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| ==[[Right ventricular myocardial infarction secondary prevention|Secondary Prevention]]== | | ==[[Right ventricular myocardial infarction secondary prevention|Secondary Prevention]]== |
| == Treatment ==
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| * Therapy in '''symptomatic patients''' is aimed at reversing the decreased filling and right-sided stroke volume and at improving right ventricular function.
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| * '''Aggressive fluid resuscitation'''
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| *:* Intravenous fluid, usually isotonic saline, should be given to raise the central filling pressure in an attempt to maximize forward flow out of the right ventricle, thereby preventing inappropriate low left-sided filling pressures <ref>Kinch, JW, Ryan, TJ. Right ventricular infarction. N Engl J Med 1994; 330:1211. PMID 8139631</ref> <ref>Dell'Italia, LJ, Starling, MR, Crawford, MH, et al. Right ventricular infarction: Identification by hemodynamic measurements before and after volume loading and correlation with noninvasive techniques. J Am Coll Cardiol 1984; 4:931. PMID 6092446</ref> In most cases, several liters of saline are infused rapidly until there is an increase in the [[pulmonary capillary wedge pressure]] to approximately 15 mmHg. If central hemodynamic monitoring in not available, one to two liters of saline can be infused while closely following the blood pressure and urine output and examining the patient for [[pulmonary edema|signs of pulmonary congestion]].
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| * '''Avoid drugs which decrease [[preload]]'''
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| *:* Systemic [[cardiac output]] is dependent upon filling of the left ventricle. In the setting of right ventricular dysfunction and decreased contractility, reduced preload results sequentially in diminished right sided stroke volume, reduced flow to the left heart, and a fall in [[cardiac output]]. As a result, any medication (such as [[diuretics]] or [[nitrates]]) or maneuver which decreases [[preload]] should be avoided. Even an increase in vagal tone caused by insertion of a bladder catheter can acutely decrease [[preload]] and lead to [[cardiogenic shock]].
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| * '''[[Inotropic]] stimulation'''
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| *:* When fluid resuscitation is insufficient, [[inotropic]] and [[chronotropic]] stimulation with [[dobutamine]] may increase forward flow and augment [[cardiac output]]. [[Dobutamine]] may also act by reducing [[pulmonary vascular resistance]] and therefore right ventricular [[afterload]]. The usual starting dose is 5 µg/kg per min. The dose is titrated up to 20 µg/kg per min depending upon the clinical response. However, frequent ventricular ectopy and [[ventricular tachycardia]] may limit the use of doses above 10 µg/kg per min. Additionally, since [[dobutamine]] decreases [[peripheral vascular resistance]], higher doses may cause [[hypotension]] as a result of an inadequate rise in [[cardiac output]] to match the decrease in [[systemic vascular resistance]].
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| * '''[[Transvenous pacing|Pacing]]'''
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| *:* [[Transvenous pacing|Right ventricular pacing]] may be necessary if the infarction results in [[complete heart block]] or loss of AV synchrony.
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| * '''[[Reperfusion]]'''
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| *:* Early [[reperfusion]] using either [[thrombolytic therapy]] or direct angioplasty is useful for preserving both right and left ventricular function and results in decreased mortality and morbidity <ref>Goldberger, JJ, Himelman, RB, Wolfe, CL, Schiller, NB. Right ventricular infarction: Recognition and assessment of its hemodynamic significance by two-dimensional echocardiography. J Am Soc Echocardiogr 1991; 4:140. PMID 2036226</ref> <ref>Berger, PB, Ruocco, NA, Ryan, TJ, et al. Frequency and significance of right ventricular dysfunction during inferior wall left ventricular myocardial infarction treated with thrombolytic therapy. Am J Cardiol 1993; 71:1148. PMID 8097614</ref> <ref>Kinn, JW, Aljuni, SC, Samyn, JG, et al. Rapid hemodynamic improvement after reperfusion during right ventricular infarction. J Am Coll Cardiol 1995; 26:1230. PMID 7594036 </ref> <ref>Bowers, TR, O'Neill, WW, Grines, C, et al. Effect of reperfusion on biventricular function and survival after right ventricular infarction. N Engl J Med 1998; 338:933. PMID 9521980 </ref>
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| The indications for these modalities are similar to those in [[Acute myocardial infarction|left ventricular infarction]]. Patients in whom [[reperfusion]] is achieved typically show a dramatic improvement in the hemodynamic profile within 24 hours <ref>Kinn, JW, Aljuni, SC, Samyn, JG, et al. Rapid hemodynamic improvement after reperfusion during right ventricular infarction. J Am Coll Cardiol 1995; 26:1230. PMID 7594036 </ref> <ref>Bowers, TR, O'Neill, WW, Grines, C, et al. Effect of reperfusion on biventricular function and survival after right ventricular infarction. N Engl J Med 1998; 338:933. PMID 9521980 </ref>
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| * As an example, one study of 53 patients reported that [[primary angioplasty]] resulted in normal flow in the [[right coronary artery]] and its major right ventricular branches in 77 percent of patients; [[reperfusion]] was associated with prompt and striking recovery of right ventricular function at three days <ref>Bowers, TR, O'Neill, WW, Grines, C, et al. Effect of reperfusion on biventricular function and survival after right ventricular infarction. N Engl J Med 1998; 338:933. PMID 9521980 </ref> Failure to reperfuse resulted in lack of functional recovery, persistent [[hypotension]], low [[cardiac output]], and a higher mortality rate (58 versus 2 percent for those with successful [[reperfusion]], p=0.001).
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| == References == | | == References == |
| {{Reflist|2}} | | {{Reflist|2}} |