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Biomedical subjects

H Rastegar

Publications and source records attributed to H Rastegar.

At least 37 records · Page 2Linked to original sources
PubMed1990

Apical hypertrophic cardiomyopathy presenting with sustained monomorphic ventricular tachycardia and electrocardiographic changes simulating coronary artery disease and left ventricular aneurysm.

A 52-year-old male presented with sustained monomorphic ventricular tachycardia as the initial manifestation of apical hypertrophic cardiomyopathy. The electrocardiogram during normal sinus rhythm showed a pattern of an old anterior wall myocardial infarction with aneurysm formation. Cardiac catheterization documented angiographically normal coronary arteries. Apical hypertrophic cardiomyopathy was documented at cardiac catheterization and by echocardiogram and Doppler studies. Monomorphic ventricular tachycardia was reproducibly initiated and terminated during electrophysiological studies and antiarrhythmic drugs failed to control the tachycardia. At the time of implantation of a cardioverter defibrillator, left ventricular apical biopsy revealed pathologic findings characteristic of hypertrophic cardiomyopathy.

Cardiomyopathy, Hypertrophic↗
PubMed1989

Automatic implantable cardioverter defibrillator. Current status.

The automatic implantable cardioverter defibrillator was conceived by Mirowski as an implantable device for detection and termination of ventricular fibrillation. Since the initial human implant of the defibrillator in 1980, there has been a dramatic expansion of the clinical experience with more than 5000 implants. The technology of the device, which is now capable of sensing and terminating both ventricular tachycardia and fibrillation, has evolved rapidly. Although still not an ideal antiarrhythmic device, it has already had a major impact on arrhythmic mortality with a marked reduction in the sudden death rates in a high-risk patient population.

Arrhythmias, Cardiac↗
PubMed1989

Clinical experience in seventy-seven patients with the automatic implantable cardioverter defibrillator.

Seventy-seven patients with drug-refractory sustained ventricular tachycardia (VT) (28 patients) or ventricular fibrillation (VF) (49 patients) underwent implantation of an automatic cardioverter defibrillator (AICD). The 67 men and 10 women, with a mean age of 60 +/- 12 years (range 18 to 79), had coronary artery disease (60 patients), idiopathic cardiomyopathy (eight patients), mitral valve prolapse (four patients), hypertensive heart disease (one patient), Ebstein's anomaly (one patient), long QT syndrome (one patient), and primary electrical disease (two patients). The mean left ventricular ejection fraction was 35 +/- 16% (range 10% to 75%). Sustained VT/VF was induced in 64 patients (83%) at baseline electrophysiologic testing. A mean of 4.1 +/- 1.3 antiarrhythmic drugs failed to control the arrhythmia. Associated surgery at AICD implantation included coronary artery bypass in 19 patients, coronary bypass with aneurysmectomy in six patients, and aneurysmectomy alone in one patient. Five patients had only prophylactic patches implanted during aneurysmectomy or coronary bypass and the AICD device was subsequently implanted under local anesthesia to prevent arrhythmia recurrence or to control persistently inducible VT. Operative mortality was 2.6% with two deaths from intractable VF. Fifty-two patients (69%) continued receiving antiarrhythmic drugs to suppress spontaneous VT. During a mean follow-up of 15 +/- 13 months (range 1 to 63), six patients died: two suddenly due to probable pulse generator failure (greater than 2 years old), one of acute myocardial infarction, two of heart failure, and one of respiratory failure.(ABSTRACT TRUNCATED AT 250 WORDS)

Actuarial Analysis↗
PubMed1989

Surgical therapy for drug-refractory ventricular tachycardia: results with mapping-guided subendocardial resection.

Surgical therapy with mapping-guided subendocardial resection was used in 30 patients with drug-refractory ventricular tachycardia. Results of preoperative, intraoperative and postoperative electrophysiologic evaluation and long-term clinical follow-up are reported. Left ventricular aneurysm was located in the inferior wall in 8 patients and in the anterior wall in 22. Left ventricular mapping was performed in 15 patients preoperatively and in all 30 patients intraoperatively. Subendocardial resection was supplemented with cryoablation in 26 patients and with laser photocoagulation in 4. Coronary bypass surgery was performed in 27 patients. The surgical mortality rate was 10%; the three deaths were due to cardiogenic shock, pneumonia and sepsis, respectively. At postoperative electrophysiologic study, ventricular tachycardia was inducible in 8 (30%) of 27 patients. Previously ineffective antiarrhythmic drugs were effective in preventing the induction of ventricular tachycardia in four of these eight patients. Two of the remaining four patients received an automatic implantable cardioverterdefibrillator; the other two were treated with amiodarone. At a mean follow-up period of 18 +/- 17 months (range 1 to 52), there has been one sudden death and one nonfatal recurrence of ventricular tachycardia in the 18 patients without inducible arrhythmias postoperatively. Among the eight patients with inducible ventricular tachycardia after subendocardial resection, there has been one nonfatal ventricular tachycardia recurrence. Thus, among the 27 patients surviving surgery, 17 (63%) were cured with surgery alone, and another 7 (26%) had their ventricular tachycardia controlled with drugs (n = 5) or the defibrillator (n = 2). Inability to completely map the tachycardia, a clinical history of cardiac arrest requiring resuscitation and the presence of myocardial infarction within 2 months predicted postoperative arrhythmia inducibility and recurrence.

