Richard H. Martin

Sensitivity and specificity of commonly used electrocardiographic criteria for left atrial enlargement determined by m-mode echocardiography

To assess the sensitivity and specificity of 6 commonly used electrocardiographic criteria for left atrial (LA) enlargement, the rest ECGs of 99 patients in normal sinus rhythm were analyzed. Fifty-seven of the patients had LA enlargement and 42 had a normal LA dimension as determined by M-mode echocardiography. The 6 criteria studied and their respective sensitivities and specificities were as follows: (1) duration of the negative phase of the P wave in lead V1 greater than 40 ms: sensitivity, 83%; specificity, 80%; (2) notched P wave in any standard lead with an interpeak duration greater than 40 ms: sensitivity, 15%; specificity, 100%; (3) P terminal force (depth X duration of the terminal portion of the P wave) in lead V1 more negative than -0.04 mm X s: sensitivity, 69%; specificity 93%; (4) depth of the negative phase of the P wave in lead V1 greater than or equal to 1 mm: sensitivity, 60%; specificity, 93%; (5) total P-wave duration greater than 110 ms in any standard lead: sensitivity, 33%; specificity, 88%; (6) total P wave duration/P-R interval duration greater than 1.6: sensitivity, 31%; specificity, 64%. Combining 2 or more of these criteria did not substantially improve sensitivity and specificity.

Technetium 99m stannous pyrophosphate myocardial imaging in patients with and without left ventricular aneurysm.

To further explore the usefulness of technetium 99m pyrophosphate (99mTc-PYP) myocardial imaging and test its validity in the diagnosis of acute myocardial infarction, 99mTc-PYP myocardial scintigrams were performed in 50 patients. Out of 28 patients with acute myocardial infarction, myocardial scintigrams demonstrated localized activity in the 15 patients with transmural, and diffuse activity in the 13 patients with subendocardial myocardial infarction. Twenty-two patients with significant coronary artery disease documented by coronary angiography but without acute myocardial infarction were also studied. Nine of ten patients with clinical evidence of left ventricular aneurysm from previous myocardial infarction and definite left ventricular dyskinesis had positive scintigrams with activity localized to the site of the wall motion abnormality. Two of five patients without definite aneurysm but with left ventricular akinesis also had localized uptake in the involved area of the left ventricle. Seven patients with normal left ventricular wall motion had negative scintigrams. These findings suggest caution in interpreting positive 99mTc-PYP scintigrams as being indicative of acute myocardial infarction when evidence of a left ventricular aneurysm is also present.

Left ventricular aneurysm. Preoperative hemodynamics, chamber volume, and results of aneurysmectomy.

Angiocardiographic characteristics of the residual contracting left ventricle (LV) have been examined in 16 patients with anterolateral ventricular aneurysms (VA). In each patient a contractile section (CS) of the LV was clearly demarcated from the remaining aneurysmal section (AS). Using a double hemispheroid model, volumes of CS and AS were separately estimated by a modified area-length method. The volume of CS plus AS agreed closely with the volume of total LV estimated by the conventional area-length method. End-diastolic volume (EDV) of total LV ranged from 79 to 312 ml/m2. Aneurysmal section volume ranged from 8 to 264 ml/m2. End-diastolic volume of the contractile section ranged from 52 to 159 ml/m2 (mean, 100 ± 8 (se); normal, 78 ± 6). Contractile section ejection fraction (EF) showed a wide range, from 15% to 79% (mean 40% ± 17% sd). Nine patients underwent resection of VA. Three of six operated patients with CS EF < 44% died; no survivor in this group has improved by more than one functional class (New York Heart Association classification). Three operated patients had CS EF > 45%; all survived and are improved, two having moved from class IV to class I. These data suggest that the EF of the contracting residual LV may be an important predictor of the outcome of resection of VA.

Limited clinical diagnostic specificity of technetium-99m stannous pyrophosphate myocardial imaging in acute myocardial infarction.

