PubMed Health⌕ Search

Biomedical subjects

G C Fonarow

Publications and source records attributed to G C Fonarow.

48 records · Page 3Linked to original sources
PubMed1996

Improving survival for patients with atrial fibrillation and advanced heart failure.

OBJECTIVES: We attempted to determine whether changes in heart failure therapy since 1989 have altered the prognostic significance of atrial fibrillation. BACKGROUND: Atrial fibrillation occurs in 15% to 30% of patients with heart failure. Despite the recognized potential for adverse effects, the impact of atrial fibrillation on prognosis is controversial. METHODS: Two-year survival for 750 consecutive patients discharged from a single hospital after evaluation for heart transplantation from 1985 to 1989 (Group I, n = 359) and from 1990 to April 1993 (Group II, n = 391) was analyzed in relation to atrial fibrillation. In Group I, class I antiarrhythmic drugs and hydralazine vasodilator therapy were routinely allowed. In Group II, amiodarone and angiotensin-converting enzyme inhibitors were first-line antiarrhythmic and vasodilating drugs. RESULTS: A history of atrial fibrillation was present in 20% of patients in Group I and 24% of those in Group II. Patients with atrial fibrillation in the two groups had similar clinical and hemodynamic profiles. Among patients with atrial fibrillation, those in Group II had a markedly better 2-year survival (0.66 vs. 0.39, p = 0.001) and sudden death-free survival (0.84 vs. 0.70, p = 0.01) than those in Group I. In each time period, survival was worse for patients with than without atrial fibrillation in Group I (0.39 vs. 0.55, p = 0.002) but not in Group II (0.66 vs. 0.75, p = 0.09). CONCLUSIONS: The prognosis of patients with advanced heart failure and atrial fibrillation is improving. These findings support the practice of avoiding class I antiarrhythmic drugs in this group and may reflect recent beneficial changes in heart failure therapy.

Adult↗
PubMed1996

Dynamics of muscle sympathetic nerve activity in advanced heart failure patients.

Muscle sympathetic nerve activity (MSNA) is increased in patients with heart failure compared with healthy subjects. We applied spectral and correlation techniques to determine if qualitative as well as quantitative differences in MSNA differentiate heart failure patients from healthy subjects. We recorded MSNA, heart rate, and respiration in 11 heart failure patients and 10 healthy humans. Our results are as follows. 1) Statistically significant low-frequency modulation of MSNA at 0.029 +/- 0.002 Hz (mean +/- SE; range 0.026-0.038 Hz) was found in 10 of 11 heart failure patients but in only 2 of 10 healthy controls (differences between groups, P < 0.01; chi 2 test). 2) Heart rate and respiration also demonstrated significant low-frequency modulation in a similar range. 3) Spectral and correlation techniques revealed that low-frequency modulation of MSNA was highly correlated with low-frequency modulation of respiration in heart failure patients, but not in healthy subjects. In contrast, low-frequency modulation of MSNA did not correlate well with low-frequency modulation of heart rate. In summary, low-frequency modulation of respiration is coupled to low-frequency modulation of MSNA in heart failure patients, but not in normal subjects. We speculate that this low-frequency modulation of respiration may represent subclinical Cheyne-Stokes breathing, which has marked qualitative effects on MSNA in patients with heart failure.

Adolescent↗
PubMed1995

Improving survival for patients with advanced heart failure: a study of 737 consecutive patients.

