Right ventricular alterations in scuba divers: findings on electrocardiography and echocardiography.

BACKGROUND: Scuba diving imposes uncommon environmental stresses. This study assesses the effects of recreational scuba diving on the electrocardiogram (ECG) and echocardiogram and compares them with those of normal controls. METHODS: We studied 50 recreational scuba divers and 50 age-matched and sex-matched normal control subjects. Each subject had a medical history, physical examination, resting 12-lead ECG, and transthoracic echocardiogram. RESULTS: Electrocardiographic findings occurring significantly more frequently in scuba divers than in controls were sinus bradycardia, sinus arrhythmia, QRS duration (> or = 0.10 sec, right axis duration and R > or =S in V2. The mean right ventricular internal dimension (RVID) was significantly larger in divers than in controls. High-normal RVID (2.0 to 2.3 cm) occurred significantly more regularly in divers than in controls (10 vs 1). CONCLUSION: Recreational scuba diving produced right ventricular alterations characterized by chamber dilation and electrocardiographic signs of right ventricular hypertrophy, sinus bradycardia, and arrhythmia.

Relation of occupation to presence or absence of coronary artery disease: an angiographic study.

To determine the relation of occupation to the presence or absence of coronary artery disease (CAD) and cardiovascular risk factors, the authors compared the occupations of a series of 116 consecutive patients who underwent coronary angiography and were found to have normal or near-normal coronary arteries (< 30% stenosis of all major coronary arteries) with those of a series of 116 patients with moderate to severe CAD (> or = 60% stenosis of one or more major coronary artery). The usual lifetime occupational status of each study participant was classified as sedentary, intermediate, or strenuous. The presence of the usual cardiovascular risk factors in the patients was also recorded. There was no significant difference in the frequency of the three occupational categories between the two groups (those with or without CAD) when subjects of all ages were considered or when subjects less than 40 years or more than 60 years old were considered. However, the results indicate that among 40-60-year-old individuals CAD occurred significantly more frequently in those engaged in strenuous occupations than in those engaged in sedentary occupations. Cardiovascular risk factors occurred significantly more frequently in patients with CAD than in those with normal coronary arteries and in those engaged in strenuous occupations compared with those in sedentary occupations.

Coronary artery slow flow associated with angina pectoris and hypotension--a case report.

A 56-year-old woman with a history of angina pectoris developed substernal chest pressure and hypotension during coronary angiography. Her baseline coronary angiogram appeared normal. During this episode, injection of contrast medium into the left coronary artery demonstrated coronary artery slow flow in the left anterior descending artery and branches of the circumflex coronary artery, which normalized following the sublingual administration of nitroglycerin. There were no focal areas of coronary artery spasm. This phenomenon may represent a heretofore undescribed mechanism for myocardial ischemia and its sequelae.

Diminished short-term heart rate variability predicts inducible ventricular tachycardia.

PURPOSE: The purpose of this study is to determine whether short-term heart rate variability (HRV) can be used successfully to predict inducible ventricular tachycardia (VT). METHODS: A high-speed (300 mm/s) electrocardiographic recording was obtained in 32 patients in the supine position prior to programmed ventricular stimulation. Beat-to-beat RR intervals (in milliseconds) were derived from an 11-beat strip (10 RR intervals). Logistic regression was used to study the relationship between several variables and a dichotomous dependent variable (inducible, clinical, or electrocardiographic evidence of VT). RESULTS: Of 32 patients, 12 had inducible VT (inducible VT group) and 20 had no clinical or electrocardiographic evidence of VT (control group). Mean short-term HRV values were significantly lower in those with inducible VT than in the control group in all patients (25+/-15 ms, n=12 vs 67+/-22 ms, n=20; p<0.0001) and in patients with coronary artery disease or congestive heart failure or both (22+/-13 ms, n=11 vs 63+/-23 ms, n=11; p<0.0001). For the group as a whole, short-term HRV was < or =50 ms in 11 of 12 patients (92%) with inducible VT, but was < or =50 ms in only 3 of 20 control subjects (15%; p<0.001). As a result of a stepwise selection procedure conducted within the logistic regression, only the short-term HRV was found to be predictive of inducible VT (p<0.0001). CONCLUSION: Short-term HRV is significantly lower in subjects with inducible VT than in those without clinical or electrocardiographic evidence of VT. The probability of developing sudden death increases substantially when short-term HRV decreases below 50 ms.

Cardiac morphology and left ventricular function in normotensive morbidly obese patients with and without congestive heart failure, and effect of weight loss.

