BRIEF REPORTS

Atrial

Fibrillation

in Inferior

Wall Q-Wave Acute Myocardial

Infarction

Tetsuro Sugiura, MD, Toshiji Iwasaka, MD, Nobuyuki Takahashi, MD, Seishi Nakamura, MD, Hiroya Taniguchi, MD, Yo Nagahama, MD, Masahide Matsutani, MD, and Mitsuo Inada, MD

lthough atria1 fibrillation (AF) is a relatively common arrhythmia oxxu-ring during the course of acute myocardial infarction (AMI), the mechanismsinvolved in its genesisremain controversial and are mostly focused on the left ventricle and atrium: left ventricular failure, pericarditis and left atrial ischemia.1-4 In contrast, the role of hemodynamic change imposed on the right ventricle and right atrium related to the onset of AF after AM1 is poorly understood. Becausehemodynamic changeof the right ventricle is often observedin inferior AMI, we hypothesized that hemodynamic impairment, audible pericardial friction rub, electrocardiographic evidenceof right ventricular AM1 and age may be important clinical factors associated with the occurrenceof AF. In this study, multivariate analysis was used to assessthe clinical settings associatedwith the Occurrenceof AF in patients with their first Q-wave inferior AMI.

A

We studied 161 consecutive patients after Q-wave inferior AMI who fulfilled the following criteria: (1) admitted to the coronary care unit within 24 hours from the onset of chest pain and survived the first 3 days after admission; (2) no history of AMZ, chronic renal failure, collagen disease, cardiac surgery within the previous 6 months or metastatic disease; (3) normal thyroid function; and (4) sinus rhythm without intraventricular conduction defect at the time of admission. In our hospital, it is routine to insert a SwanGanz catheter into patients with an AMI admitted within 24 hours from the onset of chest pain. All patients were examined by a physician and written informed consent was received before the Swan-Cam catheter insertion. The diagnosis of inferior AMI was made when patients had ST elevation with new Q waves (ZZ, III and aVF) on serial electrocardiograms and at least twice the normal elevation in serum creatine kinase with MB isoenzyme 25%. At least 1 mm of STsegment elevation and QS or QR intervals in the right precordial lead ( VdR) at the time of admission were considered diagnostic of right ventricular AM1.j All patients were monitored continuously in the coronary From the Coronary Care Unit, the Second Department of Internal Medicine, Kansai Medical University, 1 Fumizonc-cho Moriguchi City, Osaka, Japan 570. Manuscript received December 31, 1990; revised manuscript received and accepted February 11, 199 1.

care unit and AF was observed or triggered by the rate-dependent alarm system. AF was defined electrocardiographically by fine, irregular atria1 waves associated with irregular RR intervals. All patients were examined by careful auscultation at least twice daily. Pericardial friction rub was considered as a toand-fro, scratchy or grating noise heard in systole, mid-diastole and before systole or during any one of these phases: the diagnosis of pericardial friction rub was made after confirmation by at least 2 cardiologists. A pericardial friction rub recognized as such during the first 3 days after admission was considered diagnostic of acute pericarditis. Pulmonary artery wedge and mean right atria1 pressures were determined at least once every 4 hours, and cardiac output was measured every 12 hours. Hemodynamic measurements were evaluated just before the first episode of AF, whereas the lowest cardiac output and highest pulmonary artery wedge and mean right atria1 pressures were recorded during the first 3 days in patients without AF. Two-dimensional and M-mode echocardiography were performed with an SSD 870 phased-array sector scanner (Aloka, Tokyo). All classic views were recorded on videotape for subsequent analysis by observers unaware of the patients’ clinical data. Regional left ventricular wall motion abnormalities were assessed by 2-dimensional echocardiography obtained on the third day of hospitalization. Analysis of the left ventricular wall was performed with 11 segments obtained by long- and short-axis images,6 and the number of segments with advanced asynergy (akinesia or dyskinesia) was calculated. A coronary arteriogram was recorded before hospital discharge. Coronary artery lesions with 270% reduction in diameter were considered to be obstructive. Each patient was classified as having I-, 2- or 3vessel disease. The proximal right coronary artery lesions were located before the acute marginal branch and the proximal left circumflex artery was located before the obtuse marginal branch. Results are reported as mean f standard deviation. Student’s t test was used for quantitative data, and chi-square analysis for qualitative data. Logistic regression analysis was used to evaluate the important variables related to the occurrence of AF. The

BRIEF REPORTS

1135

TABLEI

Comparison of Seven Variables

Age (years) Cardiac output (liters/min) Pulmonary artery wedge pressure (mm Hg) Mean right atrial pressure (mm Hg) Asynergic segments Pericardial rub 0 Right ventricular infarction AF = atrml fibrillation;

AF Group (n = 28)

Non-AF Group (n = 133)

68f 10

64kll

4.11 f 1.08 12*4

3.0f 1.7

NS

4.76 f 1.42 lOf5

5f4

9f4

p Value

2.3f 1.5 113

+

18 10

0 +

15 13

105

Atrial fibrillation in inferior wall Q-wave acute myocardial infarction.

BRIEF REPORTS Atrial Fibrillation in Inferior Wall Q-Wave Acute Myocardial Infarction Tetsuro Sugiura, MD, Toshiji Iwasaka, MD, Nobuyuki Takahas...
256KB Sizes 0 Downloads 0 Views