Right axis deviation in acute myocardial infarction. Clinical significance, hospital evolution, and long-term follow-up

Rescue Percutaneous Coronary Intervention for a Lethal "Jailed" Septal Perforator Branch to Resolve Delayed Complete Atrioventricular Block

Delayed complete atrioventricular (AV) block associated with an occluded septal perforator branch (SPB) is an uncommon complication after performing percutaneous coronary intervention (PCI) for the left anterior descending coronary artery (LAD). Here we report the case of a 74-year-old man who underwent elective PCI for proximal LAD complicated with occlusion of the first major SPB and developed a complete AV block 78 hours after PCI was performed. The patient received a temporary transvenous pacemaker via the jugular vein and successfully underwent balloon angioplasty of the lethal "jailed" SPB, resulting in recovery from the complete AV block. Permanent pacemaker implantation was avoided. Our findings indicate the importance of postprocedural monitoring and consideration of rescue PCI for an occluded SPB in cases of complicated AV conduction disturbances.

Tachyarrhythmias, bradyarrhythmias and acute coronary syndromes

The incidence of bradyarrhythmias in patients with acute coronary syndrome (ACS) is 0.3% to 18%. It is caused by sinus node dysfunction (SND), high-degree atrioventricular (AV) block, or bundle branch blocks. SND presents as sinus bradycardia or sinus arrest. First-degree AV block occurs in 4% to 13% of patients with ACS and is caused by rhythm disturbances in the atrium, AV node, bundle of His, or the Tawara system. First- or second-degree AV block is seen very frequently within 24 h of the beginning of ACS; these arrhythmias are frequently transient and usually disappear after 72 h. Third-degree AV blocks are also frequently transient in patients with infero-posterior myocardial infarction (MI) and permanent in anterior MI patients. Left anterior fascicular block occurs in 5% of ACS; left posterior fascicular block is observed less frequently (incidence <0.5%). Complete bundle branch block is present in 10% to 15% of ACS patients; right bundle branch block is more common (2/3) than left bundle branch block (1/3). In patients with bradyarrhythmia, intravenous (IV) atropine (1-3 mg) is helpful in 70% to 80% of ACS patients and will lead to an increased heart rate. The need for pacemaker stimulation (PS) is different in patients with inferior MI (IMI) and anterior MI (AMI). Whereas bradyarrhythmias are frequently transient in patients with IMI and therefore do not need permanent PS, there is usually a need for permanent PS in patients with AMI. In these patients bradyarrhythmias are mainly caused by septal necrosis. In patients with ACS and ventricular arrhythmias (VTA) amiodarone is the drug of choice; this drug is highly effective even in patients with defibrillation-resistant out-of-hospital cardiac arrest. There is general agreement that defibrillation and advanced life support is essential and is the treatment of choice for patients with ventricular flutter/fibrillation. If defibrillation is not available in patients with cardiac arrest due to VTA, cardiopulmonary resuscitation is mandatory.

Post-myocardial infarction intraventricular conduction defects and B-type natriuretic peptide levels

BACKGROUND

Levels of B-type natriuretic peptide (BNP), a significant marker of left ventricular (LV) dysfunction, may provide information on the severity of heart failure in patients with intraventricular conduction defects (IVCD).The aim of this study was to measure serum BNP levels in post-myocardial infarction (MI) patients with IVCD.

METHODS

In 2004-2005 during standard follow-up at 6 mo after acute MI in 158 subjects, BNP was measured using an immunoenzymatic method. Of them, 126 patients had IVCD: 31, left bundle branch block (LBBB); 36, right bundle branch block (RBBB); 30, left anterior hemiblock (LAH); and 29, left posterior hemiblock (LPH). Thirty two patients with a previous MI, but without IVCD, served as controls, whereas 15 healthy subjects entered the comparative group.

RESULTS

In post-MI patients with IVCD, the mean BNP level was significantly higher than in their counterparts without IVCD (p < 0.001) and in healthy subjects (p < 0.001). The highest BNP level was found in patients with LBBB and RBBB. In patients with LAH and LPH, levels of BNP were insignificantly higher than in patients without IVCD.