To assess cardiac morphology and left ventricular (LV) function in normotensive morbidly obese patients with and without congestive heart failure (CHF) we performed a physical examination and obtained a transthoracic echocardiogram and cardiac Doppler studies before and after substantial weight loss in patients whose actual body weight was initially equal to or more than twice their ideal body weight and who were free from systemic hypertension and underlying organic heart disease. There were 24 patients with CHF, 14 of whom were studied after weight loss. There were 50 patients without CHF, 39 of whom were studied after weight loss. Compared to patients without CHF, those with CHF had significantly greater mean LV internal dimension in diastole, LV end-systolic wall stress, LV mass/height index values, left atrial dimension and right ventricular internal dimension values, significantly lower mean LV fractional shortening, and transmitral Doppler E/A ratio values, and significantly longer mean transmitral E-wave deceleration time and duration of morbid obesity than patients without CHF. Substantial weight loss in those with and without CHF produced comparable reductions in mean LV internal dimension in diastole, LV end-systolic wall stress, LV mass/height index, transmitral Doppler E-wave deceleration time, and left atrial dimension, and comparable increases in LV fractional shortening and transmitral Doppler E/A ratio. Linear regression analysis identified duration of morbid obesity as the strongest predictor of CHF (p <0.00000002). Thus, LV mass is greater and LV systolic function and diastolic filling are more impaired in normotensive morbidly obese subjects with CHF than in those without CHF. Duration of morbid obesity is the strongest predictor of CHF among the variables studied. Substantial weight loss produces comparable changes in cardiac morphology and function in those with and without CHF.

Relation of duration of morbid obesity to left ventricular mass, systolic function, and diastolic filling, and effect of weight loss.

Longer duration of morbid obesity is associated with higher LV mass, poorer LV systolic function, and greater impairment of LV diastolic filling. Weight loss-induced decreases in LV mass and improvements in LV systolic function and diastolic filling are due in part to favorable alterations in LV loading conditions.

Influence of left ventricular mass on left ventricular diastolic filling in normotensive morbid obesity.

To identify factors influencing left ventricular (LV) diastolic filling in patients with morbid obesity, we performed transthoracic and Doppler echocardiography on 50 subjects whose actual body weight was > or = twice their ideal body weight and on 50 normal lean control subjects. The transmitral Doppler E/A ratio and E wave deceleration half-time were used to assess LV diastolic filling. Significant negative correlations were seen between the E/A ratio and the LV internal dimension in diastole (r = 0.819, p = 0.0001), systolic blood pressure (r = 0.751, p = 0.0001), LV end-systolic wall stress (r = 0.782, p = 0.0001), and LV mass/height index (r = 0.901, p = 0.0001). Significant positive correlations were seen between the E wave deceleration half-time and the LV internal dimension in diastole (r = 0.743, p = 0.0001), systolic blood pressure (r = 0.789, p = 0.0001), LV end-systolic wall stress (r = 0.828, p = 0.0001), and LV mass/height index (r = 0.831, p = 0.0001). No correlation was seen between diastolic blood pressure and either index of LV diastolic filling. Thus increasing LV mass is associated with progressive impairment of LV diastolic filling in morbidly obese individuals. The aforementioned alterations in LV loading conditions may contribute to impairment of LV diastolic filling directly or by increasing LV mass.

Interrelationship of left ventricular mass, systolic function and diastolic filling in normotensive morbidly obese patients.

OBJECTIVE: To determine the interrelationship of left ventricular (LV) mass, systolic function and diastolic relaxation in morbidly obese subjects. METHOD: We obtained echocardiograms (M-mode, two dimension) and cardiac Doppler studies (pulse wave, continuous wave colour flow) on 50 subjects whose actual body weight was > or = twice ideal body weight. LV mass/height index was calculated from echocardiographic data (Penn Convention). LV systolic function was assessed by calculating LV fractional shortening. LV diastolic filling was assessed by measuring the transmitral Doppler E/A ratio and the transmitral E wave deceleration time. RESULTS: There were significant positive correlations between LV mass/height index and the LV internal dimensions in diastole, systolic blood pressure, LV end-systolic wall wall stress and the transmitral E wave deceleration time. There were significant negative correlations between LV mass/height index and both LV fractional shortening and the transmitral Doppler E/A ratio. There were significant negative correlations between LV fractional shortening and the LV internal dimension in diastole, systolic blood pressure LV end-systolic wall stress and the transmitral E wave deceleration time. There was a significant positive correlation between LV fractional shortening and the transmitral Doppler E/A ratio. There were significant positive correlations between the transmitral E wave deceleration time and LV internal dimension in diastole, systolic blood pressure and LV end-systolic wall stress. There were significant negative correlations between the transmitral Doppler E/A ratio and the aforementioned variables. CONCLUSIONS: Unfavourable alterations in LV loading conditions contribute to the development of LV hypertrophy and impairment systolic dysfunction in morbidly obese subjects. Increasing LV mass and altered loading conditions may synergistically contribute to impairment of LV diastolic filling in such individuals.

The prevalence of rheumatologic disorders in patients with chest pain and angiographically normal coronary arteries.

The purpose of this study was to determine the prevalence of musculoskeletal disorders in patients with chest pain and angiographically normal coronary arteries. The authors studied 40 consecutive patients with chest pain presenting at an Internal Medicine Clinic who had undergone coronary angiography and were found to have < 30% stenosis of all major coronary arteries. Patients with any known noncardiac cause of chest pain were excluded from the study. Each patient underwent a complete rheumatologic examination with x-rays and blood tests when indicated. The diagnosis of fibromyalgia was based on the presence of at least eight paired tender points. The diagnosis of costochondritis was made when palpation of the costal cartilages elicited tenderness. In the normal coronary artery group, 30% of the patients had fibromyalgia and 10% had costochondritis. In the control group of 40 patients with coronary artery disease, only 1 patient had fibromyalgia and none had costochondritis (P < 0.04). Other rheumatologic disorders were uncommon, with no statistical difference between the two groups. The authors conclude that many patients with chest pain and angiographically normal coronary arteries suffer from rheumatologic disorders with fibromyalgia being the most common.

