a case of an atherosclerotic occlusion of the first septal perforator leading to CHB requiring permanent pacemaker placement in a young patient. A 33-year-old healthy white male presented to the emergency department with an episode of syncope. His vitals were stable, and his physical exam was unremarkable. His electrocardiogram (EKG) showed CHB and ST elevations in V1, V2, and V3 suggestive of septal MI. He underwent emergent left heart catheterization which revealed significant stenosis of the proximal left anterior descending (LAD) artery, proximal diagonal artery, and the first septal perforator. An intervention was done with stent placement in the LAD and insertion of a temporary pacemaker. After removal of the temporary pacemaker two days later, the patient developed asystole with alternating bundle branch block which prompted immediate reinsertion of the temporary pacemaker which was replaced later with a permanent pacemaker. The patient was stable afterward and discharged.

The persistent atherosclerotic occlusion of the first septal perforator prevented adequate perfusion of the conduction system, even after revascularization of the proximal LAD. In conclusion, it is essential to acknowledge that difficulty to revascularize an occluded septal perforator raises the need for a permanent pacemaker to prevent a CHB.

Spontaneous recovery of complete atrioventricular block complicating acute anterior wall ST elevation myocardial infarction

BACKGROUND

Complete atrioventricular block complicating acute anterior wall ST elevation myocardial infarction (MI) is classically considered one of the worst prognostic indicators.

METHODS

We present the case of a gentleman who developed complete atrioventricular block during the course of acute anterior wall ST elevation MI, and had spontaneous resolution of the same. Mechanisms of spontaneous resolution of complete atrioventricular block in the setting of acute MI are discussed. Attention is drawn to a subgroup of patients, albeit a minority, who have a better prognosis owing to reversible causes than classically expected and seen.

RESULTS

Clinical features suggested that this patient had reocclusion of the infarct-related artery after thrombolysis on presentation and spontaneous reperfusion.

CONCLUSION

Coronary angiography provides invaluable information for decision making in such clinical scenarios. Complete atrioventricular block due to reversible ischaemia produced by reocclusion of an infarct-related artery should be reversible by percutaneous coronary angioplasty of the infarct-related artery. We suggest that reversible causes be considered before attributing atrioventricular block to irreversible damage, which would require a permanent pacemaker implantation. This would be more significant in most of the developing world, where resources are scarce.

Prognostic significance of bundle-branch block in acute myocardial infarction: the importance of location and time of appearance

BACKGROUND

The presence of bundle-branch block (BBB) is associated with high mortality rates and is considered an important predictor of poor outcome in patients with acute myocardial infarction (AMI).

HYPOTHESIS

The objective of this study was to assess the prognostic significance of BBB in patients with AMI depending on its form of presentation.

METHODS

A multicenter prospective 1-year follow-up study involving 1,239 consecutive patients diagnosed with AMI was performed.

RESULTS

Bundle-branch block was present in 177 cases (14.2%), associated with worse clinical characteristics, lower rate of thrombolytic therapy, and higher mortality: in-hospital (23.8 vs. 9.7%, p < .01) and 1-year (40.9 vs. 16.9%, p < 0.01). Compared with right BBB (n = 135), left BBB (n = 42) was more often associated with female gender and higher prevalence of cardiovascular diseases, but had a similar 1-year mortality. In the absence of heart failure or complete atrioventricular (AV) block, there was no difference in in-hospital mortality of patients with BBB (n = 76) and without BBB (n = 786) (2.6 vs. 3.9%). Compared with existing BBB (n = 113), BBB of new appearance (n = 64) was more often accompanied by complete AV block and heart failure and higher in-hospital and 1-year mortality rates. Only BBB of new appearance was an independent predictor of mortality: in-hospital (odds ratio [OR] 2.3, 95% confidence interval [CI] 1.1-4.7) and 1-year mortality (OR 3.2, 95% CI, 1.7-9.1).

CONCLUSIONS

In patients with AMI, the classification of BBB according not only to location but also to time of appearance is of practical interest. New BBB is an independent predictor of short- and long-term mortality.

Usefulness of either or both left and right bundle branch block at baseline or during follow-up for predicting death in patients following acute myocardial infarction

The presence or onset of bundle branch block (BBB) is associated with increased mortality in patients after acute myocardial infarction (AMI). The risk increases with age. We assessed the prognostic power of BBB patterns for predicting clinical outcomes in patients after high-risk AMI. In the OPTIMAAL trial, the effects of losartan versus captopril were compared in 5,477 patients with heart failure and/or evidence of left ventricular dysfunction after MI. The association between clinical outcomes and the presence of left or right BBB at randomization (median 3 days after AMI) or occurring during follow-up (mean 2.7 years) was assessed using Cox regression models. At randomization, 8% of patients (n = 438) showed BBB patterns; 3.7% (n = 203) showed left BBB and 4.3% (n = 235) showed right BBB patterns. In patients with left BBB, there was an increased risk of all-cause death and cardiovascular death. In patients with right BBB, there was increased risk of sudden cardiac death/resuscitated cardiac arrest. During follow-up, another 4.9% (n = 272) developed BBB patterns; 2.8% (n = 153) developed left BBB and 2.17% (n = 119) developed right BBB. Left BBB was associated with increased risk for all-cause death, cardiovascular death, and sudden cardiac death/resuscitated cardiac arrest, whereas right BBB was related to increased risk of sudden cardiac death/resuscitated cardiac arrest. In conclusion, our results confirm and quantify previous observations showing substantially increased mortality in patients with BBB patterns at baseline or occurring soon after AMI.