CONCLUSIONS

Significantly higher BNP levels in patients with previous MI and IVCD suggest more severe heart failure than in their counterparts without IVCD with comparable LV ejection fraction.

Atrial fibrillation associated with exogenous subclinical hyperthyroidism, changing axis deviation, troponin-I positive and without acute coronary syndrome

Changing axis deviation has been rarely reported also during atrial fibrillation or atrial flutter. Changing axis deviation has been also rarely reported during acute myocardial infarction associated with atrial fibrillation or at the end of atrial fibrillation during acute myocardial infarction. Subclinical hyperthyroidism is an increasingly recognized entity that is defined as a normal serum free thyroxine and free triiodothyronine levels with a thyroid-stimulating hormone level suppressed below the normal range and usually undetectable. It has been reported that subclinical hyperthyroidism is not associated with coronary heart disease or mortality from cardiovascular causes but it is sufficient to induce arrhythmias including atrial fibrillation and atrial flutter. It has also been reported that increased factor X activity in patients with subclinical hyperthyroidism represents a potential hypercoagulable state. Serum troponin-I is a sensitive indicator of myocardial damage but abnormal troponin-I levels have been also reported without acute coronary syndrome and without cardiac damage. Abnormal troponin-I levels after supraventricular tachycardia have been also reported. We present a case of changing axis deviation in a 49-year-old Italian man with atrial fibrillation, exogenous subclinical hyperthyroidism and troponin-I positive without acute coronary syndrome. Also this case focuses attention on changing axis deviation, on subclinical hyperthyroidism and on the importance of a correct evaluation of abnormal troponin-I levels.

Laboratory screening prior to ECT

INTRODUCTION

Screening for occult disease using laboratory testing prior to electroconvulsive therapy (ECT) is a common practice with little empirical support.

METHOD

In a pre-ECT and post-ECT sample of 73 and 562 (respectively) patients evaluated for ECT, the utility of the electrocardiogram, serum sodium, serum potassium, serum creatinine, chest radiograph, hemoglobin level, and white blood cell count was examined.

RESULTS AND DISCUSSION

Reviewing the electrocardiogram and measuring sodium and potassium levels prior to the administration of ECT appear to be useful screening tests because they detect correctable unexpected conditions that are relevant to the risk of the procedure. Hemoglobin and white blood cell count abnormalities did not influence the administration of ECT or predict ECT complications. An abnormal creatinine level or abnormal chest radiograph prior to the administration of ECT predicted a poor medical prognosis that appeared largely unrelated to the administration of ECT.

Transient right axis deviation during acute anterior wall infarction or ischemia: electrocardiographic and angiographic correlation

Eleven patients, three with acute anterior myocardial infarction and eight with anterior ischemia, who developed transient right axis deviation with a left posterior hemiblock pattern during the acute phase of myocardial infarction or ischemia are described (study group). A correlation between their electrocardiographic pattern and the angiographic findings was made. The arteriographic findings were compared with those of a group of 24 patients with acute anterior myocardial infarction or ischemia without transient right axis deviation (control group). The main electrocardiographic characteristics of the right axis deviation pattern were: an average shift of the mean frontal axis to the right of 42 degrees (10 degrees to 94 degrees); increased voltage of R waves in leads II, III and a VF and appearance of small Q waves or decreased voltage of Q waves if previously present in the same leads; decreased voltage of R waves and appearance of deep S waves in lead aVL; and inverted T waves and isoelectric ST segments in leads II, III and aVF. Coronary angiography revealed that the study group had a higher incidence of significant right coronary artery obstruction and collateral circulation between the left coronary system and the posterior descending artery than did the control group (100 versus 25% and 73 versus 0%, respectively; p less than 0.01). There were no differences between the groups regarding left anterior descending and circumflex artery disease.(ABSTRACT TRUNCATED AT 250 WORDS)