OBJECTIVES: This study sought to determine whether survival and risk of sudden death have improved for patients with advanced heart failure referred for consideration for heart transplantation as advances in medical therapy were systematically implemented over an 8-year period. BACKGROUND: Recent survival trials in patients with mild to moderate heart failure and patients after a myocardial infarction have shown that angiotensin-converting enzyme inhibitors are beneficial, type I antiarrhythmic drugs can be detrimental, and amiodarone may be beneficial in some groups. The impact of advances in therapy may be enhanced or blunted when applied to severe heart failure. METHODS: One-year mortality and sudden death were determined in relation to time, baseline variables and therapeutics for 737 consecutive patients referred for heart transplantation and discharged home on medical therapy from 1986 to 1988, 1989 to 1990 and 1991 to 1993. Medical care was directed by a single team of physicians with policies established by consensus. From 1986 to 1990, the hydralazine/isosorbide dinitrate combination or angiotensin-converting enzyme inhibitors were the initial vasodilators, and class I antiarrhythmic drugs were allowed. After 1990, captopril was the initial vasodilator, given to 86% of patients compared with 46% of patients before 1989. After mid-1989, class I agents were routinely withdrawn, and amiodarone was used for frequent ventricular ectopic beats or atrial fibrillation (53% of patients after 1990 vs. 10% before 1989). RESULTS: The total 1-year mortality rate decreased from 33% before 1989 to 16% after 1990 (p = 0.0001), and sudden death decreased from 20% to 8% (p = 0.0006). Adjusted for clinical and hemodynamic variables in multivariate proportional hazards models, total mortality and sudden death were lower after 1990. CONCLUSIONS: The large reduction in mortality, particularly in sudden death, from advanced heart failure since 1990 may reflect an enhanced impact of therapeutic advances shown in large randomized trials when they are incorporated into a comprehensive approach in this population. This improved survival supports the growing practice of maintaining potential heart transplant candidates on optimal medical therapy until clinical decompensation mandates transplantation.

Adult↗
PubMed1995

Evidence for preserved cardiopulmonary baroreflex control of renal cortical blood flow in humans with advanced heart failure. A positron emission tomography study.

BACKGROUND: The effect of cardiopulmonary baroreflexes on the renal circulation in healthy humans and patients with heart failure is unknown because of the technical limitations of studying the renal circulation. Positron emission tomography (PET) imaging is a new method to measure renal cortical blood flow in humans that is precise, rapid, reproducible, and noninvasive. The purpose of this study was to compare the effect of acute cardiopulmonary baroreceptor unloading by phlebotomy on regional blood flow in healthy humans and humans with advanced heart failure. METHODS AND RESULTS: We compared renal cortical blood flow and forearm blood flow in 10 healthy volunteers and 8 patients with heart failure (left ventricular ejection fraction, 0.24 +/- 0.02) during cardiopulmonary baroreceptor unloading with phlebotomy (450 mL). The major findings of this study are: (1) At rest, renal cortical blood flow is markedly diminished in humans with heart failure compared with healthy humans (heart failure, 2.4 +/- 0.1 versus healthy, 4.3 +/- 0.2 mL.min-1.g-1, P < .001). (2) In healthy humans, during phlebotomy, forearm blood flow decreased substantially (basal, 3.3 +/- 0.4 versus phlebotomy, 2.6 +/- 0.3 mL.min-1.100 mL-1, P = .02) and renal cortical blood flow decreased slightly but significantly (basal, 4.3 +/- 0.2 versus phlebotomy, 4.0 +/- 0.3 mL.min-1.g-1, P = .01). (3) The small magnitude of reflex renal vasoconstriction is not explained by the inability of the renal circulation to vasoconstrict, since the cold pressor stimulus induced substantial decreases in renal cortical blood flow in healthy subjects (basal, 4.4 +/- 0.1 versus cold pressor, 3.7 +/- 0.1 mL.min-1.g-1, P = .003). (4) In humans with heart failure, during phlebotomy, forearm blood flow did not change (basal, 2.6 +/- 0.3 versus phlebotomy, 2.7 +/- 0.2 mL.min-1.100 mL-1, P = NS), but renal cortical blood flow decreased slightly but significantly (basal, 2.4 +/- 0.1 versus phlebotomy, 2.1 +/- 0.1 mL.min-1.g-1, P = .01). (5) The cold pressor stimulus induced substantial decreases in renal cortical blood flow in patients with heart failure (basal, 2.9 +/- 0.1 versus cold pressor, 2.3 +/- 0.1 mL.min-1.g-1, P = .008). Thus, in patients with heart failure, there is an abnormality in cardiopulmonary baroreflex control of the forearm circulation but not the renal circulation. CONCLUSIONS: This study demonstrates the power of PET imaging to study normal physiological and pathophysiological reflex control of the renal circulation in humans and describes the novel finding of selective dysfunction of cardiopulmonary baroreflex control of one vascular region but its preservation in another in patients with heart failure.