To test the sensitivity and specificity of technetium-99m stannous pyrophosphate myocardial imaging in the diagnosis of acute myocardial infarction, myocardial scintigrams were performed in 115 patients. Positive scintigrams were found in all 48 patients with acute myocardial infarction; uptake was localized in 29 patients with transmural infarction and diffuse in 2 patients with transmural infarction and in the remaining 17 patients with subendocardial myocardial infarction. Positive scintigrams were also found in 31 of 67 patients without clinical evidence of acute myocardial infarction. Diffusely positive scintigrams were found in 3 of 3 patients with unstable angina pectoris, 7 of 30 patients with stable angina pectoris, 4 of 13 patients who had undergone aortocoronary bypass surgery, 4 of 4 patients with congestive cardiomyopathy and 1 patient studied 1 day after direct current cardioversion. Localized uptake of 99mTc-pyrophosphate was found in 9 of 10 patients with left ventricular aneurysm and in 3 of 13 patients after aortocoronary bypass surgery. All four patients with atypical chest pain and two patients with pericarditis had normal scintigrams. Our data confirm the previously reported sensitivity of 99mTc-pyrophosphate imaging in detection of acute myocardial infarction but indicate that positive scintigrams are not specific for this entity.

True and false aneurysms of the left ventricle following myocardial infarction

Anterolateral myocardial infarction resulted in the formation of both true and false aneurysms in a 75 year old man in whom severe congestive heart failure subsequently developed as the false aneurysm became progressively larger. Left ventriculography detected and quantified both aneurysms, and demonstrated reasonable function of the remaining volume-overloaded left ventricle. Resection of both aneurysms was accomplished with marked relief of symptoms. The literature on false aneurysm is reviewed, and the dilemma posed by the need to recognize false aneurysms before they become symptomatic or rupture is discussed.

Doughnut Pattern of Technetium-99m Pyrophosphate Myocardial Uptake in Patients With Acute Myocardial Infarction: A Sign of Poor Long-Term Prognosis

Thirty survivors of acute myocardial infarction with 3+ or 4+ positive technetium-99m pyrophosphate myocardial scintigrams were followed up for 28 +/- 3.1 months (mean +/- standard deviation). Three patient groups were identified from the pattern of radioactive uptake in the scintigram: Group I, 16 patients with focal uptake (anterior in 7, lateral in 2, posterior in 3 and inferior in 4); Group II, 6 patients with anterior myocardial infarction and a doughnut pattern of uptake; Group III, 8 patients with nontransmural myocardial infarction and a diffuse pattern of uptake. Late complications developed in all patients with the doughnut pattern of uptake compared with 43 percent of patients with the focal pattern and 12 percent of patients with the diffuse pattern. After discharge from the hospital, five of six patients with a doughnut pattern of uptake died (mean survival time 9.8 months after the initial myocardial infarction). This mortality rate (83 percent) was significantly greater than that of patients with a focal (mortality rate 6 percent) or diffuse (no mortality) pattern of uptake. The doughnut pattern of technetium-99m pyrophosphate myocardial uptake in patients with acute myocardial infarction appears to identify a subgroup of patients with a very poor long-term prognosis.

Clinical improvement after ventricular aneurysm repair: Prediction by angiographic and hemodynamic variables

Surgical repair of a left ventricular aneurysm is associated with significant perioperative mortality and substantial mortality in the first 2 years after operation. In a retrospective review of 42 patients undergoing repair of an anteroapical aneurysm, two cardiac catheterization variables were identified that predicted a good surgical outcome, defined as perioperative survival and improved functional status. Specifically, patients with an ejection fraction of the contractile section (nonaneurysmal) of the left ventricle of 35% or greater and a left ventricular end-diastolic pressure of 25 mm Hg or less had a low perioperative mortality rate (6.5%), experienced no late mortality and had sustained clinical improvement of at least one New York Heart Association functional class (93.5%). In contrast, patients with a contractile section ejection fraction of less than 35% or a left ventricular end-diastolic pressure greater than 25 mm Hg had a higher perioperative mortality rate (27.3%), experienced a substantial late mortality rate (27.3%) or had no significant functional class improvement (9%); only 36.4% had sustained clinical improvement. This study suggests that the postoperative results of left ventricular aneurysm repair are dependent on the hemodynamic status of the nonresected left ventricle.