Studies on prosthetic valve function--a transesophageal echocardiographic assessment.

Haemodynamic assessment was done by colour flow mapping and Doppler interrogation by both Transthoracic (TTE) and Transesophageal echocardiography (TEE) in 40 consecutive patients (mean age 36.6 +/- 12.35 years) with prosthetic valves. There were 30 cases of mitral (MVR) and 12 aortic (AVR) valve replacement. Major purpose of the study was to detect the sensitivity of TEE in detecting prosthetic valve malfunction particularly in comparison to TTE. Pannus was detected in 3 and 8 cases of MVR (p < 0.01) by TTE and TEE respectively; however, TEE was found to be of equal status in detecting pannus over AV (2 cases). Physiological regurgitation in MVR and AVR was detected in 13% and 25% by TTE and 20% and 33% by TEE respectively. Paravalvular leak was detected in 3 cases of MVR by TEE compared to only case by TTE. Though it is difficult to deduce any specific conclusion from this small number of patients, there is definite trend to higher sensitivity in detecting disorders with TEE specially for mitral prostheses.

Intravenous thrombolytic therapy in unstable angina.

One hundred consecutive age and sex-matched patients of 3 different subsets of unstable angina (recent onset angina -65, crescendo angina -20, post-infarct angina-15) were randomized 1:1 after coronary angiography to receive I.V., either 1.5 x 10(6) units of streptokinase (SK) in 200 ml of normal saline or 200 ml of normal saline alone (control) in 1 hour. Repeat angiography was done in those patients having intra-coronary thrombi (37.3%) during the initial angiography. Both groups received optimal doses of heparin followed by warfarin, aspirin and other standard drugs and were followed up for 6 months. Anginal pain subsided significantly in the SK group-41 (82%) vs 25 (50%) (P < 0.005), especially in patients with recent onset angina (92.5% vs 60%, P < 0.005). Incidence of acute myocardial infarction (AMI) was much less in the SKgp (4(8%) vs 17 (34%) (p < 0.05). Four cases of fatal MI and four cases of sudden cardiac death (SCD) occurred in the control group against none in the SKgp. Requirements of mechanical revascularization was significantly less (P < 0.05) in the SK gp. Angiographic evidence of partial or complete clot lysis was noted in 90% of SK gp. vs 4.8% of control (P < 0.01). Echocardiographically assessed LV function improved significantly with SK-therapy in recent onset (P < 0.05) and crescendo angina (P < 0.001) subsets--however, the improvements in post infarct angina subset were not statistically significant. The beneficial outcome with SK therapy was observed in patients irrespective of angiographic evidence of thrombi.(ABSTRACT TRUNCATED AT 250 WORDS)

Haemodynamic advantage with single chamber rate responsive pacemakers over dual chamber pacemakers during exercise in chronotropic incompetence.

Sequential cardiac chamber activation and chronotropic response are amongst the important determinants of cardiac performance. This study compared VVIR mode with DDD and VVI mode to assess the contribution of these two factors in the determination of cardiac performance during exercise. Ten patients with a mean age of 68 +/- 5 years were studied during 1988-90, who had complete heart block and sinus node dysfunction with a mean LV ejection fraction of 51.5 +/- 6.25%. Five patients had DDD pacemakers and the rest had VVIR pacemakers. Patients were exercised first in VVI mode followed by either DDD or VVIR mode. Exercise duration, maximum rate pressure product, exercise capacity and cardiac output were measured with graded treadmill test in Bruce protocol. There was remarkable increase in the exercise duration (P < 0.001) and the maximum rate pressure product (P < 0.001) in patients with VVIR as compared to DDD and VVI mode. In DDD mode, as compared to VVI mode, this increase was less remarkable, though statistically significant (P < 0.005). Therefore, it is concluded that patients with chronotropic incompetence as well as complete heart block do better during dynamic exercise when they have VVIR mode compared to VVI or DDD mode.

Risk factors and their implication on silent myocardial ischaemia.

Sixty-five cases were evaluated for silent myocardial ischaemia (SMI) by computerised treadmill test (TMT) and ambulatory electrocardiographic monitoring (AEM). There were 59 males and 6 females. The cases were divided into GP-I-stable angina (35 cases) GP-II-stable angina after myocardial infarction (15 cases) and GP-III-asymptomatic (15 cases). Age in each group ranged from 36 years to 62 years (GP-I), 40 years to 68 years (GP-II) and 36 years to 48 years (GP-III). Conventional risk factors viz. hypertension, diabetes mellitus, hyperlipidemia, smoking and family history were assessed with a view to see their implication on SMI. 43 patients (62.2%) were found to have SMI including mixed episodes. Out of these 43, TMT was positive in 29 patients (67.4%), AEM was positive in 41 patients (95.3%) and both TMT and AEM were positive in 27 patients (62.7%). Correlative analysis between risk factors and SMI revealed that higher number of was associated with not only more positive TMT and AEM test along with increased episodes of SMI but also increased degree of ST-T depression. It was also found that AEM is more sensitive than TMT (80% Vs 48%) for diagnosing SMI (SED = 9.03%), though specificity of the tests is same (93.3%).