Adult↗
PubMed1994

Prediction of improvement in recent onset cardiomyopathy after referral for heart transplantation.

OBJECTIVES: The purpose of this investigation was to determine how often left ventricular function improves in recent onset dilated cardiomyopathy of sufficient severity to cause referral for heart transplantation and how to predict this improvement at the time of evaluation for transplantation. BACKGROUND: Improvement has been reported to occur frequently in patients with acute dilated cardiomyopathy but has not been described specifically in these patients referred for transplantation. To avoid potentially needless transplantation, it would be useful to know the frequency of improvement and how to predict it in these patients. METHODS: A consecutive series of 297 patients with primary dilated cardiomyopathy evaluated for heart transplantation was reviewed to identify those with onset of heart failure symptoms within the preceding 6 months and to examine their outcome. The clinical, echocardiographic, hemodynamic and laboratory profiles of patients with improvement in left ventricular function (defined as an increase in left ventricular ejection fraction > or = 0.15 to a final ejection fraction of > or = 0.30) were compared with those of patients without improvement to assess which variables might predict improvement. RESULTS: Of 49 patients with recent onset dilated cardiomyopathy, 13 (27%) showed improvement, with an increase in mean left ventricular ejection fraction from 0.22 +/- 0.08 to 0.49 +/- 0.09. All patients with improvement had survived without heart transplantation at 43 +/- 29 months. Survival time was shorter in the remaining 36 patients without improvement with recent onset cardiomyopathy than in the 248 with chronic symptoms (p = 0.03) and in younger compared with older patients with recent onset cardiomyopathy (p = 0.0001). By multivariate analysis, predictors of improvement were shorter duration of symptoms, lower pulmonary wedge and right atrial pressures and higher serum sodium levels. CONCLUSIONS: A minority of patients with dilated cardiomyopathy and symptoms for < or = 6 months will have marked improvement in left ventricular function, after which prognosis is excellent despite previous referral for heart transplantation. Those with symptom duration > 3 months and more severe initial decompensation as reflected by higher filling pressures and lower serum sodium levels are unlikely to show improvement and may require earlier consideration for heart transplantation.

Actuarial Analysis↗
PubMed1994

The impending crisis awaiting cardiac transplantation. Modeling a solution based on selection.

BACKGROUND: Each month, the number of transplant candidates added to the waiting list exceeds the number of transplantations performed, and many outpatients deteriorate to require transplantation urgently. The current list of 2400 candidates and the average wait of 8 months continue to increase. METHODS AND RESULTS: To determine the size at which the outpatient and critical candidate pools will stabilize, population models were constructed using current statistics for donor hearts, candidate listing, sudden death, and outpatient decline to urgent status and revised to predict the impact of alterations in policies of candidate listing. If current practices continue, within 48 months the predicted list will stabilize as the sum of an estimated 270 hospitalized candidates, among whom, together with newly listed urgent candidates, all hearts will be distributed and 3700 outpatient candidates with virtually no chance of transplantation unless they deteriorate to an urgent status. Decreasing the upper age limit now to 55 years would reduce the number listed each month by 30% and result within 48 months in a list of only 1490. The list could also be decreased by 30%, however, if it were possible to list only a candidate group with an 80% chance (compared with 52% estimated currently) of sudden death or deterioration during the next year. With this strategy, the waiting list would equilibrate within 48 months to one-third the current size, with 50% of hearts for outpatient candidates, who would then have an 11% chance each month of receiving a heart compared with 0% if recent policies prevail. Total deaths, with and without transplantation, would be minimized by this rigorous selection of outpatient candidates. CONCLUSIONS: This study implies that immediate provisions should be made to limit candidate listing and revise expectations to reflect the diminishing likelihood of transplantation for outpatient candidates. Future emphasis should be on improved selection of candidates at highest risk without transplantation.

