Short-term outcome of acute inferior wall myocardial infarction with emphasis on conduction blocks: a prospective observational study in Indian population

OBJECTIVE

The primary aim of the present study was to evaluate the complications, particularly conduction blocks, subsequent morbidity and mortality, and effect of thrombolytic therapy in Indian patients with inferior wall myocardial infarction (IWMI).

METHODS

This was a prospective, observational, single-center study conducted at LPS Institute of Cardiology, Kanpur, from December 2011 to May 2014. Patients who presented with typical chest pain and were subsequently diagnosed by standardized diagnostic criteria as having IWMI were enrolled. Patients were grouped on basis of conduction abnormalities, right ventricular (RV) infarction and thrombolytic treatment. Each group was analyzed for comparison of complication profile and mortality.

RESULTS

Of 573 patients with IWMI enrolled in the study (mean age: 58.90±12.3 years), 81.2% were male, 225 (39.3%) had conduction blocks, and 189 (32.9%) had RV infarction. In patients with conduction blocks, mortality occurred in 27 patients (12.0%) in contrast to 3.4% of patients without conduction block (p<0.03). Also, there were 27 cases of in-hospital mortality in patients with RV infarction compared with 9 cases in patients without RV infarction (p<0.01). Thrombolytic therapy significantly reduced mortality in patients with IWMI (p<0.001). A significant reduction was observed in cardiogenic shock (p=0.002), severe mitral regurgitation (p=0.007), and left ventricular failure (p<0.001) in patients undergoing thrombolytic therapy.

CONCLUSION

In Indian patients with IWMI, incidence of conduction blocks was higher than previously reported studies. Major complications such as atrioventricular block and RV infarction are associated with increased mortality and poor clinical outcomes. Thrombolytic therapy has a beneficial role in reduction of mortality rate and other complications.

ST-Segment Elevated Acute Myocardial Infarction: Changing Profile Over Last 24 Years

BACKGROUND

Coronary artery disease (CAD) is rising in epidemic proportions with India not being an exception. CAD in Indian scenario has its onset at a younger age with multitude of risk factors.

OBJECTIVE

This study was carried out to obtain complete information about demographic profile, risk factors, clinical scenario, therapeutic modalities, natural course, outcome and changing profile of acute ST-segment elevated myocardial infarction (STEMI) patients.

METHODS

This cross-sectional study was conducted in 45,122 acute STEMI patients admitted 1st March 1990 to 1st March 2014. A predefined performa was completed in every patient with detailed clinical history, physical examination, laboratory and investigation parameters, therapeutic interventions and inhospital outcome.

RESULTS

Our population cohort presented with STEMI at age of 56.34±11.88 years with 82.48% male. Urban residency (64.35%), lower level of education (61.03%), middle and low socioeconomic status (81.01%), unemployment (56.47%), lack of exercise (78.80%) and poor dietary pattern including low intake of fruits and vegetables (58.80%) were pivotal players. Smoking was prevalent in 48.80% cases, with overweight and obesity (51.11%), diabetes mellitus (27.34%), hypertension (38.85%), hyperlipidemia (28.15%), alcoholism (28.80%) and family history (16.66%). Our population had mildly elevated LDL (101.4±33.38 mg/dl), low HDL (36.6±10.7 mg.dl) and high TC/HDL ratio (4.05±1.36). Majority harbored (52.06%) two or more risk factors, while in 16.60% no conventional risk factors were identified. Anterior wall STEMI (56.78%) far exceeded the inferior wall (37.55%). Less than half (47.77%) presented within the window period of 12 hours while only 0.8% of patients availed the golden period of 1 hour. 50.27% presented in Killip Class II or beyond. Angiography revealed single vessel disease (46.76%) with LAD involvement being most common (58.85%). Thrombolytic therapy was provided in 38.95% and primary PCI in 2.1%. Complications in the form of CHF (34.7%), cardiogenic shock (8.65%), reinfarction (6.5%), arrhythmia (59.2%) and mortality (10.57%) were seen. Mortality decreased from 13.9% (from 1990-2000) to 8.8% (2000-2014).

CONCLUSIONS

With recent increased use of β-blocker, ACEI/ARB, aldosterone antagonist and reperfusion strategy, we have brought down the mortality to lower level.

Clinical and angiographic findings of complete atrioventricular block in acute inferior myocardial infarction

INTRODUCTION

The angiographic findings and prognosis of patients with complete atrioventricular block (AVB) complicating acute inferior myocardial infarction (MI) remain unclear.

MATERIALS AND METHODS

The clinical and angiographic findings of 70 consecutive patients with complete AVB were compared with those of 319 patients with inferior MI without AVB (control group) admitted within the same study period.

RESULTS

Patients with complete AVB were older (68 +/- 12 vs 63 +/- 13 years; P = 0.004) and clustered with clinical features indicative of larger infarct size, such as right ventricular infarction, cardiogenic shock, or low left ventricular ejection fraction (LVEF). The onset of the complete AVB was observed within 24 hours in 62 (88.6%), preceded by second-degree AVB in 26 (37.1%) and the escape QRS complex was wide in 8 (11.4%) patients. In patients with complete AVB, a dominant right coronary artery occlusion was found in >95% of cases and in-hospital mortality was increased (27.1% vs 10.7%; P = 0.000), especially in those with widen QRS escape rhythm (75.0%). Reperfusion therapy had a positive impact on the natural course of complete AVB.

CONCLUSIONS

Complete AVB in acute inferior MI was associated with advanced age and larger infarct size. Complete AVB was virtually always caused by dominant right coronary artery occlusion. The in-hospital mortality was significantly higher, but improved by reperfusion therapy. No permanent pacemaker is performed at a mean follow-up of 47 months.