Mechanisms and clinical significance of transient atrioventricular block during dobutamine stress echocardiography

OBJECTIVES

The purpose of this study was to investigate the possible mechanism and the clinical significance of transient atrioventricular block (AVB) during dobutamine stress echocardiography (DSE).

BACKGROUND

Transient AVB occurs rarely during DSE; however, the mechanisms responsible for blocks are unclear.

METHODS

A retrospective analysis of clinical, echocardiographic, catheterization, revascularization and head-up tilting test data was conducted in patients who developed transient AVB during DSE.

RESULTS

A total of 302 patients with known or suspected coronary artery disease (CAD) underwent DSE before coronary angiography between November 1997 and August 1998. Transient AVB developed in 12 patients during the test. Mobitz I block was noted in six patients and Mobitz II block in the other six patients. Nine of these 12 patients were subsequently shown to have CAD and three had no significant coronary artery stenosis. Mobitz II block was observed only in patients with CAD, while Mobitz I block occurred in three patients with and three patients without CAD (p < 0.05). Eight of the nine patients with CAD underwent a successful coronary angioplasty with or without stenting and a repeat DSE revealed no recurrence of heart block except in one patient. Head-up tilting test in the 12 patients revealed a positive response in three of the nine patients with and all three patients without CAD. A negative head-up tilting test was likely to be observed in patients with, as compared with those without, CAD in this study population (p < 0.05).

CONCLUSIONS

Transient AVB is not an infrequent manifestation during DSE. Both myocardial ischemia and neurally mediated vagal reflex may be responsible for this phenomenon. The development of Mobitz II block during DSE is indicative of the presence of CAD. A successful revascularization in patients with CAD who develop transient AVB may abolish this phenomenon.

Acute myocardial infarction and complete bundle branch block at hospital admission: clinical characteristics and outcome in the thrombolytic era. GUSTO-I Investigators. Global Utilization of Streptokinase and t-PA [tissue-type plasminogen activator] for Occluded Coronary Arteries

OBJECTIVES

We sought to assess the outcome of patients with acute myocardial infarction (MI) and bundle branch block in the thrombolytic era.

BACKGROUND

Studies of patients with acute MI and bundle branch block have reported high mortality rates and poor overall prognosis.

METHODS

The North American population with acute MI and bundle branch block enrolled in the Global Utilization of Streptokinase and t-PA [tissue-type plasminogen activator] for Occluded Coronary Arteries (GUSTO-I) trial was matched by age and Killip class with an equal number of GUSTO-I patients without conduction defects.

RESULTS

Of all 26,003 North American patients in GUSTO-I, 420 (1.6%) had left (n = 131) or right (n = 289) bundle branch block. These patients had higher 30-day mortality rates than matched control subjects (18% vs. 11%, p = 0.003, odds ratio [OR] 1.8) and were more likely to experience cardiogenic shock (19% vs. 11%, p = 0.008, OR 1.78) or atrioventricular block/asystole (30% vs. 19%, p < 0.012, OR 1.57) and to require ventricular pacing (18% vs. 11%, p = 0.006, OR 1.73). Bundle branch block also carried an independent 53% higher risk for 30-day mortality. Thirty-day mortality rates for patients with complete, partial and no reversion of the bundle branch block were 8%, 12% and 20%, respectively (two-tailed chi-square test for trend 5.61, p = 0.02, OR 0.34 for complete reversion, OR 0.55 for partial reversion).

CONCLUSIONS

Bundle branch block at hospital admission in patients with acute MI predicts in-hospital complications and poor short-term survival.

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.

Coronary reperfusion enhances recovery of atrial natriuretic peptide secretion. Salvaging endocrine function in patients with acute right ventricular infarction

BACKGROUND

The heart has been demonstrated not only to be a pumping organ but also an endocrine organ secreting atrial natriuretic peptide (ANP). We hypothesized that myocardial ischemia may affect ANP secretion and that reperfusion therapy for acute myocardial infarction can preserve endocrine function of the heart.

METHODS AND RESULTS

Twenty patients with acute right ventricular infarction were examined who underwent reperfusion therapy on admission. These patients had proximal occlusion of the dominant right coronary artery involving the right atrial branches: 9 patients with successful reperfusion (SRP group) and the remaining 11 patients with unsuccessful reperfusion (URP group). Within 24 hours after the onset of infarction, a volume loading test was performed after reperfusion therapy with measurements for plasma ANP levels and hemodynamics. Before the volume loading test, the plasma ANP level and mean right atrial pressure were similar between these two groups. However, in the URP group, percent increase in ANP in response to volume loading was strikingly smaller (URP, 45 +/- 18% versus SRP, 133 +/- 25%; P < .01) despite similar percent increase in mean right atrial pressure (URP, 100 +/- 46% versus SRP, 86 +/- 23%). The peak ANP level occurred significantly later in the URP group (69 +/- 16 hours) than in the SRP group (28 +/- 9 hours, P < .001) after the onset of infarction.

CONCLUSIONS

The response of ANP release to volume loading is attenuated in patients with right ventricular infarction without coronary reperfusion. However, successful reperfusion induces a rapid recovery of cardiac endocrine function as well as its mechanical function. A sufficiently elevated plasma ANP level may be a useful predictor of hemodynamic improvement in patients with right ventricular infarction.

Rapid hemodynamic improvement in right ventricular infarction after coronary angioplasty

A patient is described where the hemodynamic disturbance caused by a right ventricular infarction was promptly corrected after coronary angioplasty (PTCA). This indicates that reperfusion may be useful in managing hypotension due to predominant right ventricular infarction.