Robotically enhanced coronary artery bypass surgery.

BACKGROUND: Robotically enhanced telemanipulation surgery is a fast developing technique which allows totally endoscopic cardiac surgery with utmost precision and perfection on both beating heart as well as arrested heart. METHODS AND RESULTS: Between December 2002 and February 2004, 125 patients underwent robotically enhanced coronary artery bypass surgery using the da Vinci telemanipulation system (Intuitive Surgical Inc., California). Eleven patients underwent totally endoscopic coronary artery bypass surgery. Of them 9 were done on beating heart while 2 were done on arrested heart. One hundred and fourteen patients had endoscopic takedown of internal mammary artery followed by minimally invasive direct coronary artery bypass in 63 patients and left anterolateral thoracotomy in 51 patients. The internal mammary artery mobilization time was 42 min (35-74 min) while the left internal mammary artery to left anterior descending artery anastomosis time ranged from 20 to 36 min for the totally endoscopic coronary artery bypass patients. In 1 patient, the right internal mammary artery was anastomosed to diagonal artery totally endoscopically. The mean internal mammary artery flow by Doppler measurement done in patients undergoing minimally invasive direct coronary artery bypass was 64 ml/min. Seven patients required conversion to median sternotomy and coronary bypass surgery on beating heart. The mean intensive care unit stay was 1.2 days and the mean hospital stay 4.5 days. There was 1 in-hospital mortality. All 11 patients who underwent totally endoscopic bypass surgery had coronary angiography done at 3 months interval which showed 100% patency in 10 patients while one patient had 50% anastomotic narrowing for which coronary angioplasty was done in the same sitting. CONCLUSIONS: Using telematic technology, a complete endoscopic anastomosis is possible in both single vessel and suitable double vessel disease patients. The use of robotics is now extended to achieve complete myocardial revascularization by harvesting both the internal mammary arteries and making a small thoracotomy for direct anastomosis as well.

Isolated cardiac aspergillosis.

A 40-year-old man, a known case of Wolff-Parkinson-White syndrome, was admitted to the hospital in an unconscious state. In spite of medical treatment, the patient died within two hours of admission. At autopsy, the deceased was found to have aspergillosis involving the interatrial septum, aortic valve and root of the aorta. The rest of the organs were unremarkable. The patient did not show any obvious signs of being immunocompromised. We report this case of isolated cardiac aspergillosis in an apparently healthy individual.

Pulsed Doppler echocardiographic study of left ventricular diastolic function in patients with idiopathic dilated cardiomyopathy.

Dilated cardiomyopathy is basically regarded as a disease of left ventricular systolic dysfunction. There are only a few studies evaluating diastolic function in patients with dilated cardiomyopathy. To assess the LV diastolic function, 25 patients with idiopathic dilated cardiomyopathy and 20 age and sex matched normal subjects were studied with transmitral spectral tracings derived from pulsed Doppler echocardiography. All cardiomyopathy patients were in New York Heart Association class III to IV with dilated left ventricles and reduced systolic function (mean ejection fraction of 36.6 +/- 6.7 Vs 65 +/- 6 in normal subjects, p < 0.001). Patients with cardiomyopathy demonstrated an increased ratio of early to late diastolic velocity (E/A) (1.89 +/- 0.59 Vs 1.50 +/- 0.27 m/sec, p < 0.05), short deceleration time (E-E/2) (57.05 +/- 13.36 Vs 70.20 +/- 16.56 msec, p < 0.01) and short isovolumic relaxation time (IVRT) (53.5 +/- 22.7 Vs 72 +/- 12 msec, p < 0.05) as compared to normal subjects. The early filling fraction (EFF) was higher (0.71 +/- 0.11 Vs 0.66 +/- 0.06, p < 0.05) and atrial filling fraction (AFF) was lower (0.28 +/- 0.11 Vs 0.33 +/- 0.06, p < 0.05) in cardiomyopathy patients than in normal subjects. Our observations in a select group of dilated cardiomyopathy patients with advanced disease demonstrate a restrictive pattern on pulsed Doppler echocardiography.

Analysis of local electrograms at successful and unsuccessful sites for slow pathway ablation of atrioventricular nodal reentrant tachycardia.

