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Principles of Heart Failure Pharmacotherapy
Published in Andreas P. Kalogeropoulos, Hal A. Skopicki, Javed Butler, Heart Failure, 2023
Erika L. Hellenbart, Stephanie Dwyer Kaluzna, Robert J. DiDomenico
In addition to hypotension, headache is a common and treatment-limiting adverse effect seen with nitroglycerin. Although rare, cyanide and thiocyanate toxicity are possible with nitroprusside and the risk increases with higher doses (>2 mcg/kg/min), longer infusion durations (>72 hours), and CKD (SCr >3 mg/dL or eGFR <30 mL/min).105,107 In patients with coronary artery disease, the phenomenon of coronary steal has also been linked to nitroprusside, due to dilation of smaller coronary vessels and a decrease in coronary perfusion pressure in ischemic areas. Coronary steal may explain why nitroprusside has been associated with increased mortality when started early (within nine hours) in patients hospitalized for acute myocardial infarction complicated by left ventricular failure.107,110
The Coronary Arteries: Atherosclerosis and Ischaemic Heart Disease
Published in Mary N. Sheppard, Practical Cardiovascular Pathology, 2022
The majority of patients with coronary artery fistulas are asymptomatic for 20 or so years. Once the fistulas start to become haemodynamically significant, signs and symptoms start to develop. One way that coronary artery fistulas affect the myocardium is to shunt blood away, through a coronary ‘steal’ syndrome. In these situations, the vessels distal to the fistula do not receive blood, and the areas they supply become ischaemic. Another mechanism causing myocardial ischaemia is thrombosis at the junction of the normal and aberrant coronary arteries. Coronary artery fistulas that increase ‘left to right shunting’ can lead to volume overload of the pulmonary circulation and to right-sided heart failure.
Angina pectoris in the elderly
Published in Wilbert S. Aronow, Jerome L. Fleg, Michael W. Rich, Tresch and Aronow’s Cardiovascular Disease in the Elderly, 2019
Wilbert S. Aronow, William H. Frishman
Calcium channel blockers are usually divided into the dihydropyridine and non-dihydropyridine groups (Table 10.6). Nifedipine was the first dihydropyridine made available for the treatment of angina, but newer generations of dihydropyridine agents are now available, including nicardipine, nisoldipine, nimodipine, felodipine, amlodipine, and isradipine. Nifedipine is a potent coronary and peripheral artery vasodilator with negative inotropic properties. Significant afterload reduction occurs due to the vasodilation. At therapeutic doses, nifedipine has only a minor effect on the sinus and atrioventricular nodes; thus due to the decrease in afterload, sympathetic reflex increases in heart rate commonly occur when the drug is administered. The increased heart rate may ameliorate the negative inotropic effect, and clinically hemodynamic indices of contractility generally are unaffected. Due to intense vasodilation of the peripheral coronary circulation, however, the possibility of a coronary steal phenomenon has to be considered when using the drug (59). Such a phenomenon is more common when using a short-acting drug preparation and in patients with severe three-vessel CAD. Therefore, a beta-blocker should be added if nifedipine is used to treat elderly patients with acute ischemic syndromes. A sustained-release preparation of nifedipine is available, which results in less sympathetic activity and is considered to be a safer agent than the shorter-acting preparations. Nevertheless, the addition of a beta-blocker with nifedipine, regardless of the type of preparation, is considered the best approach when managing elderly patients with acute ischemic syndromes. The second-generation dihydropyridines, amlodipine and felodipine, have greater vascular selectivity and less negative inotropy and have no clinical effect on the sinus or atrioventricular nodes. Therefore, coronary artery steal does not appear to be a major concern with these drugs, and the drugs can be used in elderly patients with LV systolic dysfunction.
