Hemodynamic effects of intravenous amiodarone.

Amiodarone is a potent antiarrhythmic agent that is effective in controlling both atrial and ventricular arrhythmias. Recently, intravenous administration was demonstrated to be effective in the acute management of rhythm disorders and, in addition, appeared to shorten the loading period normally required for oral drug administration. This investigation examined the hemodynamic effects of amiodarone after both acute intravenous bolus and continuous intravenous administration. Patients with a left ventricular ejection fraction greater than 0.35 experienced improved cardiac performance due to both acute and chronic peripheral vasodilation. However, patients with a lower ejection fraction developed a 20% decrease in cardiac index and clinically significant elevation of right heart pressures after acute bolus administration; these changes were variably compensated for by peripheral vasodilation when the drug was administered intravenously over 3 to 5 days continuously. Therefore, intravenous amiodarone can result in significant impairment of left ventricular performance in patients with preexisting left ventricular dysfunction.

Application of the ambulatory 24-hour electrocardiogram in the prediction of cardiac death in dialysis patients.

The value of a 24-hour ambulatory electrocardiogram (AmECG) in assessing the risk of cardiac death was studied in 122 stable-condition dialysis patients followed up from two to six years after monitoring. An abnormal AmECG was defined by second-degree or greater AV block or by Lown grade 3 or greater ventricular ectopy. The incidence of cardiac mortality or an abnormal AmECG was not influenced by hypokalemia or beta-blockers. Digitalis was associated with both an abnormal AmECG and a twofold increase in mortality whether or not the AmECG was normal. Cardiac mortality accounted for 26 of 33 deaths within the first year after the AmECG. In the absence of coronary artery disease, survival at six months was 100% in patients with normal AmECG vs 90% (abnormal AmECG). In the presence of coronary artery disease, survival at six months was 83% (normal AmECG) vs 54% (abnormal AmECG).

Decreased insulin requirement in acute renal failure in diabetic nephropathy.

Twelve of 13 diabetics with azotemic nephropathy experienced exacerbation of renal failure and decreased insulin requirement after coronary angiography utilizing radiographic contrast material. The single patient who did not develop acute renal failure had no evidence of decreased insulin requirement. Eleven of 12 patients had decreased insulin requirement: mean decrement in insulin dose, 40%; mean decrement in fasting blood glucose level, 33%; mean decrement in peak blood glucose level, 42%. The 12th patient underwent peritoneal dialysis against hypertonic glucose without need of an increased insulin dose. Eight of 11 patients experienced a total of 19 insulin reactions; one patient was hypoglycemic continuously, despite infusion of glucose and discontinuation of insulin. The decrement of insulin requirement was not proportional to the rise in either serum creatinine or potassium concentrations. We suggest that when acute renal failure occurs in diabetics, decreased insulin requirement should be anticipated and the insulin dose lowered.

Improving survival after renal transplantation for diabetic patients with severe coronary artery disease.

After successful renal transplantation, seven diabetic renal failure patients with severe coronary artery disease returned to productive employment. Despite the requirement for additional peripheral vascular or ophthalmologic surgery in four patients, their renal function remained adequate. Following transplantation, diabetic complications included angina in three, myocardial infarction in three, and cerebrovascular accident in two patients. Two patients with adequate renal function died suddenly at 29 and 62 mo. Despite severe coronary artery disease, an increasing number of diabetic dialysis patients may be able to return to work after a successful kidney transplant.

Usefulness of dipyridamole-thallium-201 perfusion scanning for distinguishing ischemic from nonischemic cardiomyopathy.

To determine noninvasively the etiology of left ventricular (LV) dysfunction, 22 patients with a diagnosis of cardiomyopathy determined via cardiac catheterization and 5 normal control subjects underwent radionuclide ventriculography and intravenous dipyridamole-thallium-201 perfusion scanning. Both ischemically and nonischemically induced LV dysfunction had comparable global LV ejection fractions (24 +/- 6 vs 23 +/- 8%, respectively) and extent of segmental wall motion abnormalities. Right ventricular ejection fraction was significantly better in the group with an ischemic etiology of LV dysfunction (41 +/- 26 vs 13 +/- 10%, p less than 0.005) but significant group overlap was present. However, computer-assisted analysis of dipyridamole-thallium-201 myocardial perfusion scanning demonstrated more homogeneous myocardial perfusion in idiopathic cardiomyopathy (mean perfusion defect 25 +/- 11 vs 6 +/- 6%, p less than 0.001) and successfully predicted the correct etiology of LV dysfunction in 20 of 22 (91%) patients.