Anatomic and electrogram approaches have been described for ablation of slow pathway in patients with atrioventricular nodal tachycardia. The purpose of this study was to identify parameters to predict successful slow pathway ablation using the anatomic approach. Local electrograms at successful and unsuccessful sites were compared in 36 patients undergoing slow pathway ablation using anatomic approach. A total of 208 local electrograms were studied. Fragmented atrial electrogram was seen in 24/36 (67%) of successful and in 46/172 (26%) of unsuccessful sites (p < 0.001). The sensitivity, specificity and positive and negative predictive values of fragmented atrial electrogram were 67, 73, 34 and 91 percent respectively. A slow pathway potential was noted in three of successful sites. There was no difference in the atrial to ventricular amplitude ratio in these sites. In conclusion, fragmentation of atrial electrogram and presence of possible slow pathway potential are seen more often at successful than at unsuccessful sites. In our opinion, while using an anatomic approach for slow pathway ablation, an analysis of local electrogram may help in identifying the proper site and avoiding unnecessary radiofrequency energy delivery.

Changes in circulatory biogenic amines during head-up tilt testing in neurocardiogenic syncope.

The pathogenesis of neurocardiogenic syncope is not completely understood. To examine the possible role of biogenic amines in patients with neurocardiogenic syncope, 18 consecutive patients (age 30 +/- 13 years, 15 males, 3 females) of unexplained syncope were subjected to Head-Up Tilt Testing (HUTT). Blood was sampled by an indwelling cannula at baseline, end of tilt test (or at syncope) and 1 min after returning to the supine position. Biogenic amines, epinephrine (E), norepinephrine (NE), serotonin (5-HT) and their metabolites, homovanillic acid (HVA) and 5-hydroxy indole acetic acid (5-HIAA), were measured in the serum after serial organic phase extraction by high-performance liquid chromatography (HPLC) using ultraviolet detection at a wavelength of 280 nm. Twelve patients were found to be HUTT negative while 6 patients were HUTT positive. Baseline E, NE and 5-HT levels were significantly greater in the HUTT positive patients [E 510 +/- 154 versus 302 +/- 96 pg/ml (p < 0.01), NE 253 +/- 99 versus 159 +/- 62 pg/ml (p < 0.05), 5-HT 174 +/- 32 versus 118 +/- 22 pg/ml (p < 0.01)]. E and HVA levels at the end of the test were significantly higher in HUTT positive patients [E 788 +/- 268 versus 465 +/- 119 pg/ml (p < 0.01), HVA 308 +/- 91 versus 112 +/- 12 pg/ml (p < 0.001)]. A significantly greater rise of E from the baseline was observed in HUTT positive patients (510 +/- 154 versus 112 +/- 12 pg/ml (p < 0.01)]. The increase in the levels of E and HVA both at baseline and after the tilt test, without a corresponding rise in NE levels indicates enhanced activity of the adrenomedullary axis which is not paralleled by NE release from sympathetic nerve endings in patients of neurocardiogenic syncope.

In-hospital results of radiofrequency ablation of supraventricular tachycardia.

Two hundred and one consecutive patients with symptomatic paroxysmal supraventricular tachycardia (PSVT) underwent a diagnostic electrophysiological test and catheter ablation with radiofrequency (RF) current. In 102 (51%) patients, the mechanism of PSVT was found to be atrioventricular nodal reentry (AVNRT, typical in 101, atypical in 1). Atrioventricular reentrant tachycardia (AVRT) involving accessory pathway was present in 94 (47%) and ectopic atrial tachycardia in 5 patients. A successful outcome was achieved in 100 of 102 patients (98%) with AVNRT and in 85 of 94 patients (90%) with AVRT. The anatomical approach was used for ablation in patients with AVNRT. The focus was ablated in 4 patients with ectopic atrial tachycardia whereas it was modified in the remaining one patient. Procedure-related complications occurred in 4 patients (2 AVNRT, 2 AVRT). One patient each developed haemothorax, pericardial effusion, mitral valve endocarditis and high-grade AV block requiring permanent pacemaker implantation. The electrode and ablation catheters were repeatedly used after ethylene oxide sterilisation to reduce the cost of the procedure. RF ablation is an effective, safe and curative modality of treatment for patients with symptomatic PSVT due to AVNRT and AVRT. The experience with this modality in patients with ectopic atrial tachycardia is limited.

Low-dose intravenous diltiazem--efficacy and safety in supraventricular tachyarrhythmias.