Cardiac involvement in the adult primary vasculitides
Published in Expert Review of Clinical Immunology, 2020
Giulia Pazzola, Nicolò Pipitone, Carlo Salvarani
Overall, aortic regurgitation is the most common type of valve disease in TAK, while pulmonary, mitral, and tricuspid regurgitation is less common and usually mild [3]. Patients with active disease tend to show a higher incidence of aortic regurgitation [4]. Aortic regurgitation in TAK is thought to be due to thickening of the aortic valves and enlargement of the aortic root [1]. On the other hand, myocardial involvement can be due to myocarditis, coronary artery disease, volume overload secondary to aortic insufficiency, while hypertension (secondary to renal artery stenosis) and premature atherosclerosis can be contributing factors [2,5,6]. Dilated cardiomyopathy is rare, but has been reported; histological examination showed evidence of myocardial inflammation [7]. Arrhythmia has been reported in the presence of myocardial disease [2]. With regard to coronary artery disease, the typical lesion of TAK is coronary stenosis [8], which mainly affects the coronary ostia and proximal vessel segments [2,9]. Aneurysms may also occur, but are less frequent [8]. Finally, occlusion of the pulmonary arteries and pulmonary hypertension can cause coronary steal phenomenon [8]. Pericarditis is uncommon, but may be the presenting feature of TAK [10,11].
Vulnerability for ventricular arrhythmias in patients with chronic coronary total occlusion
Published in Expert Review of Cardiovascular Therapy, 2020
Amira Assaf, Roberto Diletti, Mark G. Hoogendijk, Marisa van der Graaf, Felix Zijlstra, Tamas Szili-Torok, Sing-Chien Yap
The proarrhythmogenic milieu is further enhanced by the presence of chronic residual ischemia in the CTO territory despite the presence of collaterals. It is well-known that ischemia is an important trigger for VA. Collateral connections are observed in almost all CTOs and they have the capability to prevent myocardial necrosis [44]. Rentrop grade ≤1 collateral flow (poor collateral flow) varies between 10% to 28% depending on patient population [5,10]. Collateral function can develop to a similar functional level in patients after myocardial infarction with large areas of akinesia as it does in patients with normal preserved regional function [44,45]. During exercise, collaterals have limited functional reserve and most patients will experience ischemia due to coronary steal despite angiographically well-developed collaterals [45]. Using fraction flow reserve (FFR), Sachdeva et al. demonstrated that the majority of CTO patients have an ischemic FFR (<0.80), even those with severe regional dysfunction or well-developed collaterals [46]. Furthermore, resting ischemia was present in 78% of CTO patients despite a negative noninvasive stress test. These data suggest that the myocardium supplied by a CTO is chronically repetitive ischemic in a majority of patients. Sympathetic stimulation, for example during exercise, increases the difference in refractoriness in ischemic areas, potentially leading to regional conduction block and the propensity to reentrant arrhythmias [47].
Operative approach for right coronary artery to coronary sinus fistula
Published in Baylor University Medical Center Proceedings, 2020
Jonathan Liu, Subbareddy Konda
In our patient, coronary angiography revealed aneurysmal dilation of the RCA and a diminutive posterior descending coronary artery, and transesophageal echocardiogram revealed a shunt between the RCA and coronary sinus. The operation eliminated the shunt. We used the transcardiac approach as indicated for a single, large, symptomatic fistula presenting with aneurysmal formation.2 Less-invasive transcatheter techniques using occlusion coils, detachable balloons, and covered stents have comparable outcomes in select patients. Transcatheter closure has optimal results in patients with small CAFs with nontortuous, nondilated vessels and a single drainage site.3 While the benefits of a less-invasive procedure were considered, the literature suggests that our patient with coronary artery aneurysm, symptomatic coronary steal, and a fistula to the right atrium required open intracardiac ligation. Definitive surgical treatment of the RCA to coronary sinus fistula resolved symptoms and hopefully prevented future complications, including further dilation or rupture of the RCA, heart failure, infective endocarditis, and thrombosis.1