Pathogenesis, recognition, and management of common cardiac arrhythmias. Part I: Ventricular premature beats and tachyarrhythmias.

Cardiac arrhythmias are disorders of impulse formation, impulse conduction, or both. Part I of this two-part review discusses clinically relevant cardiac electrophysiology, as well as the pathogenesis, recognition, and management of ventricular premature beats and ventricular tachyarrhythmias. Part II will review the pathogenesis, recognition, and management of supraventricular premature beats and supraventricular tachyarrhythmias.

Pharmacotherapy of chronic pulmonary arterial hypertension: value and limitations. Part II: Secondary pulmonary hypertension.

Part I of this review discussed pharmacotherapy of primary pulmonary hypertension (PHT). Part II describes the value and limitations of oxygen and vasodilator therapy of secondary PHT, focusing on patients with PHT associated with selected connective tissue disease and chronic nonthrombotic hypoxic lung disease.

Pharmacotherapy of chronic pulmonary arterial hypertension: value and limitations. Part I: Primary pulmonary hypertension.

Efforts aimed at assessing pharmacotherapy of pulmonary arterial hypertension (PHT) have largely focused on patients with primary PHT, PHT associated with selected connective tissue diseases, and various forms of hypoxic secondary PHT. Part I of this review discusses the value and limitations of a wide variety of vasodilator drugs, oxygen, and warfarin in the treatment of primary PHT with special reference to their effects on pulmonary and systemic hemodynamics, functional capacity, and survival.

Factors influencing left ventricular systolic function in nonhypertensive morbidly obese patients, and effect of weight loss induced by gastroplasty.

Heart rate and blood pressure were measured, and echocardiography was performed in 39 patients whose actual body weight was greater than twice their ideal body weight to identify factors influencing left ventricular (LV) systolic function in morbidly obese patients and assess the effect of weight loss on LV systolic function. Patients were studied before and after weight loss induced by gastroplasty. The study cohort was 133 +/- 8% overweight before weight loss and 39 +/- 7% overweight at the nadir of weight loss. Before weight loss, LV fractional shortening varied inversely with LV internal dimension in diastole (an indirect index of preload), LV end-systolic wall stress and systolic blood pressure (indexes of afterload). The weight loss-induced change in LV fractional shortening varied directly with the pre-weight loss LV internal dimension in diastole, LV end-systolic wall stress and systolic blood pressure, and inversely with the pre-weight loss LV fractional shortening. The weight loss-induced change in LV fractional shortening varied inversely with the weight loss-induced changes in LV end-systolic stress and systolic blood pressure. In patients with reduced LV fractional shortening (n = 14), weight loss produced a significant increase in LV fractional shortening that was accompanied by a significant decrease in LV internal dimension in diastole, LV end-systolic stress and systolic blood pressure. The results suggest that LV loading conditions have an important role in determining LV systolic function in morbidly obese patients. Improvement in LV systolic function in these patients is closely related to weight loss-induced alterations in LV loading conditions.

Chest pain and angiographically normal coronary arteries. Implications for treatment.

Approximately 20% to 30% of patients who undergo coronary arteriography for the evaluation of chest pain are found to have normal coronary arteries. These patients have a survival rate comparable to that of the normal population, yet they continue to complain of symptoms on extended follow-up, and about half of this group are disabled on account of chest pain. Once other clinically obvious disorders have been ruled out, common diagnostic considerations include microvascular angina, esophageal dysfunction, and perhaps fibromyalgia. Panic disorder, however, is the most common condition affecting these patients and can be diagnosed in at least one third of the group, with or without the presence of the other conditions mentioned. Appropriate diagnosis and treatment can reduce the psychosocial morbidity so frequently seen in these patients.

Substrate use by elderly men during walking and low-sit cycling.

To compare the cardiovascular and metabolic responses to different exercise modes, ten healthy, elderly men (aged 71.4 +/- 4.2 yr) walked and cycled in the low-sit position for 15 min each at 70% of peak heart rate. Fifteen minutes of recovery separated the exercise bouts. Analysis of expired air was used to calculate oxygen consumption (VO2), respiratory exchange ratio (RER), O2 pulse, total energy expenditure (TE) and fat oxidation (FO). Ratings of perceived exertion (RPE) were recorded for both legs and breathing. Each subject maintained similar heart rates on each of the exercise bouts (mean = 108 beats.min-1). No significant differences were found in VO2, O2 pulse and TE. RPE's were significantly lower during walking than cycling (P < 0.05). FO was 42% higher during walking than cycling (P < 0.05). These results suggest that although the cardiovascular response and TE use during these two modes are similar, elderly men burn more fat during walking than low-sit cycling.