Magnitude and determinants of coronary artery disease in juvenile-onset, insulin-dependent diabetes mellitus.

The risk of premature coronary artery disease (CAD) and its determinants were investigated in a cohort of 292 patients with juvenile-onset, insulin-dependent diabetes mellitus (IDDM) who were followed for 20 to 40 years. Although patients with juvenile-onset IDDM had an extremely high risk of premature CAD, the earliest deaths due to CAD did not occur until late in the third decade of life. After age 30 years, the mortality rate due to CAD increased rapidly, equally in men and women, and particularly among persons with renal complications. By age 55 years the cumulative mortality rate due to CAD was 35 +/- 5%. This was far higher than the corresponding rate for nondiabetic persons in the Framingham Heart Study, 8% for men and 4% for women. Angina and acute nonfatal myocardial infarction followed a similar pattern, as did asymptomatic CAD detected by stress test, so that their combined prevalence rate was 33% among survivors aged 45 to 59 years. Age at onset of IDDM and the presence of eye complications did not contribute to risk of premature CAD. This pattern suggests that juvenile-onset diabetes and its renal complications are modifiers of the natural history of atherosclerosis in that although they profoundly accelerate progression of early atherosclerotic lesions to very severe CAD, they may not contribute to initiation of atherosclerosis.

Discordance of exercise thallium testing with coronary arteriography in patients with atypical presentations.

Eighty-one patients with diagnostically difficult clinical presentations suggesting coronary disease underwent symptom-limited maximal-exercise treadmill testing (ETT) and exercise radionuclide scanning with thallium-201. Results of these tests were in agreement in only 47 percent of the cases. Either exercise thallium or ETT was positive in 94 percent of patients with disease. Among a population with a disease prevalence of 67 percent, agreement between exercise thallium an ETT predicted disease in 92 percent of instances or excluded disease in 82 percent of instances. Frequent discordance between these two tests in 53 percent of the cases unfortunately limits this usefulness.

Mitral valve prolapse in rheumatic mitral stenosis.

Four adult women with histories of rheumatic fever and clinical findings of mitral stenosis and regurgitation had echocardiograms demonstrating moderately severe mitral stenosis (EF slope less than 20 mm/sec, mean left atrial size 3.0 cm/m2, mean anterior mitral leaflet excursion 25 mm) as well as typical mitral valve prolapse. Three patients underwent cardiac catheterization which confirmed the presence of mitral stenosis, as well as systolic prolapse and excessive scalloping of the mitral valve with no visible mitral calcium and no coronary artery disease. One patient had associated mild aortic stenosis and regurgitation. Two patients underwent mitral valve surgery which revealed anterior and posterior commissural fusion consistent with rheumatic disease and intact chordal apparatus. Both leaflets were large and the anterior leaflets were redundant. There were no vegetations. Pathology revealed myxomatous degeneration of the valve leaflets. In the absence of heavy calcification and thickening, the presence of mitral stenosis with commisural fusion does not exclude the possibility of a redundant mitral valve. When these entities coexist, systolic clicks may be absent.

Angina and exertional myocardial ischemia in diabetic and nondiabetic patients: assessment by exercise thallium scintigraphy.

Patients with diabetes mellitus and coronary artery disease are thought to have painless myocardial ischemia more often than patients without diabetes. We studied 50 consecutive patients with diabetes and 50 consecutive patients without diabetes, all with ischemia, on exercise thallium scintigraphy to show the reliability of angina as a marker for exertional ischemia. The two groups had similar clinical characteristics, treadmill test results, and extent of infarction and ischemia, but only 14 [corrected] patients with diabetes compared with 34 [corrected] patients without diabetes had angina during exertional ischemia. In diabetic patients the extent of retinopathy, nephropathy, or peripheral neuropathy was similar in patients with and without angina. Angina is an unreliable index of myocardial ischemia in diabetic patients with coronary artery disease. Given the increased cardiac morbidity and mortality in such patients, periodic objective assessments of the extent of ischemia are warranted.

Coronary bypass surgery in juvenile onset diabetes.

