\s=b\Obesity has been documented to be an independent risk factor for sudden death and other cardiovascular mortality. The present study was designed to monitor and quantify cardiac arrhythmias in obese subjects with and without eccentric left ventricular hypertrophy, who were matched with regard to arterial pressure, age, sex, and height with lean subjects. Prevalence of premature ventricular (but not atrial) contractions was 30 times higher in obese patients with eccentric left ventricular

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... ertrophy compared with lean subjects. Similarly, obese patients with left ventricular hypertrophy scored higher with regard to the classification of Lown and Wolf than those without left ventricular hypertrophy and lean subjects having the same level of arterial pressure. Patients' class in the Lown and Wolf system correlated with ventricular diastolic diameter and left ventricular mass. Thus, heart enlargement of the eccentric type as a consequence of obesity predisposes to excessive ventricular ectopy. Echocardiographic assessment and electrocardiographic monitoring allow us to identify the patients who are at highest risk of more serious arrhythmias or possibly sudden death and to subject them to the most specific preventive and therapeutic measures. (Arch Intern Med 1987;147:1725-1728 l\/Tore than half a century ago Smith and Willius at the '-1-Mayo Clinic attempted to untangle the cardiac effects of obesity from those of hypertension.2 They reported average normal heart weight values of 272 g in their autopsy study compared with heart weights averaging 376 g in obese subjects with no evidence of other cardiovascular disease and 467 g in subjects who were both obese and hypertensive.2 We recently showed that cardiac adaptation to obesity results in cardiac hypertrophy of the eccentric type, ie, an increase in myocardial mass combined with chamber dilatation.3 5 In contrast, left ventricular hypertro¬ phy as a consequence of longstanding hypertension is most often of the concentric type, ie, an increase in myocardial mass at the expense of chamber volume.5"8 Concentric left ventricular hypertrophy has been documented to give rise to increased ventricular ectopy and to put the patient at risk for more serious arrhythmias.9"11 Indeed, data from the Framingham cohort identify left ventricular hypertrophy as a pressure-independent risk factor for sudden death and other cardiovascular mortality.12 However, since the Fra¬ mingham Study also established that obesity per se in¬ creases the risk of dying suddenly,1314 we wondered whether 24-hour electrocardiographic monitoring would allow us to identify those patients with cardiopathy of obesity who are at the highest risk. The present study was designed to monitor and quantify cardiac arrhythmias in obese subjects with and without eccentric left ventricular hypertrophy who were matched with regard to arterial pressure, age, and sex with the same number of lean subjects. PATIENTS AND METHODS The study population consisted of a total of 53 patients, of whom 24 were lean and 29 obese with uncomplicated established essential hypertension. Patients were classified as obese when their body weight exceeded 150% of the ideal weight and as lean when they were less than 105% of the ideal weight according to the Metro¬ politan Insurance Weight Tables.15 Established essential hyper¬ tension was said to be present if diastolic pressures measured in the outpatient department were consistently higher than 90 mm Hg. All patients had appropriate clinical and laboratory evaluation to exclude secondary forms of hypertension. We also excluded patients with coronary artery disease or other organic heart disease as evidenced by clinical criteria and, when indicated, by exercise testing and/or thallium scintigraphy. Antihypertensive therapy was discontinued at least four weeks before the study. All patients provided informed consent to the protocol which was previously approved by our institution's review committee. Obese patients were enrolled into the study in a prospective, randomized way. Only patients with uncomplicated moderately severe obesity in whom a good echocardiographic window was obtained were included. According to echocardiographic criteria, obese patients were further subdivided into a group with and one without eccentric left ventricular hypertrophy. Eccentric left ventricular hypertrophy was said to be present if posterior wall thickness exceeded 1.1 cm and the left ventricular internal diame¬ ter was greater than 5.0 cm. Both obese patient groups were matched with regard to systolic, diastolic, and mean arterial pressure with 24 lean subjects who were selected from our investigational data bank. The match also took age, sex, and race of the three patient groups into consideration. Electrocardiographic tracings were recorded during one 24-hour period starting and ending at 9 am, as previously described.16 Each tape was initially scanned at high speed and subsequently reviewed for a detailed analysis by two independent investigators. Left ventricular function and structure were assessed by M-mode