Adult↗
PubMed1989

Prophylactic automatic implantable cardioverter-defibrillator patches in patients at high risk for postoperative ventricular tachyarrhythmias.

The strategy of placing prophylactic patches for the automatic implantable cardioverter-defibrillator (AICD) without the AICD was employed in 34 patients with coronary artery disease at risk for postoperative ventricular tachycardia undergoing coronary bypass graft surgery (12 patients) or subendocardial resection (22 patients). Patients were selected on the basis of the presence of preoperative sustained ventricular tachycardia (25 patients) or ventricular fibrillation (9 patients) and absence of control of the arrhythmia with 3.6 +/- 1.3 antiarrhythmic drugs by programmed stimulation. Patients having subendocardial resection were also selected on the basis of multiple configurations of ventricular tachycardia, inability to map the tachycardia or posterior wall aneurysm. The surgical mortality rate was 12%, with two deaths after coronary bypass graft surgery and two deaths after subendocardial resection. The AICD patches were removed in 1 of the 34 patients a few hours after surgery because of left atrial laceration and bleeding. Among 10 patients surviving coronary bypass surgery alone, ventricular arrhythmia was not inducible in 6 and in 4 it remained inducible postoperatively. One of the four patients with inducible arrhythmia had the AICD implanted with use of local anesthesia; the other three were treated with drugs. Among 20 patients surviving subendocardial resection, ventricular arrhythmia was noninducible in 15 and remained inducible in 5. Three of these five patients had an AICD implanted; the other two were treated with drugs. At 12 +/- 7 month follow-up, there were no late deaths.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1989

Clinical and hemodynamic performance of the Ionescu-Shiley valve in the small aortic root. Results in 117 patients with 17 and 19 mm valves.

The Ionescu-Shiley pericardial valve was our bioprosthetic valve of choice between 1981 and 1985 for patients in whom the aortic anulus could not accept a valve larger than 19 mm in outer diameter or in whom the avoidance of warfarin sodium (Coumadin) was important. A series of 117 consecutive patients who received 17 or 19 mm valves for isolated aortic valve replacement or aortic valve replacement combined with coronary artery bypass grafting or other valvular procedures was analyzed. Overall, 74% of the patients were female, with a mean age of 70.9 years and a body surface area of 1.67 +/- 0.19 m2; 92.3% were in New York Heart Association class III-IV, and the operation was urgent or emergent in 46%. The operative mortality rate was 7.7%, with no deaths in patients undergoing isolated elective first-time aortic valve replacement. Mean follow-up for survivors was 2.5 years (10 to 62 months). There were 20 late deaths, of which three were valve related, three were due to sudden death or arrhythmias, and two were due to persistent heart failure. The actuarial survival rate at 5 years was 68%. Clinical follow-up revealed a low incidence of valve-related complications, and 96.4% of survivors were in class I-II. Postoperative echocardiography before hospital discharge revealed a maximum instantaneous gradient of 18.4 +/- 3.0 mm Hg in five patients having a 17 mm valve and 31.3 +/- 12.7 mm Hg in 20 patients having a 19 mm valve. Doppler echocardiography was performed in 22 patients at a mean follow-up of 39.3 +/- 11.7 months. The maximum instantaneous gradient was 25 +/- 17.2 mm Hg for 17 mm and 17.41 +/- 5.4 mm Hg for 19 mm valves at late follow-up. The effective orifice area was 0.85 +/- 0.1 cm2 for 17 mm and 1.21 +/- 0.21 cm2 for 19 mm valves. This study defines the normal range of Doppler echocardiographic transprosthetic gradients for the Ionescu-Shiley valve and confirms that low operative mortality and excellent clinical improvement can result from the use of small Ionescu-Shiley valves in elderly patients despite moderate postoperative transvalvular gradients.