Atherosclerotic cardiovascular disease is the major cause of death in insulin-dependent diabetics of juvenile onset (JODM). This report summarizes our experience in coronary artery bypass surgery performed between 1971 and 1980 on 13 JODM patients. Preoperatively, 12 of 13 patients had NYHA class IV symptoms with 78% of patients having either left main or multivessel coronary artery disease. With a mean follow-up of 4 years, 12 of 13 patients are alive and 8 of 12 are either NYHA class I or II. We conclude that in a select subset of JODM, bypass surgery can be performed with a low operative morbidity and mortality and results in long-term symptomatic improvement.

Asymptomatic coronary artery disease: angiographic assessment of diabetics evaluated for renal transplantation.

Twenty-one insulin-dependent diabetics with azotemic nephropathy were evaluated for renal transplantation by selective coronary angiography and cine left ventriculography. All had hypertension, retinopathy, neuropathy, and required salt restriction plus diuretics for volume overload. There was no clinical or electrocardiographic evidence of ischemic coronary artery disease in twenty. Ten patients (five males, five females, mean age 29.3 years; mean duration of diabetes 21.9 years; mean serum cholesterol 239 mg%) had significant coronary artery disease, seven demonstrating focal abnormalities in left ventricular wall motion. Two patients (one male, one female; mean age 36.5 years; mean duration of diabetes 28.5 years; mean serum cholesterol 250 mg%) had no significant coronary artery disease, but demonstrated diffusely abnormal left ventricular wall motion with diminished ejection fraction. Thirty-eight percent had significant coronary artery disease unpredictable by electrocardiographic or clinical data. The finding of no significant coronary artery disease in 52% of a group with severe renal-hypertensive complications of diabetes is surprising. Two patients may have a demonstrated cardiomyopathy.

Coronary angiography and acute renal failure in diabetic azotemic nephropathy.

Thirteen juvenile-onset diabetics with azotemic diabetic nephropathy (mean serum creatinine level, 6.8 mg/dl) being evaluated fro renal transplantation underwent cardiac catheterization with angiography. All were followed for development of acute renal failure. Twelve (92%) developed some evidence of acute renal failure. Two required potassium exchange resin therapy. Six required dialysis acutely. There were no deaths. All patients who received greater than 65 ml/m2 of iodinated contrast developed acute renal failure. No patient with a hemoglobin value greater than 9.9 g/dl required dialysis or potassium exchange resin. The single patients without acute renal failure received less than 50 ml/m2 of iodinated contrast and had the highest hemoglobin value (12.0 g/dl). No cardiac or angiographic variables were predictive of acute renal failure. In this group at high risk for acute renal failure, radiographic contrast procedures should only be done if the information to be obtained is weighed against the potential for injury.

Asymptomatic coronary artery disease: angiography in diabetic patients before renal transplantation. Relation of findings to postoperative survival.

Twenty-one juvenile-onset diabetic patients with azotemic nephropathy underwent coronary angiography and left ventriculography before renal transplantation or chronic hemodialysis. Two-year survival of 12 patients with no coronary artery disease (group A) was 88% compared to 22% for nine patients with coronary artery disease (group B) (P less than 0.025). Each group A patient underwent renal transplantation (nine live-related, three cadaveric). Four group B patients received cadaveric allografts. Among group A patients two cadaveric allografts functioned while in group B patients no allografts were successful. In the absence of coronary artery disease, results were similar to those reported for nondiabetic persons. In the presence of coronary artery disease, 62% of the deaths were due to myocardial infarction or sudden death. These results indicate that atherosclerotic coronary artery disease is a major determinant of survival in diabetic patients undergoing chronic hemodialysis or renal transplantation.

Cardiorenal failure: treatment of refractory biventricular failure by peritoneal dialysis.

Fifteen patients with New York Heart Association Class IV functional cardiac disability whose mild-to-moderately severe renal failure had produced life-threatening fluid overload underwent dialytic therapy. Ten were dialyzed by the peritoneal route initially and five were switched from hemodialysis to peritoneal dialysis because of hemodynamic instability. All patients improved, resulting in renewed responsiveness to more conservative measures (2), stabilization for cardiac surgery (4), or less-restricted lifestyle out of hospital (9). We recommend consideration of peritoneal dialysis when biventricular and renal failure are refractory to conventional therapy.