Computer Simulation↗
PubMed1993

Transesophageal echocardiography during radiofrequency catheter ablation of ventricular tachycardia.

Radiofrequency lesion formation requires stable catheter tip/endocardial contact. Energy delivery is limited when temperatures are > 100 degrees C due to coagulum formation at the catheter tip. Transesophageal echocardiographic imaging may be useful for monitoring catheter position and detecting boiling. Transesophageal echocardiographic images were recorded during production of 22 radiofrequency lesions in bovine myocardium in a saline bath. Lesion size, tissue temperature and appearance of echo contrast (bubbles) were assessed. In 11 patients, transesophageal echocardiography was used to guide catheter movement and detect boiling during radiofrequency ablation for ventricular tachycardia. In the tissue bath, the appearance of echo bubbles was associated with visual bubbling at the catheter tip, tissue temperatures > 60 degrees C and larger lesions (284 +/- 165 vs 30 +/- 54 mm3; p < 0.001). In humans, transesophageal images easily identified the catheter tip in either ventricle and enabled continuous observation of electrode-tissue contact during radiofrequency application. Transesophageal echocardiographic bubbles appeared in 59 of 217 radiofrequency applications (27%). Continued radiofrequency application after appearance of bubbles was followed by an increase in impedance. Prolonged placement of the probe in heavily sedated patients resulted in a mild sore throat, but no other complications. Transesophageal echocardiographic imaging enables continuous monitoring of catheter position during radiofrequency energy application. The abrupt appearance of echo bubbles indicates boiling and impending coagulum formation at the catheter tip.

Adult↗
PubMed1993

Impact of left ventricular cavity size on survival in advanced heart failure.

Although left ventricular (LV) dilation has been assumed to be deleterious, the physiologic significance of severe LV dilation in advanced heart failure and its impact on survival have not been defined. LV end-diastolic dimension was measured by M-mode echocardiography in 382 patients with class III or IV heart failure symptoms (mean LV ejection fraction 20 +/- 8%) referred for evaluation for cardiac transplantation. All patients underwent right-sided heart catheterization, and received vasodilator and diuretic therapy adjusted to hemodynamic goals. Although 183 patients with massive LV dilation by LV index > 4 cm/m2 (LV index = LV end-diastolic dimension/estimated body surface area) had a similar severity of hemodynamic impairment to that of 199 patients with only moderate dilation (LV index < or = 4 cm/m2), with baseline mean cardiac index of 2 liters/m/m2 and mean pulmonary arterial wedge pressure of 26 mm Hg in both groups, their actuarial 2-year survival without transplantation was much lower (49 vs 75%; p = 0.004). In the Cox proportional-hazards model, LV index predicted total and sudden death, independent of etiology of heart failure, ejection fraction and other parameters of disease severity. Follow-up echocardiograms (mean 13 +/- 6 months) in 80 heart failure survivors without transplantation showed an increase in mean LV ejection fraction (22 +/- 8% to 26 +/- 13%), but no change in mean LV index in either the massive or moderately dilated groups. Thus, massive LV dilation is an independent contributor to poor outcome in patients with advanced heart failure, and may be stabilized by aggressive vasodilator and diuretic therapy.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1992

Effect of direct vasodilation with hydralazine versus angiotensin-converting enzyme inhibition with captopril on mortality in advanced heart failure: the Hy-C trial.

