ABSTRACT
Critical care patients are submitted to multiple derangements of vital parameters. Even in patients with a normally performing heart, its electrical activity can be strongly influenced by dyselectrolytemias, acid-base imbalance and aggressive drug therapy. In this paper, the basic principles of the electrophysiologic properties of the heart are reviewed, and the impact of dyselectrolytemias on heart excitability are underlined. Some clinically relevant aspects are described in greater depth, with respect to life-threatening arrhythmias.
Subject(s)
Acid-Base Imbalance/complications , Arrhythmias, Cardiac/etiology , Electrolytes/blood , Action Potentials/drug effects , Animals , Anti-Arrhythmia Agents/pharmacology , Arrhythmias, Cardiac/drug therapy , Electrocardiography/drug effects , HumansABSTRACT
BACKGROUND: Recent application of brain natriuretic peptide and N-terminal prohormone brain natriuretic peptide (NT-proBNP) in cardiac valvular disease is very promising. AIMS: To test the usefulness of NT-proBNP in the assessment of patients with aortic or mitral regurgitation. PATIENTS AND METHODS: Sixty-seven patients - 23 with aortic and 12 with mitral regurgitation vs. 32 controls - were examined by color Doppler echocardiography, cardiopulmonary exercise testing, Minnesota Living with Heart Failure Questionnaire (MLWHFQ) and plasma NT-proBNP assay at rest (T0) and after maximal physical exercise (T1). RESULTS: NT-proBNP was significantly higher in patients than in controls, both at T0 (298 +/- 85 vs. 46 +/- 11 pg/ml; P < 0.01) and at T1 (366 +/- 106 vs. 50 +/- 12 pg/ml; P < 0.01). MLWHFQ score was significantly higher in patients (19 +/- 3 vs. 1 +/- 0.6; P < 0.001) with a significant inverse correlation with VO2max (r = -0.538, P < 0.001) and a direct correlation with NT-proBNP (T0: r = 0.415, P < 0.01; T1: r = 0.458, P < 0.01). NT-proBNP was inversely correlated with VO2max (T0: r = -0.444, P < 0.001; T1:r = -0.428, P < 0.001) and directly correlated with left atrial diameter (T0: r = 0.370, P < 0.01; T1: r = 0.409, P = 0.001), and left ventricular mass index (r = 0.279, P < 0.01, and r = 0.272, P < 0.01). No correlations were found between echocardiographic parameters of valvular disease severity and VO2max, NT-proBNP and MLWHFQ. CONCLUSIONS: NT-proBNP is useful in the assessment of the cardiac functional damage secondary to mitral and aortic regurgitation.
Subject(s)
Aortic Valve Insufficiency/blood , Mitral Valve Insufficiency/blood , Natriuretic Peptide, Brain/blood , Peptide Fragments/blood , Aortic Valve Insufficiency/physiopathology , Biomarkers/blood , Case-Control Studies , Exercise/physiology , Female , Humans , Male , Middle Aged , Mitral Valve Insufficiency/physiopathology , Oxygen ConsumptionABSTRACT
Myocarditis is an inflammatory heart muscle disease, resulting from various etiologies, both noninfectious and infectious, which may be associated or not with cardiac dysfunction. Its course is unpredictable: it may spontaneously resolve or evolve into dilated cardiomyopathy and heart failure. A possible connection between myocarditis and dilated cardiomyopathy has long been postulated, but the intimate mechanisms linking these two conditions are still poorly understood. Viral myocarditis could induce a dilated cardiomyopathy through viral persistence and/or by triggering an autoimmune process. Understanding the mechanisms underlying the relationship between myocarditis and dilated cardiomyopathy will help in identifying an effective strategy of treatment aimed to stop and prevent cardiac damage. Specifically, we need to (a) evaluate the potential role of autoantibodies in disease prevention and progression, and understand their importance as markers of disease progression; (b) clarify the role of immunoregulation in exacerbating the disease.
Subject(s)
Cardiomyopathy, Dilated/therapy , Myocarditis/therapy , Animals , Autoimmunity , Cardiomyopathy, Dilated/diagnosis , Cardiomyopathy, Dilated/immunology , Humans , Immunoglobulins, Intravenous/therapeutic use , Immunologic Factors/therapeutic use , Immunosorbent Techniques , Immunosuppressive Agents/therapeutic use , Myocarditis/diagnosis , Myocarditis/immunologyABSTRACT
Pulmonary arterial hypertension has a poor prognosis quoad vitam et valitudinem. Herein, we report on a middle-aged woman affected by idiopathic pulmonary arterial hypertension whose quality of life and exercise tolerance improved remarkably after a six-month course of treatment with the long-acting phosphodiesterase-5 inhibitor tadalafil.