Adult↗
PubMed1988

Use of self-adhesive external defibrillator pads for complex cardiac surgical procedures.

We describe a useful technique for the management of life-threatening arrhythmias that occur during complex or reoperative cardiac surgical procedures when internal defibrillation cannot be achieved. Two self-adhesive external pads are attached to the patient before draping to enable the delivery of current for defibrillation or cardioversion without the need for removal of adhesive surgical drapes and the cumbersome use of external defibrillator paddles.

Arrhythmias, Cardiac↗
PubMed1988

Efficacy of retrograde coronary sinus cardioplegia in patients undergoing myocardial revascularization: a prospective randomized trial.

The efficacy of retrograde coronary sinus cardioplegia (RCSC) administered through the right atrium compared with aortic root cardioplegia (ARC) has not been examined critically in patients undergoing coronary artery bypass grafting (CABG). Twenty patients having elective CABG were randomized prospectively to receive cold blood ARC (Group I, 10 patients) or cold blood RCSC (Group II, 10 patients). Patient demographics were similar in both groups. Ventricular function was assessed preoperatively by radionuclide ventriculography and postoperatively by simultaneous hemodynamic and radionuclide ventriculographic studies with volume loading. There was no change in ejection fraction (EF) (preoperative versus postoperative value) in Group I (50 +/- 6% versus 53 +/- 6%) but in group II, at similar peak systolic pressure and similar left ventricular end-diastolic volume index (LVEDVI), LVEF improved significantly (49 +/- 6% versus 60 +/- 12%, p less than 0.05). Postoperative ventricular function (stroke work index versus EDVI) for the left ventricle and right ventricle were similar in both groups. Evaluation of postoperative LV systolic function (end-systolic blood pressure versus end-systolic volume index) and diastolic function (pulmonary capillary wedge pressure versus EDVI) were also similar in both groups. Retrograde coronary sinus cardioplegia is as effective as ARC for intraoperative myocardial protection, and provides excellent postoperative function in patients undergoing elective CABG.

Blood↗
PubMed1988

Successful repair of postoperative ascending aortic mycotic false aneurysms using circulatory arrest.

Mediastinal wound infections following open-heart operations are successfully managed in most patients by aggressive debridement and placement of substernal drainage catheters or application of omental or muscle flaps. Nonetheless, the involvement of foreign bodies, such as felt pledgets adjacent to cardiac structures, can result in infections that persist despite flap coverage and can present as mycotic false aneurysms of the ascending aorta. We present the cases of 3 patients who underwent successful repair of such aneurysms late after surgical treatment of mediastinal wound infections. We describe our technique of repair using groin cannulation for bypass, moderate hypothermia, and circulatory arrest to improve exposure and minimize bleeding.

Aged↗
PubMed1987

Laser-assisted endocardiectomy for refractory ventricular tachyarrhythmias: preliminary intraoperative experience.

Previous in vitro investigations utilizing necropsy specimens have suggested a potential role for laser irradiation in the treatment of refractory ventricular tachyarrhythmias associated with pathologically thickened endocardium. In the patient described in the present report, findings of these previous in vitro studies were applied intraoperatively to a patient undergoing surgery for ischemic heart disease associated with ventricular tachyarrhythmias. Aneurysm resection and manual subendocardial resection were performed using standard techniques. Laser irradiation was used to ablate pathologically thickened endocardium involving the papillary muscle and thereby avoid mitral valve replacement. Postoperatively, there was no auscultatory evidence of mitral regurgitation, and ventricular tachycardia could not be induced by electrophysiologic provocative testing. This preliminary experience confirms that laser irradiation is both a feasible and potentially advantageous means of accomplishing endocardial debridement in patients undergoing arrhythmia-ablation procedures.

Cardiomegaly↗
PubMed1987

Methemoglobinemia from intravenous nitroglycerin: a word of caution.

The dose of intravenously administered nitroglycerin (IV NTG) used to control ischemic chest pain usually is limited by hypotension from decreased preload. Herein we describe 2 patients who tolerated IV NTG without hemodynamic compromise but in whom severe impairment of blood oxygen content developed from methemoglobinemia noted during coronary bypass surgery. Methemoglobinemia must be suspected if chocolate-brown blood is encountered despite a normal arterial oxygen tension and calculated oxygen saturation. Before a methemoglobin level is available, the extent of hypoxemia can be determined by an oximetric oxygen saturation and therapy begun with intravenous administration of methylene blue. These case reports focus attention on the potential deleterious effects of undetected hypoxemia from methemoglobinemia in patients being stabilized with high-dose IV NTG for urgent cardiac surgery.