To compare the benefit of angiotensin-converting enzyme inhibition and direct vasodilation on the prognosis of advanced heart failure, 117 patients evaluated for cardiac transplantation who had severe symptoms and abnormal hemodynamic status at rest were randomized to treatment with either captopril or hydralazine plus isosorbide dinitrate (Hy-C Trial). Comparable hemodynamic effects of the two regimens were sought by titrating vasodilator doses to match the hemodynamic status achieved with nitroprusside and diuretic agents, attempting to achieve a pulmonary capillary wedge pressure of 15 mm Hg and a systemic vascular resistance of 1,200 dynes.s.cm-5. Treatment with the alternate vasodilator was started because of poor hemodynamic response or side effects (40% of patients in the captopril group and 22% in the hydralazine group). Adequate hemodynamic response in patients with a serum sodium level less than 135 mg/dl was more likely with hydralazine than with captopril (71% vs. 33%, p = 0.04). Isosorbide dinitrate was prescribed in 88% of the hydralazine-treated patients and 84% of the captopril-treated patients. The hemodynamic improvements from each regimen were equivalent. After 8 +/- 7 months of follow-up, the actuarial 1-year survival rate was 81% in the captopril-treated patients and 51% in the hydralazine-treated patients (p = 0.05). The improved survival with captopril resulted from a lower rate of sudden death, which occurred in only 3 of 44 captopril-treated patients compared with 17 of 60 hydralazine-treated patients (p = 0.01). In the subset of patients who continued treatment with the initial vasodilator, results were similar to those for the entire treatment group.(ABSTRACT TRUNCATED AT 250 WORDS)

Actuarial Analysis↗
PubMed1992

Modeling distribution of donor hearts to maximize early candidate survival.

BACKGROUND: Priority for cardiac transplantation should reflect the relative waiting list mortality and operative mortality of outpatient candidates and critical candidates. METHODS AND RESULTS: To determine how to distribute donor hearts for maximal overall survival, a Markov model of eight states was constructed from current statistics for outpatient sudden death, deterioration to critical status, operative mortality for outpatients, and operative mortality for critical candidates. Because the fraction of hearts offered to critical candidates varied, expected survival at 1 year was calculated. To determine the factors most critical in determining priority policy, current conditions were then varied over a fourfold range. Priority for critical candidates maximized overall candidate survival (with and without transplantation), increasing 1-year survival to 78% compared with 66% if hearts were offered only to outpatients. The benefit of giving priority to critical patients persisted when current group mortality rates were individually halved or doubled because these rates were still small compared with the 100% expected mortality of critical patients without transplantation. If the outpatient sudden death rate and the operative mortality for critical patients were doubled simultaneously, however, there was a slight negative impact on survival if critical candidates received priority. Regardless of changes in subgroup outcomes, the distribution of donor hearts had a relatively modest impact on survival because of the large excess of candidates. CONCLUSIONS: Critical candidates for transplantation should continue to receive priority even if their operative mortality increases above current levels. However, postoperative outcomes must be assessed in relation to changing pretransplantation risks. Distribution of donor hearts will be most beneficial when it is possible to identify the waiting patients at greatest risk for sudden death and deterioration without transplantation.

Death, Sudden, Cardiac↗
PubMedDate not supplied

Extended comparison of quality of life between stable heart failure patients and heart transplant recipients.

Heart failure has been associated with poor quality of life, which can improve after heart transplantation. Long-term quality-of-life comparisons between patients with heart failure stabilized with medical therapy and heart transplant recipients have not been performed. We assessed quality of life at the time of heart transplantation evaluation and again after 41 months in 12 patients with advanced heart failure stabilized with medical therapy and in 19 patients who had gone on to undergo heart transplantation. Quality of life was measured by three questionnaires. Both groups had similar quality-of-life and clinical features during the transplantation evaluation. Over time, feelings of anxiety and depression, psychologic adaptation, and perceived functional capability improved in the transplant recipients. However, transplant recipients reported more weakness after surgery; this was the major symptom that limited activities. At follow-up 41 months later, we found no significant differences in quality-of-life changes over time between patients stabilized with medical therapy and heart transplant recipients. Overall quality of life for patients who remain stable while receiving medical therapy may not be significantly different from patients who have undergone transplantation.

Aged↗