Intravenous diltiazem has been used to rapidly reduce ventricular rate in patients with supraventricular tachyarrhythmias (SVTs). This study assesses the efficacy and safety of a low-dose (0.1 mg/kg) intravenous bolus of diltiazem on the heart rate and blood pressure. Fifteen consecutive patients were treated for 21 episodes of atrial fibrillation, sinus tachycardia or ectopic atrial tachycardia. The bolus dose reduced the heart rate significantly in all patients with atrial fibrillation within 5 min (173 +/- 21 to 144 +/- 27 beats/min, p < 0.05) with the maximum response seen at 10 min (128 +/- 26.7 beats/min, p < 0.05). However, patients with sinus tachycardia showed a significant decrease in heart rate only at 15 min (147 +/- 12 to 123 +/- 15 beats/min, p < 0.05). One patient with ectopic atrial tachycardia required maintenance infusion of diltiazem. Conversion to sinus rhythm was observed in another patient with atrial fibrillation. The drug was well tolerated with no significant hypotension, bradyarrhythmia or aggravation of pre-existing congestive heart failure. It is concluded that Indian patients require a lower dose of intravenous diltiazem as compared to Western ones (0.1 mg/kg versus 0.25-0.33 mg/kg) which gives a prompt, effective and safe response in patients with SVTs.

Atherosclerosis in transplant heart.

Graft atherosclerosis in the transplant heart is essentially asymptomatic due to denervation of the transplant heart and also is rapidly progressive. After one year it is the major cause of transplant rejection. Histopathologically, graft atherosclerosis differs from the conventional atherosclerosis. Intra-vascular ultrasound and repeated coronary angiography help in its early diagnosis. Angioplasty and bypass graft surgery are not of much help. Preventive measures through dietary means to keep triglycerides under control and prophylactic use of calcium channel blocker, diltiazem are rewarding. Many patients with graft coronary atherosclerosis end up with retransplant.

Ischaemic preconditioning: an intracoronary electrocardiographic study.

Brief episodes of myocardial ischaemia may enhance the tolerance to subsequent ischaemic episodes. This phenomenon has been called ischaemic preconditioning. Intracoronary electrocardiograms (ECG) were obtained during coronary angioplasty in 15 patients (13 males, 2 females; age 49 +/- 12 years) by attaching the external end of the balloon angioplasty guide wire to the V1 lead on the surface electrocardiogram. Surface leads I, II and III and intracoronary ECG were recorded at baseline and during balloon occlusion. The pattern of ST segment change during the first and subsequent inflation were compared. A significant reduction in ST segment deviation was observed in intracoronary ECG between the first and second inflation (10 +/- 1 vs 5 +/- 3 mm, p < 0.05). However, surface ECG showed no significant difference in ST segment deviation between the two inflations (3 +/- 1 vs 2 +/- 1 mm, p = NS). Thus, intracoronary ECG detects acute ischaemia more readily as compared to the routinely monitored surface ECG. A significant reduction noted in ST segment deviation during the second inflation suggests the phenomenon of ischaemic preconditioning in humans.

Atherosclerosis in transplant heart.

Graft atherosclerosis in the transplant heart is essentially asymptomatic due to denervation of the transplant heart and also is rapidly progressive. After one year it is the major cause of transplant rejection. Histopathologically, graft atherosclerosis differs from the conventional atherosclerosis. Intravascular ultrasound and repeated coronary angiography help in its early diagnosis. Angioplasty and bypass graft surgery are not of much help in treatment. Preventive measures through dietary means to keep triglycerides under control and prophylactic use of calcium channel blocker diltiazem are rewarding. Many patients with graft coronary atherosclerosis end up with retransplant.

Radiofrequency ablation of idiopathic ventricular tachycardia.

Eleven patients (9 male, 2 female) with ventricular tachycardia (VT) and structurally normal heart underwent radiofrequency (RF) ablation of VT focus. The detailed electrophysiological mapping localized the VT focus in the left ventricular (LV) apicoseptal region in 5, LV posteroseptal region in 2, right ventricular (RV) outflow tract in 2 and RV midseptal and inflow regions in one patient each. The technique of endocardial activation mapping during VT, pacemapping and the presence of His-Purkinje potential (for LV focus) were used to identify the precise site of delivery of RF energy. The procedure was successful in 9 patients. There was no complication. The mean fluoroscopic time was 45 +/- 21 (range 20-120) minutes. RF ablation is effective and may be considered as therapy of choice for patients with ventricular tachycardia and normal heart.