Aged↗
PubMed1987

Arterial bypass of the descending thoracic aorta with the BioMedicus centrifugal pump.

Bypass of the descending thoracic aorta is frequently advocated as an adjunct for repair of traumatic tears and degenerative aneurysms. Many methods of bypass have been proposed to provide distal perfusion and reduce left ventricular afterload during cross-clamp of the thoracic aorta. We describe a simple method of direct arterial (aortoaortic or aortofemoral) bypass using the BioMedicus centrifugal pump with limited systemic heparinization.

Aorta, Thoracic↗
PubMed1984

Delineation of myocardial ischemia in an isolated blood-perfused rabbit heart preparation.

Isolated perfused heart preparations provide controlled conditions for the study of myocardial respiration and metabolism. Most studies utilize a hemoglobin-free perfusate which requires high arterial oxygen tension and high coronary perfusion rate. A blood-perfused rabbit heart preparation using an "assist" rabbit to maintain blood homeostasis has been developed which is suitable for respiratory, metabolic, and spectroscopic studies of myocardial function under controlled conditions. Fluorescence emission of reduced nicotinamide adenine dinucleotide (NADH) from the surface of blood-perfused rabbit heart was photographed to delineate areas of myocardial ischemia detectable as NADH fluorescence from reduced mitochondria. Blood reperfusion of ischemic myocardium resulted in disappearance of NADH fluorescence. Reocclusion of the coronary artery resulted in the same pattern and amplitude of NADH fluorescence.

Animals↗
PubMed1984

Pulmonary artery balloon counterpulsation for right ventricular failure: II. Clinical experience.

The use of pulmonary artery balloon counterpulsation (PABC) provided immediate salvage following cardiac surgical procedures in 2 patients with biventricular failure in whom inotropic drugs and intraaortic balloon counterpulsation did not provide sufficient support to allow weaning from cardiopulmonary bypass. Although both patients eventually died, the hemodynamic effectiveness of PABC was documented. The various clinical settings for right ventricular as well as biventricular failure are reviewed, the currently available options for treatment are summarized, and the directions for future laboratory investigation and possible clinical applications are presented.

Aged↗
PubMed1982

Neointimal obstruction of Carpentier-Edwards valved conduit in two patients with modified Fontan procedure.

In 2 patients (single ventricle and dextrotransposition of the great arteries with hypoplastic right ventricle) who underwent a modified Fontan procedure, significant disruption of the tricuspid patch developed. The valved conduits remained patent until reoperation at two and six months, respectively. At the time of reclosure of the tricuspid patch, unavoidable manipulation of the conduits from dissection of adhesions led to detachment and collapse of the neointima, thereby producing complete obstruction of the conduit. The problem was detected immediately in the first patient and prompted clearance of the conduit of the collapsed neointima. In the second patient, the diagnosis was made six months later and conduit replacement was required. Both patients did well following reoperation. We suggest that in patients with woven valved conduits inserted for a Fontan procedure who require reoperation and extensive manipulation of the conduit, removal of the neointima or conduit replacement should be considered.

Adult↗
PubMed1980

Evaluation and therapy of mediastinal thymic cyst.

Two cases of mediastinal thymic cyst are presented. The clinical features of this entity are presented, as well as the case history of the 48-year-old man with an asymptomatic, calcified, cystic anterior mediastinal mass who was followed for four years without significant changes in the mediastinal lesion. Thymic cyst is an identifiable anterior mediastinal mass, in which recurrence following excision or malignant degeneration has never been reported. The risk of mediastinal exploration in a well-demarcated, anterior mediastinal cyst with calcific rim approximates or exceeds the risk of malignancy.

Adult↗
PubMedDate not supplied

Right ventricular outflow tract and pulmonary artery obstruction by postoperative mediastinal hematoma: delineation by multiplane transesophageal echocardiography.

A 53-year-old man with osteogenesis imperfecta underwent valve replacement and coronary artery bypass surgery. Unexplained symptoms of dyspnea and fatigue in the late postoperative period prompted further evaluation. Transthoracic echocardiography demonstrated obstruction of the right ventricular outflow tract and pulmonary artery by a mass, with a maximum gradient of 50 mm Hg. Multiplane transesophageal echocardiography revealed that the mediastinal hematoma was more extensive than was suggested by the transthoracic echocardiogram. This finding prompted the decision to resort to a more extensive surgical procedure. Surgical drainage continued until no residual hematoma could be visualized by multiplane transesophageal echocardiography. This case report demonstrates the value of multiplane transesophageal echocardiography in the assessment of mediastinal masses.

Aortic Valve↗